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

Abstract

To provide a toner for electrostatic charge image development that can prevent transfer unevenness in a high temperature and high humidity environment, while having low temperature fixability.SOLUTION: A toner for electrostatic charge image development has toner particles including an amorphous polyester resin and a crystalline polyester resin as a binder resin, and internally added cross-linked resin particles. The internally added cross-linked resin particles are styrene-(meth) acrylic copolymer particles having a storage elastic modulus G' of 1×105 Pa or more and 1×106 or less within a range of 60°C or more and 100°C or less. The average dispersion diameter of the cross-linked resin particles is 100 nm or more and 300 nm or less. In cross-sectional observation of the toner particles, when, in n×n division areas, the coefficient of variation of the ratio of the area of the cross-linked resin particles to the area of the division areas is defined as DAR(n), and the slope of an approximation straight line in a dispersion diagram in which n is changed to 3, 4, 6, 8, 12, and 16, and log[1 / n] and log[DAR(n)] are plotted to an X-axis and a Y-axis, respectively, is defined as slopeF(16), the following formula (1) is satisfied. Formula (1): 0.6≤slopeF(16).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Patent Document 1 states, "An electrostatic image developing toner containing toner particles containing a binder resin, wherein in a dynamic viscoelasticity measurement of the electrostatic image developing toner, when the loss tangent tanδ at a temperature of 90°C and a strain of 1% is D1(90), the loss tangent tanδ at a temperature of 90°C and a strain of 50% is D50(90), the loss tangent tanδ at a temperature of 150°C and a strain of 1% is D1(150), and the loss tangent tanδ at a temperature of 150°C and a strain of 50% is D50(150) , D1(90), D50(90), D1(150), and D50(150) are each 0.5 or more and 2.5 or less, the value of D50(150) - D1(150) is less than 1.5, and the value of D50(90) - D1(90) is less than 1.0, the toner particles further contain resin particles, and the number average molecular weight of the tetrahydrofuran soluble matter in the toner particles is 5,000 or more and 15,000 or less."

[0003] Patent Document 2 discloses "a toner for developing electrostatic images, which contains a binder resin and rubber particles, and in which the compression set of the rubber particles at a temperature at which the melt viscosity of the toner reaches 104 Pa is 20% or more and 50% or less."

[0004] Patent Document 3 discloses "a toner for developing electrostatic images, which comprises toner particles containing a binder resin containing a polyester resin, a release agent containing a hydrocarbon wax, and a styrene (meth)acrylic resin, wherein 70% or more of the total release agent is present within 800 nm from the surface of the toner particles, and the styrene (meth)acrylic resin forms domains with an average diameter of less than 0.3 μm in the toner particles."

[0005] Patent Document 4 discloses "a toner for developing electrostatic images, which contains at least a binder resin, and includes a continuous phase containing the binder resin, and a discontinuous phase having a core containing the binder resin and a coating layer containing the binder resin and coating the core, the discontinuous phase being scattered throughout the continuous phase."

[0006] Patent Document 5 discloses "a toner for developing electrostatic images, which comprises toner particles containing a binder resin containing a polyester resin, a release agent containing a hydrocarbon wax, and a styrene (meth)acrylic resin, wherein 70% or more of the total release agent is present within 800 nm from the surface of the toner particles, the styrene (meth)acrylic resin forms domains in the toner particles having an average diameter of 0.3 μm or more and 0.8 μm or less, and the proportion of the number of the domains falling within the range of the average diameter ±0.1 μm is 65% or more." [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-048127 [Patent Document 2] Japanese Patent Application Publication No. 2020-046499 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-062042 [Patent Document 4] Japanese Patent Publication No. 2020-160204 [Patent Document 5] Japanese Patent Application Laid-Open No. 2016-062040 Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide a toner for developing an electrostatic image, which toner particles contain an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, wherein the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or higher and 100° C. or lower. 5 Less than Pa or 1×10 6The present invention provides a toner for developing electrostatic images that has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to a case in which the styrene-(meth)acrylic copolymer particles have an average dispersed diameter exceeding 100 nm, a case in which the formula (1) is not satisfied, or a case in which the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm. [Means for solving the problem]

[0009] Means for solving the above problems include the following aspects. <1> The toner particles include an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, The internally crosslinked resin particles have a storage modulus G' of 1×10 5 Pa or more 1×10 6 The following styrene-(meth)acrylic copolymer particles: the average dispersed diameter of the internally added crosslinked resin particles is 100 nm or more and 300 nm or less, In observing the cross section of the toner particle, when a 3 μm×3 μm square region of 600 pix×600 pix is ​​divided into n×n regions, In the n×n divided regions, the coefficient of variation of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided region is DAR(n), The n was changed to 3, 4, 6, 8, 12, and 16, and the slope of the approximated line in the scatter diagram, in which log[1 / n] was plotted on the X axis and log[DAR(n)] on the Y axis, was defined as slopeF(16). When the formula (1) is satisfied, the toner for developing electrostatic images satisfies the following formula (1): Formula (1): 0.6≦slopeF(16) <2> Satisfy the following formula (11) <1> 2. The toner for developing electrostatic images according to claim 1. Equation (11): 0.7≦slopeF(16) <3> The content of the crystalline polyester resin is 10% by mass or more and 40% by mass or less with respect to the binder resin. <1> or <2> 2. The toner for developing electrostatic images according to claim 1. <4> The ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is 0.13 or more and 1.50 or less in mass ratio. <3> 2. The toner for developing electrostatic images according to claim 1. <5> The ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is 0.25 or more and 1.25 or less in mass ratio. <4> 2. The toner for developing electrostatic images according to claim 1. <6> When a cross section of the toner particle is observed, the area ratio of the internally added crosslinked resin particles to the cross section of the toner particle is more than 15% and 48% or less. <1> ~ <5> 10. The toner for developing electrostatic images according to claim 9. <7> The average dispersed diameter of the internally added crosslinked resin particles is 120 nm or more and 250 nm or less. <1> ~ <6> 10. The toner for developing electrostatic images according to claim 9. <8> The dielectric loss factor at 1 kHz of the toner after being left at a temperature of 28°C and a relative humidity of 85% is 35×10 -3 is <1> ~ <7> 10. The toner for developing electrostatic images according to claim 9. <9> The toner particles contain carbon black as a colorant. <1> ~ <8> 10. The toner for developing electrostatic images according to claim 9. <10> <1> ~ <9> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <11> <1> ~ <9> The toner for developing electrostatic images according to any one of the above items is contained, A toner cartridge that is detachably attached to an image forming device. <12> <10> a developing device that contains the electrostatic image developer according to claim 1 and develops an electrostatic image formed on a surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus. <13> an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; <10> a developing device that contains the electrostatic image developer according to claim 1 and develops the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: <14> a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; <10> a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to claim 1; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of: [Effects of the Invention]

[0010] <1> According to the invention, in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or more and 100° C. or less. 5 Less than Pa or 1×10 6 When the styrene-(meth)acrylic copolymer particles have an average dispersed diameter exceeding 100 nm, the toner for developing electrostatic images has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the formula (1) is not satisfied or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm. <2> According to the invention relating to (1), there is provided a toner for developing electrostatic images that can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to a case where formula (11) is not satisfied. <3> According to the invention, a toner for developing electrostatic images is provided which has low-temperature fixability and can suppress transfer unevenness in a high-temperature and high-humidity environment, compared to when the content of the crystalline polyester resin is less than 10% by mass or more than 40% by mass relative to the binder resin. <4> According to the invention, there is provided a toner for developing electrostatic images that has low-temperature fixing ability and can suppress transfer unevenness in high-temperature, high-humidity environments, compared to when the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is less than 0.13 or exceeds 1.50 by mass. <5> According to the invention, there is provided a toner for developing electrostatic images which has low-temperature fixing ability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is less than 0.25 or exceeds 1.25 in mass ratio. <6> According to the invention relating to (1), a toner for developing electrostatic images is provided which, when observed in cross section of a toner particle, has an area ratio of internally added crosslinked resin particles to the cross section of the toner particle of 15% or less or more than 48%, while having low temperature fixability and capable of suppressing transfer unevenness in a high temperature and high humidity environment. <7> According to the invention, a toner for developing electrostatic images is provided which has low-temperature fixability and can suppress transfer unevenness in high-temperature and high-humidity environments, compared to when the average dispersed diameter of the internally added crosslinked resin particles is less than 120 nm or more than 250 nm. <8> According to the invention, the dielectric loss factor of the toner at 1 kHz after being left at a temperature of 28°C and a relative humidity of 85% RH is 35×10 -3 As compared with the case where the temperature exceeds 1000°C, the toner for developing electrostatic images has low-temperature fixability and can suppress transfer unevenness under high-temperature and high-humidity environments. <9> According to the invention, in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or more and 100° C. or less. 5 Less than Pa or 1×10 6When the toner particles contain carbon black as a colorant, the toner particles have low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the toner particles contain styrene-(meth)acrylic copolymer particles having an average dispersed diameter exceeding 100 nm, which do not satisfy formula (1), or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm.

[0011] <10> , <11> , <12> , <13> or <14> According to the invention, in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or more and 100° C. or less. 5 Less than Pa or 1×10 6 When the styrene-(meth)acrylic copolymer particles have an average dispersed diameter exceeding 100 nm, the electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, or image forming method can suppress transfer unevenness in a high-temperature, high-humidity environment while maintaining low-temperature fixability, compared to when formula (1) is not satisfied or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram illustrating an example of a process cartridge that is detachably mounted to an image forming apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples. In this specification, (meth)acrylic means both acrylic and methacrylic.

[0014] In this specification, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified.

[0015] [Electrostatic image developing toner] The toner for developing electrostatic images (hereinafter also referred to as "toner") according to the present embodiment comprises toner particles containing an amorphous resin and a crystalline resin as a binder resin, and internally added crosslinked resin particles. The internal cross-linked resin particles have a storage modulus G' of 1 x 10 in the range of 60°C to 100°C. 5 Pa or more 1×10 6 The particles are styrene-(meth)acrylic copolymer particles with a viscosity of 0.1 Pa or less. The average dispersed diameter of the internally added crosslinked resin particles is 100 nm or more and 300 nm or less. In cross-sectional observation of a toner particle, when a 3 μm × 3 μm square region, which is 600 pix × 600 pix, is divided into n × n regions, the coefficient of variation of the area ratio of the internally added crosslinked resin particles to the area of ​​the n × n divided regions is DAR(n), and n is changed to 3, 4, 6, 8, 12, and 16, and log[1 / n] is plotted on the X axis and log[DAR(n)] on the Y axis. When the slope of the approximated line in the dispersion diagram is defined as slopeF(16), the following formula (1) is satisfied.

[0016] The toner according to the present embodiment has the above-described configuration, and can suppress transfer unevenness in a high-temperature and high-humidity environment (for example, an environment of a temperature of 28°C and a relative humidity of 85% RH) while having low-temperature fixability. The reason for this is presumed to be as follows.

[0017] Toners that combine amorphous polyester resins and crystalline polyester resins have been known to achieve both low-temperature fixability and heat storage stability. However, because crystalline polyester resins have lower resistance than amorphous polyester resins, the inclusion of crystalline polyester resins causes crystalline polyester resin domains to grow within toner particles, making it easier to create conductive paths within the toner. Furthermore, in high-temperature, high-humidity environments (e.g., environments with a temperature of 28°C and a relative humidity of 85% RH), the resistance decreases due to temperature and humidity influences, making the toner more conductive. As a result, charge injection performance deteriorates, leading to poor transferability and the resulting image being prone to transfer unevenness.

[0018] In order to improve the deterioration of transferability, it is preferable to keep the domain size of the crystalline polyester resin small inside the toner particle. However, for example, a technique of incorporating internally added crosslinked resin particles into toner particles has been known (Patent Document 1, etc.). Although the presence of internally added crosslinked resin particles can partially suppress domain growth of the crystalline polyester resin, it is difficult to control the arrangement of the internally added crosslinked resin particles and the crystalline polyester resin during toner particle production, making it difficult to suppress domain growth of the crystalline polyester resin.

[0019] Here, in order to properly arrange the internally added crosslinked resin particles and the crystalline polyester resin inside the toner particles, it is particularly preferable to prepare the toner particles by an emulsion aggregation method. In the emulsion aggregation method, amorphous polyester resin particles, crystalline polyester resin particles, and internally added crosslinked resin particles are dispersed in water and aggregated to form the toner particle structure. During this toner particle formation process, it is desirable that the internally added crosslinked resin particles and the crystalline polyester resin particles aggregate close to each other and that this state be maintained until the end of the toner particle fusion process. In conventional toners, when the temperature slightly exceeds room temperature, it is equal to or exceeds the glass transition temperature of the internally-added crosslinked resin particles, while it is lower than the glass transition temperature of the amorphous polyester resin. In this case, only the internally-added crosslinked resin particles have strong adhesive properties and tend to aggregate independently, resulting in uneven distribution of the internally-added crosslinked resin particles within the aggregated particles. As a result, the number of internally-added crosslinked resin particles present near the crystalline polyester resin decreases, and factors that inhibit domain growth of the crystalline polyester resin in the temperature range near the melting point of the crystalline polyester resin are reduced. This tendency for the crystalline polyester resin to easily grow domains results in a structure that is more likely to form conductive paths, which deteriorates the charge injection ability of toner particles in high-temperature, high-humidity environments. As a result, uneven transfer occurs.

[0020] In contrast, in the toner according to the present embodiment, the internally added crosslinked resin particles have an average dispersed diameter within the above range, and the internally added crosslinked resin particles are set to an appropriate size, and then are dispersed in the toner particles in a nearly uniform state so as to satisfy formula (1). As a result, the internally added crosslinked resin particles are appropriately present near the crystalline polyester, which inhibits domain growth of the crystalline polyester resin, making it difficult for the crystalline polyester domain to grow. In addition, the internally added crosslinked resin particles having the above storage modulus G' have elastic properties at high temperatures in the range of 60° C. to 100° C. Therefore, in the fusion and coalescence step of the emulsion aggregation method, the internally added crosslinked fine particles do not fuse with each other and form domains, and can exist in the toner particles in a nearly uniform state that satisfies formula (1), thereby suppressing the migration of the crystalline polyester resin and the growth of domains. As a result, deterioration of the charge injection property of the toner particles is suppressed in a high-temperature and high-humidity environment, and the occurrence of transfer unevenness is suppressed.

[0021] From the above, it is presumed that the toner according to this exemplary embodiment has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment.

[0022] The toner according to this embodiment will be described in detail below. The toner according to the present embodiment includes toner particles. may have

[0023] (toner particles) The toner particles contain an amorphous resin and a crystalline resin as binder resins, and internally added crosslinked resin particles. The toner particles may also contain a colorant, a release agent, and other additives.

[0024] -Binder resin- As the binder resin, an amorphous polyester resin and a crystalline polyester resin are used. However, from the viewpoint of ensuring low-temperature fixability and suppressing uneven transfer in a high-temperature, high-humidity environment, the content of the crystalline polyester resin relative to the binder resin is preferably 10% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and even more preferably 15% by mass or more and 20% by mass or less. If the content of the crystalline polyester resin is less than 10% by mass, the low-temperature fixability tends to decrease. If the content of the crystalline polyester resin exceeds 40% by mass, it becomes difficult to suppress domain growth of the crystalline polyester resin, and uneven transfer tends to occur in a high-temperature, high-humidity environment.

[0025] The "crystalline" nature of a resin refers to the presence of a clear endothermic peak rather than a stepwise change in endothermic heat in differential scanning calorimetry (DSC). Specifically, this refers to the half-width of the endothermic peak being within 10°C when measured at a heating rate of 10°C / min. On the other hand, the term "amorphous" for a resin means that the half-width exceeds 10°C, that the endothermic amount exhibits a stepwise change, or that no clear endothermic peak is observed.

[0026] The amorphous polyester resin will now be described. Examples of the amorphous polyester resin include a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. Note that, as the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0027] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0028] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0029] The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0030] The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0031] The amorphous polyester resin can be obtained by a known manufacturing method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense the monomer with the main component.

[0032] Here, the amorphous polyester resin may be used alone or in combination of two or more kinds. For example, it is preferable to use two or more amorphous polyesters having different molecular weights in combination as the amorphous polyester resin. An example of the use of two types in combination is the combination of a low molecular weight amorphous polyester resin (L-form) and a high molecular weight amorphous polyester resin (H-form). The low molecular weight (L-form) is preferably an amorphous polyester resin having a weight average molecular weight measured by GPC of 9000 to 20000. If the molecular weight is lower than 9000, offset tends to occur at high temperatures, while if the molecular weight is 20000 or higher, gloss is difficult to achieve at low temperatures. The high molecular weight polymer (H polymer) is preferably an amorphous polyester resin having a weight average molecular weight measured by GPC of 25,000 to 70,000. If the molecular weight is 70,000 or more, gloss may not be achieved at high temperatures, and the fixing temperature may become high. The acid value of the non-crystalline polyester resin used in combination is preferably about 13 mgKOH / g or more and 20 mgKOH / g or less for low molecular weight (L-form) and about 10 mgKOH / g or more and 15 mgKOH / g or less for high molecular weight (H-form).

[0033] The crystalline polyester resin will now be described. The crystalline polyester resin may be, for example, a polycondensate of a polycarboxylic acid and a polyhydric alcohol. Note that, as the crystalline polyester resin, a commercially available product or a synthesized product may be used. Here, the crystalline polyester resin is preferably a polycondensate using a polymerizable monomer having a linear aliphatic group rather than a polymerizable monomer having an aromatic group, since it easily forms a crystalline structure.

[0034] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., dibasic acids such as phthalic acid, isophthalic acid, terephthalic acid, and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acid may be a tricarboxylic or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the tricarboxylic acid include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). As the polycarboxylic acid, a dicarboxylic acid having a sulfonic acid group and a dicarboxylic acid having an ethylenic double bond may be used in combination with these dicarboxylic acids. The polycarboxylic acids may be used alone or in combination of two or more.

[0035] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include 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 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0036] Here, the polyhydric alcohol has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0037] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0038] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0039] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester.

[0040] The content of the binder resin is, for example, preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0041] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, ultramarine blue, and the like. Examples of the dyes include various pigments such as phosphorus blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The colorant may be used alone or in combination of two or more kinds.

[0042] Here, carbon black as a colorant has electrical conductivity, and when the domains of the crystalline polyester resin grow, it becomes easy for the carbon black and the crystalline polyester resin to form conductive paths, particularly inside the toner particles, which results in a decrease in transferability and manifests itself as transfer unevenness in the resulting image under high-temperature and high-humidity conditions. However, in the toner according to this embodiment, even if carbon black is used as the colorant, conductive paths are unlikely to be formed inside the toner particles, and transfer unevenness in a high-temperature, high-humidity environment is suppressed.

[0043] The colorant may be surface-treated as needed, or may be used in combination with a dispersant. Furthermore, a plurality of colorants may be used in combination.

[0044] The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0045] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0046] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" as described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0047] The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner particles.

[0048] -Internally added crosslinked resin particles- The internally added crosslinked resin particles are resin particles contained inside the toner particles, and refer to resin particles having a crosslinked structure between specific atoms in the polymer structure of the resin particles. The internally added crosslinked resin particles are, for example, particles that exist in the toner particles in a state in which they are incompatible with the binder resin.

[0049] Examples of the internally crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (i.e., ionic crosslinked particles), crosslinked resin particles crosslinked by covalent bonds (i.e., covalently crosslinked resin particles), etc. Among these, crosslinked resin particles crosslinked by covalent bonds are preferred as the internally crosslinked resin particles.

[0050] The internal cross-linked resin particles have a storage modulus G' of 1 x 10 in the range of 60°C to 100°C. 5 Pa or more 1×10 6 Styrene-(meth)acrylic copolymer particles having a viscosity of 0.1 Pa or less are applied. The storage modulus G' of the styrene-(meth)acrylic copolymer particles as the internally added crosslinked resin particles is 1×10 5 If the pressure is less than Pa, the viscosity of the internal crosslinked resin particles will increase, causing the internal crosslinked resin particles to adhere and fuse together, making it impossible to form a structure that satisfies formula (1), resulting in uneven transfer in high-temperature, high-humidity environments. The storage modulus G' of the styrene-(meth)acrylic copolymer particles as the internally added crosslinked resin particles is 1×10 6 If the pressure exceeds Pa, the internally added crosslinked resin particles become too hard, impairing the low temperature fixability of the toner.

[0051] To set the storage modulus G' of the styrene-(meth)acrylic copolymer particles as the internally added crosslinked resin particles within the above range, for example, the ratio of the styrene monomer to the (meth)acrylic monomer and the amount of crosslinking are adjusted within suitable ranges.

[0052] The storage modulus G' of the styrene-(meth)acrylic copolymer particles as the internally added crosslinked resin particles is measured as follows. Pressure is applied to the internally-added crosslinked resin particles to be measured to prepare a disk-shaped sample with a thickness of 2 mm and a diameter of 8 mm, which is used as the measurement sample. When measuring the internally-added crosslinked resin particles contained in toner particles, the internally-added crosslinked resin particles are removed from the toner particles before preparing the measurement sample. One method for removing the internally-added crosslinked resin particles from the toner particles includes, for example, immersing the toner particles in a solvent that dissolves the binder resin but not the internally-added crosslinked resin particles, and removing the internally-added crosslinked resin particles by dissolving the binder resin in the solvent. The resulting disk-shaped sample is then sandwiched between parallel plates with a diameter of 8 mm, and the measurement temperature is raised from 10°C to 150°C at a rate of 2°C / min at a strain of 0.1 to 100%, and dynamic viscoelasticity measurement is performed under the following conditions: The storage modulus G' is determined from each curve of the storage modulus obtained by the measurement. -Measurement conditions- Measurement device: Rheometer ARES-G2 (manufactured by TA Instruments) Gap: Adjusted to 3mm Frequency: 1Hz

[0053] The styrene-(meth)acrylic copolymer particles as the internally crosslinked resin particles contain 50% by mass or more of the styrene-(meth)acrylic copolymer as the main component in the resin particles, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably substantially all of which is the styrene-(meth)acrylic copolymer. The total amount of the styrene monomer and (meth)acrylic monomer constituting the copolymer is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 95% by mass or more, with the remainder being a crosslinking agent, which will be described later.

[0054] Examples of the styrene-(meth)acrylic copolymer include resins obtained by radical polymerization of the following styrene monomers and (meth)acrylic monomers.

[0055] Examples of styrene-based monomers include styrene, α-methylstyrene, vinylnaphthalene, alkyl-substituted styrenes having alkyl chains such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, and 4-ethylstyrene, halogen-substituted styrenes such as 2-chlorostyrene, 3-chlorostyrene, and 4-chlorostyrene, and fluorine-substituted styrenes such as 4-fluorostyrene and 2,5-difluorostyrene, etc. Among these, styrene and α-methylstyrene are preferred.

[0056] Examples of the (meth)acrylic monomer include (meth)acrylic acid, n-methyl (meth)acrylate, n-ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, Examples of such acrylates include neopentyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-carboxyethyl (meth)acrylate, (meth)acrylonitrile, and (meth)acrylamide. Among these, n-butyl (meth)acrylate and 2-carboxyethyl (meth)acrylate are preferred.

[0057] Examples of crosslinking agents for crosslinking the resin in the internally crosslinked resin particles include aromatic polyvalent vinyl compounds such as divinylbenzene and divinylnaphthalene; polyvalent vinyl esters of aromatic polyvalent carboxylic acids such as divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate, trivinyl trimesate, divinyl naphthalenedicarboxylate, and divinyl biphenylcarboxylate; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridinedicarboxylate; vinyl esters of unsaturated heterocyclic carboxylic acids such as vinyl pyromethane, vinyl furancarboxylate, vinyl pyrrole-2-carboxylate, and vinyl thiophenecarboxylate; butanediol diacrylate, butanediol dimethacrylate, hexanediol diacrylate, hexanediol dimethacrylate, octanediol diacrylate, octanediol dimethacrylate, nonanediol diacrylate, nonanediol dimethacrylate, decanediol diacrylate, decanediol diacrylate, (Meth)acrylic acid esters of linear polyhydric alcohols such as dodecanediol dimethacrylate, dodecanediol diacrylate, and dodecanediol dimethacrylate; (meth)acrylic acid esters of branched or substituted polyhydric alcohols such as neopentyl glycol dimethacrylate and 2-hydroxy, 1,3-diacryloxypropane; polyethylene glycol di(meth)acrylate, polypropylene polyethylene glycol di(meth)acrylates, divinyl succinate, divinyl fumarate, and maleic acid Examples of the crosslinking agent include polyvalent vinyl esters of polyvalent carboxylic acids such as vinyl, divinyl maleate, divinyl diglycolate, vinyl itaconate, divinyl itaconate, divinyl acetonedicarboxylate, divinyl glutarate, divinyl 3,3'-thiodipropionate, divinyl trans-aconitate, trivinyl trans-aconitate, divinyl adipate, divinyl pimelate, divinyl suberate, divinyl azelaate, divinyl sebacate, divinyl dodecanedioate, and divinyl brassylate. One type of crosslinking agent may be used alone, or two or more types may be used in combination.

[0058] Among these, it is preferable to use a bifunctional alkyl acrylate having an alkylene chain with 6 or more carbon atoms as the crosslinking agent for crosslinking the resin. That is, it is preferable that the internally crosslinked resin particles have a bifunctional alkyl acrylate as a constituent unit, and that the alkylene chain in the bifunctional alkyl acrylate has 6 or more carbon atoms. By using internally-added crosslinked resin particles having a bifunctional alkyl acrylate as a structural unit and an alkylene chain with 6 or more carbon atoms, it becomes easier to obtain a toner that undergoes a moderate range of toner deformation during fixing and has particularly good low-temperature fixing properties. If the crosslinking density of the internally-added crosslinked resin particles is high (i.e., the distance between crosslinking points is short), the elasticity becomes too high, whereas if a bifunctional acrylate having a long alkylene chain is used as the crosslinking agent, the crosslinking density becomes low (i.e., the distance between crosslinking points is long), and it is possible to prevent the elasticity of the internally-added crosslinked resin particles from becoming too high.

[0059] From the viewpoint of adjusting the crosslink density within an appropriate range, the number of carbon atoms in the alkylene chain in the bifunctional alkyl acrylate is preferably 6 or more, more preferably 6 to 12, and even more preferably 8 to 12. More specific examples of the bifunctional alkyl acrylate include 1,6-hexanediol acrylate, 1,6-hexanediol methacrylate, 1,8-octanediol diacrylate, 1,8-octanediol dimethacrylate, 1,9-nonanediol diacrylate, 1,9-nonanediol dimethacrylate, 1,10-decanediol diacrylate, 1,10-decanediol dimethacrylate, 1,12-dodecanediol diacrylate, and 1,12-dodecanediol dimethacrylate, of which 1,10-decanediol diacrylate and 1,10-decanediol dimethacrylate are preferred. Other examples of crosslinking agents include 2-carboxyethyl acrylate, and it is preferable to use at least one of these together with the above-mentioned bifunctional alkyl acrylate.

[0060] The fixability of the styrene-(meth)acrylic copolymer particles as the internally crosslinked resin particles may be controlled by adjusting the amount of crosslinking agent contained in the composition. For example, increasing the amount of crosslinking agent contained in the composition makes it easier to obtain internally crosslinked resin particles with good fixability. The content of the crosslinking agent in the internally crosslinked resin particle-forming composition is, for example, preferably 0.3 to 5.0 parts by mass, more preferably 0.5 to 3.0 parts by mass, and even more preferably 0.8 to 2.5 parts by mass, relative to 100 parts by mass of the total of the styrene monomer, the (meth)acrylic monomer, and the crosslinking agent.

[0061] The glass transition temperature Tg(E) of the internally crosslinked resin particles is preferably 10°C or higher and 40°C or lower, more preferably 15°C or higher and 35°C or lower.

[0062] The glass transition temperature Tg(E) of the internally crosslinked resin particles is measured as follows. Pressure is applied to the internally-added crosslinked resin particles to be measured to prepare a disk-shaped sample with a thickness of 2 mm and a diameter of 8 mm, which is used as the measurement sample. When measuring the internally-added crosslinked resin particles contained in toner particles, the internally-added crosslinked resin particles are removed from the toner particles before preparing the measurement sample. One method for removing the internally-added crosslinked resin particles from the toner particles includes, for example, immersing the toner particles in a solvent that dissolves the binder resin but not the internally-added crosslinked resin particles, and removing the internally-added crosslinked resin particles by dissolving the binder resin in the solvent. The resulting disk-shaped sample for measurement is then sandwiched between parallel plates with a diameter of 8 mm, and the measurement temperature is raised from 10°C to 150°C at a rate of 2°C / min at a strain of 0.1 to 100%, and dynamic viscoelasticity measurement is performed under the following conditions. The loss tangent tanδ at each temperature is determined from the loss modulus curve obtained by the measurement. The peak temperature of the loss tangent tanδ is then taken as the glass transition temperature Tg(E) of the internally added crosslinked resin particles. -Measurement conditions- Measurement device: Rheometer ARES-G2 (manufactured by TA Instruments) Gap: Adjusted to 3mm Frequency: 1Hz

[0063] In the internally crosslinked resin particles, when the glass transition temperature calculated by the Fox equation from the ratio (mass proportion) of the constituent monomers of the styrene-(meth)acrylic copolymer in the entire resin particle is Tg1, and the glass transition temperature calculated by the Fox equation from the ratio (mass proportion) of the constituent monomers of the styrene-(meth)acrylic copolymer calculated from the surface analysis of the resin particle is Tg2, it is preferable that the following formulas (T11) and (T21) are satisfied, and it is more preferable that the following formulas (T12) and (T22) are satisfied. This improves low-temperature fixability. Formula (T11): 5℃ <Tg2―Tg1<40℃ Formula (T12): 10℃ <Tg2―Tg1<35℃ Formula (T21): 100>Tg2>0℃ Formula (T22): 90>Tg2>10℃

[0064] Here, the difference between the glass transition temperatures Tg1 and Tg2 according to the Fox equation is thought to mean that the styrene monomer and (meth)acrylic monomer are not randomly bonded, but rather that there is a mixture of a large amount of styrene-derived components, with an arrangement localized on the particle surface, and a large amount of (meth)acrylic monomer-derived components, with an arrangement localized inside the particle. In other words, since the glass transition temperature of polystyrene resin is about 100°C and the glass transition temperature of (meth)acrylic resin is usually lower than that; for example, polyethyl acrylate is about -20°C, this is thought to indicate that the region with a large amount of styrene-based units is unevenly distributed on the surface of the internally crosslinked resin particles.

[0065] The ratio of the constituent monomers of the styrene-(meth)acrylate copolymer in the entire resin particle is determined by NMR analysis. The ratio of the constituent monomers of the styrene-(meth)acrylate copolymer calculated from the surface analysis of the resin particles is determined by the following measurement. The resin particles are dried and the surface composition is analyzed using an X-ray photoelectron spectrometer (XPS). The XPS measurement device used is a JPS-9000MX manufactured by JEOL Ltd. The measurement uses MgKα rays as the X-ray source, an acceleration voltage of 10 kV, and an emission current of 30 mA. The ratio O(p) of oxygen elements to the total of carbon and oxygen elements in the resin particles is calculated using the following formula. O(p) = number of oxygen atoms / (number of carbon atoms + number of oxygen atoms) In addition, a resin consisting of only (meth)acrylate is prepared, and the ratio O(a) of oxygen elements in the (meth)acrylate is determined in the same manner. From these measurement results, when the sum of styrene and (meth)acrylate is set to 1, the surface (meth)acrylate ratio Wa(S) and the surface styrene ratio Ws(S) can be calculated using the following formulas. Wa(S)=O(p) / O(a) Ws(S)=1-(O(p) / O(a))

[0066] Then, the glass transition temperatures Tg1 and Tg2 are calculated from the ratio of each constituent monomer determined above using the Fox equation. Specifically, this is as follows. The following FOX equation holds true for the glass transition temperature of a homopolymer of a (meth)acrylic monomer as TgA (K), the (meth)acrylic monomer ratio (mass ratio: mass%) as WA, the glass transition temperature of a homopolymer of a styrene monomer as TgS (K), the styrene monomer ratio (mass ratio: mass%), and the target glass transition temperature Tg0 (K). FOX formula: 1 / Tg0=(WA / TgA)+(WS / TgS) Using the Fox formula, the glass transition temperature and ratio of each (meth)acrylic monomer and the glass transition temperature and ratio of the styrene monomer in the entire resin particle or on the surface of the resin particle are substituted, and T0 = "target glass transition temperature Tg1 or T2" is calculated using the Fox formula. The glass transition temperature of the homopolymer of the (meth)acrylic monomer and the glass transition temperature of the homopolymer of the styrene monomer may be an actually measured value or a catalog value.

[0067] In the internally crosslinked resin particles made of a styrene-(meth)acrylic copolymer, adjustment of Tg(E), Tg1, Tg2, etc. can be achieved by adjusting the polymerization conditions for the copolymer. In particular, to obtain resin particles in which a composition gradient occurs within the internally crosslinked resin particles and regions rich in styrene units are unevenly distributed on the surface, it is preferable to increase the content ratio of styrene monomer to (meth)acrylic monomer in the monomer-containing liquid as the polymerization progresses when producing the resin particles by polymerization of a monomer-containing liquid containing a styrene monomer and a (meth)acrylic monomer. "Increasing as the polymerization progresses" typically refers to gradually increasing the content ratio of styrene monomer in the monomer-containing liquid, but also includes operations such as gradually increasing the content of styrene monomer in the additional monomer when adding additional monomer to the monomer-containing liquid in multiple installments, or gradually increasing the amount of added styrene monomer to gradually increase the concentration of styrene monomer in the monomer-containing liquid. For example, when preparing a styrene-(meth)acrylic copolymer by emulsion polymerization, the content of styrene monomer in the emulsion can be gradually increased by adding the emulsion dropwise multiple times. Furthermore, it is also possible to control the progress of the reaction by adjusting the polymerization temperature, polymerization time, the method of adding the polymerization initiator, and the like.

[0068] The content of the internally added crosslinked resin particles is preferably 2% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, based on the total mass of the toner. By ensuring that the content of the internally added crosslinked resin particles is within the above range, domain growth of the crystalline polyester resin is easily suppressed, which in turn makes it easier to suppress transfer unevenness in a high-temperature, high-humidity environment, and also improves low-temperature fixability.

[0069] Here, the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is preferably 0.13 or more and 1.50 or less, more preferably 0.25 or more and 1.25 or less, and even more preferably 0.30 or more and 1.00 or less, in mass ratio. When the ratio Ws / Wc is within the above range, domain growth of the crystalline polyester resin is easily suppressed, and as a result, transfer unevenness in a high-temperature, high-humidity environment is easily suppressed.

[0070] The average dispersed diameter of the internally added crosslinked resin particles is 100 nm or more and 300 nm or less, preferably 120 nm or more and 250 nm or less, and more preferably 150 nm or more and 230 nm or less. When the average dispersed diameter of the internally added crosslinked resin particles is either less than 100 nm or more than 300 nm, the internally added crosslinked resin particles are excessively small or large, making it difficult to suppress domain growth of the crystalline polyester resin. As a result, it becomes difficult to suppress transfer unevenness under high-temperature and high-humidity environments. In addition, low-temperature fixability is reduced.

[0071] The average dispersed diameter of the internally added crosslinked resin particles is measured as follows. Toner particles or toner are mixed and embedded in epoxy resin, and the epoxy resin is solidified. The solidified material is cut using an ultramicrotome (Leica Ultracut UCT) to prepare thin section samples with thicknesses of 80 nm to 130 nm. The resulting thin section samples are then stained with ruthenium tetroxide for 3 hours in a desiccator at 30°C. SEM images of the stained thin section samples are then obtained using an ultra-high-resolution field emission scanning electron microscope (FE-SEM, Hitachi High-Technologies Corporation, S-4800). The release agent, styrene-(meth)acrylic resin, and polyester resin are stained with ruthenium tetroxide in this order, so each component is identified by the shade resulting from the degree of staining. If the shade is difficult to distinguish due to the condition of the sample, the staining time can be adjusted. In the cross section of a toner particle, the colorant domain is smaller than the release agent domain and the resin particle domain, and therefore they are distinguished by size. In the SEM image, 30 toner cross sections whose maximum length is 85% or more of the volume average particle diameter of the toner particles are selected, and a total of 100 dyed internally-added crosslinked resin particles (i.e., their domains) are observed. The maximum length of each domain is measured, and the maximum length is considered to be the diameter of the domain. The diameters are arithmetically averaged to determine the average circular equivalent diameter. The obtained average circular equivalent diameter is then used as the average dispersed diameter of the internally-added crosslinked resin particles.

[0072] The average dispersion diameter of the internally added crosslinked resin particles can be adjusted by, for example, producing toner particles by aggregation and coalescence and adjusting the volume average particle diameter of the internally added crosslinked resin particles contained in the internally added crosslinked resin particle dispersion liquid used during production; or by preparing a plurality of internally added crosslinked resin particle dispersion liquids with different volume average particle diameters and using them in combination; or the like.

[0073] The average shape factor SF-1 of the internally added crosslinked resin particles is preferably 130 or less. When the average shape factor SF-1 of the internally added crosslinked resin particles is within the above range, domain growth of the crystalline polyester resin is easily suppressed, which in turn makes it easier to suppress transfer unevenness in high-temperature, high-humidity environments, and also improves low-temperature fixability.

[0074] The average shape factor SF-1 is calculated by the following formula: SF-1=(ML / A) × (π / 4) × 100 In the above formula, ML represents the absolute maximum length of a toner particle, and A represents the projected area of ​​a toner particle. Specifically, a sample is prepared in the same manner as for measuring the average dispersion diameter of the internally-added cross-linked resin particles. Thirty toner cross sections whose maximum length is 85% or more of the volume average particle diameter of the toner particles are selected from the SEM images, and a total of 100 dyed internally-added cross-linked resin particles are observed. The observed SEM images are imported into an image analysis processing system, Luzex (manufactured by Nireco Corporation), and the maximum length and projected area of ​​the 100 particles are determined. The average value is calculated using the above formula to determine the average shape factor SF-1 of the internally-added cross-linked resin particles.

[0075] In cross-sectional observation of a toner particle, when a 3 μm × 3 μm square region, which is 600 pix × 600 pix, is divided into n × n regions, the coefficient of variation of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided region in the n × n divided regions is DAR(n), and n is changed to 3, 4, 6, 8, 12, and 16, and log[1 / n] is plotted on the X axis and log[DAR(n)] on the Y axis. In this dispersion diagram, the slope of the approximate line is slopeF(16). It is preferable that the following formula (1) is satisfied, and the following formula (11) is satisfied, and it is more preferable that the following formula (12) is satisfied. Equation (1):0.6≦slopeF(16) Equation (11): 0.7≦slopeF(16) Equation (12): 0.8≦slopeF(16)

[0076] Here, the coefficient of variation DAR(n) of the area ratio of the internally added crosslinked resin particles is a coefficient of variation calculated by the formula: DAR(n)=AR(n)sd / AR(n)ave. AR(n)sd is the standard deviation of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided region in an n×n divided region. AR(n)ave is the arithmetic mean value of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided regions of n×n.

[0077] The coefficient of variation DAR(n) of the area ratio of the internally added crosslinked resin particles is an index showing the dispersibility of the internally added crosslinked resin particles; when the dispersibility is high, there is little variation in the amount of the internally added crosslinked resin particles present in the n × n divided regions, and when the dispersibility is low, there is great variation in the amount of the internally added crosslinked resin particles present in the n × n divided regions. On the other hand, when the number of divided regions (i.e., the number n) is large, whether the dispersibility of the internally added crosslinked resin particles is too high or too low, the number of regions in the n×n divided regions where no internally added crosslinked resin particles are present increases, resulting in greater variation in the amount of internally added crosslinked resin particles present. That is, when the number of divided regions is changed, the higher the dispersibility of the internally added crosslinkable resin particles, the greater the change in the coefficient of variation DAR(n) of the area ratio of the internally added crosslinkable resin particles. Therefore, a slope F(16) value of 0.6 or more indicates good dispersibility and the presence of internally added crosslinked resin particles inside the toner particles, which suppresses domain growth of the crystalline polyester resin, making it easier to suppress transfer unevenness in high-temperature, high-humidity environments.

[0078] The standard deviation AR(n)sd of the area ratio of the internally added crosslinked resin particles, the arithmetic mean value AR(n)ave of the area ratio of the internally added crosslinked resin particles, the coefficient of variation DAR(n) of the area ratio of the internally added crosslinked resin particles, and the slope slopeF(16) are measured and calculated as follows. Toner particles or toner are mixed and embedded in epoxy resin, and the epoxy resin is solidified. The solidified material is cut using an ultramicrotome (Leica Ultracut UCT) to prepare thin section samples with a thickness of 0.2 μm to 0.3 μm. The obtained thin section samples are then stained with ruthenium tetroxide for 3 hours in a desiccator at 30°C. SEM images of the stained thin section samples are then obtained using an ultra-high-resolution field emission scanning electron microscope (FE-SEM, Hitachi High-Technologies Corporation, S-4700). The release agent, styrene-(meth)acrylic resin, and polyester resin are stained with ruthenium tetroxide in this order, so each component is identified by the shade resulting from the degree of staining. If the shade is difficult to distinguish due to the condition of the sample, the staining time can be adjusted. In the cross section of a toner particle, the colorant domain is smaller than the release agent domain and the resin particle domain, and therefore they are distinguished by size. In the SEM image, a cross section of a toner particle whose maximum length is 85% or more of the volume average particle diameter of the toner particle is selected. A 600 pixel x 600 pixel, 3 μm x 3 μm square area is cut out from the cross section of a toner particle in the SEM image, and the fractal dimension of the square area in the cross section of the toner particle is calculated using image processing software (Image J: manufactured by the National Institutes of Health, USA).

[0079] The procedure for measuring fractal dimension using image processing software (Image J: manufactured by the National Institutes of Health) is as follows. 1. Analyze → Set Scale to define the relationship between the number of pixels on the image and the actual distance. (Enter Distance in Pixes: 600, Known distance: 3, Pixel Aspect: 1, Unit of length: um, and check the Global checkbox.) 2.Select Image → Type → 8-bit. 3. Select Process → Filters → Median..., enter Radius:2.0pixels, and press OK. 4. Select Image → Adjust → Threshold, check Dark background, click the Auto button, and then click the Apply button. 5. Remove speckled image noise by going to Process → Noise → Despeckle. 6. Select Process → Filters → Median..., enter Radius:10.0pixels, and press OK.

[0080] By the above operation, a binarized image of the internally-added crosslinked resin particles in the square region is obtained. Next, the square region is divided into three (n=3), and the area ratio of the internally crosslinked resin particles for each of the six divided regions is determined. From the area ratio of the internally-added crosslinked resin particles in each of the six divided regions obtained, the standard deviation AR(n=3)sd of the area ratio of the internally-added crosslinked resin particles, the arithmetic mean value AR(n=3)ave of the area ratio of the internally-added crosslinked resin particles, and the coefficient of variation DAR(n=3) of the area ratio of the internally-added crosslinked resin particles are calculated. The standard deviation AR(n)sd of the area ratio of the internally added crosslinked resin particles is calculated by finding the difference between the arithmetic average value AR(n)ave of the area ratio of the internally added crosslinked resin particles and the area ratio of each internally added crosslinked resin particle in each divided region, and multiplying the sum of the squared values ​​by (1 / 2).

[0081] Next, similarly, the square region is divided into 4, 6, 12, and 16 (i.e., n = 4, 6, 12, and 16), and the area ratio of each of the resulting divided regions is determined. From the area ratio of each of the resulting divided regions, the standard deviation AR (n = 4, 6, 12, and 16) sd of the area ratio of the internally added crosslinked resin particles, the arithmetic mean value AR (n = 4, 6, 12, and 16) ave of the area ratio of the internally added crosslinked resin particles, and the coefficient of variation DAR (n = 4, 6, 12, and 16) of the area ratio of the internally added crosslinked resin particles are determined.

[0082] Then, a scatter diagram is obtained by plotting log[1 / n] on the X axis and log[DAR(n)] on the Y axis when the number of divisions n = 3, 4, 6, 8, 12, and 16, and the slope of the approximated line in the scatter diagram, slopeF(16), is calculated. The slope of the approximated line is calculated using the least squares method.

[0083] The above operation is carried out for 200 toner particles, and the average value of the slope F(16) is calculated.

[0084] When observing the cross section of a toner particle, the area ratio of the internally added crosslinked resin particles to the cross section of the toner particle is preferably more than 15% and not more than 48%, more preferably more than 16% and not more than 40%, and even more preferably more than 18% and not more than 35%. When the area ratio of the internally added crosslinked resin particles is within the above range, domain growth of the crystalline polyester resin is easily suppressed, which in turn makes it easier to suppress transfer unevenness in a high-temperature, high-humidity environment, and also improves low-temperature fixability.

[0085] The area ratio of the internally added crosslinked resin particles is measured as follows. In the same manner as described above for calculating "slopeF(16)", an SEM image of the cross section of the toner particle is obtained, and the area ratio of the internally added crosslinked resin particles to the cross section of the toner particle is determined from the image. The above operation is carried out for 200 toner particles, and the average area ratio of the internally added crosslinked resin particles is calculated.

[0086] -Method of manufacturing internally crosslinked resin particles- As a method for producing the internally crosslinked resin particles, known methods such as emulsion polymerization, melt kneading using a Banbury mixer or a kneader, suspension polymerization, and spray drying can be applied. However, emulsion polymerization is preferred in order to unevenly distribute units derived from a styrene-based monomer on the particle surface. In the method for producing the internally crosslinked resin particles, it is preferable to use a styrene-based monomer and a (meth)acrylic-based monomer as the monomers and polymerize them in the presence of a crosslinking agent. In the method for producing the internally crosslinked resin particles, it is preferable to carry out emulsion polymerization multiple times.

[0087] The method for producing the internally crosslinked resin particles will be described in more detail below. The method for producing the internally crosslinked resin particles includes the steps of: a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water (emulsion preparation step); and a step of adding a polymerization initiator to the emulsion and heating the emulsion to polymerize the monomer (first emulsion polymerization step). a step (second emulsion polymerization step) of adding an emulsion containing a monomer and a crosslinking agent to the reaction solution after the first emulsion polymerization step and heating the mixture to polymerize the monomer; It is preferred that it contains Furthermore, in the second emulsion polymerization step, in order to adjust the composition of the particle surface, the emulsion may be adjusted by changing the ratio of the styrene-based monomer and the (meth)acrylic monomer, and then the emulsion may be added multiple times.

[0088] --Emulsion preparation process-- This is a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water. It is preferable to obtain an emulsion by emulsifying the monomer, crosslinking agent, surfactant, and water using an emulsifier. Examples of emulsifiers include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitating blades; static mixers such as static mixers; rotor-stator emulsifiers such as homogenizers and Clearmix; mill-type emulsifiers equipped with a grinding function; high-pressure emulsifiers such as Manton-Gaulin pressure emulsifiers; high-pressure nozzle-type emulsifiers that generate cavitation under high pressure; high-pressure collision-type emulsifiers such as microfluidizers that apply shear force by causing liquids to collide with each other under high pressure; ultrasonic emulsifiers that generate cavitation using ultrasound; and membrane emulsifiers that emulsify through fine pores.

[0089] As the monomer, it is preferable to use a styrene-based monomer and a (meth)acrylic-based monomer. As the crosslinking agent, those already mentioned above are applicable.

[0090] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. Among these, anionic surfactants are preferred. The surfactants may be used alone or in combination of two or more.

[0091] The emulsion may contain a chain transfer agent. There are no particular limitations on the chain transfer agent, but a compound having a thiol component can be used. Specifically, alkyl mercaptans such as hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan, and dodecyl mercaptan are preferred. The mass ratio of the styrene-based monomer to the (meth)acrylic monomer in the emulsion (styrene-based monomer / (meth)acrylic monomer) is preferably 0.2 or more and 1.1 or less. The content of the crosslinking agent in the entire emulsion is preferably 0.5% by mass or more and 3% by mass or less.

[0092] --First emulsion polymerization step-- This is a process in which a polymerization initiator is added to the emulsion and heated to polymerize the monomers. Here, when carrying out the polymerization, it is preferable to stir the emulsion (reaction solution) containing the polymerization initiator with a stirrer. Examples of the agitator include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitator blades. As the polymerization initiator, ammonium persulfate is preferably used.

[0093] --Second emulsion polymerization step-- This is a step in which an emulsion containing a monomer is added to the reaction solution after the first emulsion polymerization step, and the mixture is heated to polymerize the monomer. During the polymerization, it is preferable to stir the reaction solution in the same manner as in the first emulsion polymerization step. In this step, the emulsion containing the monomers may be added in multiple portions by changing the ratio of the styrene-based monomer to the (meth)acrylic monomer in the emulsion. The emulsion containing the monomer is preferably obtained by emulsifying the monomer, surfactant, and water using an emulsifier, for example.

[0094] -Other additives- Examples of other additives include well-known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0095] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may preferably be composed of, for example, a core containing a binder resin, internally added crosslinked resin particles, and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing a binder resin and internally added crosslinked resin particles.

[0096] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0097] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0098] The average circularity of the toner particles is preferably 0.90 or more and 1.00 or less, and more preferably 0.92 or more and 0.98 or less.

[0099] The average circularity of toner particles is calculated by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projected area as the particle image) / (perimeter of the particle projected image)]. Specifically, this value is measured by the following method. First, the toner particles to be measured are sucked and collected, forming a flat flow, and a still image of the particles is captured by instantaneously activating a strobe light, and the particle image is analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation).The number of samples to be sampled when calculating the average circularity is 3,500. When the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0100] (external additives) Examples of external additives include inorganic particles, such as SiO2, TiO2, Al2O3, SrTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0101] The surfaces of inorganic particles as external additives are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is usually, for example, 1 part by mass or more and 10 parts by mass or less per 100 parts by mass of the inorganic particles.

[0102] Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning agents (for example, metal salts of higher fatty acids such as zinc stearate, and particles of fluorine-based polymers).

[0103] The amount of the external additive added is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.01% by mass or more and 6.0% by mass or less, based on the toner particles.

[0104] (Dielectric loss factor of toner) In the toner according to this embodiment, the dielectric loss factor at 1 kHz after being left at a temperature of 28°C and a relative humidity of 85% RH is 35×10 -3 Less than 30 x 10 is preferable. -3 Less than 25×10 is preferable. -3 The following is even more preferred: When the dielectric loss factor of the toner according to this embodiment is within the above range, the domains of many crystalline polyester resins do not grow excessively, and conductive paths are not formed inside the toner particles. Therefore, even if the moisture content of the toner particles increases under high-temperature, high-humidity conditions, the charge injection property is unlikely to deteriorate. As a result, transfer unevenness under high-temperature, high-humidity conditions is easily suppressed.

[0105] The dielectric loss factor of the toner can be adjusted by controlling the contents of the crystalline polyester and the internally added crosslinked resin particles, the dispersion state of the internally added crosslinked resin particles inside the toner particles, the glass transition temperature Tg(E) of the internally added crosslinked resin particles, and the amount of trace impurities (such as Na) present in the toner particles.

[0106] Here, the dielectric loss factor of toner will be explained. First, the dielectric loss tangent (tanδ) is expressed as the ratio of the real part ε' to the imaginary part ε" in the complex dielectric constant ε = ε' - iε" (i is the imaginary unit), and is expressed as dielectric loss tangent (tanδ) = ε" / ε'. Of these, the imaginary part ε" is called the dielectric loss factor. The method for measuring the dielectric loss factor of the toner is as follows. Six grams of toner to be measured is weighed out and left for at least three hours in an environment with a temperature of 28°C and a relative humidity of 85%RH, after which it is formed into pellets by applying a 10 ton load for one minute.The resulting pellets are again left for at least one hour in an environment with a temperature of 28°C and a relative humidity of 85%RH, and then placed between electrodes with a diameter of 3.8 cm.The dielectric loss factor of the toner is measured using an LCR meter (LCR meter type 6440A: manufactured by Toyo Corporation) under conditions of 28°C, 85%RH, a frequency of 1 kHz, and a voltage of 5 V.

[0107] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to this exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0108] The toner particles may be produced by any of a dry production method (for example, a kneading and pulverization method) and a wet production method (for example, an aggregation and coalescence method, a suspension polymerization method, a dissolution and suspension method). The method for producing the toner particles is not particularly limited, and any well-known production method may be used. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0109] Specifically, for example, when toner particles are produced by an aggregation and coalescence method, for example, a step of mixing a first amorphous resin particle dispersion liquid in which first amorphous resin particles to be a binder resin are dispersed, a crystalline resin particle dispersion liquid in which crystalline resin particles to be a binder resin are dispersed, an internally crosslinked resin particle dispersion liquid in which internally crosslinked resin particles are dispersed, a colorant dispersion liquid in which a colorant is dispersed, and a release agent particle dispersion liquid in which release agent particles (hereinafter also referred to as "release agent particles") are dispersed, and aggregating the particles and the colorant in the obtained dispersion liquid to form first aggregated particles (first aggregated particle forming step); a step of adding second amorphous resin particles, which serve as a binder resin, to the first aggregated particle dispersion liquid after obtaining the first aggregated particle dispersion liquid in which the first aggregated particles are dispersed, to aggregate the second amorphous resin particles onto the surfaces of the first aggregated particles, thereby forming second aggregated particles (second aggregated particle forming step); a step of heating the second aggregate particle dispersion liquid in which the second aggregate particles are dispersed to fuse and coalesce the second aggregate particles to form toner particles (fusion and coalescence step); Toner particles are produced through the above steps. Here, amorphous polyester resin particles are used as the first amorphous resin particles and the second amorphous resin particles, crystalline polyester resin particles are used as the crystalline resin particles, and styrene-(meth)acrylic copolymer particles are used as the internally crosslinked resin particles. The aggregation-coalescence method will be described as a method for producing toner particles containing a binder resin, a colorant, and a release agent, but the colorant and release agent are components that are contained in the toner particles as needed.

[0110] Each step will be described in detail below.

[0111] -Each dispersion preparation process- First, the various dispersions to be used in the aggregation-coalescence method are prepared. Specifically, a first amorphous resin particle dispersion in which a first amorphous resin serving as a binder resin is dispersed, a crystalline resin particle dispersion in which crystalline resin particles are dispersed, an internally crosslinked resin particle dispersion in which internally crosslinked resin particles are dispersed, a colorant dispersion in which a colorant is dispersed, a second amorphous resin particle dispersion in which second amorphous resin particles serving as a binder resin are dispersed, and a release agent particle dispersion in which release agent particles are dispersed are prepared. In each dispersion preparation step, the first amorphous resin, the second amorphous resin particles, and the crystalline resin particles will be referred to as "resin particles" in the following description.

[0112] Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0113] Examples of the dispersion medium used in the resin particle dispersion include aqueous media. Examples of aqueous media include water such as distilled water and ion-exchanged water, alcohols, etc. These may be used alone or in combination of two or more.

[0114] Examples of surfactants include anionic surfactants such as sulfate ester salts, sulfonate salts, phosphate esters, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly preferred. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. The surfactants may be used alone or in combination of two or more.

[0115] In the resin particle dispersion, resin particles can be dispersed in a dispersion medium by a general dispersion method such as a rotary shear homogenizer, a ball mill having a medium, a sand mill, a dyno mill, etc. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion by, for example, a phase inversion emulsification method. The phase inversion emulsification method involves dissolving the resin to be dispersed in a hydrophobic organic solvent in which the resin is soluble, adding a base to the organic continuous phase (O phase) to neutralize it, and then adding an aqueous medium (W phase), thereby converting the resin from W / O to O / W (so-called phase inversion) and forming a discontinuous phase, and dispersing the resin in particulate form in the aqueous medium.

[0116] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and even more preferably 0.1 μm or more and 0.6 μm or less. The volume average particle size of the resin particles is measured using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (e.g., LA-700 manufactured by Horiba, Ltd.), and the cumulative distribution for the volume of the divided particle size range (channel) is subtracted from the small particle size side, and the particle size at which the cumulative 50% of all particles is measured is defined as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are also measured in the same way.

[0117] The content of resin particles contained in the resin particle dispersion is, for example, preferably from 5% by mass to 50% by mass, and more preferably from 10% by mass to 40% by mass.

[0118] Note that, in the same manner as in the resin particle dispersion, for example, a colorant dispersion, a release agent particle dispersion, and an internally-added crosslinked resin particle dispersion are also prepared. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant dispersed in the colorant dispersion, the release agent particles dispersed in the release agent particle dispersion, and the internally-added crosslinked resin particles dispersed in the internally-added crosslinked resin particle dispersion.

[0119] -First agglomerated particle formation process- Next, the first amorphous resin particle dispersion, the crystalline resin particle dispersion, the internally crosslinked resin particle dispersion, the colorant dispersion, and the release agent particle dispersion are mixed together. Then, in this mixed dispersion, the first amorphous resin, the crystalline resin particles, the internally added crosslinked resin particles, the colorant, and the release agent particles are hetero-aggregated to form first aggregated particles containing the first amorphous resin, the internally added crosslinked resin particles, the colorant, and the release agent particles.

[0120] Specifically, for example, a first amorphous resin particle dispersion, a crystalline resin particle dispersion, an internally crosslinked resin particle dispersion, a colorant dispersion, and a release agent particle dispersion are mixed together, and an aggregating agent is added to the mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, a pH of 2 or more and 5 or less), a dispersion stabilizer is added as needed, and then the temperature is set to a range of 20°C or more and 50°C or less, and the particles dispersed in the mixed dispersion are aggregated to form first aggregated particles. In the first aggregate particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, the aggregating agent may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to an acidic value (e.g., a pH of 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the heating may be carried out.

[0121] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant used as the dispersant added to the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of surfactant used can be reduced and the charging characteristics can be improved. If necessary, an additive that forms a complex or a similar bond with the metal ions of the flocculant may be used, and a chelating agent is preferably used as this additive.

[0122] Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, as well as inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, such as hydroxycarboxylic acid (e.g., tartaric acid, citric acid, gluconic acid), iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), etc. The amount of chelating agent added is, for example, preferably 0.01 to 5.0 parts by mass, more preferably 0.1 to less than 3.0 parts by mass, per 100 parts by mass of resin particles (first resin particles, crystalline resin particles, and internally crosslinked resin particles).

[0123] -Second agglomerated particle formation process- Next, after obtaining the first aggregated particle dispersion liquid in which the first aggregated particles are dispersed, the second amorphous resin particle dispersion liquid in which the second amorphous resin particles are dispersed is added to the first aggregated particle dispersion liquid. The second amorphous resin particles may be of the same type as the first amorphous resin, or may be of a different type.

[0124] Then, in the dispersion of the first aggregated particles and the second amorphous resin particles, the second amorphous resin particles are aggregated on the surfaces of the first aggregated particles. At this time, a release agent particle dispersion may also be added to aggregate the second amorphous resin particles and the release agent particles on the surfaces of the first aggregated particles. Specifically, for example, in the first aggregated particle forming step, when the first aggregated particles reach a target particle size, the second amorphous resin particle dispersion is added to the first aggregated particle dispersion, and the mixture is heated at a temperature equal to or lower than the glass transition temperature of the second amorphous resin particles. Then, the pH of the dispersion is adjusted to, for example, a range of about 6.5 to 8.5, thereby stopping the progress of aggregation. In this manner, the second aggregated particles are obtained by aggregating the first aggregated particles so that the second amorphous resin particles adhere to the surfaces of the first aggregated particles.

[0125] -Fusion / unification process- Next, the second aggregate particle dispersion liquid in which the second aggregate particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the first and second amorphous resin particles (for example, a temperature 10 to 30°C higher than the glass transition temperature of the first and second resin particles) to fuse and coalesce the second aggregate particles and form toner particles.

[0126] Through the above steps, toner particles are obtained. In the above-described aggregation and coalescence method, the first aggregated particles may be fused and coalesced to form toner particles without performing the second aggregated particle forming step. Also, the second aggregated particle forming step may be repeatedly performed multiple times. In the second aggregate particle forming step, a crystalline resin particle dispersion may be used, or an internally crosslinked resin particle dispersion may be used.

[0127] In the toner manufacturing method using the aggregation and coalescence method, to obtain toner particles that satisfy the formula (1), it is preferable to carry out the first aggregate particle forming step as follows, for example. First, a small diameter amorphous resin particle dispersion in which small diameter amorphous resin particles are dispersed and a large diameter amorphous particle dispersion in which large diameter amorphous resin particles are dispersed are prepared as the first amorphous resin particle dispersion. The volume average particle size of the small-diameter amorphous resin particles is, for example, 60 nm or more and 130 nm or less. On the other hand, the volume average particle size of the large-diameter amorphous resin particles is, for example, 150 nm or more and 200 nm or less. The volume average particle size is measured by the same method as the measurement method using the laser diffraction particle size distribution analyzer described above.

[0128] Next, the pH of the small diameter amorphous resin particle dispersion is adjusted to a range of 2 to 5, and the pH of the internally crosslinked resin particle dispersion is adjusted to a range of ±0.5 of the adjusted pH of the small diameter amorphous resin particle dispersion. Next, the dispersion of the small-diameter amorphous resin particles is added dropwise to the dispersion while stirring to obtain a mixed dispersion A1. A flocculant is added to the mixed dispersion A1 to obtain a mixed dispersion A2, which is then kept at 30°C for a certain period of time while stirring.

[0129] Meanwhile, a large diameter amorphous resin particle dispersion, a crystalline resin particle dispersion, a colorant dispersion, and a release agent particle dispersion are mixed to obtain a mixed dispersion B1, and the pH of the mixed dispersion B1 is adjusted to within a range of ±0.5 of the pH of the mixed dispersion A2.

[0130] Next, while stirring the mixed dispersion A2, the mixed dispersion B2 is added dropwise to obtain the mixed dispersion C1. After the addition, the mixed dispersion C1 is heated to increase the temperature, and the aggregates of the small-diameter amorphous resin particles and the internally crosslinked resin particles, the large-diameter amorphous resin particles, the crystalline resin particles, the colorant, and the release agent particles are aggregated to obtain the mixed dispersion C2.

[0131] Then, the mixed dispersion C2 is used to carry out the second aggregation step.

[0132] When each dispersion is added dropwise, it is advisable to set the stirring speed (that is, the stirring blade tip speed) to a low speed to reduce aggregation of unstable particles when mixing each dispersion. It is advisable to slow down the rate at which the flocculant is added to prevent the flocculant concentration from becoming locally high, thereby reducing the aggregation of unstable particles. During aggregation, it is advisable to lower the solid content concentration of each mixed dispersion to reduce the frequency of collisions between particles and to reduce aggregation between unstable particles.

[0133] By carrying out the first aggregation step, it is possible to obtain toner particles that satisfy the above formula (1).

[0134] After the fusion and coalescence process is completed, the toner particles formed in the solution are subjected to a known washing process, solid-liquid separation process, and drying process to obtain dry toner particles. In the washing step, it is preferable to carry out sufficient replacement washing with ion-exchanged water from the viewpoint of electrostatic chargeability. Furthermore, the solid-liquid separation step is not particularly limited, but from the viewpoint of productivity, it is preferable to carry out suction filtration, pressure filtration, etc. Furthermore, in the drying step, there is no particular limitation on the method, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0135] The toner according to this embodiment is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them. The mixing can be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Furthermore, if necessary, coarse particles may be removed from the toner using a vibrating sieve, an air sieve, or the like.

[0136] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner and a carrier mixed therewith.

[0137] The carrier is not particularly limited, and examples thereof include known carriers, such as coated carriers in which the surface of a core material made of magnetic powder is coated with a coating resin, magnetic powder dispersion carriers in which magnetic powder is dispersed and blended in a matrix resin, and resin-impregnated carriers in which porous magnetic powder is impregnated with a resin. The magnetic powder dispersion type carrier and the resin impregnated type carrier may be a carrier in which the constituent particles of the carrier are used as a core material and are coated with a coating resin.

[0138] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0139] Examples of coating resins and matrix resins include styrene-(meth)acrylic acid resins; polyolefin resins such as polyethylene resins and polypropylene resins; polyvinyl or polyvinylidene resins such as polystyrene, (meth)acrylic resins, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; vinyl chloride-vinyl acetate copolymers; straight silicone resins or modified silicone resins consisting of organosiloxane bonds; fluororesins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; polyesters; polyurethanes; polycarbonates; amino resins such as urea-formaldehyde resins; and epoxy resins. The coating resin and the matrix resin preferably contain a (meth)acrylic resin, more preferably contain 50% by mass or more of the (meth)acrylic resin relative to the total mass of the resin, and even more preferably contain 80% by mass or more of the (meth)acrylic resin relative to the total mass of the resin. In particular, the coating resin and the matrix resin preferably contain an alicyclic (meth)acrylic resin as the (meth)acrylic resin. The coating resin and the matrix resin may contain other additives such as conductive particles. Examples of conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0140] Here, the method of coating the surface of the core material with a coating resin includes a method of coating with a solution for forming a coating layer, in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the coating resin to be used, its applicability, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer, a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material, a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air, and a kneader coater method in which the core material of the carrier and the solution for forming a coating layer are mixed in a kneader coater and the solvent is removed.

[0141] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0142] <Image forming device / image forming method> An image forming apparatus and an image forming method according to this embodiment will be described. The image forming apparatus according to the present embodiment includes an image carrier, a charging device that charges the surface of the image carrier, an electrostatic image forming device that forms an electrostatic image on the surface of the charged image carrier, a developing device that contains an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer, a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing device that fixes the toner image transferred to the surface of the recording medium. The electrostatic image developer according to the present embodiment is used as the electrostatic image developer.

[0143] The image forming apparatus according to this embodiment carries out an image forming method (the image forming method according to this embodiment) that includes a charging step of charging the surface of an image carrier, an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier, a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to this embodiment, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0144] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an intermediate transfer type apparatus that primarily transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer medium, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer medium to the surface of a recording medium; an apparatus equipped with a cleaning device that cleans the surface of the image carrier after the transfer of the toner image but before charging; and an apparatus equipped with a static elimination device that irradiates the surface of the image carrier with static elimination light to eliminate static after the transfer of the toner image but before charging. In the case of an intermediate transfer type device, the transfer device is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer device that performs primary transfer of the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer device that performs secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

[0145] In the image forming apparatus according to the present embodiment, for example, the portion including the developing device may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with a developing device that accommodates the electrostatic image developer according to the present embodiment is preferably used.

[0146] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0147] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Fig. 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K that output images in the colors yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side horizontally spaced a predetermined distance apart from one another. Note that these units 10Y, 10M, 10C, and 10K may also be process cartridges that are detachable from the image forming apparatus.

[0148] Above each of the units 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are spaced apart from each other and arranged from left to right in the drawing, and is configured to run in a direction from the first unit 10Y to the fourth unit 10K. Note that a force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), thereby applying tension to the intermediate transfer belt 20 wound around them. In addition, an intermediate transfer body cleaning device 30 is provided on the outer circumferential surface of the intermediate transfer belt 20, facing the drive roll 22. In addition, the developing devices (examples of developing devices) 4Y, 4M, 4C, and 4K of each unit 10Y, 10M, 10C, and 10K are each supplied with toner including four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0149] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit 10Y, which forms a yellow image and is disposed upstream in the direction of travel of the intermediate transfer belt, will be described here as a representative. Note that parts equivalent to those of the first unit 10Y are given reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y), and descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0150] The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there are arranged in this order: a charging roll (an example of a charging device) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming device) 3 that exposes the charged surface to a laser beam 3Y based on a color-separated image signal to form an electrostatic image; a developing device (an example of a developing device) 4Y that supplies charged toner to the electrostatic image to develop it; a primary transfer roll (an example of a primary transfer device) 5Y that transfers the developed toner image onto the intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning device) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, a bias power supply (not shown) that applies a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0151] The operation of forming a yellow image in first unit 10Y will be described below. First, prior to operation, the surface of the photosensitive member 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has conductivity (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistivity of Ωcm or less. This photosensitive layer normally has a high resistance (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the irradiated portion changes. Therefore, a laser beam 3Y is output to the charged surface of the photosensitive element 1Y via an exposure device 3 in accordance with image data for yellow sent from a control unit (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photosensitive element 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 1Y.

[0152] An electrostatic image is an image formed on the surface of the photosensitive element 1Y by charging it; the laser beam 3Y reduces the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photosensitive element 1Y to flow, while the charges remain in the portions not irradiated by the laser beam 3Y, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0153] The developing device 4Y contains an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally charged by stirring inside the developing device 4Y and is held on a developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The photoreceptor 1Y with the yellow toner image formed thereon continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0154] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y to the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the (-) polarity of the toner, and in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

[0155] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit 10M and subsequent units is also controlled in accordance with the first unit. In this way, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is conveyed sequentially through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are transferred onto the intermediate transfer belt 20 in a superimposed manner.

[0156] The intermediate transfer belt 20, onto which the four-color toner images have been multiplex-transferred through the first to fourth units, reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer device) 26 arranged on the outer circumferential surface of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a feed mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a negative polarity, the same as the negative polarity of the toner. Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection device (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0157] Thereafter, the recording paper P is sent to the pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of a fixing device) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0158] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, examples of the recording medium include overhead projector sheets and the like. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of plain paper is coated with resin or the like, or art paper for printing, is preferably used.

[0159] The recording paper P on which the color image has been fixed is conveyed toward the discharge section, and the series of color image forming operations is completed.

[0160] <Process cartridges / toner cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that is detachably attached to an image forming apparatus and that contains the electrostatic image developer according to this embodiment and is equipped with a developing device that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

[0161] The process cartridge according to this embodiment is not limited to the above configuration, but may also be configured to include a developing device and, if necessary, at least one other device selected from an image carrier, a charging device, an electrostatic image forming device, and a transfer device.

[0162] An example of a process cartridge according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0163] FIG. 2 is a schematic diagram showing the configuration of the process cartridge according to the present embodiment. The process cartridge 200 shown in FIG. 2 is configured to integrally combine and hold a photosensitive member 107 (an example of an image carrier), a charging roll 108 (an example of a charging device) provided around the photosensitive member 107, a developing device 111 (an example of a developing device), and a photosensitive member cleaning device 113 (an example of a cleaning device), which are held by a housing 117 having, for example, a mounting rail 116 and an opening 118 for exposure, and is formed into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming device), 112 denotes a transfer device (an example of a transfer device), 115 denotes a fixing device (an example of a fixing device), and 300 denotes recording paper (an example of a recording medium).

[0164] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge contains replenishment toner to be supplied to a developing device provided in the image forming apparatus.

[0165] 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced. [Example]

[0166] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass.

[0167] [Preparation of emulsions (1-1) to (1-4)] <Emulsion (1-1)> Styrene: 40 parts n-Butyl acrylate: 58.5 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials are placed in a mixing vessel equipped with a stirrer and stirred to prepare emulsion (1-1). Prepared.

[0168] <Emulsion (1-2)> Styrene: 45 parts n-Butyl acrylate: 53.5 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (1-2).

[0169] <Emulsion (1-3)> Styrene: 55 parts n-Butyl acrylate: 43.5 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (1-3).

[0170] <Emulsion (1-4)> Styrene: 60 parts n-Butyl acrylate: 38.5 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (1-4).

[0171] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (1)] A reaction vessel equipped with a stirrer and a nitrogen inlet tube was purged with nitrogen, and then 1.1 parts of anionic surfactant (Eleminol MON-2) and 400 parts of ion-exchanged water were added. The reaction solution was heated in an oil bath with stirring until the temperature of the reaction solution reached 75°C. 10 parts of emulsion (1-1) were added, followed by 20 parts of an aqueous ammonium persulfate solution adjusted to a concentration of 10% by mass, and the mixture was maintained for 30 minutes. Thereafter, while maintaining the temperature of the reaction solution at 75°C, 190 parts of emulsion (1-1) was gradually added dropwise to the reaction vessel over 30 minutes using a pump. 200 parts of emulsion (1-2) were then added dropwise over 30 minutes. Subsequently, 200 parts of emulsion (1-3) were added dropwise over 40 minutes, and 200 parts of emulsion (1-4) were then added dropwise over 40 minutes. After the dropwise addition, the mixture was held for 60 minutes, and then 2 parts of 10% by mass ammonium persulfate was added, and the mixture was held for another 3 hours, and then cooled to room temperature. Ion-exchanged water and nitric acid were then added to the mixture so that the solid content became 20% by mass, to obtain an internally-added crosslinked resin particle dispersion (1). The resulting resin particles had a volume average particle size of 165 nm and a glass transition temperature of 17°C as measured by a differential scanning calorimeter.

[0172] [Preparation of emulsions (2-1) to (2-4)] <Emulsion (2-1)> Styrene: 40 parts n-Butyl acrylate: 59.7 parts 1,10-decanediol diacrylate: 0.32 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (2-1). <Emulsion (2-2)> Styrene: 45 parts n-Butyl acrylate: 54.7 parts 1,10-decanediol diacrylate: 0.32 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (2-2). <Emulsion (2-3)> Styrene: 55 parts n-Butyl acrylate: 44.7 parts 1,10-decanediol diacrylate: 0.32 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (2-3). <Emulsion (2-4)> Styrene: 60 parts n-Butyl acrylate: 39.7 parts 1,10-decanediol diacrylate: 0.32 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (2-4).

[0173] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (2)] A reaction vessel equipped with a stirrer and a nitrogen inlet tube was purged with nitrogen, and then 1.1 parts of anionic surfactant (Eleminol MON-2) and 400 parts of ion-exchanged water were added. The reaction solution was heated in an oil bath with stirring until the temperature of the reaction solution reached 75°C. 10 parts of emulsion (2-1) were added, followed by 60 parts of an aqueous ammonium persulfate solution adjusted to a concentration of 10% by mass, and the mixture was maintained for 30 minutes. Thereafter, while maintaining the temperature of the reaction solution at 75°C, 190 parts of emulsion (2-1) was gradually added dropwise to the reaction vessel over 30 minutes using a pump. 200 parts of emulsion (2-2) were then added dropwise over 30 minutes. Subsequently, 200 parts of emulsion (2-3) were added dropwise over 40 minutes, and 200 parts of emulsion (2-4) were then added dropwise over 40 minutes. After the dropwise addition, the mixture was held for 60 minutes, and then 6 parts of 10% by mass ammonium persulfate was added, and the mixture was held for another 3 hours, and then cooled to room temperature. Thereafter, ion-exchanged water and nitric acid were added to the mixture so that the solid content became 20% by mass, to obtain an internally-added crosslinked resin particle dispersion (2). The resulting resin particles had a volume average particle size of 166 nm and a glass transition temperature of 13°C as measured by a differential scanning calorimeter.

[0174] [Preparation of emulsions (3-1 to 3-4)] <Emulsion (3-1)> Styrene: 55.9 parts n-Butyl acrylate: 42.6 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (3-1). <Emulsion (3-2)> Styrene: 62.9 parts n-Butyl acrylate: 35.6 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (3-2). <Emulsion (3-3)> Styrene: 76.9 parts n-Butyl acrylate: 21.6 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (3-3). <Emulsion (3-4)> Styrene: 83.9 parts n-Butyl acrylate: 14.6 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (3-4).

[0175] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (3)] Internally-added crosslinked resin particle dispersion liquid (3) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion liquid (1), except that emulsion (1-1) was changed to emulsion (3-1), emulsion (1-2) to emulsion (3-2), emulsion (1-3) to emulsion (3-3), and emulsion (1-4) to emulsion (3-4). The resulting resin particles had a volume average particle size of 164 nm and a glass transition temperature of 51°C as measured by a differential scanning calorimeter.

[0176] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (4)] Internally-added crosslinked resin particle dispersion (4) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2) was changed from 1.2 parts to 4.4 parts. The resulting resin particles had a volume average particle size of 100 nm and a glass transition temperature of 18°C ​​as measured by a differential scanning calorimeter.

[0177] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (5)] Internally-added crosslinked resin particle dispersion (5) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2) was changed from 1.2 parts to 2.7 parts. The resulting resin particles had a volume average particle size of 120 nm and a glass transition temperature of 18°C ​​as measured by a differential scanning calorimeter.

[0178] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (6)] Internally-added crosslinked resin particle dispersion (6) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2) was changed from 1.2 parts to 0.34 parts. The resulting resin particles had a volume average particle size of 250 nm and a glass transition temperature of 18°C ​​as measured by a differential scanning calorimeter.

[0179] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (7)] Internally-added crosslinked resin particle dispersion (7) was prepared in the same manner as in preparing internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2): was changed from 1.2 parts to 0.20 parts. The resulting resin particles had a volume average particle size of 300 nm and a glass transition temperature of 18°C ​​as measured by a differential scanning calorimeter.

[0180] [Preparation of emulsions (8-1) to (8-4)] <Emulsion (8-1)> Styrene: 40 parts n-Butyl acrylate: 60 parts 1,10-decanediol diacrylate: 0.05 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (8-1). <Emulsion (8-2)> Styrene: 45 parts n-Butyl acrylate: 55 parts 1,10-decanediol diacrylate: 0.05 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (8-2). <Emulsion (8-3)> Styrene: 55 parts n-Butyl acrylate: 45 parts 1,10-decanediol diacrylate: 0.05 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (8-3). <Emulsion (8-4)> Styrene: 60 parts n-Butyl acrylate: 40 parts 1,10-decanediol diacrylate: 0.05 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (8-4).

[0181] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (8)] In preparing the dispersion liquid of the internally added crosslinked resin particles (1), the emulsion ( 1-1) into emulsion (8-1), emulsion (1-2) into emulsion (8-2), and emulsion (1- The same except that 3) was changed to emulsion (8-3) and emulsion (1-4) was changed to emulsion (8-4). This gave an internal crosslinked resin particle dispersion (8). The volume average particle size of the resulting resin particles was 167 nm, and the glass transition temperature measured by a differential scanning calorimeter was 8°C.

[0182] [Preparation of emulsions (9-1) to (9-4)] <Emulsion (9-1)> Styrene: 60.3 parts n-Butyl acrylate: 38.2 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (9-1). <Emulsion (9-2)> Styrene: 67.8 parts n-Butyl acrylate: 30.7 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (9-2). <Emulsion (9-3)> Styrene: 82.9 parts n-Butyl acrylate: 15.6 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (9-3). <Emulsion (9-4)> Styrene: 90.4 parts n-Butyl acrylate: 8.1 parts 1,10-decanediol diacrylate: 1.5 parts Anionic surfactant (Eleminol MON-2, manufactured by Sanyo Chemical Industries, Ltd.): 1.2 parts Ion-exchanged water: 98.8 parts The above materials were placed in a mixing vessel equipped with a stirrer and stirred to prepare an emulsion (9-4).

[0183] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (9)] An internally-added crosslinked resin particle dispersion (9) was prepared in the same manner as in the preparation of the internally-added crosslinked resin particle dispersion (1), except that emulsion (1-1) was changed to emulsion (9-1), emulsion (1-2) to emulsion (9-2), emulsion (1-3) to emulsion (9-3), and emulsion (1-4) to emulsion (9-4). The resulting resin particles had a volume average particle size of 166 nm and a glass transition temperature of 60°C as measured by a differential scanning calorimeter.

[0184] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (10)] Internally-added crosslinked resin particle dispersion (10) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2): was changed from 1.2 parts to 5.98 parts. The resulting resin particles had a volume average particle size of 90 nm and a glass transition temperature of 18°C ​​as measured by a differential scanning calorimeter.

[0185] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (11)] Internally-added crosslinked resin particle dispersion (11) was prepared in the same manner as in the preparation of internally-added crosslinked resin particle dispersion (1), except that the amount of anionic surfactant (Eleminol MON-2): was changed from 1.2 parts to 0.17 parts. The resulting resin particles had a volume average particle size of 320 nm and a glass transition temperature of 14°C as measured by a differential scanning calorimeter.

[0186] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (C6)] Styrene 47.9 parts n-Butyl acrylate 51.8 parts 2-carboxyethyl acrylate 0.3 parts Anionic surfactant (Dowfax2A1, manufactured by The Dow Chemical Company) 0.8 parts 1,10-decanediol diacrylate 1.65 parts The above raw materials were mixed and dissolved, and 60 parts of ion-exchanged water was added thereto, followed by dispersion and emulsification in a flask to prepare an emulsion. Next, 1.3 parts of an anionic surfactant (Dowfax2A1, manufactured by The Dow Chemical Company) was dissolved in 90 parts of ion-exchanged water, and 1 part of the emulsion was added thereto. Further, 10 parts of ion-exchanged water in which 5.4 parts of ammonium persulfate had been dissolved was added. Thereafter, the remainder of the emulsion was added over 180 minutes, and the atmosphere in the flask was replaced with nitrogen. The solution in the flask was then heated to 65°C in an oil bath while stirring, and emulsion polymerization was continued for 500 minutes, after which an internally added crosslinked resin particle dispersion C6 was obtained, with the solid content adjusted to 24.5% by mass. The volume average particle size of the resulting resin particles was 165 nm, and the glass transition temperature measured by differential scanning calorimetry was 14°C.

[0187] [Preparation of amorphous polyester resin particle dispersion (1-1)] Terephthalic acid: 28 molar parts Isophthalic acid: 15 molar parts Adipic acid: 5 mole parts Trimellitic anhydride: 2 molar parts Bisphenol A propylene oxide 2 mole adduct: 50 mole parts The above materials were charged into a reaction vessel equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a distillation column, and the temperature was raised to 190°C over 1 hour, followed by adding 1.2 parts of dibutyltin oxide per 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the generated water, and then the temperature was maintained at 240°C for 3 hours to continue the dehydration condensation reaction, followed by cooling to obtain amorphous polyester resin (1).

[0188] The acid value of the amorphous polyester resin (1) was 10.5 and the glass transition temperature was 59.0°C. Amorphous polyester resin (1): 100 parts Methyl ethyl ketone: 60 parts Isopropanol: 10 parts 10% ammonia solution: 3.5 parts The above materials were charged into a jacketed reaction vessel equipped with a condenser, a thermometer, a water dropping device, and an anchor blade, and the amorphous polyester resin (1) was dissolved in a water-circulating thermostatic bath while stirring and mixing at 100 rpm while maintaining the liquid temperature at 50° C. Next, the water-circulating thermostatic bath was set to 40° C., and a total of 300 parts of ion-exchanged water maintained at 40° C. was added dropwise at a rate of 3 parts / min to cause phase inversion and produce an emulsion. The resulting emulsion was placed in a recovery flask and set in an evaporator equipped with a vacuum control unit via a trap bulb. The recovery flask was rotated and heated in a 60°C hot water bath, and the pressure was reduced to 7 kPa while taking care to prevent bumping, to remove the solvent. The pressure was then returned to normal pressure, and the recovery flask was water-cooled to obtain a dispersion. Ion-exchange water was added to the resulting dispersion to obtain an amorphous polyester resin particle dispersion (1) with a solids content of 20% by mass. The volume average particle size of the amorphous polyester resin particles in the amorphous polyester resin particle dispersion (1) was 180 nm.

[0189] [Preparation of amorphous polyester resin particle dispersion (1-2)] Amorphous polyester resin dispersion (1-2) was obtained in the same manner as in preparing amorphous polyester resin dispersion (1-1), except that the amount of methyl ethyl ketone was changed from 60 parts to 120 parts and the amount of isopropanol was changed from 10 parts to 20 parts. The volume average particle size of the amorphous polyester resin particles in amorphous polyester resin dispersion (1-2) was 80 nm.

[0190] [Preparation of amorphous polyester resin particle dispersion (2-1)] Bisphenol A ethylene oxide 2.2 mole adduct: 40 mole parts Bisphenol A propylene oxide 2.2 mole adduct: 60 mole parts Dimethyl terephthalate: 60 parts by mole Dimethyl fumarate: 15 parts by mole Dodecenyl succinic anhydride: 20 parts by mole Trimellitic anhydride: 5 mole parts A reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with the above monomers other than fumaric acid and trimellitic anhydride, and 0.25 parts of tin dioctanoate per 100 parts of the total monomers. After reacting for 6 hours at 235°C under a nitrogen gas stream, the temperature was lowered to 200°C, and fumaric acid and trimellitic anhydride were added and reacted for 1 hour. The temperature was then raised to 220°C over 5 hours, and polymerization was continued under a pressure of 10 kPa until the desired molecular weight was reached. The mixture was then cooled to obtain amorphous polyester (2).

[0191] Amorphous polyester resin (2): 100 parts Methyl ethyl ketone: 60 parts Isopropanol: 10 parts 10% ammonia solution: 3.5 parts The above materials were charged into a jacketed reaction vessel equipped with a condenser, a thermometer, a water dropping device, and an anchor blade, and the amorphous polyester resin (1) was dissolved in a water-circulating thermostatic bath while stirring and mixing at 100 rpm while maintaining the liquid temperature at 50° C. Next, the water-circulating thermostatic bath was set to 40° C., and a total of 300 parts of ion-exchanged water maintained at 40° C. was added dropwise at a rate of 3 parts / min to cause phase inversion and produce an emulsion. The resulting emulsion was placed in a recovery flask and placed in an evaporator equipped with a vacuum control unit via a trap bulb. The recovery flask was rotated and heated in a 60°C hot water bath. While taking care to prevent bumping, the pressure was reduced to 7 kPa to remove the solvent, and the pressure was then returned to normal pressure. The recovery flask was then cooled with water to obtain a dispersion. Ion-exchange water was added to the resulting dispersion to obtain an amorphous polyester resin particle dispersion (2-1) with a solids content of 20% by mass. The volume average particle size of the amorphous polyester resin particles in the amorphous polyester resin particle dispersion (2-1) was 185 nm.

[0192] [Preparation of amorphous polyester resin particle dispersion (2-2)] Amorphous polyester resin dispersion (2-2) was obtained in the same manner as in preparation of amorphous polyester resin dispersion (2-1), except that the amount of methyl ethyl ketone was changed from 60 parts to 120 parts and the amount of isopropanol was changed from 10 parts to 20 parts. The volume average particle size of the amorphous polyester resin particles in amorphous polyester resin dispersion (2-2) was 84 nm.

[0193] <Preparation of amorphous polyester resin dispersion (C6)> Terephthalic acid 28 parts Fumaric acid 164 parts 10 parts adipic acid Bisphenol A ethylene oxide 2 mole adduct 26 parts Bisphenol A propylene oxide 2 mole adduct 542 parts The above materials were charged into a reaction vessel equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a rectification column, the temperature was raised to 190°C over 1 hour, and 1.2 parts of dibutyltin oxide was added per 100 parts of the above materials. The temperature was raised to 240°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 3 hours while maintaining the temperature at 240°C, after which the reaction product was cooled.

[0194] The reaction product was transferred to a Cavitron CD1010 (Eurotech) in a molten state at a rate of 100 g / min. Simultaneously, a 0.37% by mass aqueous ammonia solution was heated to 120°C in a heat exchanger and transferred to the Cavitron CD1010 at a rate of 0.1 L / min. The Cavitron CD1010 was operated at a rotor speed of 60 Hz and a pressure of 5 kg / cm2 to obtain a resin particle dispersion containing amorphous polyester resin particles with a volume average particle size of 169 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solids content to 20% by mass, resulting in amorphous polyester resin particle dispersion (C6).

[0195] [Preparation of Crystalline Polyester Resin Particle Dispersion (1)] Dodecanedioic acid: 50 parts by mole 1,6-Hexanediol: 50 parts by mole The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts of dibutyltin oxide was added per 100 parts of the above materials. The temperature was raised to 180°C over 6 hours while distilling off the generated water, and the mixture was stirred for 5 hours while maintaining at 180°C and refluxed to allow the reaction to proceed. The temperature was then gradually raised to 230°C under reduced pressure (3 kPa), and the mixture was stirred for 2 hours while maintaining at 230°C. The reaction mixture was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain crystalline polyester resin (1). The weight-average molecular weight of crystalline polyester resin (1) was 29,000.

[0196] Crystalline polyester resin (1): 100 parts Methyl ethyl ketone: 70 parts Isopropanol: 12 parts 10% ammonia solution: 3 parts The above materials were charged into a jacketed reaction vessel equipped with a condenser, thermometer, water dropping device, and anchor blades, and the resin was dissolved by stirring and mixing at 100 rpm while maintaining the liquid temperature at 80°C in a water-circulating thermostatic bath. Next, the water-circulating thermostatic bath was set to 60°C, and a total of 300 parts of ion-exchanged water maintained at 60°C was added dropwise at a rate of 3 parts / min to cause phase inversion, yielding an emulsion. The resulting emulsion was placed in a recovery flask and set in an evaporator equipped with a vacuum control unit via a trap bulb. The recovery flask was rotated and heated in a 60°C hot water bath, and the pressure was reduced to 7 kPa while taking care to prevent bumping, to remove the solvent. The pressure was then returned to normal pressure, and the recovery flask was water-cooled to obtain a dispersion. Ion-exchange water was added to the dispersion to obtain a crystalline polyester resin particle dispersion (1) with a solids content of 20%. The volume average particle size of the resin particles in the crystalline polyester resin particle dispersion (1) was 160 nm.

[0197] [Preparation of crystalline polyester resin particle dispersion (C6)] 1,10-dodecanedioic acid: 225 parts 1,6-Hexanediol: 143 parts The above materials were charged into a reaction vessel equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column. The temperature was raised to 160°C over 1 hour, and 0.8 parts by mass of dibutyltin oxide was added. The temperature was raised to 180°C over 6 hours while distilling off the produced water, and the dehydration condensation reaction was continued for 5 hours while maintaining the temperature at 180°C. The temperature was then gradually raised to 230°C under reduced pressure, and stirring was continued for 2 hours while maintaining the temperature at 230°C. The reaction product was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain crystalline polyester resin (C6).

[0198] Crystalline polyester resin (C6) 100 parts 40 parts methyl ethyl ketone 30 parts isopropyl alcohol 6 parts 10% aqueous ammonia solution The above materials were added to a 3-liter jacketed reactor (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dripper, and anchor blade. The resin was dissolved by stirring at 100 rpm while maintaining the temperature at 80°C in a water-circulating thermostatic bath. The water-circulating thermostatic bath was then set to 50°C, and a total of 400 parts of ion-exchanged water maintained at 50°C was added dropwise at a rate of 7 parts by mass / min to induce phase inversion, yielding an emulsion. 576 parts by mass of the resulting emulsion and 500 parts by mass of ion-exchanged water were placed in a 2-liter recovery flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. The recovery flask was heated in a 60°C hot water bath while rotating, and the pressure was reduced to 7 kPa, taking care to avoid bumping, to remove the solvent. The volume average particle size (D50v) of the resin particles in this dispersion was 185 nm. Thereafter, ion-exchanged water was added to obtain a crystalline polyester resin particle dispersion (C6) with a solid content concentration of 22.1% by mass.

[0199] [Preparation of Colorant Dispersion (1)] Cyan pigment (Pigment Blue 15:3 (copper phthalocyanine), manufactured by Dainichi Seika Chemicals): 98 parts Anionic surfactant (Tayca Power manufactured by Tayca Corporation) 2 parts Ion-exchanged water: 400 parts The above components were mixed and then dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA Corporation) to obtain a colorant dispersion (1) having a volume average particle size of 164 nm and a solid content of 20%.

[0200] [Preparation of Colorant Dispersion (2)] Carbon black (Regal 330, manufactured by Cabot Corporation): 98 parts Anionic surfactant (Neopelex G-65, manufactured by Kao): 2 parts Ion-exchanged water: 400 parts The above components were mixed and then dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA Corporation) to obtain a colorant dispersion (2) having a volume average particle size of 180 nm and a solid content concentration of 20%.

[0201] [Preparation of release agent dispersion (1)] Synthetic wax (FT100, manufactured by Nippon Seiro): 100 parts Anionic surfactant (Neopelex G-65, manufactured by Kao): 5 parts Ion-exchanged water: 300 parts After mixing the above components, the mixture was heated to 100°C and dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA). The mixture was further dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin), and ion-exchanged water was added to the dispersion to obtain a release agent dispersion (1) with a solid content of 20%. The volume average particle size of the release agent particles in the release agent dispersion (1) was 230 nm.

[0202] [Preparation of release agent dispersion (2)] Synthetic wax (Nippon Seiro Co., Ltd., FNP92, melting temperature Tw: 92°C): 50 parts Anionic surfactant (Tayca Power manufactured by Tayca Corporation): 1 part Ion-exchanged water: 200 parts The above materials were mixed and heated to 130°C, dispersed using a homogenizer (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent dispersion (2) (solid content 20% by mass) in which release agent particles were dispersed. The volume average particle size of the release agent particles was 214 nm.

[0203] [Example 1] (Preparation of Toner 1) Amorphous polyester resin particle dispersion (1-2) (solid content 20% by mass): 255 parts 720 parts ion-exchanged water The above materials were placed in a reaction vessel 1 equipped with a thermometer, a pH meter and a stirrer, and while maintaining the temperature at 20°C and stirring at 35 rpm, a 0.3N aqueous nitric acid solution was added to adjust the pH to 4.5. Next, 150 parts of the internal crosslinked resin particle dispersion (1) (solid content 20% by mass) was placed in a vessel equipped with a stirrer and stirring blades, and a 0.3N aqueous nitric acid solution was added with stirring to adjust the pH to 4.5. Next, while the reaction vessel 1 was kept at 20° C. and stirred at a rotation speed of 35 rpm, the pH-adjusted internal crosslinked resin particle dispersion (1) was added dropwise at a rate of 7 g / min. Next, a 2% aqueous aluminum sulfate solution was added while dispersing with a homogenizer (Ultra Turrax T50), and then the temperature was raised to 30°C at a rate of 0.4°C / min while stirring and maintained at that temperature.

[0204] Next, the following materials were placed in a container equipped with a stirrer and stirring blades, and a 0.3N aqueous nitric acid solution was added with stirring to adjust the pH to 4.5, thereby preparing a material mixture. 255 parts of amorphous polyester resin particle dispersion (1-1) (solid content 20% by mass) ·Crystalline polyester fat and oil particle dispersion (1) (solid content 20% by mass) 233 parts Colorant dispersion (1) (solid content 20% by mass) 104 parts 83 parts of release agent dispersion (1) (solid content 20% by mass)

[0205] Next, the material mixture liquid adjusted to pH 4.5 was added dropwise to the reaction vessel 1 kept at 30°C at a rate of 7 g / min. Next, the temperature of the reaction vessel 1 was raised to 45°C at a rate of 0.4°C / min while stirring, and maintained at that temperature for 30 minutes. Next, 420 parts of the amorphous polyester resin particle dispersion (1-1) was added and maintained for 30 minutes. Next, a 0.1 N aqueous solution of sodium hydroxide was added to adjust the pH to 8.5 and maintained for 15 minutes. Then, with continued stirring, the temperature was raised to 80°C at a rate of 1°C / min and maintained at 80°C for 5 hours. Next, the mixture was cooled, solid-liquid separated, and the solid matter was washed with ion-exchanged water, and then dried for 24 hours in a vacuum freeze dryer to obtain toner particles (1) having a volume average particle size of 5.5 μm. Then, 100 parts of the toner particles (1) and 2.0 parts of hydrophobic silica (manufactured by Nippon Aerosil: trade name RY200) were mixed in a Henschel mixer to obtain toner (1).

[0206] [Examples 2 to 25 and Comparative Examples 1 to 6] (Preparation of Toners 2 to 25 and Toners C1 to C4) Toners 2 to 25 and toners C1 to C4 were obtained in the same manner as in the preparation of toner 1, except that the types and amounts of the resin particle dispersions were changed as shown in Table 1.

[0207] (Production of Toner C5) Amorphous polyester resin dispersion (1-1): 511 parts Crystalline polyester dispersion (1): 233 parts Colorant dispersion (1): 104 parts Release agent dispersion (1): 83 parts ·Internally added crosslinked resin particle dispersion (1): 150 parts 720 parts ion-exchanged water The above materials were placed in a reaction vessel equipped with a thermometer, pH meter, and stirrer, and the temperature of the reaction vessel was maintained at 20°C while stirring at 150 rpm for 30 minutes. A 0.3N aqueous nitric acid solution was added to adjust the pH to 5.0, and then a 2% aqueous aluminum sulfate solution was added while dispersing using a homogenizer (Ultra-Turrax T50). The mixture was then heated to 45°C at a rate of 0.4°C / min while stirring, and maintained at this temperature for 30 minutes. Next, 420 parts of amorphous polyester resin particle dispersion (1-1) was added and held for 30 minutes. Next, 0.1N aqueous sodium hydroxide solution was added to adjust the pH to 8.5 and held for 15 minutes, after which the temperature was raised to 80°C at a rate of 1°C / min while continuing to stir, and held at 80°C for 5 hours. Next, the mixture was cooled, solid-liquid separated, the solid matter was washed with ion-exchanged water, and then dried in a vacuum freeze dryer for 24 hours to obtain toner particles (C5) with a volume average particle size of 5.5 μm. 100 parts of the toner particles (C5) and 2.0 parts of hydrophobic silica (manufactured by Nippon Aerosil: trade name RY200) were mixed in a Henschel mixer to obtain toner C5.

[0208] (Production of Toner C6) Amorphous polyester resin particle dispersion (C6): 169 parts ·Internally added crosslinked resin particle dispersion (C6): 33 parts Crystalline polyester resin particle dispersion (C6): 53 parts Release agent dispersion (2): 25 parts Colorant dispersion (1): 34.8 parts Anionic surfactant (Dowfax2A1, manufactured by The Dow Chemical Company): 4.8 parts The above materials, adjusted to a liquid temperature of 10°C, were placed in a 3 L cylindrical stainless steel container and dispersed and mixed for 2 minutes using a homogenizer (IKA Ultra Turrax T50) at 4000 rpm while applying shear force. Next, 1.75 parts of a 10% aqueous solution of aluminum sulfate in nitric acid as a flocculant was gradually added dropwise, and the homogenizer was rotated at 10,000 rpm for 10 minutes to disperse and mix, thereby obtaining a raw material dispersion. The raw material dispersion was then transferred to a polymerization kettle equipped with a stirrer using two paddle stirrers and a thermometer, and the stirring speed was set to 550 rpm and heating was started using a mantle heater to promote the growth of aggregated particles at 40°C. The pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 using 0.3 M nitric acid and 1 M aqueous sodium hydroxide. The pH was maintained within this range for approximately 2 hours to form aggregated particles. Next, a dispersion of 21 parts of the amorphous polyester resin particle dispersion (C6) and 8 parts of the internally added crosslinked resin particle dispersion (C6) was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles and the internally added crosslinked resin particles (C6) to adhere to the surfaces of the aggregated particles. The temperature was further increased to 53°C, and then 21 parts of the amorphous polyester resin particle dispersion (C6) was added, and the mixture was maintained for 60 minutes, allowing the binder resin particles to adhere to the surfaces of the aggregated particles. The aggregated particles were adjusted while checking the particle size and shape using an optical microscope and a Multisizer 3. Thereafter, the pH was adjusted to 7.8 using a 5% aqueous sodium hydroxide solution, and the mixture was maintained for 15 minutes. The pH was then increased to 8.0 to fuse the aggregated particles, and the temperature was then raised to 85°C. After confirming that the aggregated particles had fused using an optical microscope, heating was stopped after 2 hours, and the mixture was cooled at a rate of 1.0°C / min. The mixture was then sieved through a 20 μm mesh, washed repeatedly with water, and dried in a vacuum dryer to obtain toner particles (C6) with a volume average particle size of 5.3 μm. Then, 100 parts of the toner particles (C6) and 2.0 parts of hydrophobic silica (manufactured by Nippon Aerosil: trade name RY200) were mixed in a Henschel mixer to obtain toner C6.

[0209] The following items are shown for the toners obtained in Examples 1 to 25 and Comparative Examples 1 to 6. The methods for measuring the properties of the toners are as described above. ·slopeF(16) Crystalline polyester resin content relative to crystalline resin Content of crystalline polyester resin in toner particles Wc Content of internally added crosslinked resin particles in toner particles Ws Storage modulus G' of internally crosslinked resin particles (styrene-(meth)acrylic copolymer particles: StAc particles) in the range of 60°C to 100°C Average dispersion diameter of internally added cross-linked resin particles - When observing the cross section of a toner particle, the area ratio of the internally added cross-linked resin particles to the cross section of the toner particle Dielectric loss factor at 1 kHz for toner after being left at a temperature of 28°C and a relative humidity of 85%

[0210] [evaluation] (Preparation of developer) Developers were obtained by mixing 8 parts of each toner obtained in each example with 92 parts of the following carrier, and the obtained developers were used in the evaluations described below. (Creating the carrier) Ferrite particles (average particle size 35 μm): 100 parts Toluene: 14 parts Styrene / methyl methacrylate copolymer (copolymerization ratio 15 / 85): 3 parts Carbon black: 0.2 parts The above components except for the ferrite particles were dispersed in a sand mill to prepare a dispersion, and this dispersion was placed in a vacuum degassing kneader together with the ferrite particles, and the mixture was dried under reduced pressure while stirring to obtain a carrier.

[0211] (low temperature fixability) The developer obtained was filled into the developing unit of a color copier Apeos C6570 (manufactured by Fujifilm Business Innovation Co., Ltd.) from which the fixing unit had been removed, and the toner loading amount was 9.0 g / cm 2 An unfixed image was output after adjusting the image density to be as follows. Colotech 90 paper (manufactured by Xerox / basis weight 90 gsm) was used as the recording medium. The output image was a 50 mm x 50 mm image with an image density of 100%. The unfixed image was then fixed using a fixing evaluation device to evaluate low-temperature fixability. The fixing device used was an Apeos C6570 manufactured by Fujifilm Business Innovation Co., Ltd., with the fixing unit removed and modified so that the fixing temperature could be changed. The fixing temperature was raised from 120°C to 190°C in 5°C increments, and the temperature at which image defects due to offset (a phenomenon in which toner is excessively insufficiently melted and adheres to the fixing member) no longer occurred was defined as the lowest fixing temperature, and low-temperature fixability was evaluated according to the following criteria. A rating of C or lower was considered acceptable. A: Minimum fixing temperature is 145°C or less B: Minimum fixing temperature is over 145°C and below 155°C C: Minimum fixing temperature is over 155℃ and below 165℃ D: Minimum fixing temperature is 165°C or higher

[0212] (Uneven transfer in high temperature and humidity environments) Each of the prepared developers was filled into a developer container of a modified color copying machine ApeosPort-VC5585 (manufactured by Fujifilm Business Innovation Co., Ltd.) as an apparatus for image evaluation. Images were formed using an image evaluation device with the fixing temperature set at 15°C above the minimum fixing temperature. Specifically, 100,000 images with 1% image density were continuously printed on C2 paper (A4 size) at a temperature of 28°C and a relative humidity of 85%. The paper was then left in the tray for 24 hours under the same conditions, and then, first thing in the morning, 10 full-page halftone images with 80% image density were printed on C2 paper (A4 size). The density of the image printed on the 10th sheet was measured at 10 random points using an X-Rite 938 image densitometer (manufactured by X-Rite). The image density difference, which is the difference between the maximum and minimum values, was determined, and the image density unevenness was evaluated according to the following criteria. A rating of C or lower was considered acceptable. A+: Image density difference is 1% or less A: Image density difference is 5% or less B: Image density difference is more than 5% and less than 8% C: Image density difference is more than 8% and less than 10% D: Image density difference exceeds 10%

[0213] [Table 1-1]

[0214] [Table 1-2]

[0215] From the above results, it can be seen that the toner of this example has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to the toner of the comparative example.

[0216] This embodiment includes the following aspects. (((1))) The toner particles include an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, The internally crosslinked resin particles have a storage modulus G' of 1×10 5 Pa or more 1×10 6 The following styrene-(meth)acrylic copolymer particles: the average dispersed diameter of the internally added crosslinked resin particles is 100 nm or more and 300 nm or less, In observing the cross section of the toner particle, when a 3 μm×3 μm square region of 600 pix×600 pix is ​​divided into n×n regions, In the n×n divided regions, the coefficient of variation of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided region is DAR(n), The n was changed to 3, 4, 6, 8, 12, and 16, and the slope of the approximated line in the scatter diagram, in which log[1 / n] was plotted on the X axis and log[DAR(n)] on the Y axis, was defined as slopeF(16). When the formula (1) is satisfied, the toner for developing electrostatic images satisfies the following formula (1): Formula (1): 0.6≦slopeF(16) (((2))) The toner for developing electrostatic images according to (1) satisfies the following formula (11): Equation (11): 0.7≦slopeF(16) (((3))) The toner for developing electrostatic images according to (((1))) or (((2))), wherein the content of the crystalline polyester resin is 10% by mass or more and 40% by mass or less with respect to the binder resin. (((4))) The toner for developing electrostatic images according to (((3))), wherein the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is 0.13 or more and 1.50 or less in mass ratio. (((5))) The toner for developing electrostatic images according to (((4))), wherein the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is 0.25 or more and 1.25 or less in mass ratio. (((6))) The toner for developing electrostatic images according to any one of (((1))) to (((5))), wherein, upon cross-sectional observation of the toner particle, the area ratio of the internally added crosslinked resin particles to the cross-section of the toner particle is more than 15% and 48% or less. (((7))) The toner for developing electrostatic images according to any one of ((1))) to (((6))), wherein the average dispersed diameter of the internally added crosslinked resin particles is 120 nm or more and 250 nm or less. (((8))) The dielectric loss factor at 1 kHz of the toner after being left at a temperature of 28°C and a relative humidity of 85% is 35×10 -3 The toner for developing electrostatic images according to any one of the following (((1))) to (((7))): (((9))) The toner for developing electrostatic images according to any one of ((1))) to (((8))), wherein the toner particles contain carbon black as a colorant. (((10))) An electrostatic image developer comprising the toner for developing electrostatic images according to any one of (((1))) to (((9))). (((11))) The toner for developing electrostatic images according to any one of (((1))) to (((9))) is contained, A toner cartridge that is detachably attached to an image forming device. (((12))) a developing device that contains the electrostatic image developer according to (((10))) and develops an electrostatic image formed on the surface of an image carrier into a toner image by using the electrostatic image developer, A process cartridge is detachably mounted in an image forming apparatus. (((13))) an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; a developing device that contains the electrostatic image developer according to (((10))) and develops the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising: (((14))) a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to (((10))); a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of:

[0217] The effects of the above embodiment are as follows. According to the invention related to (((1))), in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or higher and 100° C. or lower. 5 Less than Pa or 1×10 6When the styrene-(meth)acrylic copolymer particles have an average dispersed diameter exceeding 100 nm, the toner for developing electrostatic images has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the formula (1) is not satisfied or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm. According to the invention related to (((2))), there is provided a toner for developing electrostatic images that can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to a case where formula (11) is not satisfied. According to the invention related to (((3))), a toner for developing electrostatic images is provided which has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the content of the crystalline polyester resin is less than 10% by mass or more than 40% by mass relative to the binder resin. According to the invention related to (((4))), there is provided a toner for developing electrostatic images which has low-temperature fixability and can suppress transfer unevenness in high-temperature, high-humidity environments, compared to when the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is less than 0.13 or exceeds 1.50 by mass. According to the invention related to (((5))), there is provided a toner for developing electrostatic images which has low-temperature fixability and can suppress transfer unevenness in high-temperature, high-humidity environments, compared to when the ratio Ws / Wc of the content Wc of the crystalline polyester resin to the content Ws of the internally added crosslinked resin particles in the toner particles is less than 0.25 or exceeds 1.25 by mass. According to the invention related to (((6))), a toner for developing electrostatic images is provided which, when observed in cross section of a toner particle, has an area ratio of internally added crosslinked resin particles to the cross section of the toner particle of 15% or less or more than 48%. This toner has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment. According to the invention related to (((7))), a toner for developing electrostatic images is provided which has low-temperature fixability and can suppress transfer unevenness in high-temperature and high-humidity environments, compared to when the average dispersed diameter of the internally added crosslinked resin particles is less than 120 nm or more than 250 nm. According to the invention (((8))), the dielectric loss factor at 1 kHz of the toner after being left at a temperature of 28°C and a relative humidity of 85% RH is 35×10 -3As a result, a toner for developing electrostatic images is provided which has low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the toner is above 1000 kJ / cm 2 . According to the invention related to (((9))), in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1×10 in the range of 60° C. or higher and 100° C. or lower. 5 Less than Pa or 1×10 6 When the toner particles contain carbon black as a colorant, the toner particles have low-temperature fixability and can suppress transfer unevenness in a high-temperature, high-humidity environment, compared to when the toner particles contain styrene-(meth)acrylic copolymer particles having an average dispersed diameter exceeding 100 nm, which do not satisfy formula (1), or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm.

[0218] According to the invention of (((10))), (((11))), (((12))), (((13))) or (((14))), in a toner for developing an electrostatic image having toner particles containing an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, the internally added crosslinked resin particles have a storage modulus G' of 1 x 10 in the range of 60°C or higher and 100°C or lower. 5 Less than Pa or 1×10 6 When the styrene-(meth)acrylic copolymer particles have an average dispersed diameter exceeding 100 nm, the electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, or image forming method can suppress transfer unevenness in a high-temperature, high-humidity environment while maintaining low-temperature fixability, compared to when formula (1) is not satisfied or when the internally added crosslinked resin particles have an average dispersed diameter of less than 100 nm or more than 300 nm. [Explanation of symbols]

[0219] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (example of charging device) 3. Exposure device (an example of an electrostatic image forming device) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (example of developing device) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer device) 6Y, 6M, 6C, 6K Photoconductor cleaning device (example of cleaning device) 8Y, 8M, 8C, 8K toner cartridges 10Y, 10M, 10C, 10K image forming units 20 Intermediate transfer belt (an example of an intermediate transfer body) 22 Drive Roll 24 Support Roll 26 Secondary transfer roll (an example of a secondary transfer device) 28 Fixing device (example of fixing device) 30 Intermediate transfer body cleaning device 107 Photoconductor (an example of an image carrier) 108 Charging roll (an example of a charging device) 109 Exposure device (an example of an electrostatic image forming device) 111 Developing device (an example of a developing device) 112 Transcription device (an example of a transcription device) 113 Photosensitive drum cleaning device (an example of a cleaning device) 115 Fixing device (an example of a fixing device) 116 Mounting Rail 118 Exposure opening 117 Cabinet 200 Process Cartridge 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. The toner particles include an amorphous polyester resin and a crystalline polyester resin as binder resins, and internally added crosslinked resin particles, The internally crosslinked resin particles have a storage modulus G' of 1 x 10 ５ Pa or more 1×10 ６ The following styrene-(meth)acrylic copolymer particles are used: the average dispersed diameter of the internally added crosslinked resin particles is 100 nm or more and 300 nm or less, In observing the cross section of the toner particle, when a square region of 3 μm×3 μm, which is 600 pixels×600 pixels, is divided into n×n regions, In the n × n divided regions, the coefficient of variation of the area ratio of the internally added crosslinked resin particles to the area of ​​the divided region is DAR(n), The n is changed to 3, 4, 6, 8, 12, and 16, and the slope of the approximated line in the scatter diagram plotted on the X axis and the Y axis is log[1 / n] and is defined as slopeF(16). When the formula (1) is satisfied, the toner for developing electrostatic images satisfies the following formula (1): Formula (1): 0.6≦slopeF (16)

2. 2. The toner for developing electrostatic images according to claim 1, which satisfies the following formula (11): Formula (11): 0.7≦slopeF (16)

3. 2. The toner for developing electrostatic images according to claim 1, wherein the content of the crystalline polyester resin is 10% by mass or more and 40% by mass or less with respect to the binder resin.

4. 4. The toner for developing electrostatic images according to claim 3, wherein a ratio Ws / Wc of a content Wc of the crystalline polyester resin to a content Ws of the internally added crosslinked resin particles in the toner particles is 0.13 or more and 1.50 or less in mass ratio.

5. 5. The toner for developing electrostatic images according to claim 4, wherein a ratio Ws / Wc of a content Wc of the crystalline polyester resin to a content Ws of the internally added crosslinked resin particles in the toner particles is 0.25 or more and 1.25 or less in mass ratio.

6. 2. The toner for developing electrostatic images according to claim 1, wherein, upon cross-sectional observation of the toner particle, the area ratio of the internally added crosslinked resin particles to the cross-section of the toner particle is more than 15% and 48% or less.

7. 2. The toner for developing electrostatic images according to claim 1, wherein the average dispersion diameter of the internally added crosslinked resin particles is 120 nm or more and 250 nm or less.

8. The dielectric loss factor at 1 kHz of the toner after being left at a temperature of 28°C and a relative humidity of 85% RH is 35 x 10 －３ 2. The toner for developing electrostatic images according to claim 1, wherein the toner is:

9. 2. The toner for developing electrostatic images according to claim 1, wherein the toner particles contain carbon black as a colorant.

10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9.

11. A toner for developing electrostatic images according to any one of claims 1 to 9 is contained therein, A toner cartridge that is detachably attached to an image forming device.

12. a developing device containing the electrostatic image developer according to claim 10 and developing an electrostatic image formed on a surface of an image carrier into a toner image by using the electrostatic image developer; A process cartridge is detachably mounted in an image forming apparatus.

13. an image carrier; a charging device that charges the surface of the image carrier; an electrostatic image forming device for forming an electrostatic image on the charged surface of the image carrier; a developing device containing the electrostatic image developer according to claim 10 and developing the electrostatic image formed on the surface of the image carrier into a toner image by the electrostatic image developer; a transfer device that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing device for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

14. a charging step of charging the surface of the image carrier; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier; a developing step of developing the electrostatic image formed on the surface of the image carrier into a toner image by using the electrostatic image developer according to claim 10; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing step of fixing the toner image transferred onto the surface of the recording medium; An image forming method comprising the steps of:

Images