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

Abstract

To provide a toner for electrostatic charge image development which enables suppression of ununiformity of glossiness between black and magenta images occurring when exposed to outdoors, while securing low temperature fixability.SOLUTION: A toner set for electrostatic charge image development including a black toner and a magenta toner. A binder resin included in a black toner particle and a magenta toner particle contains an amorphous polyester resin and a crystalline polyester resin. A content of the crystalline polyester resin in the black and magenta toner particles is 7 mass% or more and 40 mass% or less. A relationship between a mass ratio (mass%) P(K) of a constitutional unit derived from phthalic acid except terephthalic acid, in the amorphous polyester resin included in the black toner particle and a mass ratio (mass%) P(M) of a constitutional unit derived from phthalic acid except terephthalic acid in the amorphous polyester resin included in the magenta toner particle satisfies Formula (P1) bellow. Formula (P1): 10≤P(M)-P(K)≤40.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Patent Document 1 discloses "a toner containing at least a polyester resin, the polyester resin having a specific structural unit."

[0003] Patent Document 2 discloses "a full-color toner consisting of a black toner and at least one color toner, each containing a binder resin and a colorant, wherein the aromatic concentration of the binder resin contained in the black toner (black toner aromatic concentration) is lower than the aromatic concentrations of the binder resins contained in any of the color toners (color toner aromatic concentrations), the difference between the black toner aromatic concentration and the lowest color aromatic concentration is greater than any of the differences between the color toner aromatic concentrations, and the difference between the black toner aromatic concentration and any of the color toner aromatic concentrations is 1 to 14% by weight."

[0004] Patent Document 3 discloses "a full-color toner consisting of a black toner and at least one color toner, each containing a binder resin and a colorant, wherein the degree of unsaturation of the binder resin contained in the black toner (black toner unsaturation) is lower than the degree of unsaturation of the binder resin contained in any of the color toners (color toner unsaturation), the difference between the black toner unsaturation and the lowest color toner unsaturation is greater than any of the differences between the color toner unsaturation degrees, and the difference between the black toner unsaturation and any of the color toner unsaturation degrees is 0.1 to 1.5 mol / 1000g."

[0005] Patent Document 4 discloses "an image forming method comprising: an electrostatic image forming step of forming an electrostatic image on the surface of an image carrier; a developing step of developing the electrostatic image with black toner for optical fixation and color toners for optical fixation to form black toner images and color toner images; a transfer step of transferring the black toner image and the color toner images formed in the developing step onto the surface of a transfer recipient; and a light fixing step of fixing the black toner image and the color toner images transferred to the surface of the transfer recipient by exposure to light in the infrared region, wherein the black toner is a black toner that melts when exposed to light in the infrared region in the light fixing step, and the color toner contains an infrared absorber, and the light absorptance at the peak wavelength of light in the infrared region irradiated in the light fixing step is 79% or more and 98% or less of the light absorptance of the black toner at the peak wavelength, and the color toner has a color difference ΔE of 20 or less."

[0006] Patent Document 5 discloses "a toner set for developing electrostatic images, comprising two or more toners of different hues, characterized in that the difference between the maximum and minimum values ​​of absorptivity α of each toner in the range of 380 to 1,500 nm is 0.1 or less." [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-257363 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-361520 [Patent Document 3] Japanese Patent Application Laid-Open No. 2004-361817 [Patent Document 4] Japanese Patent Application Laid-Open No. 2010-230914 [Patent Document 5] Japanese Patent Application Laid-Open No. 2011-43662 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 electrostatic images, which comprises a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant, wherein the binder resin of the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, and the content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less. The object of the present invention is to provide a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the mass ratio (mass %) P(K) of structural units derived from phthalic acids other than terephthalic acid to the structural units derived from polycarboxylic acids and the mass ratio (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid to the structural units derived from polycarboxylic acids in the amorphous polyester resin contained in the magenta toner particles does not satisfy formula (P1). [Means for solving the problem]

[0009] Means for solving the above problems include the following aspects. <1> a black toner having black toner particles containing a binder resin and a black colorant; a magenta toner having magenta toner particles containing a binder resin and a magenta colorant; Equipped with the binder resin contained in the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, a content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less; the amorphous polyester resin contained in the black toner particles and the magenta toner particles comprises a structural unit derived from a polycarboxylic acid and a structural unit derived from a polyhydric alcohol, The relationship between the mass ratio (mass%) P(K) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the black toner particles and the mass ratio (mass%) P(M) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the magenta toner particles satisfies the following formula (P1): Formula (P1): 10≦P(M)-P(K)≦40 <2> The relationship between the mass proportion (mass%) P(K) of the constituent units derived from phthalic acid other than terephthalic acid in the black toner particles and the mass proportion (mass%) P(M) of the constituent units derived from phthalic acid other than terephthalic acid in the magenta toner particles satisfies the following formula (P2): <1> 10. The toner set for developing electrostatic images according to claim 19. Formula (P2): 15≦P(M)-P(K)≦35 <3> The mass proportion (mass%) P(M) of the structural units derived from phthalic acids other than terephthalic acid is 11 mass% or more and 80 mass% or less. <1> or <2> 10. The toner set for developing electrostatic images according to claim 19. <4> The mass proportion (mass%) P(M) of the structural units derived from phthalic acids other than terephthalic acid is 15 mass% or more and 50 mass% or less. <3> 10. The toner set for developing electrostatic images according to claim 19. <5> In the amorphous polyester resin contained in the black toner particles, the structural unit derived from a polycarboxylic acid contains a structural unit derived from terephthalic acid as a main component. <1> ~ <4> 10. The toner set for developing electrostatic images according to claim 1, wherein the toner set is a toner set for developing electrostatic images according to any one of claims 1 to 9. <6> The relationship between the content (mass%) WC(K) of the crystalline polyester resin relative to the binder resin in the black toner particles and the content (mass%) WC(M) of the crystalline polyester resin relative to the binder resin in the magenta toner particles satisfies the following formula (WC1): <1> ~ <5> 10. The toner set for developing electrostatic images according to claim 1, wherein the toner set is a toner set for developing electrostatic images according to any one of claims 1 to 9. Formula (WC1)0.90≦WC(K) / WC(M)≦1.10 <7> The relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles is 10% by mass or more and 40% by mass or less, and satisfies the following formula (WT1): <1> ~ <6> 10. The toner set for developing electrostatic images according to claim 1, wherein the toner set is a toner set for developing electrostatic images according to any one of claims 1 to 9. Formula (WT1): WT(K)>WT(M) <8> The relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles satisfies the following formula (WT2): <7> 10. The toner set for developing electrostatic images according to claim 19. Formula (WT2): 2≦WT(K)-WT(M)≦10 <9> The tetrahydrofuran insoluble matter in the black toner particles and the magenta toner particles contains a resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower. <7> or <8> 10. The toner set for developing electrostatic images according to claim 19. <10> The resin having a glass transition temperature Tg of 0°C or higher and 30°C or lower is a styrene-(meth)acrylic copolymer. <9> 10. The toner set for developing electrostatic images according to claim 19. <11> The black toner and the magenta toner have a peak that reaches a maximum in the range of 50° C. or more and 70° C. or less in the second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC). <1> ~ <10> Item 1. The toner set for developing electrostatic images according to any one of items 1 to 1. <12> <1> ~ <11> a first electrostatic image developer containing the black toner in the toner set for developing an electrostatic image according to any one of the preceding items; <1> ~ <11> a second electrostatic image developer containing the magenta toner of the toner set for developing electrostatic images according to any one of the preceding items; Electrostatic image developer set comprising: <13> <1> ~ <11> a first toner cartridge containing the black toner in the toner set for developing an electrostatic image according to any one of the above items; <1> ~ <11> a second toner cartridge containing the magenta toner in the toner set for developing electrostatic images according to any one of the above items; and A toner cartridge set that is detachably attached to an image forming apparatus. <14> <12> a first developing device containing the first electrostatic image developer of the electrostatic image developer set described in <12> a second developing device containing the second electrostatic image developer of the electrostatic image developer set described in Equipped with A process cartridge is detachably mounted in an image forming apparatus. <15> <1> ~ <11> a first image forming unit that forms a black image using the black toner in the toner set for developing an electrostatic image according to any one of the above items; <1> ~ <11> a second image forming unit that forms a magenta image using the magenta toner in the toner set for developing electrostatic images according to any one of the above items; a transfer device that transfers the black image and the magenta image onto a recording medium; a fixing device that fixes the black image and the magenta image onto the recording medium; An image forming apparatus comprising: <16> <1> ~ <11> a first image forming step of forming a black image using the black toner of the toner set for developing electrostatic images according to any one of the above items; <1> ~ <11> a second image forming step of forming a magenta image using the magenta toner of the toner set for developing electrostatic images according to any one of the above items; a transfer step of transferring the black image and the magenta image onto a recording medium; a fixing step of fixing the black image and the magenta image on the recording medium; An image forming method comprising the steps of: [Effects of the Invention]

[0010] <1> According to the invention, there is provided a toner for developing electrostatic images, which comprises a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant, wherein the binder resin of the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, and the content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less. The present invention provides a toner set for developing electrostatic images that can suppress uneven gloss levels between black and magenta images that occur when exposed to the outdoors while ensuring low-temperature fixability, compared to when the relationship between the mass ratio (mass %) P(K) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the magenta toner particles and the mass ratio (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the amorphous polyester resin contained in the magenta toner particles does not satisfy formula (P1). <2> According to the invention, a toner set for developing electrostatic images is provided that can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the mass proportion (mass%) P(K) of constituent units derived from phthalic acid other than terephthalic acid in the black toner particles and the mass proportion (mass%) P(M) of constituent units derived from phthalic acid other than terephthalic acid in the magenta toner particles does not satisfy formula (P2). <3> According to the invention, a toner set for developing electrostatic images is provided that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the mass proportion (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid is less than 11 mass % or more than 80 mass %. <4> According to the invention, a toner set for developing electrostatic images is provided that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the mass proportion (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid is less than 15 mass % or more than 50 mass %. <5> According to the invention, there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the structural unit derived from a polycarboxylic acid in the amorphous polyester resin contained in the black toner particles does not contain terephthalic acid. <6> According to the invention, there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the content (mass %) of crystalline polyester resin relative to the binder resin in black toner particles, WC(K), and the content (mass %) of crystalline polyester resin relative to the binder resin in magenta toner particles, WC(M), does not satisfy formula (WC1). <7> According to the invention, a toner set for developing electrostatic images is provided that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) in black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) in magenta toner particles is less than 10% by mass or more than 40% by mass, or when formula (WT1) is not satisfied. <8> According to the invention, there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the relationship between the tetrahydrofuran insoluble content (mass %) WT(K) in black toner particles and the tetrahydrofuran insoluble content (mass %) WT(M) in magenta toner particles does not satisfy formula (WT2). <9> According to the invention, there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness of black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the tetrahydrofuran-insoluble matter in the black toner particles and the magenta toner particles contains a resin whose glass transition temperature Tg is lower than 0°C or higher than 30°C. <10> According to the invention, there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the resin having a glass transition temperature Tg of 0°C or higher and 30°C or lower is styrene-butadiene rubber. <11> According to the invention, a toner set for developing electrostatic images is provided that can suppress uneven glossiness of black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the black toner and magenta toner have a peak that is maximum in the range of less than 50°C or more than 70°C during the second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC).

[0011] <12> , <13> , <14> , <15> , or <16> According to the invention, a toner for developing electrostatic images is provided, which comprises a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant, wherein the binder resin of the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, and the content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less, and Provided is an electrostatic image developer set, toner cartridge set, process cartridge, image forming apparatus, or image forming method that can suppress uneven gloss levels between black and magenta images that occur when exposed to the outdoors while ensuring low-temperature fixability, compared to when an electrostatic image developing toner is used in which the relationship between the mass proportion (mass%) P(K) of structural units derived from phthalic acid other than phthalic acid and the mass proportion (mass%) P(M) of structural units derived from phthalic acid other than terephthalic acid relative to the structural units derived from polycarboxylic acids in an amorphous polyester resin contained in the magenta toner particles does not satisfy formula (P1). [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 set] The toner set for developing electrostatic images (hereinafter also referred to as "toner set") according to this embodiment includes a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant. The binder resin contained in the black toner particles and the magenta toner particles includes an amorphous polyester resin and a crystalline polyester resin. In the black toner particles and the magenta toner particles, the content of the crystalline polyester resin relative to the binder resin is 7% by mass or more and 40% by mass or less. The amorphous polyester resin contained in the black toner particles and the magenta toner particles is composed of a structural unit derived from a polycarboxylic acid and a structural unit derived from a polyhydric alcohol. The relationship between the mass ratio (mass %) P(K) of structural units derived from phthalic acid other than terephthalic acid to structural units derived from polycarboxylic acid in the amorphous polyester resin contained in the black toner particles (i.e., all amorphous polyester resins contained in the toner particles) and the mass ratio (mass %) P(M) of structural units derived from phthalic acid other than terephthalic acid to structural units derived from polycarboxylic acid in the amorphous polyester resin contained in the magenta toner particles (i.e., all amorphous polyester resins contained in the toner particles) satisfies formula (P1) described below.

[0016] The toner set according to the present embodiment, with the above-described configuration, can ensure low-temperature fixability while suppressing uneven glossiness between black and magenta images that occurs when the toner is exposed to the outdoors. The reason for this is presumed to be as follows.

[0017] Conventionally, toners using a combination of an amorphous polyester resin and a crystalline polyester resin have been known in order to achieve both low-temperature fixability and high-temperature storage stability. However, in toners that use a combination of amorphous polyester resin and crystalline polyester resin, the crystalline polyester resin is prone to molecular motion at high temperatures, and therefore, when an image is exposed outdoors (i.e., under direct sunlight), the outermost surface of the image softens due to the heat, which can cause a slight increase in image gloss. In the case of a monochrome image, the entire image becomes hot almost uniformly, and the glossiness also rises almost uniformly, so there is little non-uniformity in the glossiness of the image and the image is unlikely to feel unnatural. On the other hand, in the case of a multicolor image having a black image and a color image other than black, the black image is more likely to absorb light at its surface and become hotter than the color images other than black. As a result, the glossiness of the black image changes more than that of the color images other than black. This can result in high-gloss and low-gloss areas within the same image, resulting in uneven glossiness. In particular, under visible light, a magenta image absorbs less light than other colors, so the difference in glossiness between the magenta image and the black image becomes larger, and non-uniformity in glossiness is easily visible.

[0018] In contrast, in the toner set according to this embodiment, the relationship between the mass proportion (mass%) P(K) of constituent units derived from phthalic acid other than terephthalic acid in the amorphous polyester resin contained in the black toner particles and the mass proportion (mass%) P(M) of constituent units derived from phthalic acid other than terephthalic acid in the amorphous polyester resin contained in the magenta toner particles satisfies formula (P1) described below. That is, the mass proportion of constituent units derived from phthalic acid other than terephthalic acid is made higher in the amorphous polyester resin contained in the magenta toner particles than in the amorphous polyester resin contained in the black toner particles. When the main chain of the amorphous polyester resin contains structural units derived from phthalic acid other than terephthalic acid, bending portions exist in the main chain, and gaps tend to form between the molecular chains. In toner particles containing an amorphous polyester resin and a crystalline polyester resin, if there are voids in the amorphous polyester resin, the crystalline polyester resin will infiltrate into the voids in the amorphous polyester resin due to heating and cooling during toner fixing. In this case, the toner using an amorphous polyester resin having many structural units derived from phthalic acids other than terephthalic acid has a higher proportion of crystalline polyester resin on the surface of the image formed. In other words, if the mass proportion of structural units derived from phthalic acids other than terephthalic acid in the amorphous polyester resin contained in the magenta toner particles is made higher than that in the amorphous polyester resin contained in the black toner particles, the magenta image produced by the magenta toner will have a higher proportion of crystalline polyester resin on the image surface than the black image produced by the black toner. Therefore, compared to a black image produced by a black toner, a magenta image produced by a magenta toner exhibits increased molecular motion of the crystalline polyester resin on the image surface at high temperatures. As a result, when the image is exposed outdoors (i.e., under direct sunlight) and the temperature of the image surface rises, the glossiness of the magenta image produced by the magenta toner increases to the same level as that of a black image produced by a black toner. In other words, the decrease in glossiness of the black image produced by the black toner is suppressed to the same level as that of the magenta image produced by the magenta toner. As a result, the difference in glossiness between the black image and the magenta image is reduced, and non-uniformity in glossiness between the black image and the magenta image can be suppressed.

[0019] From the above, it is presumed that the toner set according to this embodiment can ensure low-temperature fixability while suppressing uneven glossiness between black and magenta images that occurs when exposed to the outdoors.

[0020] The toner set according to this embodiment will be described in detail below. In the following description, matters common to the black toner or black toner particles and the magenta toner or magenta toner particles will be described simply as "toner or toner particles," or will be described without specifying.

[0021] <Toner> Each toner in the toner set according to this embodiment (hereinafter also referred to as "toner according to this embodiment") contains toner particles. The toner according to this embodiment may contain an external additive.

[0022] (toner particles) The toner particles contain an amorphous resin and a crystalline resin as binder resins, and a colorant. The toner particles may also contain a colorant, a release agent, internally added crosslinked resin particles, and other additives. Specifically, the black toner particles contain an amorphous resin and a crystalline resin as binder resins, and a black colorant, The magenta toner particles contain an amorphous resin and a crystalline resin as binder resins, and a magenta colorant.

[0023] -Binder resin- As the binder resin, an amorphous polyester resin and a crystalline polyester resin are used. However, the content of the crystalline polyester resin relative to the binder resin is 7% by mass or more and 40% by mass or less, for example, preferably 10% by mass or more and 35% by mass or less, and more preferably 15% by mass or more and 30% by mass or less. If the content of the crystalline polyester resin is less than 7% by mass, the low-temperature fixability decreases. If the content of the crystalline polyester resin exceeds 40% by mass, the glossiness of each color image changes excessively, and it is not possible to prevent the glossiness of the black image and the magenta image from becoming non-uniform.

[0024] The relationship between the content (mass %) WC(K) of the crystalline polyester resin relative to the binder resin in the black toner particles and the content (mass %) WC(M) of the crystalline polyester resin relative to the binder resin in the magenta toner particles preferably satisfies, for example, the following formula (WC1), more preferably the following formula (WC2), and even more preferably the following formula (WC3). When the following (WC1), (WC2), or (WC3) is satisfied, the difference in the amount of crystalline polyester resin between the black toner particles and the magenta toner particles is small, and when exposed to outdoors, the difference in gloss between the black image and the magenta image after the gloss level increases is small, making it easier to suppress non-uniformity between the black image and the magenta image.Furthermore, the difference in gloss between the black image and the magenta image in an indoor high-temperature, high-humidity environment is small, making it easier to suppress non-uniformity between the black image and the magenta image. Formula (WC1)0.90≦WC(K) / WC(M)≦1.10 Formula (WC2)0.93≦WC(K) / WC(M)≦1.07 Formula (WC3)0.96≦WC(K) / WC(M)≦1.04

[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. The amorphous polyester resin is a condensation polymer of a polycarboxylic acid and a polyhydric alcohol, that is, an amorphous polyester resin having structural units derived from a polycarboxylic acid and structural units derived from a polyhydric alcohol. The amorphous polyester resin includes an amorphous polyester resin having a structural unit derived from a phthalic acid other than terephthalic acid as a structural unit derived from a polycarboxylic acid.

[0027] The mass ratio (mass%) P(K) of the structural units derived from phthalic acid other than terephthalic acid in the amorphous polyester resin (S) to the structural units derived from polycarboxylic acid in the amorphous polyester resin contained in the black toner particles (i.e., the total amorphous polyester resin contained in the toner particles) and the mass ratio (mass%) P(K) of the structural units derived from phthalic acid other than terephthalic acid in the amorphous polyester resin (S) to the structural units derived from polycarboxylic acid in the amorphous polyester resin contained in the magenta toner particles (i.e., the total amorphous polyester resin contained in the toner particles) The relationship between the mass proportion (mass %) P(M) of structural units derived from phthalic acid other than terephthalic acid in the amorphous polyester resin (S) relative to the structural units derived from polycarboxylic acid in the amorphous polyester resin (S) satisfies, for example, the following formula (P1), preferably the following formula (P2), and more preferably the following formula (P3): Formula (P1): 10≦P(M)-P(K)≦40 Formula (P2): 15≦P(M)-P(K)≦35 Formula (P3): 20≦P(M)-P(K)≦30

[0028] When the "P(M)-P(K)" value is less than 10% by mass or more than 40% by mass, the difference in gloss between the black image and the magenta image after the gloss increase becomes large when exposed to the outdoors, and the non-uniformity between the black image and the magenta image cannot be suppressed.

[0029] Here, from the viewpoint of suppressing uneven glossiness between the black image and the magenta image, the mass proportion (mass %) P(M) of structural units derived from phthalic acid other than terephthalic acid contained in the magenta toner particles is, for example, preferably 11 mass % or more and 80 mass % or less, more preferably 15 mass % or more and 50 mass % or less, and even more preferably 20 mass % or more and 35 mass % or less.

[0030] In the amorphous polyester resin contained in the black toner, the polycarboxylic acid-derived structural units preferably contain, for example, terephthalic acid-derived structural units as a main component. In particular, it is preferred that all of the polycarboxylic acid-derived structural units, excluding structural units derived from phthalic acids other than terephthalic acid, are terephthalic acid-derived structural units. The phrase "the polycarboxylic acid-derived structural units contain terephthalic acid-derived structural units as the main component" means that the terephthalic acid-derived structural units account for the largest mass proportion of the polycarboxylic acid-derived structural units.

[0031] The mass proportion (mass %) of the structural units derived from each polycarboxylic acid in the non-amorphous polyester resin (that is, the total amorphous polyester resin contained in the toner particles) is measured as follows. The toner is dissolved in a solvent in which the binder resin is soluble, such as tetrahydrofuran (THF), and the insoluble matter is removed and then dried. Furthermore, the amorphous polyester resin and the crystalline resin in the binder resin are separated using a solvent in which the amorphous polyester resin is soluble and the crystalline resin is insoluble, taking advantage of the difference in solubility between the amorphous polyester resin and the crystalline resin in the solvent. After confirming the absence of an endothermic peak due to the crystalline resin in the obtained amorphous polyester resin using a DSC (differential scanning calorimeter), 1 H-NMR measurement is performed. The obtained NMR spectrum is analyzed to determine the chemical shift and integral ratio. Then, from the chemical shift and the integral value ratio, the mass proportion (mass %) of the structural units derived from each polycarboxylic acid in the amorphous polyester resin (that is, the total amorphous polyester resin contained in the toner particles) can be determined.

[0032] Examples of phthalic acids other than terephthalic acid include substituted or unsubstituted orthophthalic acid and substituted or unsubstituted isophthalic acid. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an ethyl group, and a sulfonic acid group. Specific examples of phthalic acids other than terephthalic acid include unsubstituted orthophthalic acid, unsubstituted isophthalic acid, methyl orthophthalic acid, methyl isophthalic acid, diethyl phthalate, and 1,3-benzenedisulfonic acid. Examples of terephthalic acid include substituted and unsubstituted terephthalic acid. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an ethyl group, and a sulfonic acid group. Specific examples of terephthalic acid include unsubstituted terephthalic acid, methyl terephthalic acid, and diethyl terephthalate. Examples of polycarboxylic acids other than phthalic acid include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., Examples of polycarboxylic acids other than phthalic acid include aromatic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, preferred polycarboxylic acids other than phthalic acid include aromatic dicarboxylic acids. The polycarboxylic acid other than phthalic acid may be used in combination with a dicarboxylic acid and a trivalent or higher carboxylic acid having a crosslinked or branched structure. 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.

[0033] The glass transition temperature (Tg) of the amorphous polyester resin is, for example, 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."

[0034] The weight average molecular weight (Mw) of the amorphous polyester resin is, for example, 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, for example, 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous polyester resin is, for example, 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.

[0035] 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, for example, the monomer with poor compatibility may be condensed in advance with the acid or alcohol to be polycondensed, and then polycondensed with the main component.

[0036] 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 polyester resins having different molecular weights in combination. For example, a low molecular weight amorphous polyester resin (L-form) and a high molecular weight amorphous polyester resin (H-form) are used in combination. The low molecular weight (L-form) is preferably an amorphous polyester resin having a weight average molecular weight measured by GPC of 5,000 to 30,000. If the molecular weight is lower than 5,000, offset tends to occur at high temperatures, while if the molecular weight is 30,000 or higher, gloss is difficult to achieve at low temperatures. The high molecular weight material (H material) is preferably, for example, an amorphous polyester resin having a weight average molecular weight measured by GPC of 25,000 to 200,000. If the molecular weight is 200,000 or more, gloss may not be achieved at high temperatures, and the fixing temperature may become high. The acid value of the amorphous polyester resin used in combination is preferably, for example, about 5 mgKOH / g or more and 20 mgKOH / g or less for low molecular weight (L-form) and about 5 mgKOH / g or more and 15 mgKOH / g or less for high molecular weight (H-form). When two or more types of amorphous polyester resins are used in combination, the mass proportions (mass %) P(K) and P(M) of the structural units derived from phthalic acids other than terephthalic acid can be calculated by calculating the mass proportions of the structural units derived from polycarboxylic acids in the total amorphous polyester resin contained in the toner particles.

[0037] 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 the crystalline polyester resin can easily form a crystalline structure.

[0038] 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.

[0039] 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, preferred aliphatic diols include 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. 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.

[0040] Here, the polyhydric alcohol may have an aliphatic diol content of, for example, 80 mol % or more, and preferably 90 mol % or more.

[0041] The melting temperature of the crystalline polyester resin is preferably, for example, 50°C or higher and 100°C or lower, and is preferably 55°C or lower. The temperature is more preferably from 60°C to 85°C, and even more preferably from 60°C to 85°C. 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."

[0042] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably, for example, 6,000 or more and 50,000 or less.

[0043] The crystalline polyester resin can be obtained by a known manufacturing method, for example, in the same manner as the amorphous polyester resin.

[0044] 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.

[0045] -Coloring agent- As for the colorant, a black colorant is applied to the black toner particles, and a magenta colorant is applied to the magenta toner particles.

[0046] Examples of black colorants include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, non-magnetic ferrite, and magnetite.

[0047] Examples of magenta colorants include β-naphthol pigments, azo lake pigments, quinacridone pigments, disazo pigments, benzimidazolone pigments, disazo condensation pigments, dioxazine pigments, and diketopyrrolopyrrole pigments. Specific examples of magenta colorants include: CIPigment Red 146, 2, 5, 7, 8, 9, 10, 11, 12, β-naphthol pigments such as 13, 14, 15, 16, 17, 18, 21, 22, 23, 31, 32, 95, 112, 114, 119, 136, 147, 148, 150, 164, 170, 184, 187, 188, 210, 212, 213, 222, 223, 238, 245, 253, 256, 258, 261, 266, 267, 268, and 269; CIPigment Red 57:1, 18:1, 48:2, 48:3, 48: Azo lake pigments such as 4, 48:5, 50:1, 51, 52:1, 52:2, 53:1, 53:2, 53:3, 58:2, 58:4, 64:1, 68, and 200; CIPigment Red 209, 122, 192, 202, 207, CI Quinacridone pigments such as Pigment Violet 19; CIPigment Red 37, 38, 41, 111, CIPigmen Disazo pigments such as t Orange 13, 15, 16, 34, and 44; CIPigment Red 171, 175, 176, 185, 208, CI Benzimidazolone pigments such as CI Pigment Violet 32, CI Pigment Orange 36, 60, 62, and 72; CIPigment Red 144, 166, 214, 220, 221, 242 , 248, 262, CI Pigment Orange 31, and other disazo condensation pigments; Dioxazine pigments such as CI Pigment Violet 23 and 37; CIPigment Red 254, 255, 264, 272, CIPigment diketopyrrolopyrrole pigments such as Cement Orange 71 and 73. Note that "CI" stands for Color Index.

[0048] The colorant may be used alone or in combination of two or more kinds.

[0049] 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.

[0050] 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.

[0051] -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.

[0052] The melting temperature of the release agent is, for example, 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."

[0053] 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.

[0054] -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.

[0055] Examples of the internally crosslinked resin particles include crosslinked resin particles crosslinked by ionic bonds (i.e., ionically crosslinked resin particles), crosslinked resin particles crosslinked by covalent bonds (i.e., covalently crosslinked resin particles), etc. Among these, for example, crosslinked resin particles crosslinked by covalent bonds are preferred as the internally crosslinked resin particles.

[0056] The styrene-(meth)acrylic copolymer particles as the internally crosslinked resin particles are, for example, particles containing 50% by mass or more of a styrene-(meth)acrylic copolymer as a main component in the resin particles, preferably 80% by mass or more, more preferably 90% by mass or more, and particularly particles that are substantially entirely styrene-(meth)acrylic copolymer. The total amount of the monomers constituting the copolymer, for example, the styrene-based monomer and the (meth)acrylic monomer, 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.

[0057] Examples of the styrene-(meth)acrylic copolymer include resins obtained by radical polymerization of the following styrene monomers and (meth)acrylic monomers.

[0058] 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, for example, styrene and α-methylstyrene are preferred.

[0059] 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, for example, n-butyl (meth)acrylate and 2-carboxyethyl (meth)acrylate are preferred.

[0060] 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.

[0061] Among these, it is preferable to use, as the crosslinking agent for crosslinking the resin, for example, a bifunctional alkyl acrylate having an alkylene chain with 6 or more carbon atoms. That is, it is preferable that the internally crosslinked resin particles have, for example, a bifunctional alkyl acrylate as a constituent unit, and that the alkylene chain in the bifunctional alkyl acrylate has 6 or more carbon atoms. It has a bifunctional alkyl acrylate as a structural unit and the alkylene chain has 6 or more carbon atoms. By using certain internally-added crosslinked resin particles, toner deformation during fixing is within a moderate range, making it easier to obtain a toner with 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 will be too high, but if a bifunctional acrylate having a long alkylene chain is used as the crosslinking agent, the crosslinking density will be low (i.e., the distance between crosslinking points will be long), and it will be possible to prevent the elasticity of the internally-added crosslinked resin particles from becoming too high.

[0062] 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, for example, 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 crosslinking agents include, for example, 2-carboxyethyl acrylate, and it is preferable to use at least one of them together with the above-mentioned bifunctional alkyl acrylate.

[0063] 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.

[0064] The glass transition temperature Tg(E) of the internally crosslinked resin particles is, for example, preferably 0°C or more and 30°C or less, and more preferably 5°C or more and 25°C or less.

[0065] The glass transition temperature Tg of the internally crosslinked resin particles is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for measuring the transition temperature of plastics." The internally added crosslinked resin particles can be extracted from the toner by dissolving the toner in a solvent in which the binder resin is soluble, such as tetrahydrofuran (THF), recovering the insoluble matter, and then drying the recovered matter.

[0066] In the internally crosslinked resin particles made of a styrene-(meth)acrylic copolymer, the Tg(E) can be adjusted by adjusting the polymerization conditions for the copolymer. In particular, in order to obtain resin particles in which a composition gradient occurs within the internally crosslinked resin particles and regions with a high styrene unit content are unevenly distributed on the surface, when producing the resin particles by polymerization of a monomer-containing liquid containing a styrene monomer and a (meth)acrylic monomer, it is preferable to increase, for example, the content ratio of the styrene monomer to the (meth)acrylic monomer in the monomer-containing liquid as the polymerization progresses. "Increasing as the polymerization progresses" typically refers to gradually increasing the content ratio of the styrene monomer in the monomer-containing liquid, but it may also be the case that when additional monomer is added to the monomer-containing liquid in multiple installments, the content of the styrene monomer in the additional monomer is gradually increased, or the amount of added styrene monomer is increased to gradually increase the concentration of the styrene monomer in the monomer-containing liquid, etc. For example, when preparing a styrene-(meth)acrylic copolymer by emulsion polymerization, the content of the 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.

[0067] The content of the internally added crosslinked resin particles is, for example, preferably 2% by mass or more and 20% 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.

[0068] The average dispersed diameter of the internally added crosslinked resin particles is, for example, preferably 50 nm or more and 300 nm or less, and more preferably 80 nm or more and 250 nm or less.

[0069] 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 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-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.

[0070] 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.

[0071] The average shape factor SF-1 of the internally crosslinked resin particles is preferably, for example, 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 and improves low-temperature fixability.

[0072] 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.

[0073] -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, for example, 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, for example, it is preferable to carry out emulsion polymerization multiple times.

[0074] The method for producing the internally crosslinked resin particles will be described in more detail below. The internally crosslinked resin particles can be produced, for example, by a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water (emulsion preparation step); a step of adding a polymerization initiator to the emulsion and heating the emulsion to polymerize the monomers (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, an emulsion may be prepared by changing the ratio of the styrene-based monomer and the (meth)acrylic monomer, and the emulsion may be added multiple times.

[0075] --Emulsion preparation process-- The emulsion preparation step is a step of obtaining an emulsion containing a monomer, a crosslinking agent, a surfactant, and water. For example, it is preferable to obtain an emulsion by emulsifying a monomer, a crosslinking agent, a 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.

[0076] As the monomer, for example, a styrene-based monomer and a (meth)acrylic-based monomer are preferably used. As the crosslinking agent, those already mentioned above are applicable.

[0077] 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.

[0078] 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. Mass ratio of styrene-based monomer and (meth)acrylic monomer in emulsion (styrene-based monomer The (meth)acrylic monomer / (meth)acrylic monomer) is preferably, for example, 0.2 or more and 1.1 or less. The content of the crosslinking agent in the entire emulsion is preferably, for example, 0.5% by mass or more and 3% by mass or less.

[0079] --First emulsion polymerization step-- The first emulsion polymerization step is a step in which a polymerization initiator is added to an emulsion and the emulsion is 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, for example. Examples of the agitator include rotary agitators equipped with propeller-type, anchor-type, paddle-type, or turbine-type agitator blades. As the polymerization initiator, for example, ammonium persulfate is preferably used.

[0080] --Second emulsion polymerization step-- The second emulsion polymerization step is a step in which an emulsion containing a monomer is added to the reaction solution obtained after the first emulsion polymerization step, and the mixture is heated to polymerize the monomer. During 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.

[0081] -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.

[0082] -Characteristics of toner particles, etc.- The relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles is, for example, preferably 15% by mass or more and 40% by mass or less, and satisfies the following formula (WT1): Furthermore, the relationship between the tetrahydrofuran insoluble content (mass %) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass %) WT(M) of the magenta toner particles preferably satisfies, for example, the following formula (WT2). Formula (WT1): WT(K)>WT(M) Formula (WT2): 2≦WT(K)-WT(M)≦10

[0083] When the tetrahydrofuran-insoluble content (mass%) of the black toner particles and the magenta toner particles is 10% by mass or more and 40% by mass or less, and the relationship between the tetrahydrofuran-insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran-insoluble content (mass%) WT(M) of the magenta toner particles satisfies the above relationship, the gloss of the black image is less likely to increase when exposed to the outdoors, while the gloss of the magenta image is more likely to increase. As a result, it is easier to suppress non-uniformity in gloss between the black image and the magenta image. This is because the tetrahydrofuran-insoluble content is thought to suppress the crystalline polyester resin from appearing on the image surface in the black image produced by the black toner compared to the magenta image produced by the magenta toner.

[0084] The tetrahydrofuran insoluble content (mass %) in the black toner particles and magenta toner particles is, for example, more preferably 15 mass % or more and 35 mass % or less, and even more preferably 18 mass % or more and 30 mass % or less. The difference between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles (the "WT(K)-WT(M)" value) is, for example, more preferably 2 or more and 10 or less, and even more preferably 3 or more and 8 or less. stomach.

[0085] The tetrahydrofuran insoluble matter in the black toner particles and magenta toner particles preferably contains, for example, a resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower (for example, preferably 5° C. or higher and 30° C. or lower). The resin having a glass transition temperature Tg of 0° C. or more and 30° C. or less is preferably, for example, a styrene-(meth)acrylic copolymer. The styrene-(meth)acrylic copolymer corresponds to, for example, a crosslinked styrene-(meth)acrylic copolymer such as an internally added crosslinked resin particle in a toner particle. When the tetrahydrofuran-insoluble component contains a resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower (particularly a styrene-(meth)acrylic copolymer), it becomes easier to suppress uneven glossiness between black and magenta images. This is because the resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower as the tetrahydrofuran-insoluble component is thought to suppress the emergence of crystalline polyester resin on the image surface in black images produced by black toner compared to magenta images produced by magenta toner.

[0086] The tetrahydrofuran insoluble matter was measured as follows. (1) 0.25 g of toner is weighed, 40 mL of tetrahydrofuran is added thereto, and the mixture is mixed and stirred for 3 hours. (2) Then, the mixture obtained in (1) is centrifuged at 2,000 rpm (revolutions per minute) for 30 minutes. (3) Weigh 5 mL of the supernatant obtained after centrifugation in (2), transfer it to an aluminum dish, and evaporate and dry the tetrahydrofuran in a vacuum dryer adjusted to 50°C. (4) Using the difference in mass of the aluminum dish before and after drying, calculate the tetrahydrofuran insoluble matter excluding inorganic matter using the following formula. Tetrahydrofuran insolubles [%] = {0.25 - [(mass of supernatant and aluminum dish) - ( (mass of aluminum dish after drying) × 8}] / 0.25 × 100

[0087] The mass proportion of the resin having a glass transition temperature Tg of 0° C. or more and 30° C. or less in the tetrahydrofuran insoluble matter is, for example, preferably 5% by mass or more and 60% by mass or less, more preferably 10% by mass or more and 50% by mass or less.

[0088] 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 a core containing a binder resin, a colorant, and optionally other additives such as a release agent, and a coating layer containing the binder resin.

[0089] The volume average particle size (D50v) of the toner particles is, for example, preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

[0090] 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, for example) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution in which the sample was suspended was dispersed for 1 minute using an ultrasonic disperser, and then the particles were dispersed in a Coulter Multisizer II using an aperture of 100 μm diameter to obtain a particle size of 2 μm or more and 60 μm or less. The particle size distribution of particles with particle sizes in the range of μm or less is measured. 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:

[0091] The average circularity of the toner particles is, for example, preferably 0.90 or more and 1.00 or less, and more preferably 0.92 or more and 0.98 or less.

[0092] 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.

[0093] (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.

[0094] The surfaces of inorganic particles as external additives may be subjected to, for example, 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.

[0095] 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).

[0096] 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.

[0097] (Toner thermal analysis characteristics) The toner preferably has a peak (exothermic peak) that reaches a maximum in the range of 50°C to 70°C (preferably 55°C to 65°C) during the second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC). This facilitates the crystallization of the crystalline polyester resin in the image during the temperature rise, and prevents an excessive increase in the glossiness of the image. As a result, black This makes it easier to suppress unevenness in glossiness between the black image and the magenta image. The toner thermal analysis characteristics can be adjusted by, for example, adjusting the melting point and amount of the crystalline polyester resin, or by adding a crystal nucleating agent that promotes crystallization.

[0098] Thermal analysis measurement by differential scanning calorimetry (DSC) is carried out on the toner to be measured in accordance with ASTM D3418-8 (2008). Specifically, the measurement is carried out as follows. First, 10 mg of the toner to be measured is placed in a differential scanning calorimeter (Shimadzu DSC-60 Plus) equipped with an automatic tangent processing system, heated from room temperature (25°C) to 200°C at a heating rate of 10°C / min, and held at 200°C for 5 minutes, to obtain a heating spectrum (DSC curve) for the first heating. Subsequently, the sample is cooled to 50°C at a rate of -10°C / min using liquid nitrogen, and is kept at 50°C for 2 hours. Thereafter, the sample is heated from 50°C to 200°C at a temperature increase rate of 10°C / min, and a temperature increase spectrum (DSC curve) is obtained in the second temperature increase. In the temperature-rising spectrum (DSC curve) obtained during the second temperature rise, the maximum peak (i.e., exothermic peak) detected is identified. Here, an endothermic peak indicates a peak with a half-width of 15°C or less. Then, it is determined whether the apex of the maximum peak is in the range of 50° C. or more and 70° C. or less (for example, preferably in the range of 55° C. or more and 65° C. or less).

[0099] (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.

[0100] 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, for example, it is preferable to obtain toner particles by the aggregation and coalescence method.

[0101] 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, and crystalline polyester resin particles are used as the crystalline resin particles. The present aggregation-coalescence method will be described as a method for producing toner particles containing a binder resin, a colorant, a release agent, and internally added crosslinked resin particles, but the release agent and internally added crosslinked resin particles are components that are included in the toner particles as needed.

[0102] Each step will be described in detail below.

[0103] -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. In each dispersion preparation step, the first amorphous resin particles, the second amorphous resin particles, and the crystalline resin particles will be referred to as "resin particles" in the following description. Here, the resin particle dispersion liquid is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] The volume average particle size of the resin particles dispersed in the resin particle dispersion is, for example, preferably from 0.01 μm to 1 μm, more preferably from 0.08 μm to 0.8 μm, and even more preferably from 0.1 μm to 0.6 μm. 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.

[0108] 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.

[0109] In the same manner as in the resin particle dispersion, for example, a colorant dispersion, a release agent particle dispersion, and an internally crosslinked resin particle dispersion are also prepared. That is, with regard to the volume average particle diameter, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion, the colorant dispersed in the colorant dispersion, the release agent particles dispersed in the release agent particle dispersion, and the internally crosslinked resin particle dispersion are also prepared. The same applies to the bridge resin particles.

[0110] -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.

[0111] 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.

[0112] 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, such as a chelating agent.

[0113] 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 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, per 100 parts by mass of resin particles (first amorphous resin particles, second amorphous resin particles, and internally crosslinked resin particles).

[0114] -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.

[0115] 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.

[0116] -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 amorphous resin particles), to fuse and coalesce the second aggregate particles and form toner particles.

[0117] 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.

[0118] After the fusion and coalescence process, the toner particles formed in the solution are subjected to a known washing process, a solid-liquid separation process, and a drying process to obtain dry toner particles. The washing step is not particularly limited, but from the viewpoint of electrostatic chargeability, it is preferable to carry out sufficient displacement washing with ion-exchanged water. 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. The drying step is also not particularly limited, but from the viewpoint of productivity, it is preferable to carry out freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0119] 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.

[0120] <Electrostatic image developer set> The toner set for developing electrostatic images according to the present embodiment includes a first electrostatic image developer containing a black toner, and a second electrostatic image developer containing a magenta toner from the toner set for developing electrostatic images according to the present embodiment. Each developer of the electrostatic image developer set according to this embodiment may be a one-component developer containing only the toner in the toner set according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0121] 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.

[0122] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0123] Examples of the coating resin and the matrix resin include styrene-(meth)acrylic acid resin; polyolefin resins such as polyethylene resin and polypropylene resin; polystyrene, (meth)acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl Examples include polyvinyl or polyvinylidene resins such as ether and polyvinyl ketone; vinyl chloride-vinyl acetate copolymers; straight silicone resins or their modified products 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, for example, a (meth)acrylic resin, more preferably contain 50 mass% or more of the (meth)acrylic resin relative to the total mass of the resin, and even more preferably contain 80 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, for example, 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.

[0124] 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.

[0125] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is, for example, preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0126] <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 this embodiment includes a first image forming unit that forms a black image using black toner from the toner set for developing electrostatic images according to this embodiment, a second image forming unit that forms a magenta image using magenta toner from the toner set for developing electrostatic images according to this embodiment, a transfer device that transfers the black image and the magenta image onto a recording medium, and a fixing device that fixes the black image and the magenta image onto the recording medium. The image forming apparatus according to this embodiment may have, as a first or second image forming unit, 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, and a developing device that develops the electrostatic image formed on the surface of the image carrier with an electrostatic image developer into a toner image. The image forming apparatus according to this embodiment may have 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, and first and second developing devices that develop the electrostatic image formed on the surface of the image carrier using an electrostatic image developer as a toner image as the first or second image forming unit.

[0127] In the image forming apparatus according to the present embodiment, a first image forming process is performed to form a black image using a black toner of the toner set for developing electrostatic images according to the present embodiment, and a second image forming process is performed to form a magenta image using a magenta toner of the toner set for developing electrostatic images according to the present embodiment. An image forming method (image forming method according to the present embodiment) is carried out, which includes a step of transferring a black image and a magenta image onto a recording medium, a transfer step of transferring the black image and the magenta image onto the recording medium, and a fixing step of fixing the black image and the magenta image onto the recording medium.

[0128] The image forming apparatus according to this embodiment may be a known image forming apparatus such as a direct transfer type apparatus that transfers a toner image (in this embodiment, a black image or a magenta image) formed on the surface of an image carrier directly to a recording medium; an intermediate transfer type apparatus that performs a primary transfer of a toner image (in this embodiment, a black image or a magenta image) formed on the surface of an image carrier to the surface of an intermediate transfer body, and then performs a secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with a cleaning means that cleans the surface of the image carrier after the transfer of the toner image but before charging; or an apparatus equipped with a discharging means that irradiates the surface of the image carrier with discharging light to discharge it 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.

[0129] 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 each electrostatic image developer of the electrostatic image developer set according to the present embodiment is preferably used. Specifically, the process cartridge includes a first developing device that contains the first electrostatic image developer of the electrostatic image developer set according to this embodiment, and a second developing device that contains the second electrostatic image developer of the electrostatic image developer set according to this embodiment, and is a process cartridge that can be attached to and detached from an image forming apparatus.

[0130] 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.

[0131] 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.

[0132] 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. Further, the developing devices (examples of developing devices) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are supplied with toner including four colors of toner, namely, yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively. can be.

[0133] 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.

[0134] 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).

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] <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.

[0145] The process cartridge according to the present embodiment is not limited to the above configuration, and may include a developing device and, if necessary, other components such as an image carrier, a charging device, an electrostatic image forming device, and a transfer device. and at least one other device selected from the above.

[0146] 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.

[0147] 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).

[0148] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that accommodates each toner of the toner set according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge accommodates replenishment toner to be supplied to a developing device provided in the image forming apparatus. Specifically, the toner cartridge set according to this embodiment has a first toner cartridge that contains black toner from the toner set for developing electrostatic images according to this embodiment, and a second toner cartridge that contains magenta toner from the toner set for developing electrostatic images according to this embodiment, and is a toner cartridge set that can be attached to and detached from an image forming device.

[0149] 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]

[0150] 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.

[0151] [Preparation of emulsion (1)] Styrene: 48.4 parts n-Butyl acrylate: 50.1 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 are placed in a mixing vessel equipped with a stirrer and stirred to form emulsion (1). Prepared.

[0152] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (S1)] 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 while stirring until the temperature of the reaction solution reached 75°C. 10 parts of emulsion (1) were added, and then an aqueous solution of ammonium persulfate with a concentration adjusted to 10% by mass was added. 20 parts were added and held for 30 minutes. Thereafter, while maintaining the temperature of the reaction solution at 75° C., 190 parts of emulsion (1) was gradually added dropwise to the reaction vessel over 30 minutes using a pump, and then 200 parts of emulsion (1) was added dropwise over 30 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, after which it was cooled to room temperature. Ion-exchanged water was then added to adjust the solid content to 20% by mass, to give an internally-added crosslinked resin particle dispersion (S1). The resulting resin particles had a volume average particle size of 165 nm and a glass transition temperature of 14.5°C as measured by a differential scanning calorimeter.

[0153] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (S2)] [Preparation of emulsion (2)] Emulsion (2) was prepared in the same manner as in the preparation of emulsion (1), except that the amounts of styrene and n-butyl acrylate were changed to 39.0 parts styrene and 59.5 parts n-butyl acrylate. Internally added crosslinked resin particle dispersion (S2) was prepared in the same manner as (S1), except that emulsion (2) was used instead of emulsion (1). The resulting resin particles had a volume average particle size of 169 nm and a glass transition temperature of -1°C as measured by a differential scanning calorimeter.

[0154] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (S3)] [Preparation of emulsion (3)] Emulsion (3) was prepared in the same manner as in the preparation of emulsion (1), except that the amounts of styrene and n-butyl acrylate were changed to 57.6 parts styrene and 40.9 parts n-butyl acrylate. Internally added crosslinked resin particle dispersion (S3) was prepared in the same manner as (S1), except that emulsion (3) was used instead of emulsion (1). The volume average particle size of the resulting resin particles was 166 nm, and the glass transition temperature measured by a differential scanning calorimeter was 29.6°C.

[0155] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (S4)] [Preparation of emulsion (4)] Emulsion (4) was prepared in the same manner as in the preparation of emulsion (1), except that the amounts of styrene and n-butyl acrylate were changed to 39.7 parts styrene and 58.8 parts n-butyl acrylate. Internally added crosslinked resin particle dispersion (S4) was prepared in the same manner as (S1), except that emulsion (4) was used instead of emulsion (1). The volume average particle size of the resulting resin particles was 163 nm, and the glass transition temperature measured by a differential scanning calorimeter was 0.1°C.

[0156] [Preparation of Internally Added Crosslinked Resin Particle Dispersion (S5)] [Preparation of emulsion (5)] Emulsion (5) was prepared in the same manner as in the preparation of emulsion (1), except that the amounts of styrene and n-butyl acrylate were changed to 58.6 parts styrene and 39.9 parts n-butyl acrylate. Internally added crosslinked resin particle dispersion (S5) was prepared in the same manner as (S1), except that emulsion (5) was used instead of emulsion (1). The volume average particle size of the resulting resin particles was 168 nm, and the glass transition temperature measured by a differential scanning calorimeter was 31.2°C.

[0157] [Preparation of styrene butadiene rubber particles (S6)] Styrene: 54.0 parts Butadiene: 44.5 parts Acrylic acid: 1.4 parts 0.1 parts tert-dodecanethiol 1.2 parts anionic surfactant (Dowfax2a-1, manufactured by Dow Chemical) Ion-exchanged water: 200 parts Potassium persulfate: 1 part The above materials were placed in a polymerization reactor and polymerized for 2 hours under a nitrogen atmosphere at a temperature of 50°C, and then the reaction was continued for 3 hours to terminate the polymerization. Ion-exchanged water was added to the obtained dispersion to adjust the solid content to 20% by mass, thereby obtaining a rubber particle dispersion (1). The volume average particle size of the resulting rubber particles was 200 nm, and the glass transition temperature measured by a differential scanning calorimeter was 14.9°C.

[0158] [Preparation of amorphous polyester resin particle dispersion (KA1)] Terephthalic acid: 80 parts by mole Fumaric acid: 13 mole parts Isophthalic acid: 5 mole parts Trimellitic anhydride: 2 mole parts Bisphenol A propylene oxide 2 mole adduct: 20 mole parts Bisphenol A propylene oxide 3 mole adduct: 80 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, after which 1.2 parts of dibutyltin oxide were 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, yielding amorphous polyester resin (KA1).

[0159] Amorphous polyester resin (KA1): 100 parts Methyl ethyl ketone: 55 parts Isopropanol: 10 parts 10% ammonia solution: 3.3 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 (KA1) was dissolved while stirring and mixing at 100 rpm in a water circulation type thermostatic bath while maintaining the liquid temperature at 50°C. Next, the water circulation type thermostatic bath was set to 40°C, and a total of 300 parts of ion-exchanged water maintained at 40°C was dropped at a rate of 3 parts / min to cause phase inversion and produce an emulsion. The resulting emulsion was placed in an eggplant flask and placed in an evaporator equipped with a vacuum control unit via a trap bulb. The eggplant flask was heated in a 60°C hot water bath while rotating, 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 eggplant 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 (KA1) 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 (KA1) was 150 nm.

[0160] [Preparation of amorphous polyester resin particle dispersion (KA2)] Terephthalic acid: 85 parts by mole Fumaric acid: 13 mole parts Trimellitic anhydride 2 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 152 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (KA2).

[0161] [Preparation of amorphous polyester resin particle dispersion (KA3)] Terephthalic acid: 75 parts by mole Fumaric acid: 13 mole parts Isophthalic acid: 10 mole parts Trimellitic anhydride: 2 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 151 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (KA3).

[0162] [Preparation of amorphous polyester resin particle dispersion (KA4)] Terephthalic acid: 65 parts by mole Fumaric acid: 13 mole parts Isophthalic acid: 20 mole parts Trimellitic anhydride: 2 mole parts A resin particle dispersion containing resin particles having a volume average particle size of 155 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (K1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (KA4).

[0163] [Preparation of amorphous polyester resin particle dispersion (KA5)] Terephthalic acid: 53.5 parts by mole Isophthalic acid: 46.5 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 151 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (KA5). [Preparation of amorphous polyester resin particle dispersion (KA6)] Terephthalic acid 32 mole parts Fumaric acid 13 mole parts Isophthalic acid 33 mole parts Trimellitic anhydride 22 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 158 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (KA6).

[0164] [Preparation of amorphous polyester resin particle dispersion (MA1)] Terephthalic acid: 55 parts by mole Isophthalic acid: 30 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles having a volume average particle size of 155 nm was prepared in the same manner as in the preparation of amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA1).

[0165] [Preparation of amorphous polyester resin particle dispersion (MA2)] Terephthalic acid: 45 parts by mole Isophthalic acid: 40 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion in which resin particles having a volume average particle size of 150 nm were dispersed was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20% by mass, thereby obtaining an amorphous polyester resin particle dispersion (MA2).

[0166] [Preparation of amorphous polyester resin particle dispersion (MA3)] Terephthalic acid: 65 parts by mole Isophthalic acid: 20 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 153 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA3).

[0167] [Preparation of amorphous polyester resin particle dispersion (MA4)] Terephthalic acid: 75 parts by mole Isophthalic acid: 10 mole parts Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 152 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA4).

[0168] [Preparation of amorphous polyester resin particle dispersion (MA5)] Terephthalic acid: 74 parts by mole Isophthalic acid: 11 mole parts Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 158 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA5).

[0169] [Preparation of amorphous polyester resin particle dispersion (MA6)] Terephthalic acid: 70 parts by mole Isophthalic acid: 15 mole parts Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 152 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA6).

[0170] [Preparation of amorphous polyester resin particle dispersion (MA7)] Terephthalic acid: 35 parts by mole Isophthalic acid: 50 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 154 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA7).

[0171] [Preparation of amorphous polyester resin particle dispersion (MA8)] Terephthalic acid: 5 parts by mole Isophthalic acid: 80 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 153 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA8).

[0172] [Preparation of amorphous polyester resin particle dispersion (MA9)] Terephthalic acid: 4 parts by mole Isophthalic acid: 81 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 155 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA9).

[0173] [Preparation of amorphous polyester resin particle dispersion (MA10)] Terephthalic acid: 15 parts by mole Isophthalic acid: 70 parts by mole Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 157 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA10).

[0174] [Preparation of amorphous polyester resin particle dispersion (MA11)] Terephthalic acid: 71 parts by mole Isophthalic acid: 14 mole parts Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 152 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA11).

[0175] [Preparation of amorphous polyester resin particle dispersion (MA12)] Terephthalic acid: 39 parts by mole Isophthalic acid: 46 mol parts Trimellitic anhydride: 15 mole parts A resin particle dispersion containing resin particles with a volume average particle size of 150 nm was obtained in the same manner as in the amorphous polyester resin particle dispersion (KA1), except that the above material was used as the acid component. Ion-exchanged water was added to the resin particle dispersion to adjust the solid content to 20 mass % to obtain amorphous polyester resin particle dispersion (MA12).

[0176] [Preparation of Crystalline Polyester Resin Particle Dispersion (C1)] 1,10-dodecanedioic acid: 225 parts 1,6-Hexanediol: 174 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 160°C over 1 hour, followed by the addition of 0.8 parts by mass of dibutyltin oxide. The temperature was raised to 180°C over 6 hours while distilling off the water produced, and the mixture was stirred and refluxed for 5 hours while maintaining the temperature at 180°C to allow the reaction to proceed. Thereafter, the mixture was stirred under reduced pressure (3 kPa). The temperature was gradually increased to 230°C, and the mixture was stirred for 2 hours while maintaining the temperature at 230°C. The reaction mixture was then cooled. After cooling, solid-liquid separation was performed, and the solid was dried to obtain a crystalline polyester resin (C1). The melting point of the obtained polyester resin (C1) was 71°C.

[0177] Crystalline polyester resin (C1): 100 parts Methyl ethyl ketone: 40 parts Isopropanol: 30 parts 10% ammonia solution: 4 parts 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 and mixing 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 10 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. When the amount of solvent recovered reached 750 parts by mass, the pressure was returned to normal, and the recovery flask was water-cooled to obtain a dispersion. The volume average particle size D50v of the resin particles in this dispersion was 110 nm. Ion-exchanged water was then added to obtain a crystalline polyester resin particle dispersion (C1) with a solid content of 20% by mass.

[0178] [Preparation of crystalline polyester resin particle dispersion (C2)] Suberic acid: 225 parts 1,6-Hexanediol: 174 parts A crystalline polyester resin (C2) was obtained in the same manner as in the preparation of the crystalline polyester resin particle dispersion (C1), except that the above materials were used. The melting point was 70°C.

[0179] [Preparation of crystalline polyester resin particle dispersion (C3)] Tetradecanedioic acid: 225 parts 1,10-Decanediol: 174 parts A crystalline polyester resin (C3) was obtained in the same manner as in the preparation of the crystalline polyester resin particle dispersion (C1), except that the above materials were used. The melting point was 72°C.

[0180] [Preparation of crystalline polyester resin particle dispersion (C4)] Suberic acid: 225 parts 1,6-Hexanediol: 174 parts A crystalline polyester resin (C4) was obtained in the same manner as for the crystalline polyester resin particle dispersion (C1), except that the above materials were used and stirred for 8 hours at 180° C. The melting point was 73° C.

[0181] [Preparation of crystalline polyester resin particle dispersion (C5)] Tetradecanedioic acid: 225 parts 1,10-Decanediol: 174 parts A crystalline polyester resin (C5) was obtained in the same manner as for the crystalline polyester resin particle dispersion (C1), except that the above materials were used and stirring was carried out at 180°C for 8 hours. The melting point was 73°C.

[0182] [Preparation of Colorant Dispersion (K1)] Carbon black (Regel 330, manufactured by Cabot Corporation): 110 parts Anionic surfactant (Neopelex G-65, Kao Corporation): 6 parts Ion-exchanged water: 300 parts The above materials were mixed and homogenized using a homogenizer (Ultra Turrax T50, manufactured by IKA). The resulting dispersion was dispersed in water for 10 minutes. Ion-exchanged water was added to the resulting dispersion to obtain a colorant dispersion (K1) with a solid content of 20% by mass. The volume average particle size of the colorant particles in the colorant dispersion (K1) was 220 nm.

[0183] [Preparation of Colorant Dispersion (M1)] Magenta colorant ("CI Pigment Red 122", Zeyachem): 110 parts Anionic surfactant (Neopelex G-65, Kao Corporation): 6 parts Ion-exchanged water: 300 parts The above materials were mixed and dispersed for 10 minutes using a homogenizer (Ultra Turrax T50, manufactured by IKA). Ion-exchanged water was added to the resulting dispersion to obtain a colorant dispersion (M1) with a solid content of 20% by mass. The volume average particle size of the colorant particles in the colorant dispersion (M1) was 220 nm.

[0184] [Preparation of release agent particle dispersion] Fischer-Tropsch wax (Sasolwax H1, Sasol): 100 parts Anionic surfactant (Neopelex G-65): 6 parts Ion-exchanged water: 300 parts The above materials were mixed and heated to 100°C, and dispersed using a homogenizer (Ultra Turrax T50). Further, the mixture was dispersed using a Manton-Gaulin high-pressure homogenizer (Gaulin), and ion-exchanged water was added to the dispersion to obtain a release agent particle dispersion with a solid content of 20% by mass. The volume average particle size of the release agent particles in the release agent particle dispersion was 230 nm.

[0185] [Preparation of black toner (K1)] Amorphous polyester resin particle dispersion (KA1) (solid content 20% by mass): 68.4 parts Internal crosslinked resin particle dispersion (1) (solid content 20% by mass): 20 parts Crystalline polyester resin particle dispersion (C1) (solid content 20% by mass): 29.6 parts Colorant dispersion (K1) (solid content 20% by mass): 21 parts Release agent particle dispersion (solid content 20% by mass): 11 parts Anionic surfactant (Eleminol MON-2): 0.7 parts Ion-exchanged water: 200 parts 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. Next, 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 with 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, 50 parts of amorphous polyester resin particle dispersion (KA1) was added and held for 30 minutes. Next, 0.1 N sodium hydroxide aqueous 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 (K1) with a volume average particle size of 5.5 μm. 100 parts of the toner particles (K1) and 2.0 parts of hydrophobic silica (manufactured by Nippon Aerosil: trade name RY200) were mixed in a Henschel mixer to obtain black toner (K1).

[0186] [Preparation of Black Toners (K2) to (K22)] Black toners (K2) to (K22) were obtained in the same manner as in the preparation of black toner (K1), except that the types and amounts of each resin particle dispersion were changed as shown in Table 4. The amorphous polyester resin particle dispersion liquid added later was also prepared using the amorphous polyester resin particles shown in Table 4. However, the amount of post-added amorphous polyester resin particle dispersion was 50 parts, the same as that of the black toner (K1).

[0187] [Preparation of magenta toner (M1)] Amorphous polyester resin particle dispersion (MA1) (solid content 20% by mass): 76.4 parts Internal crosslinked resin particle dispersion (1) (solid content 20% by mass): 10 parts Crystalline polyester resin particle dispersion (C1) (solid content 20% by mass): 31.6 parts Colorant dispersion (M1) (solid content 20% by mass): 21 parts Release agent particle dispersion (solid content 20% by mass): 11 parts Anionic surfactant (Eleminol MON-2): 0.7 parts Ion-exchanged water: 200 parts 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, 50 parts of amorphous polyester resin particle dispersion (MA1) was added and held for 30 minutes. Next, 0.1 N aqueous sodium hydroxide 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 (M1) with a volume average particle size of 5.5 μm. 100 parts of the toner particles (M1) and 2.0 parts of hydrophobic silica (manufactured by Nippon Aerosil: trade name RY200) were mixed in a Henschel mixer to obtain a magenta toner (M1).

[0188] [Preparation of magenta toners (M2) to (M32)] Magenta toners (M2) to (M32) were obtained in the same manner as in the production of magenta toner (M1), except that the types and amounts of each resin particle dispersion were changed as shown in Table 4. The post-added amorphous polyester resin particle dispersion was also changed to the amorphous polyester resin particle dispersion shown in Table 4. However, the amount of the post-added amorphous polyester resin particle dispersion was 50 parts, the same as that of the magenta toner (M1).

[0189] [Examples 1 to 44, Comparative Examples 1 to 6] The combination of black toner and magenta toner shown in Table 5 was used as the toner set for each example. The following items are shown for each toner. The methods for measuring the properties of the toner are as described below. Content (mass%) of crystalline polyester resin relative to binder resin in black toner particles WC(K) Content (mass%) of crystalline polyester resin relative to binder resin in magenta toner particles WC(M) The mass ratio (mass%) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the amorphous polyester resin contained in black toner particles, P(K) The mass ratio (mass%) P(M) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the amorphous polyester resin contained in magenta toner particles The mass ratio (mass%) of the structural units derived from terephthalic acid to the structural units derived from polycarboxylic acids in the amorphous polyester resin contained in the black toner particles, PT(K) The mass ratio (mass%) of the structural units derived from terephthalic acid to the structural units derived from polycarboxylic acids in the amorphous polyester resin contained in the magenta toner particles is PT(M). Component type, glass transition temperature (Tg) and amount WT (K) (mass%) of tetrahydrofuran insoluble matter in black toner particles Component type, glass transition temperature (Tg) and amount WT(M) (mass%) of tetrahydrofuran insoluble matter in magenta toner particles The maximum peak temperature obtained in the second temperature rise in thermal analysis measurements by differential scanning calorimetry (DSC) for black toner and magenta toner (referred to as the maximum peak temperature of the DSC curve in the table).

[0190] [evaluation] (Preparation of developer) Each developer was prepared by mixing 8 parts of each toner of the toner set of each example with 92 parts of the carrier described below to obtain a developer set of black and magenta developers. The obtained developer sets were used for 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.

[0191] (low temperature fixability) The black toner and magenta toner of each of the prepared developer sets were filled into the black developing unit and magenta developing unit of a modified "RevoriaPress PC1120" manufactured by Fujifilm Business Innovation Co., Ltd., which was used as an image quality evaluation device. Using an image quality evaluation device, a black solid image and a magenta solid image were formed on Colotech 90 paper (manufactured by Xerox Corporation) using black toner and magenta toner, respectively. The resulting fixed image was visually inspected to see if cold offset (a phenomenon in which the fixed image is transferred to the fixing member due to insufficient heating of the toner) had occurred, and evaluated according to the following evaluation criteria. A: No trace of metastasis B: Minor metastasis C: Metastasis

[0192] (non-uniformity of image gloss) The black toner and magenta toner of each of the prepared developer sets were filled into the black developing unit and magenta developing unit of a modified "RevoriaPress PC1120" manufactured by Fujifilm Business Innovation Co., Ltd., which was used as an image quality evaluation device. Using an image quality evaluation device, a black solid image and a magenta solid image were formed on coated paper (OK Topcoat, manufactured by Oji Paper Co., Ltd.) using black toner and magenta toner, respectively. Then, each of the obtained images was left under direct sunlight for one month. After leaving the samples, the gloss of the black solid image and the magenta solid image was measured using a gloss meter GM-26D (manufactured by Murakami Color Research Laboratory) at an incident light angle of 75 degrees to the image. Gloss was measured at five randomly selected points on each solid image, and the average value was calculated. The difference in the average gloss level between the black solid image and the magenta solid image was then determined and evaluated according to the following evaluation criteria. In addition, the difference in the average gloss values ​​between the black solid image and the magenta solid image was calculated in the same manner as above, except that each of the obtained images was left for two weeks in a dark room in an environment of 55°C rather than in direct sunlight, and evaluated according to the following evaluation criteria. The smaller the difference in gloss, the smaller the non-uniformity in gloss between the black solid image and the magenta solid image (i.e., the less gloss unevenness). Note that a difference in gloss of 5.0 or more is not acceptable. G0: The difference in gloss is 0 or more and 1.0 or less G1: The difference in gloss is 1.1 or more and 2.0 or less G2: The difference in gloss is 2.1 or more and 3.5 or less G3: The difference in gloss is 3.6 or more and 4.9 or less G4: Glossiness difference is 5.0 or more (NG)

[0193] [Table 1]

[0194] [Table 2]

[0195] [Table 3]

[0196] [Table 4]

[0197] [Table 5-1]

[0198] [Table 5-2]

[0199] [Table 5-3]

[0200] From the above results, it can be seen that the toner of this embodiment can suppress the non-uniformity in glossiness of black and magenta images that occurs when exposed to the outdoors, while ensuring low-temperature fixability, compared to the toner of the comparative example.

[0201] This embodiment includes the following aspects. (((1))) a black toner having black toner particles containing a binder resin and a black colorant; a magenta toner having magenta toner particles containing a binder resin and a magenta colorant; Equipped with the binder resin contained in the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, a content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less; the amorphous polyester resin contained in the black toner particles and the magenta toner particles comprises a structural unit derived from a polycarboxylic acid and a structural unit derived from a polyhydric alcohol, The relationship between the mass ratio (mass%) P(K) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the black toner particles and the mass ratio (mass%) P(M) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the magenta toner particles satisfies the following formula (P1): Formula (P1): 10≦P(M)-P(K)≦40 (((2))) The toner set for developing electrostatic images according to (((1))), wherein the relationship between the mass proportion (mass%) P(K) of the constituent units derived from phthalic acid other than terephthalic acid in the black toner particles and the mass proportion (mass%) P(M) of the constituent units derived from phthalic acid other than terephthalic acid in the magenta toner particles satisfies the following formula (P2): Formula (P2): 15≦P(M)-P(K)≦35 (((3))) The toner set for developing electrostatic images according to (((1))) or (((2))), wherein the mass proportion (mass %) P(M) of the structural units derived from phthalic acid other than terephthalic acid is 11 mass % or more and 80 mass % or less. (((4))) The toner set for developing electrostatic images according to (((3))), wherein the mass proportion (mass %) P(M) of the structural units derived from phthalic acid other than terephthalic acid is 15 mass % or more and 50 mass % or less. (((5))) The toner set for developing electrostatic images according to any one of (((1))) to (((4))), wherein the structural unit derived from a polycarboxylic acid in the amorphous polyester resin contained in the black toner particles contains a structural unit derived from terephthalic acid as a main component. (((6))) The toner set for developing electrostatic images according to any one of (((1))) to (((5))), wherein the relationship between the content (mass %) WC(K) of the crystalline polyester resin relative to the binder resin in the black toner particles and the content (mass %) WC(M) of the crystalline polyester resin relative to the binder resin in the magenta toner particles satisfies the following formula (WC1): Formula (WC1)0.90≦WC(K) / WC(M)≦1.10 (((7))) The toner set for developing electrostatic images according to any one of (((1))) to (((6))), wherein the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles is 10% by mass or more and 40% by mass or less, and satisfies the following formula (WT1): Formula (WT1): WT(K)>WT(M) (((8))) The toner set for developing electrostatic images according to (((7))), wherein the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles satisfies the following formula (WT2): Formula (WT2): 2≦WT(K)-WT(M)≦10 (((9))) The toner set for developing electrostatic images according to (((7))) or (((8))), wherein the tetrahydrofuran insoluble matter in the black toner particles and the magenta toner particles contains a resin having a glass transition temperature Tg of 0°C or higher and 30°C or lower. (((10))) The toner set for developing electrostatic images according to (((9))), wherein the resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower is a styrene-(meth)acrylic copolymer. (((11))) The toner set for developing electrostatic images according to any one of items 1 to 10, wherein the black toner and the magenta toner have a peak that reaches a maximum in the range of 50°C or more and 70°C or less in a second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC). (((12))) a first electrostatic image developer containing the black toner in the toner set for developing electrostatic images according to any one of (((1))) to (((11))); a second electrostatic image developer containing the magenta toner of the toner set for developing electrostatic images according to any one of (((1))) to (((11))); Electrostatic image developer set comprising: (((13))) A first toner cartridge containing the black toner in the toner set for developing electrostatic images according to any one of (((1))) to (((11))); A second toner cartridge containing the magenta toner in the toner set for developing electrostatic images according to any one of (((1))) to (((11))), and and A toner cartridge set that is detachably attached to an image forming apparatus. (((14))) a first developing device containing the first electrostatic image developer of the electrostatic image developer set described in (((12))); a second developing device containing the second electrostatic image developer of the electrostatic image developer set described in (((12))); Equipped with A process cartridge is detachably mounted in an image forming apparatus. (((15))) a first image forming unit that forms a black image using the black toner in the toner set for developing electrostatic images according to any one of (((1))) to (((11))); a second image forming unit that forms a magenta image using the magenta toner in the toner set for developing electrostatic images according to any one of (((1))) to (((11))); a transfer device that transfers the black image and the magenta image onto a recording medium; a fixing device that fixes the black image and the magenta image onto the recording medium; An image forming apparatus comprising: (((16))) a first image forming step of forming a black image using the black toner of the toner set for developing electrostatic images according to any one of (((1))) to (((11))); a second image forming step of forming a magenta image using the magenta toner of the toner set for developing electrostatic images according to any one of (((1))) to (((11))); a transfer step of transferring the black image and the magenta image onto a recording medium; a fixing step of fixing the black image and the magenta image on the recording medium; An image forming method comprising the steps of:

[0202] The effects of the above embodiment are as follows. According to the invention of (((1))), there is provided a toner for developing electrostatic images, which comprises a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant, wherein the binder resin of the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, and the content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less, The present invention provides a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the relationship between the mass ratio (mass %) P(K) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the terephthalic acid resin and the mass ratio (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid to structural units derived from polycarboxylic acids in the amorphous polyester resin contained in the magenta toner particles does not satisfy formula (P1). According to the invention related to (((2))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the mass proportion (mass%) P(K) of constituent units derived from phthalic acid other than terephthalic acid in the black toner particles and the mass proportion (mass%) P(M) of constituent units derived from phthalic acid other than terephthalic acid in the magenta toner particles does not satisfy formula (P2). According to the invention related to (((3))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the mass proportion (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid is less than 11 mass % or more than 80 mass %. According to the invention related to (((4))), a toner set for developing electrostatic images is provided that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the mass proportion (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid is less than 15 mass % or more than 50 mass %. According to the invention related to (((5))), there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness between black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the structural unit derived from a polycarboxylic acid in the amorphous polyester resin contained in the black toner particles does not contain terephthalic acid. According to the invention related to (((6))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the content (mass %) WC(K) of the crystalline polyester resin relative to the binder resin in black toner particles and the content (mass %) WC(M) of the crystalline polyester resin relative to the binder resin in magenta toner particles does not satisfy formula (WC1). According to the invention related to (((7))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) in black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) in magenta toner particles is less than 10% by mass or more than 40% by mass, or when formula (WT1) is not satisfied. According to the invention related to (((8))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to a case in which the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) in black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) in magenta toner particles does not satisfy formula (WT2). According to the invention related to (((9))), there is provided a toner set for developing electrostatic images, which can suppress uneven glossiness of black images and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the tetrahydrofuran-insoluble components in the black toner particles and the magenta toner particles contain a resin whose glass transition temperature Tg is lower than 0°C or higher than 30°C. According to the invention related to (((10))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness between black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the resin having a glass transition temperature Tg of 0°C or higher and 30°C or lower is styrene-butadiene rubber. According to the invention related to (((11))), there is provided a toner set for developing electrostatic images that can suppress uneven glossiness of black and magenta images that occurs when exposed to the outdoors while ensuring low-temperature fixability, compared to when the black toner and magenta toner have a peak that is maximum in the range of less than 50°C or more than 70°C in the second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC).

[0203] According to the invention of (((12)), (((13))), (((14)), (((15))), or (((16)), there is provided a toner for developing electrostatic images, which comprises a black toner having black toner particles containing a binder resin and a black colorant, and a magenta toner having magenta toner particles containing a binder resin and a magenta colorant, wherein the binder resin of the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, and the content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less. The present invention provides an electrostatic image developer set, toner cartridge set, process cartridge, image forming apparatus, or image forming method that can suppress uneven gloss levels between black and magenta images that occur when exposed to the outdoors while ensuring low-temperature fixability, compared to when an electrostatic image developing toner is used in which the relationship between the mass ratio (mass %) P(K) of structural units derived from phthalic acids other than terephthalic acid to the structural units derived from polycarboxylic acids and the mass ratio (mass %) P(M) of structural units derived from phthalic acids other than terephthalic acid to the structural units derived from polycarboxylic acids in an amorphous polyester resin contained in magenta toner particles does not satisfy formula (P1). [Explanation of symbols]

[0204] 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. a black toner having black toner particles containing a binder resin and a black colorant; a magenta toner having magenta toner particles containing a binder resin and a magenta colorant; Equipped with the binder resin contained in the black toner particles and the magenta toner particles contains an amorphous polyester resin and a crystalline polyester resin, a content of the crystalline polyester resin relative to the binder resin in the black toner particles and the magenta toner particles is 7% by mass or more and 40% by mass or less; the amorphous polyester resin contained in the black toner particles and the magenta toner particles comprises a structural unit derived from a polycarboxylic acid and a structural unit derived from a polyhydric alcohol, The relationship between the mass ratio (mass %) P(K) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the black toner particles and the mass ratio (mass %) P(M) of the structural units derived from phthalic acid other than terephthalic acid to the structural units derived from the polycarboxylic acid in the amorphous polyester resin contained in the magenta toner particles satisfies the following formula (P1): Formula (P1): 10≦P(M)-P(K)≦40

2. 2. The toner set for developing electrostatic images according to claim 1, wherein the relationship between the mass percentage (mass%) P(K) of the constituent units derived from phthalic acid other than terephthalic acid in the black toner particles and the mass percentage (mass%) P(M) of the constituent units derived from phthalic acid other than terephthalic acid in the magenta toner particles satisfies the following formula (P2): Formula (P2): 15≦P(M)-P(K)≦35

3. 2. The toner set for developing electrostatic images according to claim 1, wherein the mass percentage (mass %) P(M) of the structural units derived from phthalic acid other than terephthalic acid is 11 mass % or more and 80 mass % or less.

4. 4. The toner set for developing electrostatic images according to claim 3, wherein the mass percentage (mass %) P(M) of the structural units derived from phthalic acid other than terephthalic acid is 15 mass % or more and 50 mass % or less.

5. 2. The toner set for developing electrostatic images according to claim 1, wherein the structural unit derived from a polycarboxylic acid in the amorphous polyester resin contained in the black toner particles contains a structural unit derived from terephthalic acid as a main component.

6. 2. The toner set for developing electrostatic images according to claim 1, wherein a relationship between a content (mass%) WC(K) of the crystalline polyester resin relative to the binder resin in the black toner particles and a content (mass%) WC(M) of the crystalline polyester resin relative to the binder resin in the magenta toner particles satisfies the following formula (WC1): Formula (WC1) 0.90≦WC(K) / WC(M)≦1.10

7. 2. The toner set for developing electrostatic images according to claim 1, wherein the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles is 10 mass% or more and 40 mass% or less, and satisfies the following formula (WT1): Formula (WT1): WT(K)>WT(M)

8. 8. The toner set for developing electrostatic images according to claim 7, wherein the relationship between the tetrahydrofuran insoluble content (mass%) WT(K) of the black toner particles and the tetrahydrofuran insoluble content (mass%) WT(M) of the magenta toner particles satisfies the following formula (WT2): Formula (WT2): 2≦WT(K)-WT(M)≦10

9. 8. The toner set for developing electrostatic images according to claim 7, wherein the tetrahydrofuran insoluble components of the black toner particles and the magenta toner particles contain a resin having a glass transition temperature Tg of 0°C or higher and 30°C or lower.

10. 10. The toner set for developing electrostatic images according to claim 9, wherein the resin having a glass transition temperature Tg of 0° C. or higher and 30° C. or lower is a styrene-(meth)acrylic copolymer.

11. 2. The toner set for developing electrostatic images according to claim 1, wherein the black toner and the magenta toner have a peak that reaches a maximum in the range of 50°C to 70°C in a second temperature rise in thermal analysis measurement by differential scanning calorimetry (DSC).

12. a first electrostatic image developer containing the black toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; a second electrostatic image developer containing the magenta toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; Electrostatic image developer set comprising:

13. a first toner cartridge containing the black toner of the toner set for developing an electrostatic image according to any one of claims 1 to 11; a second toner cartridge containing the magenta toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; and A toner cartridge set that is detachably attached to an image forming apparatus.

14. a first developing device containing the first electrostatic image developer of the electrostatic image developer set according to claim 12; a second developing device containing the second electrostatic image developer of the electrostatic image developer set according to claim 12; Equipped with A process cartridge is detachably mounted in an image forming apparatus.

15. a first image forming unit that forms a black image using the black toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; a second image forming unit that forms a magenta image using the magenta toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; a transfer device that transfers the black image and the magenta image onto a recording medium; a fixing device that fixes the black image and the magenta image onto the recording medium; An image forming apparatus comprising:

16. a first image forming step of forming a black image using the black toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; a second image forming step of forming a magenta image using the magenta toner of the toner set for developing electrostatic images according to any one of claims 1 to 11; a transfer step of transferring the black image and the magenta image onto a recording medium; a fixing step of fixing the black image and the magenta image on the recording medium; An image forming method comprising the steps of:

Images