Electrostatic image developing toner set, electrostatic image developer set, toner cartridge set, process cartridge, image forming apparatus, and image forming method

Abstract

To provide an electrostatic image developing toner set which produces images with a superior property to prevent color fading in a high-temperature, high-humidity environment.SOLUTION: An electrostatic image developing toner set provided herein comprises a toner A containing a binder resin A and a dye and a white toner B containing a binder resin B and a titanium oxide pigment, where an absolute value (ΔSP value) of a difference in solubility parameter between the binder resin A of the toner A and the binder resin B of the white toner B is 0.5 or greater; or comprises a toner A containing a binder resin A and a dye and a white toner B containing a binder resin B and a titanium oxide pigment, where one of the binder resin A of the toner A and the binder resin B of the white toner B contains styrene-acrylic resin and the other contains a polyester resin.SELECTED DRAWING: Figure 1

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] Methods for visualizing image information, such as electrophotography, are currently used in a variety of fields. In electrophotography, an electrostatic image is formed as image information on the surface of an image carrier by charging and forming an electrostatic image. Then, a toner image is formed on the surface of the image carrier using a developer containing toner. This toner image is then transferred to a recording medium, and the toner image is then fixed to the recording medium. Through these steps, the image information is visualized as an image.

[0003] For example, Patent Document 1 discloses a toner for developing electrostatic images, characterized in that the toner particles are formed by dispersing colored fine particles having an average primary particle diameter of 10 to 300 nm in a binder resin for forming toner particles, the colored fine particles containing a medium resin for colored fine particles different from the binder resin for forming toner particles and a dye.

[0004] Furthermore, Patent Document 2 discloses an image forming apparatus that transfers and fixes a toner image formed on an image forming body onto a transfer material, and that is characterized by forming an image using a non-glossy dark toner and a glossy light toner.

[0005] Furthermore, Patent Document 3 discloses an electrophotographic image forming method using a white toner and a chromatic toner including a cyan toner, wherein the white toner contains titanium oxide as a colorant, and the cyan toner contains a phthalocyanine compound represented by the following chemical formula 1 as a main component of the colorant:

[0006] [ka]

[0007] In the above Chemical Formula 1, M is a silicon atom, a germanium atom, or a tin atom; Ra1 to Ra4 each independently represent an electron-withdrawing substituent, na1 to na4 each independently represent an integer of 0 to 4, Z1 and Z2 each independently represent a hydroxy group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following chemical formula 2:

[0008] [ka]

[0009] In the above Chemical Formula 2, R3 to R5 each independently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms; The electrophotographic image forming method is described in which, when the average dispersion diameter of the colorant in the white toner is Dw and the average dispersion diameter of the phthalocyanine compound in the cyan toner is Dc, Dw and Dc satisfy the following mathematical formulas 1 and 2.

[0010]

number

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-140230 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-116631 [Patent Document 3] Patent Publication No. 2021-110802 Summary of the Invention [Problem to be solved by the invention]

[0012] An object of the present invention is to provide a toner set for developing electrostatic images, which has an absolute value (ΔSP value) of the difference in solubility parameters (SP values) between binder resin A contained in toner A and binder resin B contained in white toner B of less than 0.5, and which can produce images that are excellent in terms of color fading suppression under high temperature and high humidity conditions, compared to a case in which both binder resin A contained in toner A and binder resin B contained in white toner B are styrene acrylic resins or polyester resins. [Means for solving the problem]

[0013] Means for solving the above problems include the following aspects. <1> A toner set for developing electrostatic images, comprising: a toner A containing a binder resin A and a dye; and a white toner B containing a binder resin B and a titanium oxide pigment, wherein the absolute value of the difference in solubility parameter (ΔSP value) between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is 0.5 or more. <2> A toner set for developing electrostatic images, comprising: toner A containing a binder resin A and a dye; and white toner B containing a binder resin B and a titanium oxide pigment, wherein one of the binder resin A contained in toner A and the binder resin B contained in white toner B contains a styrene acrylic resin, and the other contains a polyester resin. <3> The binder resin A is a styrene acrylic resin, and the binder resin B is a polyester resin. <1> or <2> 10. The toner set for developing electrostatic images according to claim 19. <4> The dye includes at least one of a pyrazolotriazole dye and a phthalocyanine dye. <1> ~ <3> 10. The toner set for developing electrostatic images according to claim 9. <5> The dye contains a pyrazolotriazole compound represented by the following formula (I): <1> ~ <3> 10. The toner set for developing electrostatic images according to claim 9.

[0014] [ka]

[0015] In formula (I), Rx1 and Rx2 each independently represent an alkyl group which may have a substituent; Lx represents a hydrogen atom or an alkyl group which may have a substituent; Gx1 represents an alkyl group having two or more carbon atoms; Gx2 represents an aryl group or an alkyl group which may have a substituent; Gx3 represents a hydrogen atom, a halogen atom, Gx4-CO-NH-, or Gx5-N(Gx6)-CO-; Gx4 represents an aryl group or an alkyl group which may have a substituent; Gx5 and Gx6 each independently represent a hydrogen atom or an alkyl group which may have a substituent; and Qx1 to Qx5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.

[0016] <6> The dye contains a phthalocyanine compound represented by the following formula (II): <1> ~ <3> 10. The toner set for developing electrostatic images according to claim 9.

[0017] [ka]

[0018] In the formula (II), M represents a silicon atom, a germanium atom, or a tin atom; Ra1 to Ra4 each independently represent an electron-withdrawing group; na1 to na4 each independently represent an integer of 0 to 4; and Z1 and Z2 each independently represent a hydroxy group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (III):

[0019] [ka]

[0020] In the formula (III), R3 to R5 each independently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0021] <7> The content of the binder resin A is 51% by mass or more with respect to the total mass of the binder resins contained in the toner A, and the content of the binder resin B is 51% by mass or more with respect to the total mass of the binder resins contained in the white toner B. <1> ~ <6> 10. The toner set for developing electrostatic images according to claim 9. <8> The absolute value of the difference in solubility parameter between the binder resin A and the binder resin B (ΔSP value) is 0.5 or more and 3.0 or less. <1> ~ <7> 10. The toner set for developing electrostatic images according to claim 9. <9> The absolute value of the difference in solubility parameter between the binder resin A and the binder resin B (ΔSP value) is 1.0 or more and 3.0 or less. <8> 10. The toner set for developing electrostatic images according to claim 19. <10> At least a part of the dye is dispersed in the toner in the form of particles. <1> ~ <9> 10. The toner set for developing electrostatic images according to claim 9. <11> Among the dyes, the number average particle size of the particulate dye is 10 nm or more and 1,000 nm or less. <10> 10. The toner set for developing electrostatic images according to claim 19. <12> <1> ~ <11> a first electrostatic image developer containing the toner A in the toner set for developing an electrostatic image according to any one of the above items; <1> ~ <11> and a second electrostatic image developer containing the white toner B in the toner set for developing an electrostatic image according to any one of the above items. <13> <1> ~ <11> a first toner cartridge containing the toner A in the toner set for developing electrostatic images according to any one of the above items; <1> ~ <11> a second toner cartridge containing the white toner B among the toner sets for developing electrostatic images described in any one of 1 to 4, and the toner cartridge set is detachably mountable to an image forming apparatus. <14> <12> a first developing means containing the first electrostatic image developer of the electrostatic image developer set described in <12> and a second developing means containing the second electrostatic image developer of the electrostatic image developer set described in 1. above, and the process cartridge is detachably mountable to an image forming apparatus. <15> <1> ~ <11> a first image forming means for forming a colored image using the toner A in the toner set for developing electrostatic images according to any one of the above items; <1> ~ <11> an image forming apparatus comprising: a second image forming means for forming a white image using the white toner B of the toner set for developing electrostatic images described in any one of the above items; a transfer means for transferring the colored image and the white image onto a recording medium; and a fixing means for fixing the colored image and the white image on the recording medium. <16> <1> ~ <11> a first image forming step of forming a colored image using the toner A of the toner set for developing electrostatic images described in any one of the above; <1> ~ <11> a second image forming step of forming a white image using the white toner B of the toner set for developing electrostatic images described in any one of the above items; a transfer step of transferring the colored image and the white image onto a recording medium; and a fixing step of fixing the colored image and the white image on the recording medium. [Effects of the Invention]

[0022] <1> or <2> According to the invention, there is provided a toner set for developing electrostatic images, in which the absolute value of the difference in solubility parameter (ΔSP value) between binder resin A contained in toner A and binder resin B contained in white toner B is less than 0.5, and which can produce images that are excellent in terms of color fading suppression under high temperature and high humidity conditions, compared to a case in which both binder resin A contained in toner A and binder resin B contained in white toner B are styrene acrylic resins or polyester resins. <3> According to the invention, there is provided a toner set for developing electrostatic images which can produce images with better color fading suppression properties under high temperature and high humidity conditions, compared to when the binder resin A is a polyester resin and the binder resin B is a styrene acrylic resin. <4> According to the invention, there is provided a toner set for developing electrostatic images that can produce images with better fading suppression properties under high temperature and high humidity conditions, compared to when the dye does not contain at least one of pyrazolotriazole dyes and phthalocyanine dyes. <5> According to the invention, there is provided a toner set for developing electrostatic images that can produce images with better fading suppression properties under high temperature and high humidity conditions, compared to when the dye does not contain the pyrazolotriazole compound represented by formula (I). <6> According to the invention, there is provided a toner set for developing electrostatic images that can produce images that are more excellent in terms of fading suppression under high temperature and high humidity conditions, compared to when the dye does not contain the phthalocyanine compound represented by formula (II). <7> According to the invention, there is provided a toner set for developing electrostatic images that can provide images with better color fading suppression properties under high temperature and high humidity conditions, compared to when the content of the binder resin A is less than 51 mass % with respect to the total mass of the binder resins contained in the toner A, or when the content of the binder resin B is less than 51 mass % with respect to the total mass of the binder resins contained in the white toner B. <8> According to the invention, there is provided a toner set for developing electrostatic images, which can provide images with better fading suppression properties under high temperature and high humidity conditions, compared to when the absolute value of the difference in solubility parameters (ΔSP value) between the binder resin A and the binder resin B is less than 0.5. <9> According to the invention, there is provided a toner set for developing electrostatic images, which can provide images with better fading suppression properties under high temperature and high humidity conditions, compared to when the absolute value of the difference in solubility parameters (ΔSP value) between the binder resin A and the binder resin B is less than 1.0. <10> According to the invention, there is provided a toner set for developing electrostatic images that can produce images with better color fading suppression under high temperature and high humidity conditions than when the dye is molecularly dispersed in the toner. <11> According to the invention, there is provided a toner set for developing electrostatic images, which can produce images with better fading suppression under high temperature and high humidity conditions than when the particulate dye has a number average particle size of less than 10 nm. On the other hand, when the particulate dye has a number average particle size of more than 1,000 nm, the saturation of the image is significantly reduced, and the reproducibility of the target color is significantly deteriorated. <12> , <13> , <14> , <15> , or <16> According to the invention, there is provided an electrostatic image developer set, a toner cartridge set, a process cartridge, an image forming apparatus, or an image forming method, which can obtain images with better fading suppression properties under high temperature and high humidity conditions than when a toner set for developing electrostatic images is used, in which the absolute value of the difference in solubility parameter (ΔSP value) between binder resin A contained in toner A and binder resin B contained in white toner B is less than 0.5, and both binder resin A contained in toner A and binder resin B contained in white toner B are styrene acrylic resin or polyester resin. [Brief explanation of the drawings]

[0023] [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] FIG. 2 is a schematic diagram illustrating an example of a process cartridge according to the present exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described in detail. In addition, in numerical ranges described in stages, the upper limit or lower limit value described in a certain numerical range may be replaced with the upper limit or lower limit value of another numerical range described in stages. Furthermore, in a numerical range, the upper limit or lower limit value described in a certain numerical range may be replaced with a value shown in the examples. When a plurality of substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified. 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.

[0025] <Toner for developing electrostatic images> A first embodiment of the toner set for developing electrostatic images according to the present embodiment includes a toner A containing a binder resin A and a dye, and a white toner B containing a binder resin B and a titanium oxide pigment, and the absolute value of the difference in solubility parameter (ΔSP value) between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is 0.5 or more. A second embodiment of the toner set for developing electrostatic images according to the present embodiment includes a toner A containing a binder resin A and a dye, and a white toner B containing a binder resin B and a titanium oxide pigment, wherein one of the binder resin A contained in the toner A and the binder resin B contained in the white toner B contains a styrene acrylic resin, and the other contains a polyester resin.

[0026] In this specification, unless otherwise specified, simply referring to the "toner set for developing electrostatic images according to the present embodiment" or simply "toner set" refers to both the first embodiment and the second embodiment. Furthermore, unless otherwise specified, simply referring to the "dye" refers to both the dye of the first embodiment and the dye of the second embodiment.

[0027] Examples of toner A in the electrostatic image developing toner set according to this embodiment include yellow toner, cyan toner, magenta toner, black toner, red toner, green toner, blue toner, orange toner, and violet toner. Furthermore, the toner A and the white toner B in the toner set for developing electrostatic images according to this embodiment may be fluorescent toners. The toner set for developing electrostatic images according to this embodiment may contain one type of toner A and one type of white toner B, or two or more types of toner A and white toner B. The toner set for developing electrostatic images according to this embodiment may contain other toners. In particular, from the viewpoint of easily forming a full-color image, the toner set for developing electrostatic images according to this embodiment preferably includes a yellow toner, a cyan toner, and a magenta toner as toner A, and more preferably includes a yellow toner, a cyan toner, a magenta toner, and a black toner as toner A. Furthermore, the toner of each color used in this embodiment may be toner particles that do not contain external additives, or toner particles to which external additives have been added.

[0028] If the binder resin A used in dye-containing toner A and the binder resin B used in white toner B are compatible, when toner A and white toner B are heated and melted during the fixing process, the surfaces of the toner particles in toner A and white toner B will intermix. At this point, the dye present near the toner particle surface in toner A will come into contact with the titanium oxide pigment present near the toner particle surface in white toner B. Furthermore, if a fixed image is stored at high temperatures (e.g., in direct sunlight or on a hot electronic device or metal), the temperature may locally reach or exceed the glass transition temperature (Tg) of the binder resin, increasing the molecular mobility of the binder resin and causing the dye to migrate within the toner. However, as mentioned above, if the surfaces of toner A and white toner B are compatible due to the heat during fixing, there will often be no interface between toner A and white toner B. Therefore, it is thought that the dye will reach the toner image in white toner B and come into contact with the titanium oxide (radicals generated by it) in toner B, causing decomposition and fading. Furthermore, when exposed to direct sunlight, the photocatalytic action of the titanium oxide pigment is likely to progress, increasing the amount of superoxide anion radicals and hydroxide radicals generated, which is thought to further accelerate fading. In addition, under high humidity conditions, the reaction between the holes generated by the catalytic action of the titanium oxide pigment and oxygen in the air is more likely to proceed, and the amount of hydroxide radicals generated increases, which is thought to also accelerate the fading of images. In the toner set for developing electrostatic images according to this embodiment, the absolute value of the difference in solubility parameter (ΔSP value) between the binder resin A contained in toner A and the binder resin B contained in white toner B is 0.5 or more, or one of the binder resin A contained in toner A and the binder resin B contained in white toner B contains a styrene acrylic resin and the other contains a polyester resin. This is thought to control the compatibility between toner A and white toner B and maintain the interface between toner A and white toner B even after heating in the fixing process. This is thought to prevent the dye from entering the region of binder resin B in the white toner, preventing decomposition due to contact with the titanium oxide pigment and suppressing fading.

[0029] (Absolute value of the difference in solubility parameter between binder resin A contained in toner A and binder resin B contained in white toner B (ΔSP value)) In a first embodiment of the toner set for developing electrostatic images according to the present embodiment, the absolute value of the difference in solubility parameters (ΔSP value) between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is 0.5 or more, and from the viewpoint of obtaining an image with superior anti-fading properties under high temperature and high humidity (hereinafter simply referred to as "anti-fading properties under high temperature and high humidity"), the absolute value is preferably 0.7 or more, more preferably 1.0 or more, and particularly preferably 1.2 or more. Furthermore, from the viewpoint of reproducibility of target colors in halftone images in which white and color are overlaid (preventing deviation of dots of color toners containing dyes from being off target), the absolute value is preferably 3.0 or less. In a second embodiment of the toner set for developing electrostatic images according to the present embodiment, the absolute value of the difference in solubility parameter between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is preferably 0.5 or more, more preferably 0.7 or more, even more preferably 1.0 or more, and particularly preferably 1.2 or more, from the viewpoint of suppressing fading under high temperature and high humidity. Furthermore, from the viewpoint of reproducibility of target colors in halftone images in which white and color are overlaid (suppressing deviation of dots of color toners containing dyes from the target), the absolute value is preferably 3.0 or less.

[0030] In the present embodiment, the "solubility parameter (SP value)" is a value calculated by the Fedor method. Specifically, the solubility parameter (SP value) is calculated by the following formula, for example, in accordance with the description in Polym. Eng. Sci., vol. 14, p. 147 (1974). Formula: SP value = √(Ev / v) = √(ΣΔei / ΣΔvi) (where Ev: evaporation energy (cal / mol), v: molar volume (cm 3 / mol), Δei: evaporation energy of each atom or atomic group, Δvi: molar volume of each atom or atomic group) The solubility parameter (SP value) is expressed in units of (cal / cm 3 ) 1 / 2 However, in accordance with convention, the units are omitted and the value is expressed as dimensionless.

[0031] (Relationship between binder resin A contained in toner A and binder resin B contained in white toner B) In a second embodiment of the toner set for developing electrostatic images according to the present embodiment, one of the binder resin A contained in the toner A and the binder resin B contained in the white toner B contains a styrene-acrylic resin, and the other contains a polyester resin. From the viewpoint of suppressing fading under high temperature and high humidity conditions, it is preferable that the binder resin A is a styrene-acrylic resin and the binder resin B is a polyester resin. In a first embodiment of the toner set for developing electrostatic images according to the present embodiment, from the viewpoint of suppressing fading under high temperature and high humidity conditions, it is preferable that one of the binder resin A contained in the toner A and the binder resin B contained in the white toner B contains a styrene-acrylic resin, and the other contains a polyester resin, and it is more preferable that the binder resin A is a styrene-acrylic resin, and the binder resin B is a polyester resin.

[0032] (Type of dye contained in toner A) Furthermore, in the toner set for developing electrostatic images according to the present embodiment, from the viewpoint of suppressing fading under high temperature and high humidity conditions, it is preferable that the dye contains at least one of pyrazolotriazole dyes or phthalocyanine dyes, and it is more preferable that the dye contains at least one of the pyrazolotriazole compound represented by formula (I) and the phthalocyanine compound represented by formula (II).

[0033] Furthermore, in the toner set for developing electrostatic images according to the present embodiment, from the viewpoint of suppressing fading under high temperature and high humidity conditions, the content of the binder resin A is preferably 51% by mass or more of the total mass of the binder resins contained in the toner A, and the content of the binder resin B is preferably 51% by mass or more of the total mass of the binder resins contained in the white toner B. It is more preferable that the content of the binder resin A is 80% by mass or more of the total mass of the binder resins contained in the toner A, and the content of the binder resin B is 80% by mass or more of the total mass of the binder resins contained in the white toner B. It is particularly preferable that the content of the binder resin A is 95% by mass or more and 100% by mass or less of the total mass of the binder resins contained in the toner A, and the content of the binder resin B is 95% by mass or more and 100% by mass or less of the total mass of the binder resins contained in the white toner B. Furthermore, the binder resin A may be composed of multiple resins, such as "styrene acrylic resin A = styrene acrylic resin A1 + styrene acrylic resin A2." In this case, the solubility parameter (SP value) when the styrene acrylic resin A1 and the styrene acrylic resin A2 are mixed according to the composition ratio is defined as the SP value (SPA) of the binder resin A. Similarly, the binder resin B may be composed of multiple resins, such as "polyester resin B = polyester resin B1 + polyester resin B2." In this case, the solubility parameter (SP value) is the SP value (SPB) of the binder resin B when polyester resin B1 and polyester resin B2 are mixed according to the composition ratio.

[0034] (Toner A and white toner B) The toner set for developing electrostatic images according to this embodiment includes toner A containing a dye and white toner B containing a titanium oxide pigment. It is also preferred that the toner A and the white toner B each independently contain a binder resin. The toner A and the white toner B may each independently contain a release agent and other additives. Furthermore, the toner A and the white toner B may each independently be an externally added toner in which an external additive is added to toner particles.

[0035] -dye- Toner A contains a dye. As the dye, known dyes are used, and examples thereof include pyrazolotriazole-based and phthalocyanine-based dyes as well as various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. In this embodiment, a "pigment" is a colorant whose solubility in 100 g of water at 23°C and in 100 g of cyclohexanone at 23°C is less than 0.1 g, and a "dye" is a colorant whose solubility in 100 g of water at 23°C or in 100 g of cyclohexanone at 23°C is 0.1 g or more.

[0036] Preferred examples of the dye include pyrazolotriazole compounds represented by the following formula (I).

[0037] [Chemical formula]

[0038] In formula (I), Rx1 and Rx2 each independently represent an alkyl group which may have a substituent, Lx represents a hydrogen atom or an alkyl group which may have a substituent, Gx1 represents an alkyl group having 2 or more carbon atoms, Gx2 represents an aryl group or an alkyl group which may have a substituent, Gx3 represents a hydrogen atom, a halogen atom, Gx4-CO-NH-, or Gx5-N(Gx6)-CO-, Gx4 represents an aryl group or an alkyl group which may have a substituent, Gx5 and Gx6 each independently represent a hydrogen atom or an alkyl group which may have a substituent, and Qx1 to Qx5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.

[0039] [[Rx1 and Rx2]] Rx1 and Rx2 are each independently an alkyl group which may have a substituent, and are preferably an alkyl group. Here, the alkyl group which may have a substituent includes not only an alkyl group (a substituent consisting only of an alkyl group), but also a substituent formed by substituting one or more atoms constituting the alkyl group with a substituent other than an alkyl group (for example, an alkenyl group).

[0040] The alkyl group may be any of a linear alkyl group, a branched alkyl group, and a cycloalkyl group, but is preferably a linear alkyl group or a branched alkyl group.

[0041] Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group, an n-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, or a pentadecyl group or the like.

[0042] Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a tert-butyl group, an amyl group, or an isoamyl group or the like.

[0043] Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a 4-tert-butyl-cyclohexyl group.

[0044] The total number of carbon atoms contained in the alkyl group represented by Rx1 and the alkyl group represented by Rx2 is preferably 8 or more, more preferably 12 or more, and even more preferably 16 or more.

[0045] Examples of the substituent in the alkyl group that may have a substituent include an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, an aromatic heterocyclic group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, a phosphoryl group, a sulfamoyl group, an acyl group, an acyloxy group, an amido group, a carbamoyl group, a ureido group, a sulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, or an amino group. That is, Rx1 and Rx2 may each independently be configured by substituting one or more atoms constituting the alkyl group with any of these substituents. The number of substituents substituting one or more atoms constituting the alkyl group is not limited to one and may be two or more.

[0046] The alkenyl group is, for example, a vinyl group or an allyl group. The alkynyl group is, for example, an ethynyl group or a propargyl group.

[0047] The aryl group is, for example, a phenyl group or a naphthyl group. Examples of the aliphatic heterocyclic group include a pyrrolidyl group, an imidazolidyl group, a morpholyl group, and an oxazolidyl group.

[0048] Examples of the aromatic heterocyclic group include a furyl group, a thienyl group, a pyridyl group, a pyridazyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, a benzimidazolyl group, a benzoxazolyl group, a quinazolyl group, and a phthalazyl group.

[0049] Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

[0050] Examples of the cycloalkoxy group include a cyclopentyloxy group and a cyclohexyloxy group.

[0051] The aryloxy group is, for example, a phenoxy group or a naphthyloxy group. Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a pentylthio group, a hexylthio group, an octylthio group, and a dodecylthio group.

[0052] The cycloalkylthio group includes, for example, a cyclopentylthio group or a cyclohexylthio group.

[0053] The arylthio group includes, for example, a phenylthio group or a naphthylthio group. Examples of the alkoxycarbonyl group include a methyloxycarbonyl group and an ethyloxycarbonyl group. Examples of the alkyl group include a butyloxycarbonyl group, a butyloxycarbonyl group, an octyloxycarbonyl group, and a dodecyloxycarbonyl group.

[0054] The aryloxycarbonyl group includes, for example, a phenyloxycarbonyl group or a naphthyloxycarbonyl group.

[0055] The phosphoryl group may be a methoxyphosphoryl group or a diphenylphosphoryl group. Examples of the sulfamoyl group include an aminosulfonyl group, a methylaminosulfonyl group, a dimethylaminosulfonyl group, a butylaminosulfonyl group, a hexylaminosulfonyl group, a cyclohexylaminosulfonyl group, an octylaminosulfonyl group, a dodecylaminosulfonyl group, a phenylaminosulfonyl group, a naphthylaminosulfonyl group, and a 2-pyridylaminosulfonyl group.

[0056] Examples of the acyl group include an acetyl group, an ethylcarbonyl group, a propylcarbonyl group, a pentylcarbonyl group, a cyclohexylcarbonyl group, an octylcarbonyl group, a 2-ethylhexylcarbonyl group, a dodecylcarbonyl group, a phenylcarbonyl group, a naphthylcarbonyl group, and a pyridylcarbonyl group.

[0057] Examples of the acyloxy group include an acetyloxy group, an ethylcarbonyloxy group, a butylcarbonyloxy group, an octylcarbonyloxy group, a dodecylcarbonyloxy group, and a phenylcarbonyloxy group.

[0058] Examples of the amide group include a methylcarbonylamino group, an ethylcarbonylamino group, a dimethylcarbonylamino group, a propylcarbonylamino group, a pentylcarbonylamino group, a cyclohexylcarbonylamino group, a 2-ethylhexylcarbonylamino group, an octylcarbonylamino group, a dodecylcarbonylamino group, a phenylcarbonylamino group, and a naphthylcarbonylamino group.

[0059] Examples of the carbamoyl group include an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a propylaminocarbonyl group, a pentylaminocarbonyl group, a cyclohexylaminocarbonyl group, an octylaminocarbonyl group, a 2-ethylhexylaminocarbonyl group, a dodecylaminocarbonyl group, a phenylaminocarbonyl group, a naphthylaminocarbonyl group, and a 2-pyridylaminocarbonyl group.

[0060] Examples of the ureido group include a methylureido group, an ethylureido group, a pentylureido group, a cyclohexylureido group, an octylureido group, a dodecylureido group, a phenylureido group, a naphthylureido group, and a 2-pyridylaminoureido group.

[0061] Examples of the sulfinyl group include a methylsulfinyl group, an ethylsulfinyl group, a butylsulfinyl group, a cyclohexylsulfinyl group, a 2-ethylhexylsulfinyl group, a dodecylsulfinyl group, a phenylsulfinyl group, a naphthylsulfinyl group, and a 2-pyridylsulfinyl group.

[0062] Examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a cyclohexylsulfonyl group, a 2-ethylhexylsulfonyl group, and a dodecylsulfonyl group.

[0063] Examples of the arylsulfonyl group include a phenylsulfonyl group, a naphthylsulfonyl group, and a 2-pyridylsulfonyl group.

[0064] Examples of the amino group include an amino group, an ethylamino group, a dimethylamino group, a butylamino group, a dibutylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, a dodecylamino group, an anilino group, a naphthylamino group, and a 2-pyridylamino group.

[0065] In addition to the above-mentioned substituents, the substituent in the alkyl group which may have a substituent may be, for example, an azo group such as a phenylazo group, an alkylsulfonyloxy group such as a methanesulfonyloxy group, a cyano group, a nitro group, a halogen atom (for example, a fluorine atom, a chlorine atom, or a bromine atom; the same applies hereinafter), or a hydroxyl group.

[0066] The substituent in the alkyl group which may have a substituent may be any of the substituents described above, but is preferably an alkoxy group, an aryl group, a cycloalkoxy group, a halogen atom, or a hydroxyl group.

[0067] The substituent in the alkyl group which may have a substituent may have a substituent other than the aforementioned substituent bonded thereto.

[0068] < <lx>> Lx may be a hydrogen atom or an alkyl group which may have a substituent, but is preferably a hydrogen atom. When Lx is an alkyl group which may have a substituent, Lx may be any of the substituents represented by Rx1 and Rx2, and is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a methyl group or an ethyl group.

[0069] < <gx1>> Gx1 is an alkyl group having two or more carbon atoms. The alkyl group may be any of a linear alkyl group, a branched alkyl group, and a cycloalkyl group, but is preferably a branched alkyl group, more preferably a tertiary alkyl group, and further preferably a tert-butyl group.

[0070] Examples of the straight-chain alkyl group include an ethyl group, a propyl group, an n-butyl group, a pentyl group, a hexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, and a pentadecyl group.

[0071] Examples of branched alkyl groups include an isopropyl group, an isobutyl group, a tert-butyl group, an amyl group, and an isoamyl group.

[0072] Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a 4-tert-butyl-cyclohexyl group.

[0073] < <gx2>> Gx2 may be an aryl group or an alkyl group which may have a substituent. Here, the aryl group is, for example, a phenyl group or a naphthyl group. The alkyl group which may have a substituent is any of the substituents represented by Rx1 and Rx2. Among these, Gx2 is preferably an alkyl group, more preferably an alkyl group having 1 to 5 carbon atoms, and even more preferably a methyl group or an ethyl group.

[0074] < <gx3>> Gx3 is any one of a hydrogen atom, a halogen atom, Gx4-CO-NH-, and Gx5-N(Gx6)-CO-, and among these, a hydrogen atom is preferred.

[0075] < <gx4>> Gx4 may be an aryl group or an alkyl group which may have a substituent. Here, the aryl group is, for example, a phenyl group or a naphthyl group etc. Further, the alkyl group which may have a substituent is any one of the substituents represented by the above Rx1 and Rx2, and it is preferably an alkyl group represented by the above Rx1 and Rx2.

[0076] <<Gx5 and Gx6>> Gx5 and Gx6 are each independently may be a hydrogen atom or an alkyl group which may have a substituent. Here, the alkyl group which may have a substituent is any one of the substituents represented by the above Rx1 and Rx2, and it is preferably an alkyl group represented by the above Rx1 and Rx2.

[0077] <<Qx1 to Qx5>> Qx1 to Qx5 are each independently may be a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent. Here, the alkyl group which may have a substituent is any one of the substituents represented by the above Rx1 and Rx2. Preferably, Qx1 to Qx5 are each independently any one of a hydrogen atom, an alkyl group, a halogen atom, and an alkoxy group. More preferably, all of Qx1 to Qx5 are hydrogen atoms.

[0078] Specific examples of the pyrazolotriazole compound represented by the above formula (I) include (I-1) to (I-23) shown below, but it is needless to say that it is not limited to the specific examples shown below.

[0079]

Chemical formula

[0080]

Chemical formula

[0081] [ka]

[0082] [ka]

[0083] The pyrazolotriazole compounds represented by the formula (I) may be used singly or in combination of two or more.

[0084] As the dye, a phthalocyanine compound represented by the following formula (II) is preferably used.

[0085] [ka]

[0086] In the formula (II), M represents a silicon atom, a germanium atom, or a tin atom; Ra1 to Ra4 each independently represent an electron-withdrawing group; na1 to na4 each independently represent an integer of 0 to 4; and Z1 and Z2 each independently represent a hydroxy group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (III):

[0087] [ka]

[0088] In the formula (III), R3 to R5 each independently represent an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

[0089] The phthalocyanine compound represented by formula (II) has axial ligands (Z1 and Z2) with a bulky structure. The presence of such bulky axial ligands facilitates more uniform dispersion of the phthalocyanine compound in the toner particles and fixed images, further enhancing the color development of the cyan toner. Furthermore, even in an image superimposed with the white toner, which forms the bottom layer, the bulky phthalocyanine compound is less likely to move, making it less likely for the cyan toner and white toner to mix. This makes it possible to suppress color turbidity and achieve excellent color development.

[0090] In the formula (II), M represents a silicon atom (Si), a germanium atom (Ge), or a tin atom (Sn). From the viewpoint of suppressing color mixing with white toner due to a bulky structure and from the viewpoint of excellent color development properties of the compound itself, M is preferably a silicon atom (Si).

[0091] In the formula (II), Ra1 to Ra4 (Ra1, Ra2, Ra3, and Ra4) are each independently an electron-withdrawing group. Examples of the electron-withdrawing group include a chlorine group (-Cl), a monochlorodihalogenomethyl group (-CClX2), a trifluoromethyl group (-CF3), and a nitro group (-NO2). In the monochlorodihalogeno group (-CClX2), "X" represents a halogen atom.

[0092] In the formula (II), na1 to na4 (na1, na2, na3, and na4) each independently represent an integer of 0 to 4. When na1 to na4 are integers of 0 to 4, the desired color gamut can be covered as a colorant.

[0093] In the formula (II), Z1 and Z2 are each independently a hydroxy group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the formula (III).

[0094] Examples of the aryloxy group having 6 to 18 carbon atoms include a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, a 2,3-xylyloxy group, a 2,4-xylyloxy group, a 2,5-xylyloxy group, a 2,6-xylyloxy group, a 3,4-xylyloxy group, a 3,5-xylyloxy group, a 2,3,4-trimethylphenoxy group, a 2,3,5-trimethylphenoxy group, a 2,3,6-trimethylphenoxy group, a 2,4,6-trimethylphenoxy group, a 3,4,5-trimethylphenoxy group, a 2,3,4,5-tetramethylphenoxy group, and a 2,3,4,6 n-tetramethylphenoxy group, 2,3,5,6-tetramethylphenoxy group, pentamethylphenoxy group, ethylphenoxy group, n-propylphenoxy group, isopropylphenoxy group, n-butylphenoxy group, sec-butylphenoxy group, tert-butylphenoxy group, isobutylphenoxy group, n-pentylphenoxy group, neopentylphenoxy group, n-hexylphenoxy group, n-octylphenoxy group, n-decylphenoxy group, n-dodecylphenoxy group, n-tetradecylphenoxy group, naphthyloxy group, anthracenyloxy group, and the like.

[0095] Examples of the alkoxy group having 1 to 22 carbon atoms include linear, branched, and cyclic alkoxy groups such as methoxy, ethoxy, n-propyloxy, isopropyloxy, n-butyloxy, isobutyloxy, sec-butyloxy, t-butyloxy, n-pentyloxy, neopentyloxy, n-hexyloxy, isohexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-octadecyloxy, n-eicosyloxy, n-docosyloxy, 2-ethylhexyloxy, 3-ethylheptyloxy, 3-ethyldecyloxy, 2-hexyldecyloxy, cyclopentyloxy, cyclohexyloxy, and cycloheptyloxy.

[0096] From the viewpoint of suppressing color mixing with white toner due to the bulky structure and from the viewpoint of excellent color development properties of the compound itself, Z1 and Z2 are preferably groups represented by the formula (III).

[0097] Examples of the alkyl group having 1 to 6 carbon atoms used for R3 to R5 in the formula (III) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, a neopentyl group, and an n-hexyl group.

[0098] Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, an o-, m-, or p-tolyl group, a 2,3-xylyl group, a 2,4-xylyl group, a mesityl group, a naphthyl group, an anthryl group, a phenanthryl group, a triphenylenyl group, a tetracenyl group, a chrysenyl group, a pyrenyl group, a pentacenyl group, and a picenyl group.

[0099] Examples of the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propyloxy group, an isopropyloxy group, an n-butyloxy group, an isobutyloxy group, a sec-butyloxy group, a t-butyloxy group, an n-pentyloxy group, a neopentyloxy group, an n-hexyloxy group, and an isohexyloxy group.

[0100] Preferred examples of the phthalocyanine compound represented by the formula (II) are shown in the following Table 1. In Table 1, "-" indicates that the compound does not have the corresponding substituent.

[0101] [Table 1]

[0102] The phthalocyanine compounds represented by the formula (II) may be used singly or in combination of two or more.

[0103] The phthalocyanine compound represented by formula (II) may be a commercially available product or a synthesized product. As a synthesis method, a known method may be used, for example, the method described in JP-A-2011-99047.

[0104] Further, as the dye, known dyes can be used, including pyrazolotriazole compounds such as the pyrazolotriazole compounds represented by the formula (I) and phthalocyanine compounds such as the phthalocyanine compounds represented by the formula (II), as well as specific examples thereof, such as Basic Red 1 (rhodamine 6GCP), Basic Red 1:1 (rhodamine 6GCP-N), Basic Red 2, Basic Red 12, Basic Red 13, Basic Red 14, Basic Red 15, Basic Red 36, Basic Violet 7, Basic Violet 10 (rhodamine B), Basic Violet 11 (rhodamine 3B), Basic Violet 11:1 (rhodamine A), Basic Violet 15, Basic Violet 16, Basic Violet 27, Basic Violet 49, CI Pigment Yellow 101, Basic Yellow 1, Basic Yellow 2, Basic Yellow 9, Basic Yellow 24, Basic Yellow 40, and Basic Orange. 15, Basic Orange 22, Basic Blue 1, Basic Blue 3, Basic Blue 7, Basic Blue 9, Basic Blue 45, Basic Green 1, Acid Yellow 3, Acid Yellow 7, Acid Yellow 73, Acid Yellow 87, Acid Yellow 184, Acid Yellow 245, Acid Yellow 250, Acid Red 51, Acid Red 52, Acid Red 57, Acid Red 77, Acid Red 87, Acid Red 89, Acid Red 92, Acid Blue 9, Acid Black 2, Solvent Yellow 43, Solvent Yellow 44, Solvent Yellow 85, Solvent Yellow 98, Solvent Yellow 116, Solvent Yellow 131, Solvent Yellow 145, Solvent Yellow 160:1, Solvent Yellow172, Solvent Yellow 185, Solvent Yellow 195, Solvent Yellow 196, Solvent Orange 63, Solvent Orange 112, Solvent Red 49, Solvent Red 149, Solvent Red 175, Solvent Red 196, Solvent Red 197, Solvent Blue 5, Solvent Green 5, Solvent Green 7, Direct Yellow 27, Direct Yellow 85, Direct Yellow 96, Direct Orange 8, Direct Red 2, Direct Red 9, Direct Blue 22, Direct Blue 199, Direct Green 6, Disperse Yellow 11, Disperse Yellow 82, Disperse Yellow 139, Disperse Yellow 184, Disperse Yellow 186, Disperse Yellow 199, Disperse Yellow 202, Disperse Yellow 232, Disperse Orange 11, Disperse Examples of the pigments include Orange 32, Disperse Red 58, Disperse Red 274, Disperse Red 277, Disperse Red 303, Disperse Blue 7, Reactive Yellow 78, and Vat Red 41.

[0105] In the toner, the dye may be dispersed in a particulate form or molecularly dispersed in the binder resin. However, from the viewpoint of inhibiting fading under high temperature and high humidity conditions, it is preferable that at least a portion of the dye is dispersed in the toner in a particulate form. Of the dyes, the number average particle size of the dye dispersed in the toner in particulate form is preferably 10 nm or more from the viewpoint of suppressing fading under high temperature and high humidity conditions, and is preferably 1,000 nm or less from the viewpoint of target color reproducibility, more preferably 10 nm or more and 500 nm or less, and even more preferably 10 nm or more and 250 nm or less.

[0106] The number average particle size of the dye dispersed in the toner particles in particulate form is measured by staining a cross section obtained by cutting the toner or toner particles and analyzing the image observed with a transmission electron microscope (TEM). Specifically, for example, as shown below, the dye is selected from ruthenium tetroxide, osmium tetroxide, tungstophosphoric acid, uranyl acetate, iodine, etc., depending on the type of binder resin and dye, so that the degree of dyeing between the binder resin and the dye is differentiated. Seven grams of bisphenol A liquid epoxy resin (Asahi Kasei Chemicals) and 3 grams of hardener ZENAMID 250 (Henkel Japan) were gently mixed to prepare a cured product. Then, 1 gram of toner was added and the mixture was left for 24 hours to obtain a cured product. The cured product was then cut into embedded samples at -100°C using a LEICA ultramicrotome (ULTRACUT UCT, Hitachi Hyde Technologies) equipped with a diamond knife (Type Cryo, DIATOME) to create a sample for observation. The sample for observation was then placed in a desiccator under an atmosphere of ruthenium tetroxide (Soekawa Rikagaku Co., Ltd.) and stained (the degree of staining was determined by observing the degree of staining of a tape that had been left at the same time). The cross-section of the dyed toner was observed at a magnification of 10,000 to 100,000 times using a Hitachi high-resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) equipped with a transmission electron detector from the dyed observation sample. From the TEM image, the cross-sections of 300 toner particles were observed, and the dye portion of the toner particles was identified based on the difference in the degree of dyeing. The dispersed particle size of the dispersed particulate portion was measured, and the number average particle size was calculated. The dye portion was determined based on the degree of dyeing by comparing it with the dye alone, a mixture of dye and binder resin, and the binder resin alone, each dyed with the above-mentioned dyeing agent. The number average particle size of the particulately dispersed dye portion may be calculated by digitizing the observed image and processing the image. For example, a TEM image is digitized and imported into image analysis software (Win ROOF) manufactured by Mitani Corporation. The cross-sectional area of ​​the toner in the embedding material is selected as the target, and binarization is performed using the "Automatic Binarization - Discriminant Analysis" command in the "Binarization Processing" command to separate the particulately dispersed dye portion from the binder resin portion. At this time, the binarized image is compared with the image before binarization to confirm that the particulately dispersed dye portion of the binarized image is separated into individual particles. If multiple particles are binarized as connected particles, the binarization threshold is adjusted so that each particle is binarized independently, or the image is manually segmented to form a single particle for each particulately dispersed dye portion. The extracted particulately dispersed dye portion is selected, and the maximum Feret's diameter is calculated to determine the particle size of the particulately dispersed dye portion. If binarization cannot be performed properly due to factors such as photographic density or noise, you can use "filter-median" processing or edge extraction processing to sharpen the image, and then manually set the boundaries.

[0107] Toner A may contain one type of dye alone or two or more types in combination. In order to further exert the effects of this embodiment, the dye content is preferably 0.01% by mass or more and 30% by mass or less, more preferably 0.1% by mass or more and 20% by mass or less, and particularly preferably 0.2% by mass or more and 10% by mass or less, relative to the total resin particles.

[0108] -Acetylacetone metal compounds- From the viewpoint of suppressing fading under high temperature and high humidity conditions and transparency, it is preferable that Toner A further contains an acetylacetone metal compound, and it is more preferable that Toner A contains a pyrazolotriazole compound represented by the above formula (I) and an acetylacetone metal compound. In toner particles, a pyrazolotriazole-based dye and an acetylacetone metal compound form a partial complex, which acts as a nucleating agent during cooling after toner fixing, suppresses migration to the surface, and is presumed to be excellent in fade suppression and transparency under high temperature and high humidity conditions.

[0109] The acetylacetone metal compound is not particularly limited, but from the viewpoints of suppressing color bleeding and transparency of the obtained image, it is preferably an acetylacetone metal compound having an electron-withdrawing group, more preferably an acetylacetone copper, nickel or cobalt compound having an electron-withdrawing group, and particularly preferably a compound represented by the following formula (IV).

[0110]

Chemical formula

[0111] In formula (IV), R1 and R2 are each independently a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, an aromatic heterocyclic group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfamoyl group, a sulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, a cyano group, a trifluoroalkyl group, or a nitro group, at least one of R1 and R2 is an electron-withdrawing group, R3 represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, or an aromatic heterocyclic group, R2 and R3 may be bonded to each other to form a ring, and X represents a metal atom of any one of copper, nickel, or cobalt.

[0112] The total number of carbon atoms in one molecule of the acetylacetone ligand in the compound represented by formula (IV) is preferably 25 or less.

[0113] <<R1 and R2>> R1 and R2 are each independently any one of a hydrogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, an aromatic heterocyclic group, a halogen alkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an alkoxycarbonyl group, an aryloxycarbonyl group, a sulfamoyl group, an acyl group, an acyloxy group, an amido group, a carbamoyl group, a ureido group, a sulfinyl group, an alkylsulfonyl group, an arylsulfonyl group, and an amino group. The combination of R1 and R2 is not particularly limited, but either R1 or R2 is an electron-withdrawing group.

[0114] The alkyl group may be any of a linear alkyl group, a branched alkyl group, and a cycloalkyl group, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, an octyl group, a dodecyl group, a tridecyl group, a tetradecyl group, or a pentadecyl group.

[0115] The alkenyl group is, for example, a vinyl group or an allyl group. The alkynyl group is, for example, an ethynyl group or a propargyl group.

[0116] The aryl group is, for example, a phenyl group or a naphthyl group. Examples of the aliphatic heterocyclic group include a pyrrolidyl group, an imidazolidyl group, a morpholyl group, and an oxazolidyl group.

[0117] Examples of the aromatic heterocyclic group include a furyl group, a thienyl group, a pyridyl group, a pyridazyl group, a pyrimidyl group, a pyrazyl group, a triazyl group, an imidazolyl group, a pyrazolyl group, a thiazolyl group, a benzimidazolyl group, a benzoxazolyl group, a quinazolyl group, and a phthalazyl group.

[0118] The halogen alkyl group may be a monohalogen alkyl group, a dihalogen alkyl group, or a trihalogen alkyl group. The halogen may be fluorine, chlorine, bromine, or iodine. The alkyl group is not particularly limited and may be a methyl group, an ethyl group, a propyl group, or the like.

[0119] Examples of the alkoxy group include a methoxy group, an ethoxy group, a propyloxy group, a pentyloxy group, a hexyloxy group, an octyloxy group, and a dodecyloxy group.

[0120] Examples of the cycloalkoxy group include a cyclopentyloxy group and a cyclohexyloxy group.

[0121] The aryloxy group is, for example, a phenoxy group or a naphthyloxy group. Examples of the alkylthio group include a methylthio group, an ethylthio group, a propylthio group, a pentylthio group, a hexylthio group, an octylthio group, and a dodecylthio group.

[0122] Examples of the cycloalkylthio group include a cyclopentylthio group and a cyclohexylthio group.

[0123] The arylthio group includes, for example, a phenylthio group or a naphthylthio group. The alkoxycarbonyl group may be, for example, a methyloxycarbonyl group, an ethyloxycarbonyl group, a butyloxycarbonyl group, an octyloxycarbonyl group, or a dodecyloxycarbonyl group. Examples include an alkoxycarbonyl group.

[0124] The aryloxycarbonyl group includes, for example, a phenyloxycarbonyl group or a naphthyloxycarbonyl group.

[0125] Examples of the sulfamoyl group include an aminosulfonyl group, a methylaminosulfonyl group, a dimethylaminosulfonyl group, a butylaminosulfonyl group, a hexylaminosulfonyl group, a cyclohexylaminosulfonyl group, an octylaminosulfonyl group, a dodecylaminosulfonyl group, a phenylaminosulfonyl group, a naphthylaminosulfonyl group, and a 2-pyridylaminosulfonyl group.

[0126] Examples of the acyl group include an acetyl group, an ethylcarbonyl group, a propylcarbonyl group, a pentylcarbonyl group, a cyclohexylcarbonyl group, an octylcarbonyl group, a 2-ethylhexylcarbonyl group, a dodecylcarbonyl group, a phenylcarbonyl group, a naphthylcarbonyl group, and a pyridylcarbonyl group.

[0127] Examples of the acyloxy group include an acetyloxy group, an ethylcarbonyloxy group, a butylcarbonyloxy group, an octylcarbonyloxy group, a dodecylcarbonyloxy group, and a phenylcarbonyloxy group.

[0128] Examples of the amide group include a methylcarbonylamino group, an ethylcarbonylamino group, a dimethylcarbonylamino group, a propylcarbonylamino group, a pentylcarbonylamino group, a cyclohexylcarbonylamino group, a 2-ethylhexylcarbonylamino group, an octylcarbonylamino group, a dodecylcarbonylamino group, a phenylcarbonylamino group, and a naphthylcarbonylamino group.

[0129] Examples of the carbamoyl group include an aminocarbonyl group, a methylaminocarbonyl group, a dimethylaminocarbonyl group, a propylaminocarbonyl group, a pentylaminocarbonyl group, a cyclohexylaminocarbonyl group, an octylaminocarbonyl group, a 2-ethylhexylaminocarbonyl group, a dodecylaminocarbonyl group, a phenylaminocarbonyl group, a naphthylaminocarbonyl group, and a 2-pyridylaminocarbonyl group.

[0130] Examples of the ureido group include a methylureido group, an ethylureido group, a pentylureido group, a cyclohexylureido group, an octylureido group, a dodecylureido group, a phenylureido group, a naphthylureido group, and a 2-pyridylaminoureido group.

[0131] Examples of the sulfinyl group include a methylsulfinyl group, an ethylsulfinyl group, a butylsulfinyl group, a cyclohexylsulfinyl group, a 2-ethylhexylsulfinyl group, a dodecylsulfinyl group, a phenylsulfinyl group, a naphthylsulfinyl group, and a 2-pyridylsulfinyl group.

[0132] Examples of the alkylsulfonyl group include a methylsulfonyl group, an ethylsulfonyl group, a butylsulfonyl group, a cyclohexylsulfonyl group, a 2-ethylhexylsulfonyl group, and a dodecylsulfonyl group.

[0133] Examples of the arylsulfonyl group include a phenylsulfonyl group, a naphthylsulfonyl group, and a 2-pyridylsulfonyl group.

[0134] Examples of the amino group include a methylamino group, an ethylamino group, a dimethylamino group, a butylamino group, a cyclopentylamino group, a 2-ethylhexylamino group, a dodecylamino group, Examples include an anilino group, a naphthylamino group, and a 2-pyridylamino group.

[0135] Furthermore, R1 and R2 may each independently represent a cyano group, a nitro group, a halogen atom, or the like, in addition to the above-mentioned substituents.

[0136] Among the above substituents, R1 and R2 are preferably each independently an alkyl group, a trifluoroalkyl group, an aryl group, an aliphatic heterocyclic group, an aromatic heterocyclic group, an alkoxy group, a sulfamoyl group, a ureido group, an amino group, an amido group, an acyl group, an alkoxycarbonyl group, a carbamoyl group, a cyano group, or a halogen atom. R1 and R2 are more preferably each independently an alkyl group, a trifluoroalkyl group, a cyano group, an alkoxy group, an amido group, or a halogen atom, and even more preferably a trifluoroalkyl group, a cyano group, or an alkoxy group.

[0137] R1 and R2 may each independently represent the above-mentioned substituent to which another substituent is bonded. The substituent bonded to the above-mentioned substituent may be the same as the above-mentioned substituent or may be a different substituent from the above-mentioned substituent.

[0138] < <r3>> R3 is any one of an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, an aromatic heterocyclic group, and the ether group shown below. When R3 is an alkyl group, an alkenyl group, an alkynyl group, or an ether group, it preferably has 3 or more carbon atoms. Specific examples of the alkyl group, the alkenyl group, the alkynyl group, the aryl group, and the heterocyclic group may be any one of the specific examples represented by R1 and R2.

[0139] < <x>> X is, for example, any one of a metal atom of copper, nickel, and cobalt, and is preferably copper.

[0140] Specific examples of the compound represented by formula (IV) include (II-1) to (II-85) shown below, but needless to say, the compound is not limited to these specific examples. The structural formula shown below is one of the resonance structures that the example compound can adopt. In the formula, the distinction between the covalent bond shown by a solid line and the coordinate bond shown by a dashed line is merely a formal distinction and does not represent an absolute distinction.

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] The toner particles may contain only one type of acetylacetonate metal compound, or two or more types of acetylacetonate metal compounds. From the viewpoint of suppressing fading under high temperature and high humidity conditions and transparency, the content of the acetylacetone metal compound is preferably from 0.5% by mass to 30% by mass, more preferably from 1% by mass to 25% by mass, and particularly preferably from 2% by mass to 20% by mass, relative to the total mass of the toner particles. The content ratio of the acetylacetone metal compound to the pyrazolotriazole dye in the toner particles (acetylacetone metal compound content / pyrazolotriazole dye content) is preferably 1 or more and 10 or less, more preferably 1.2 or more and 5 or less, and particularly preferably 1.5 or more and 3 or less, from the viewpoints of anti-fading properties and transparency under high temperature and high humidity conditions.

[0149] -Titanium oxide pigment- White toner B contains titanium oxide pigment. The crystal structure of the titanium oxide pigment may be any of anatase, rutile, and brookite, but from the viewpoint of further exerting the effects of this embodiment, the rutile type, which has low photocatalytic activity, is preferred. The titanium oxide pigment may be surface-treated as needed, and may be used in combination with a dispersant.

[0150] The number average particle size of the titanium oxide pigment contained in white toner B is preferably 150 nm or more and 900 nm or less, more preferably 180 nm or more and 800 nm or less, and particularly preferably 200 nm or more and 700 nm or less, from the viewpoint of color development.

[0151] The dispersed number average particle diameter of the titanium oxide pigment in the white toner B in this embodiment is calculated, for example, as follows. The white toner according to this embodiment is mixed into epoxy resin, embedded, and left overnight to solidify. Then, an ultramicrotome (Ultracut UCT, manufactured by Leica) is used to create a thin section with a thickness of, for example, approximately 250 nm to 450 nm. The obtained flakes are observed using an ultra-high resolution field emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) to confirm the white colored particles inside the white toner particles. If the outline of the white colored particles is unclear, the thickness of the observation flake can be adjusted and the observation can be repeated. If there are many voids inside the white toner particles, it is possible that white colored particles fell off during flake preparation, so it is preferable to adjust the thickness of the flakes to be thicker. If many of the white colored particles inside the white toner particles appear overlapping, making it difficult to distinguish the outline of the white colored particles, it is possible that the flakes are too thick and multiple white colored particles are observed overlapping, so it is preferable to adjust the thickness of the flakes to be thinner. The observed photographs are digitized and imported into image analysis software (Win ROOF) manufactured by Mitani Shoji Co., Ltd., and the number average particle diameter of the white colored particles in the white toner particles and the proportion of white colored particles with a particle diameter of 350 nm or more and 600 nm or less in the total white colored particles are determined, for example, using the following procedure. Specifically, the cross-sectional area of ​​the toner in the embedding material is selected as the target, and binarization is performed using the "Automatic Binarization - Discriminant Analysis" command in the "Binarization Processing" command to separate the white colored particles from the binder resin. At this point, the image before binarization is compared to confirm that the white colored particle areas in the binarized image are separated into individual white colored particles. If multiple particles are connected and binarized, the binarization threshold can be adjusted so that each particle is binarized independently, or the area can be manually divided so that each white colored particle area is formed by a single white colored particle. The extracted white colored particle area is selected, and the maximum Feret's diameter is calculated to determine the particle diameter of the white colored particles. If binarization cannot be performed properly due to factors such as photographic density or noise, you can use "filter-median" processing or edge extraction processing to sharpen the image, and then manually set the boundaries. To calculate the number average particle size of white colored particles, measurements are taken of 300 or more white colored particles using an image in which 10 to 100 pigment particles are visible in one field of view, and the arithmetic mean value is used.

[0152] The titanium oxide pigment may be used alone or in combination of two or more kinds. The content of the titanium oxide pigment is more preferably from 10% to 70% by mass, more preferably from 15% to 60% by mass, and particularly preferably from 20% to 55% by mass, based on the total mass of the toner particles.

[0153] -Binder resin- From the viewpoint of image strength and suppressing uneven density in the resulting image, the binder resin preferably contains an amorphous resin and a crystalline resin. In the first embodiment of the toner set for developing electrostatic images according to the present embodiment, the binder resin is preferably a polyester resin, a styrene-acrylic resin, or an acrylic resin.

[0154] Here, the term "amorphous resin" refers to a resin that, in thermal analysis measurement using differential scanning calorimetry (DSC), does not show a clear endothermic peak but only a stepwise endothermic change, is solid at room temperature, and becomes thermoplastic at a temperature equal to or higher than the glass transition temperature. On the other hand, a crystalline resin is one that shows a clear endothermic peak rather than a stepwise change in endothermic amount in differential scanning calorimetry (DSC). Specifically, for example, a crystalline resin means a resin whose half-width of the endothermic peak when measured at a heating rate of 10°C / min is within 10°C, and an amorphous resin means a resin whose half-width exceeds 10°C or a resin in which no clear endothermic peak is observed.

[0155] The amorphous resin will be described. Examples of the amorphous resin include an amorphous polyester resin and an amorphous styrene-acrylic resin. As the amorphous resin, an amorphous polyester resin and a styrene-acrylic resin may be used in combination.

[0156] The amorphous polyester resin may be, for example, a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. As the amorphous polyester resin, a commercially available product or a synthesized product may be used.

[0157] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. The polycarboxylic acid may be a trivalent or higher carboxylic acid having a crosslinked or branched structure in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0158] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0159] Amorphous polyester resins can be obtained by known production methods. Specifically, for example, the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is reduced in pressure as necessary, and the reaction is carried out while removing water and alcohol generated during condensation. If the raw material monomers are not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, it is recommended that the poorly compatible monomer be condensed in advance with the acid or alcohol to be polycondensed, and then polycondensed with the main component.

[0160] Styrene-acrylic resins are copolymers obtained by copolymerizing at least a styrene-based monomer (a monomer having a styrene skeleton) and a (meth)acrylic-based monomer (a monomer having a (meth)acrylic group, preferably a monomer having a (meth)acryloxy group). The styrene-acrylic resins include, for example, copolymers of a styrene monomer and a (meth)acrylic acid ester monomer. The acrylic resin portion of the styrene-acrylic resin is a partial structure formed by polymerizing either an acrylic monomer or a methacrylic monomer, or both. Furthermore, the term "(meth)acrylic" includes both "acrylic" and "methacrylic."

[0161] Specific examples of styrene-based monomers include styrene, alkyl-substituted styrenes (e.g., α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrenes (e.g., 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), vinylnaphthalene, etc. The styrene-based monomers may be used alone or in combination of two or more. Of these, styrene is preferred as the styrene-based monomer in terms of ease of reaction, ease of reaction control, and availability.

[0162] Specific examples of (meth)acrylic monomers include (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl 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, and (meth) Examples of the (meth)acrylic acid monomer include neopentyl acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, etc.), aryl (meth)acrylate esters (e.g., phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, etc.), dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, and (meth)acrylamide. The (meth)acrylic acid monomers may be used alone or in combination of two or more. Among these (meth)acrylic esters among the (meth)acrylic monomers, (meth)acrylic acid esters having an alkyl group with 2 to 14 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred from the viewpoint of fixability. Of these, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0163] The copolymerization ratio of the styrene-based monomer to the (meth)acrylic monomer (based on mass, styrene-based monomer / (meth)acrylic monomer) is not particularly limited, but is preferably 85 / 15 to 70 / 30.

[0164] The styrene-acrylic resin may have a crosslinked structure. Preferred examples of the styrene-acrylic resin having a crosslinked structure include copolymers of at least a styrene-based monomer, a (meth)acrylic acid-based monomer, and a crosslinkable monomer.

[0165] Examples of the crosslinkable monomer include bifunctional or higher functional crosslinking agents. Examples of bifunctional crosslinking agents include divinylbenzene, divinylnaphthalene, di(meth)acrylate compounds (e.g., diethylene glycol di(meth)acrylate, methylene bis(meth)acrylamide, decanediol diacrylate, glycidyl (meth)acrylate, etc.), polyester-type di(meth)acrylate, 2-([1'-methylpropylideneamino]carboxyamino)ethyl methacrylate, etc. Examples of polyfunctional crosslinking agents include tri(meth)acrylate compounds (e.g., pentaerythritol tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc.), tetra(meth)acrylate compounds (e.g., pentaerythritol tetra(meth)acrylate, oligoester (meth)acrylate, etc.), 2,2-bis(4-methacryloxy, polyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diaryl chlorendate, etc. Among these, as the crosslinkable monomer, from the viewpoints of suppressing the occurrence of a decrease in image density and the occurrence of image density unevenness, and of fixability, a bifunctional or higher (meth)acrylate compound is preferred, a bifunctional (meth)acrylate compound is more preferred, a bifunctional (meth)acrylate compound having an alkylene group having from 6 to 20 carbon atoms is even more preferred, and a bifunctional (meth)acrylate compound having a linear alkylene group having from 6 to 20 carbon atoms is particularly preferred.

[0166] The copolymerization ratio of the crosslinkable monomer to the total monomers (based on mass, crosslinkable monomer / total monomers) is not particularly limited, but is preferably 2 / 1,000 to 20 / 1,000.

[0167] The method for producing the styrene-acrylic resin is not particularly limited, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) are applied. In addition, the polymerization reaction is carried out by a known operation (e.g., batchwise, semi-continuous, continuous, etc.).

[0168] The proportion of the styrene acrylic resin in the total binder resin is preferably 0% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and even more preferably 2% by mass or more and 10% by mass or less.

[0169] The proportion of the amorphous resin in the total binder resin is preferably 60% by mass or more and 98% by mass or less, more preferably 65% ​​by mass or more and 95% by mass or less, and even more preferably 70% by mass or more and 90% by mass or less.

[0170] The characteristics of the amorphous resin will be explained. The glass transition temperature (Tg) of the amorphous resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), more specifically, from the "extrapolated glass transition onset temperature" described in JIS K 7121-1987 "Method for measuring transition temperatures of plastics."

[0171] The weight average molecular weight (Mw) of the amorphous resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the amorphous resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the amorphous resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device and a Tosoh TSKgel SuperHM-M (15 cm) column in THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0172] The crystalline resin will now be described. Examples of the crystalline resin include known crystalline resins such as crystalline polyester resins and crystalline vinyl resins (e.g., polyalkylene resins, long-chain alkyl (meth)acrylate resins, etc.) Among these, crystalline polyester resins are preferred from the viewpoint of suppressing density unevenness and white spots in the resulting image.

[0173] Examples of the crystalline polyester resin include a polycondensate of a polycarboxylic acid and a polyhydric alcohol. As the crystalline polyester resin, a commercially available product or a synthesized product may be used. The crystalline polyester resin is preferably a polycondensate using a straight-chain aliphatic polymerizable monomer rather than a polymerizable monomer having an aromatic ring, since it easily forms a crystalline structure.

[0174] 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.

[0175] Examples of polyhydric alcohols include aliphatic diols (for example, straight-chain aliphatic diols having 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosanedecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. The polyhydric alcohol may be a trihydric or higher alcohol having a crosslinked or branched structure, such as glycerin, trimethylolethane, trimethylolpropane, or pentaerythritol, in combination with the diol. The polyhydric alcohols may be used alone or in combination of two or more.

[0176] The polyhydric alcohol may have an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0177] The melting temperature of the crystalline polyester resin is preferably 50°C or higher and 100°C or lower, more preferably 55°C or higher and 90°C or lower, and even more preferably 60°C or higher and 85°C or lower. The melting temperature of the crystalline polyester resin is determined from a DSC curve obtained by differential scanning calorimetry (DSC) 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."

[0178] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0179] The crystalline polyester resin can be obtained by a known production method, for example, in the same manner as the amorphous polyester resin.

[0180] As the crystalline polyester resin, a polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol is preferred from the viewpoint of easily forming a crystalline structure and having good compatibility with amorphous polyester resins, thereby improving image fixability.

[0181] The α,ω-linear aliphatic dicarboxylic acid is preferably an α,ω-linear aliphatic dicarboxylic acid in which the alkylene group connecting the two carboxy groups has 3 to 14 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. Examples of the α,ω-linear aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, 1,6-hexanedicarboxylic acid (commonly known as suberic acid), 1,7-heptanedicarboxylic acid (commonly known as azelaic acid), 1,8-octanedicarboxylic acid (commonly known as sebacic acid), 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid. Of these, 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,8-octanedicarboxylic acid, and 1,10-decanedicarboxylic acid are preferred. The α,ω-linear aliphatic dicarboxylic acids may be used alone or in combination of two or more.

[0182] The α,ω-linear aliphatic diol is preferably an α,ω-linear aliphatic diol in which the alkylene group connecting the two hydroxy groups has 3 to 14 carbon atoms, more preferably 4 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. Examples of the α,ω-linear aliphatic diol 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, 1,12-dodecanediol, 1,14-tetradecanediol, and 1,18-octadecanediol. Of these, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred. The α,ω-linear aliphatic diols may be used alone or in combination of two or more.

[0183] As the polymer of an α,ω-linear aliphatic dicarboxylic acid and an α,ω-linear aliphatic diol, from the viewpoint of easily forming a crystalline structure and having good compatibility with amorphous polyester resins, thereby improving image fixability, a polymer of at least one selected from the group consisting of 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid and at least one selected from the group consisting of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol is preferred, and among these, a polymer of 1,10-decanedicarboxylic acid and 1,6-hexanediol is more preferred.

[0184] The proportion of the crystalline resin in the total binder resin is preferably 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less.

[0185] Other binder resins Examples of binder resins include homopolymers of monomers such as ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), and copolymers of two or more of these monomers in combination. Other examples of the binder resin include non-vinyl resins such as epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binder resins may be used alone or in combination of two or more.

[0186] The content of the binder resin is 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.

[0187] -Mold release agent- The toner particles preferably contain a 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.

[0188] The ester wax is a wax having an ester bond. The ester wax may be any of a monoester, diester, triester, and tetraester, and any known natural or synthetic ester wax can be used. Examples of ester waxes include ester compounds of higher fatty acids (such as fatty acids having 10 or more carbon atoms) and monohydric or polyhydric aliphatic alcohols (such as aliphatic alcohols having 8 or more carbon atoms), and have a melting temperature of 60°C or higher and 110°C or lower (preferably 65°C or higher and 100°C or lower, more preferably 70°C or higher and 95°C or lower). Examples of ester waxes include ester compounds of higher fatty acids (caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, oleic acid, etc.) with alcohols (monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, and oleyl alcohol; and polyhydric alcohols such as glycerin, ethylene glycol, propylene glycol, sorbitol, and pentaerythritol). Specific examples include carnauba wax, rice wax, candelilla wax, jojoba oil, Japan wax, beeswax, privet wax, lanolin, and montan acid ester wax.

[0189] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature of the release agent 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."

[0190] The content of the release agent is preferably from 1% by mass to 20% by mass, and more preferably from 2% by mass to 15% by mass, based on the total mass of the toner particles.

[0191] -Other colorants- Toner A and white toner B may contain a colorant other than the dye and the titanium oxide pigment. Other colorants include, for example, carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, Balkan orange, watch young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples of the dye include various pigments such as laminarine blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, and various dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes. The other colorants may be used alone or in combination of two or more.

[0192] The other colorants may be surface-treated as needed, or may be used in combination with a dispersant. In addition, a plurality of types of other colorants may be used in combination.

[0193] -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 or external additives.

[0194] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or toner particles of a so-called core-shell structure consisting of a core (core particle) and a coating layer (shell layer) that covers the core. However, from the viewpoint of suppressing fading under high temperature and high humidity conditions, toner particles of a core-shell structure are preferred. Here, the toner particles having a core-shell structure may be composed of, for example, a core containing a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer containing the binder resin.

[0195] The volume average particle size (D50v) of the toner particles is preferably from 2 μm to 15 μm, more preferably from 3 μm to 10 μm, and even more preferably from 4 μm to 9 μm.

[0196] The various average particle sizes and particle size distribution indices of the toner particles are measured using a Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using an ISOTON-II (manufactured by Beckman Coulter). For the measurement, 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant, and this is then added to 100 ml to 150 ml of the electrolyte. The electrolyte solution containing the suspended sample is dispersed for 1 minute using an ultrasonic disperser, and the particle size distribution of particles with a particle size range of 2 μm to 60 μm is measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the particle size distribution measured, cumulative distributions of volume and number are drawn for each divided particle size range (channel) from the smallest diameter side, and the particle size at 16% of the cumulative total is defined as the volume particle size D16v, the number particle size D16p, the particle size at 50% of the cumulative total as the volume average particle size D50v, the cumulative number average particle size D50p, and the particle size at 84% of the cumulative total as the volume particle size D84v and the number particle size D84p. Using these, the volumetric particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 , the number particle size distribution index (GSDp) is (D84p / D16p) 1 / 2 It is calculated as:

[0197] The average circularity of the toner particles is preferably 0.80 or more and 1.00 or less, and more preferably 0.90 or more and 0.98 or less.

[0198] 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.

[0199] (Toner manufacturing method) Next, a method for producing toner A or white toner B will be described. Toner A or white toner B can be suitably obtained, for example, by producing toner particles and then externally adding an external additive to the toner particles.

[0200] 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). There are no particular limitations on these production methods, and any known production method may be used. Among these, it is preferable to obtain toner particles by the aggregation and coalescence method. Examples of the aggregation and coalescence method include the methods described in JP-A No. 2010-97101 and JP-A No. 2006-154641. An example of the kneading and pulverizing method is the method described in JP-A No. 2000-267338. An example of the dissolution suspension method is the method described in Japanese Patent Application Laid-Open No. 2000-258950.

[0201] Specifically, for example, when resin particles are produced by the aggregation-coalescence method, toner particles are produced through the following steps: a step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step); a step of aggregating the resin particles and dye particles or titanium oxide pigment particles (and other particles, if necessary) in the dispersion obtained by mixing the resin particle dispersion and the colorant dispersion (and other particle dispersions, if necessary) to form aggregated particles (aggregated particle formation step); and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and coalesce the aggregated particles to form resin particles (fusion and coalescence step). As the colorant in the colorant dispersion, for example, in the case of toner A, a dye and, if necessary, other colorants are preferably used, and in the case of white toner B, a titanium oxide pigment is preferably used.

[0202] Each step will be described in detail below. In the following description, a method for obtaining resin particles containing other colorants and a release agent will be described, but the other colorants and release agents are used as needed. Of course, other additives other than the other colorants and release agents may also be used.

[0203] -Resin particle dispersion preparation process- Along with the resin particle dispersion liquid in which resin particles that will become the binder resin are dispersed, for example, another colorant particle dispersion liquid in which other colorant particles are dispersed, and a release agent particle dispersion liquid in which release agent particles are dispersed are prepared.

[0204] The resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0205] 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.

[0206] 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. Of these, it is preferable to use a nonionic surfactant, and it is also preferable to use a nonionic surfactant in combination with an anionic surfactant or a cationic surfactant. The surfactants may be used alone or in combination of two or more.

[0207] In a resin particle dispersion, resin particles can be dispersed in a dispersion medium by common dispersion methods such as a rotary shear homogenizer, a ball mill with media, a sand mill, or a Dynomill. Depending on the type of resin particles, the resin particles may be dispersed in a dispersion medium by 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, neutralizing the organic continuous phase (O phase) by adding a base, and then introducing an aqueous medium (W phase) to invert the phase from W / O to O / W, thereby dispersing the resin in particulate form in the aqueous medium.

[0208] 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 0.03 μm to 0.8 μm, and even more preferably from 0.05 μm to 0.6 μm. The volume average particle size of 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 taken as the volume average particle size D50v. The volume average particle sizes of particles in other dispersions are measured in the same way.

[0209] The content of resin particles contained in the resin particle dispersion is preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

[0210] In the same manner as in the resin particle dispersion, a colorant particle dispersion of, for example, a dye or a titanium oxide pigment, and a release agent particle dispersion are also prepared. That is, the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion are the same for the colorant particles dispersed in the colorant particle dispersion and the release agent particles dispersed in the release agent particle dispersion.

[0211] -Agglomerated particle formation process- Next, the resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed together. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are hetero-aggregated to form aggregated particles containing the resin particles, other colorant particles, and release agent particles, and having a diameter close to the diameter of the target resin particles.

[0212] Specifically, for example, an aggregating agent is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 or higher and 5 or lower), and a dispersion stabilizer is added as necessary. After that, the mixed dispersion is heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, the glass transition temperature of the resin particles -30°C or higher and the glass transition temperature -10°C or lower), causing the particles dispersed in the mixed dispersion to aggregate and form aggregated particles. In the aggregate particle formation step, for example, the mixed dispersion may be stirred with a rotary shear homogenizer, an 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., pH 2 or more and 5 or less), a dispersion stabilizer may be added as needed, and then the mixture may be heated.

[0213] Examples of the flocculant include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, an inorganic metal salt, and a divalent or higher metal complex. 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 together with the flocculant, and a chelating agent is preferably used as this additive.

[0214] 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; and inorganic metal salt polymers such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. The chelating agent may be a water-soluble chelating agent, for example, hydroxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); and the like. The amount of the flocculant added is 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, relative to 100 parts by mass of the resin particles.

[0215] -Fusion / unification process- Next, the aggregated particle dispersion liquid in which the aggregated particles are dispersed is heated, for example, to a temperature equal to or higher than the glass transition temperature of the resin particles (for example, a temperature 30°C to 50°C higher than the glass transition temperature of the resin particles) and equal to or higher than the melting temperature of the release agent, to fuse and coalesce the aggregated particles and form toner particles. In the fusion and coalescence process, the resin and release agent are in a fused state at temperatures above the glass transition temperature of the resin particles and above the melting temperature of the release agent. The mixture is then cooled to obtain resin particles. The aspect ratio of the release agent in the toner particles can be adjusted by holding the toner at a temperature around the freezing point of the release agent for a certain period of time during cooling to cause crystal growth, or by using two or more types of release agents with different melting temperatures to promote crystal growth during cooling.

[0216] Through the above steps, toner particles are obtained. After obtaining an aggregated particle dispersion in which aggregated particles are dispersed, the toner particles may be produced through the following steps: further mixing the aggregated particle dispersion with a resin particle dispersion in which resin particles are dispersed, and aggregating the aggregated particles so that further resin particles adhere to the surfaces of the aggregated particles to form second aggregated particles; and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles to form resin particles having a core-shell structure.

[0217] After the fusion and coalescence process is completed, the toner particles formed in the solution are subjected to a known washing process, solid-liquid separation process, and drying process to obtain dried toner particles. In the washing process, from the viewpoint of chargeability, it is preferable to perform sufficient substitution washing with ion-exchanged water. In the solid-liquid separation process, from the viewpoint of productivity, it is preferable to perform suction filtration, pressure filtration, etc. In the drying process, from the viewpoint of productivity, it is preferable to perform freeze drying, flash drying, fluidized drying, vibration-type fluidized drying, etc.

[0218] Toner A or white toner B is produced by, for example, adding an external additive to the obtained dry toner particles and mixing them together. 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 of the resin particles may be removed using a vibrating sieve, a wind sieve, or the like.

[0219] <Electrostatic image developer set> The electrostatic image developer set according to this embodiment includes a first electrostatic image developer containing the toner A from the toner set for developing electrostatic images according to this embodiment, and a second electrostatic image developer containing the white toner B from the toner set for developing electrostatic images according to this embodiment. Each electrostatic image developer may be a one-component developer containing only toner, or may be a two-component developer containing a mixture of the toner and a carrier.

[0220] 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.

[0221] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0222] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, and epoxy resins. 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.

[0223] 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.

[0224] In the two-component developer, the mixing ratio (mass ratio) of toner to carrier is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100.

[0225] <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 means for forming a colored image using the toner of the toner set for developing electrostatic images according to this embodiment, a second image forming means for forming a white image using the white toner of the toner set for developing electrostatic images according to this embodiment, a transfer means for transferring the colored image and the white image onto a recording medium, and a fixing means for fixing the colored image and the white image onto the recording medium. The image forming apparatus according to the present embodiment may be configured to include, as first and second image forming means, image forming means each having an image carrier, a charging means for charging the surface of the image carrier, an electrostatic image forming means for forming an electrostatic image on the surface of the charged image carrier, and a developing means for developing the electrostatic image formed on the surface of the image carrier with an electrostatic image developer into a toner image. In addition, the image forming apparatus according to the present embodiment may have a configuration including an image carrier, a charging means for charging the surface of the image carrier, an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier, and first and second developing means as first and second image forming means for developing the electrostatic image formed on the surface of the image carrier with an electrostatic image developer into a toner image.

[0226] In the image forming apparatus according to this embodiment, an image forming method (the image forming method according to this embodiment) is carried out, which includes a first image forming process of forming a colored image using toner A of the toner set for developing electrostatic images according to this embodiment, a second image forming process of forming a white image using white toner B of the toner set for developing electrostatic images according to this embodiment, a transfer process of transferring the colored image and the white image onto a recording medium, and a fixing process of fixing the colored image and the white image onto the recording medium.

[0227] The image forming apparatus according to this embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus that transfers a toner image (in this embodiment, a glossy image or a colored 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 formed on the surface of an image carrier onto the surface of an intermediate transfer carrier, and then performs a secondary transfer of the toner image transferred to the surface of the intermediate transfer carrier onto 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 means is configured to have, for example, an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer means which primarily transfers the toner image formed on the surface of the image carrier onto the surface of the intermediate transfer body, and a secondary transfer means which secondarily transfers the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium.

[0228] 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. In the following description, the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0229] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment, and is a diagram showing a five-tandem type and intermediate transfer type image forming apparatus. The image forming apparatus shown in Figure 1 includes first through fifth electrophotographic image forming units 50Y, 50M, 50C, 50K, and 50B (image forming means) that output images in the colors yellow (Y), magenta (M), cyan (C), black (K), and white (B) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 50Y, 50M, 50C, 50K, and 50B are arranged side by side horizontally at predetermined distances from one another. These units 50Y, 50M, 50C, 50K, and 50B may be process cartridges that are detachably attached to the image forming apparatus.

[0230] An intermediate transfer belt (an example of an intermediate transfer body) 33 extends below each of the units 50Y, 50M, 50C, 50K, and 50B. The intermediate transfer belt 33 is wound around a drive roll 23, a support roll 22, and an opposing roll 24, which are in contact with the inner surface of the intermediate transfer belt 33, and runs in a direction from the first unit 50Y to the fifth unit 50B (the direction of arrow B in FIG. 1). An intermediate transfer body cleaning device 26 is provided on the image bearing surface side of the intermediate transfer belt 33, facing the drive roll 23. Furthermore, a voltage application device (not shown) is provided upstream of the intermediate transfer body cleaning device 26 in the rotation direction of the intermediate transfer belt 33, which generates a potential difference between the intermediate transfer belt 33 and the supporting roll 23, thereby generating an electric field between the intermediate transfer belt 33 and the intermediate transfer body cleaning device 26. The developing devices (examples of developing means) 20Y, 20M, 20C, 20K, 20B of each unit 50Y, 50M, 50C, 50K, 50B are supplied with yellow, magenta, cyan, black, and white toner contained in toner cartridges 40Y, 40M, 40C, 40K, 40B, respectively.

[0231] Since the first to fifth units 50Y, 50M, 50C, 50K, and 50B have the same configuration, operation, and function, we will explain here the first unit 50Y, which forms a yellow image and is arranged upstream in the direction of travel of the intermediate transfer belt.

[0232] The first unit 50Y has a photoconductor 21Y that acts as an image carrier. Around the photoconductor 21Y, there are arranged in this order: a charging roll (an example of a charging means) 28Y that charges the surface of the photoconductor 21Y to a predetermined potential; an exposure device (an example of an electrostatic image forming means) 19Y that exposes the charged surface to a laser beam based on a color-separated image signal to form an electrostatic image; a developing device (an example of a developing means) 20Y that supplies toner to the electrostatic image to develop it; a primary transfer roll (an example of a primary transfer means) 17Y that transfers the developed toner image onto the intermediate transfer belt 33; and a photoconductor cleaning device (an example of a cleaning means) 15Y that removes toner remaining on the surface of the photoconductor 21Y after the primary transfer. The primary transfer roll 17Y is disposed inside the intermediate transfer belt 33 and is provided at a position facing the photoconductor 21Y. A bias power supply (not shown) that applies a primary transfer bias is connected to the primary transfer rolls 17Y, 17M, 17C, 17K, and 17B of each unit. Each bias power supply changes the value of the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0233] The operation of forming a yellow image in the first unit 50Y will be described below. First, prior to operation, the surface of the photosensitive member 21Y is charged to a potential of −600V to −800V by the charging roll 28Y. The photoconductor 21Y has conductivity (for example, a volume resistivity of 1×10 at 20° C. -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, the resistivity of the irradiated portion changes. Therefore, a laser beam is irradiated from the exposure device 19Y onto the charged surface of the photosensitive element 21Y in accordance with image data for yellow sent from a control unit (not shown). This forms an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 21Y.

[0234] An electrostatic image is an image formed on the surface of the photosensitive element 21Y by charging it; the resistivity of the irradiated portion of the photosensitive layer is reduced by the laser beam from the exposure device 19Y, causing the charged charges on the surface of the photosensitive element 21Y to flow, while the charges remain in the portions not irradiated by the laser beam, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 21Y rotates to a predetermined development position as the photoreceptor 21Y travels, where the electrostatic image on the photoreceptor 21Y is developed into a toner image by the developing device 20Y and made visible.

[0235] The developing device 20Y contains an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 20Y, 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 21Y. As the surface of the photoreceptor 21Y passes through the developing device 20Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 21Y, and the latent image is developed with the yellow toner. The photoreceptor 21Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 21Y is transported to a predetermined primary transfer position.

[0236] When the yellow toner image on the photoreceptor 21Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 17Y, and an electrostatic force from the photoreceptor 21Y to the primary transfer roll 17Y acts on the toner image, causing the toner image on the photoreceptor 21Y to be transferred onto the intermediate transfer belt 33. The transfer bias applied at this time has a (+) polarity opposite to the (-) polarity of the toner, and is controlled to, for example, +10 μA by a control unit (not shown) in the first unit 50Y. On the other hand, the toner remaining on the photoreceptor 21Y is removed and collected by the photoreceptor cleaning device 15Y.

[0237] The primary transfer bias applied to the primary transfer rolls 17M, 17C, 17K, and 17B of the second unit 50M and subsequent units is also controlled in accordance with the first unit. In this way, the intermediate transfer belt 33 onto which the yellow toner image has been transferred by the first unit 50Y is transported sequentially through the second to fifth units 50M, 50C, 50K, and 50B, and the toner images of each color are superimposed and transferred.

[0238] The intermediate transfer belt 33, onto which the five-color toner images have been multiplex-transferred through the first to fifth units, reaches a secondary transfer section composed of the intermediate transfer belt 33, an opposing roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 34 arranged on the image bearing surface side of the intermediate transfer belt 33. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 34 and the intermediate transfer belt 33 at a predetermined timing, and a secondary transfer bias is applied to the opposing 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 33 toward the recording paper P acts on the toner image, and the toner image on the intermediate transfer belt 33 is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to resistance detected by resistance detection means (not shown) that detects resistance in the secondary transfer section, and is voltage-controlled.

[0239] Thereafter, the recording paper P is sent to a pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of fixing means) 35, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0240] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copiers, 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, etc., is preferably used.

[0241] 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.

[0242] 1 is an image forming apparatus having a configuration in which toner cartridges 40Y, 40M, 40C, 40K, and 40B are detachably attached, and developing devices 20Y, 20M, 20C, 20K, and 20B are connected to the toner cartridges corresponding to each developing device (color) via toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced.

[0243] <Process cartridge / toner cartridge set> The process cartridge according to this embodiment will be described. The process cartridge of this embodiment is a process cartridge that is detachably attached to an image forming apparatus and includes a first developing means that contains the first electrostatic image developer of the electrostatic image developer set of this embodiment, and a second developing means that contains the second electrostatic image developer of the electrostatic image developer set of this embodiment.

[0244] The process cartridge according to this embodiment is not limited to the above configuration, but may also be configured to include a developing device and, if necessary, at least one other means selected from an image carrier, a charging means, an electrostatic image forming means, and a transfer means.

[0245] 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.

[0246] 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 means) provided around the photosensitive member 107, a developing device 111 (an example of a developing means), and a photosensitive member cleaning device 113 (an example of a cleaning means), which are held by a housing 117 provided with, for example, mounting rails 116 and an opening 118 for exposure, and is made into a cartridge. In FIG. 2, 109 denotes an exposure device (an example of an electrostatic image forming means), 112 denotes a primary transfer roll (an example of a primary transfer means), 120 denotes an intermediate transfer belt (an example of an intermediate transfer body), 122 denotes a drive roll (an example of an intermediate transfer body de-electrification means) that also serves as an intermediate transfer belt de-electrification means, 124 denotes a support roll, 126 denotes a secondary transfer roll (an example of a secondary transfer means), 128 denotes a fixing device (an example of a fixing means), and 300 denotes recording paper (an example of a recording medium).

[0247] Next, the toner cartridge set according to this embodiment will be described. The toner cartridge set of this embodiment has a first toner cartridge that contains the toner A of the toner set for developing electrostatic images of this embodiment, and a second toner cartridge that contains the white toner B of the toner set for developing electrostatic images of this embodiment, and is a toner cartridge set that can be attached to and detached from an image forming device. Each toner cartridge contains replenishment toner to be supplied to each developing means provided in the image forming apparatus. [Example]

[0248] Hereinafter, the present embodiment will be described in more detail with reference to examples and comparative examples, but the present embodiment is not limited to these examples. Note that "parts" and "%" indicating amounts are based on mass unless otherwise specified. In addition, (I-1) to (I-23), (II-1) to (II-85), and c1 to c13 in this example are the same compounds as the above-mentioned (I-1) to (I-23), (II-1) to (II-85), and c1 to c13, respectively.

[0249] [Preparation of Toner A1] <Preparation of dye particle dispersion> Pyrazolotriazole dye I-3: 15.8 parts Acetylacetone Metal Compound II-34: 34.2 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd., Neogen RK): 5 parts Ion-exchanged water: 193 parts The above components were mixed and treated for 10 minutes at 240 MPa using an Ultimizer (manufactured by Sugino Machine Co., Ltd.) to prepare a colorant particle dispersion (solid content concentration: 20%).

[0250] The pyrazolotriazole dye I-3 and the acetylacetone metal compound II-34 are the compounds shown below.

[0251] [ka]

[0252] [ka]

[0253] <Preparation of styrene acrylic resin particle dispersion (1)> <Preparation of styrene acrylic resin particle dispersion> -Oil phase materials- Styrene (Fujifilm Wako Pure Chemical Industries, Ltd.): 30 parts n-Butyl acrylate (Fujifilm Wako Pure Chemical Industries, Ltd.): 10 parts β-Carboxyethyl acrylate (Rhodia Nikka): 1.3 parts Dodecanethiol (Fujifilm Wako Pure Chemical Industries, Ltd.): 0.4 parts

[0254] -Ingredients for aqueous phase 1- Ion-exchanged water: 17 parts Anionic surfactant: Dowfax (Dow Chemical Company): 0.4 parts

[0255] -Ingredients for aqueous phase 2- Ion-exchanged water: 40 parts Anionic surfactant: Dowfax (Dow Chemical Company): 0.05 parts Ammonium peroxodisulfate (Fujifilm Wako Pure Chemical Industries, Ltd.): 0.4 parts

[0256] The oil phase materials and the aqueous phase 1 materials were separately stirred and mixed, and the two were stirred and mixed to form an emulsified dispersion of monomer. Separately, the aqueous phase 2 materials were charged into a reaction vessel, the reaction vessel was thoroughly purged with nitrogen, and the reaction system was heated in an oil bath with stirring until the temperature reached 75°C. The emulsion dispersion of monomer was gradually added dropwise to this reaction vessel over 3 hours to carry out emulsion polymerization. After the dropwise addition was completed, the polymerization was continued at 75°C and terminated after 3 hours, yielding a styrene-acrylic resin particle dispersion with a solid content of 42% by mass. Ion-exchange water was added to this resin particle dispersion to adjust the solid content to 20%, yielding styrene-acrylic resin particle dispersion (1). The volume average particle size was measured using a particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.) and found to be 250 nm. The glass transition temperature of the resin was measured using a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corporation) at a heating rate of 10°C / min and found to be 52°C. The number average molecular weight (polystyrene equivalent) was measured using GPC and found to be 13,000.

[0257] <Preparation of Release Agent Particle Dispersion (1)> Paraffin wax (Nippon Seiro Co., Ltd., HNP-9): 100 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1 part Ion-exchanged water: 350 parts The above materials were mixed and heated to 100°C, dispersed using a homogenizer (IKA, trade name Ultra Turrax T50), and then dispersed using a Manton-Gaulin high-pressure homogenizer (Gaulin) to obtain a release agent particle dispersion (1) (solid content 20% by mass) in which release agent particles with a volume average particle size of 200 nm were dispersed.

[0258] <Preparation of Toner Particles (A1)> Styrene acrylic resin particle dispersion (1): 390 parts ·Dye particle dispersion (1): 20 parts Release agent particle dispersion (1): 40 parts Anionic surfactant (Dai-ichi Kogyo Seiyaku Co., Ltd.: Neogen RK, 20%): 1 part The above materials were placed in a round stainless steel flask, and 0.1 N (=mol / L) nitric acid was added to adjust the pH to 3.5. Then, 30 parts of a nitric acid solution containing 10% by weight of polyaluminum chloride were added. The mixture was then dispersed at 30°C using a homogenizer (Ultra Turrax T50, manufactured by IKA Corporation) and heated to 45°C in a heating oil bath and held for 30 minutes. 200 parts of styrene-acrylic resin particle dispersion (1) were then added and held for 1 hour. 0.1 N aqueous sodium hydroxide was added to adjust the pH to 8.5, and the mixture was then heated to 85°C and held for 2.5 hours. The mixture was then cooled to 20°C at a rate of 20°C / min. The solids were filtered, thoroughly washed with ion-exchanged water, and dried to obtain toner particles (A1). The volume average particle size of the toner particles (A1) was 7 μm.

[0259] <Preparation of Carrier 1> Ferrite particles (average particle size 35 μm): 100 parts Toluene: 14 parts Polymethyl methacrylate (MMA, weight average molecular weight 75,000): 5 parts Carbon black: 0.2 parts (VXC-72, manufactured by Cabot Corporation, volume resistivity: 100 Ωcm or less). The above materials except for the ferrite particles were dispersed in a sand mill to prepare a dispersion liquid. This dispersion liquid was then placed in a vacuum degassing kneader together with the ferrite particles, and the mixture was stirred while reducing the pressure and dried to obtain carrier 1.

[0260] <Preparation of Toner A1> 100 parts by mass of the obtained toner particles (A1) were mixed and blended with 1.5 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) and 1.0 part by mass of hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805) using a sample mill at 10,000 rpm (revolutions per minute) for 30 seconds. The mixture was then sieved through a vibrating sieve with 45 μm openings to prepare toner A1 (toner for developing electrostatic images). The volume average particle size of the obtained toner A1 was 7 μm.

[0261] <Preparation of Electrostatic Image Developer> Developer A1 (electrostatic image developer) was prepared by mixing 8 parts of toner A1 and 92 parts of carrier in a V blender.

[0262] [Preparation of White Toner B1] <Preparation of White Pigment Dispersion (1)> Titanium oxide (CR-60-2, manufactured by Ishihara Sangyo Kaisha, Ltd., number average particle size 210 nm): 100 parts Nonionic surfactant (Nonipol 400: manufactured by Sanyo Chemical Industries, Ltd.): 10 parts Ion-exchanged water: 400 parts The above components were mixed and stirred for 30 minutes using a homogenizer (Ultra Turrax T50, manufactured by IKA Corporation), and then dispersed for 1 hour using a high-pressure impact disperser, Ultimizer (HJP30006, manufactured by Sugino Machine Co., Ltd.) to prepare white pigment dispersion (1) (solid content concentration: 20%).

[0263] <Synthesis of amorphous polyester resin (1)> Bisphenol A ethylene oxide 2.2 mole adduct: 40 mole% Bisphenol A propylene oxide 2.2 mole adduct: 60 mole% Terephthalic acid: 47 mol% Fumaric acid: 40 mol% Dodecenylsuccinic anhydride: 15 mol% Trimellitic anhydride: 3 mol% A reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube was charged with the monomer components other than fumaric acid and trimellitic anhydride, and 0.25 parts of tin dioctanoate per 100 parts of the total monomer components. After reacting for 6 hours at 235°C under a nitrogen gas stream, the temperature was lowered to 200°C, and the fumaric acid and trimellitic anhydride were added and reacted for 1 hour. The temperature was then further raised to 220°C over 4 hours, and polymerization was continued under a pressure of 10 kPa until the desired molecular weight was reached, yielding a pale yellow, transparent amorphous polyester resin. The obtained amorphous polyester resin (1) had a glass transition temperature Tg of 59°C measured by DSC, a weight average molecular weight Mw of 25,000 measured by GPC, a number average molecular weight Mn of 7,000 measured by GPC, a softening temperature of 107°C measured by a flow tester, and an acid value AV of 13 mgKOH / g.

[0264] <Preparation of Amorphous Polyester Resin Dispersion (1)> A jacketed reactor (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, thermometer, water dripping device, and anchor blades was maintained at 40 ° C. in a water-circulating thermostatic bath. A mixed solvent of 160 parts of ethyl acetate and 100 parts of isopropyl alcohol was added to the reactor, and 300 parts of the amorphous polyester resin (1) were added and stirred at 150 rpm using a Three-One motor to dissolve the resin. 14 parts of a 10% aqueous ammonia solution were added dropwise over 5 minutes. After mixing for 10 minutes, 900 parts of ion-exchanged water were added dropwise at a rate of 7 parts per minute to invert the phase, resulting in an emulsion. Immediately, 800 parts of the resulting emulsion and 700 parts of ion-exchanged water were placed in an eggplant flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. While rotating the eggplant flask, it was heated in a hot water bath at 60°C and, while taking care to prevent bumping, the pressure was reduced to 7 kPa to remove the solvent. When the amount of recovered solvent reached 1,100 parts, the pressure was returned to normal and the eggplant flask was cooled with water to obtain a dispersion. The resulting dispersion had no solvent odor. The volume average particle size of the resin particles in this dispersion was 130 nm. Thereafter, ion-exchanged water was added to adjust the solid concentration to 20%, and this was used as amorphous polyester resin dispersion (1).

[0265] <Preparation of amorphous polyester resin dispersion (2)> In the synthesis of the amorphous polyester resin (1), the monomer components are Bisphenol A ethylene oxide 2.2 mole adduct: 5 mole% Bisphenol A propylene oxide 2.2 mole adduct: 95 mole% Terephthalic acid: 77 mol% Fumaric acid: 10 mol% Dodecenylsuccinic anhydride: 10 mol% Trimellitic anhydride: 2 mol% Amorphous polyester resin dispersion (2) was prepared in the same manner as in the preparation of amorphous polyester resin dispersion (1), except that the above was replaced with the above.

[0266] <Synthesis of crystalline polyester resin (1)> 1,10-dodecanedioic acid: 50 mol% 1,9-nonanediol: 50 mol% The monomer components were placed in a reaction vessel equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet tube, and the atmosphere in the reaction vessel was replaced with dry nitrogen gas. Then, 0.25 parts of titanium tetrabutoxide (reagent) per 100 parts of the monomer components was added. After stirring and reacting for 3 hours at 170°C under a nitrogen gas stream, the temperature was further increased to 210°C over 1 hour, the pressure in the reaction vessel was reduced to 3 kPa, and the reaction was continued under reduced pressure for 13 hours with stirring to obtain crystalline polyester resin (1). The resulting crystalline polyester resin (1) had a melting temperature of 73.6° C. by DSC, a mass average molecular weight Mw of 25,000, a number average molecular weight Mn of 10,500, and an acid value AV of 10.1 mgKOH / g by GPC.

[0267] <Preparation of Crystalline Polyester Resin Dispersion (1)> 300 parts of the crystalline polyester resin (1), 160 parts of methyl ethyl ketone (solvent), and 100 parts of isopropyl alcohol (solvent) were placed in a jacketed reaction vessel (Tokyo Rikakikai Co., Ltd.: BJ-30N) equipped with a condenser, a thermometer, a water dropping device, and an anchor blade, and the resin was dissolved by stirring and mixing at 100 rpm while maintaining the temperature at 70°C in a water circulation type thermostatic bath. Thereafter, the stirring speed was increased to 150 rpm, the water circulation type thermostatic bath was set to 66°C, and 17 parts of 10% aqueous ammonia (reagent) was added over 10 minutes, followed by adding a total of 900 parts of ion-exchanged water maintained at 66°C dropwise at a rate of 7 parts / min to cause phase inversion and obtain an emulsion. Immediately, 800 parts of the resulting emulsion and 700 parts of ion-exchanged water were placed in an eggplant flask and placed in an evaporator (Tokyo Rikakikai Co., Ltd.) equipped with a vacuum control unit via a trap bulb. While rotating the eggplant flask, the pressure was increased to 60°C in a hot water bath, and the pressure was reduced to 7 kPa, taking care to prevent bumping, to remove the solvent. When the amount of recovered solvent reached 1,100 parts, the pressure was returned to normal, and the eggplant flask was cooled with water to obtain a dispersion. The resulting dispersion had no solvent odor. The volume-average particle size of the resin particles in this dispersion was 130 nm. Ion-exchanged water was then added to adjust the solids concentration to 20%, and this was designated crystalline polyester resin dispersion (1).

[0268] <Toner particles (B1)> 250 parts of amorphous polyester resin dispersion (1), 100 parts of crystalline polyester resin dispersion (1), 300 parts of white pigment dispersion (1), 50 parts of release agent dispersion (1), and 4 parts of anionic surfactant (Tayca Power, manufactured by Tayca Corporation) were placed in a round stainless steel flask, and after adjusting the pH to 4.0 with 0.1 N nitric acid, 0.2 parts of a nitric acid solution with a polyaluminum chloride concentration of 10% was added. Subsequently, the mixture was dispersed at 30°C for 5 minutes using a homogenizer (Ultra Turrax T50 manufactured by IKA Corporation). Next, the mixture was heated to 45°C in a heating oil bath and held for 30 minutes. After that, 100 parts of amorphous polyester resin dispersion (1) was added and held for 1 hour. A 0.1N (=0.1 mol / L) aqueous sodium hydroxide solution was added to adjust the pH to 8.5, and then the mixture was heated to 73°C with continued stirring and held for 5 hours. The mixture was then cooled to 20°C at a rate of 20°C / min, filtered, thoroughly washed with ion-exchanged water, and dried to obtain toner particles (B1) with a volume average particle size of 8 μm.

[0269] <Preparation of White Toner B1> 100 parts of the toner particles (B1) and 0.7 parts of dimethylsilicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer to obtain white toner B1 (toner for developing electrostatic images).

[0270] <Preparation of Electrostatic Image Developer> Ferrite particles (average particle size 50 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 liquid, and this dispersion liquid 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 B. Then, 100 parts of the carrier B was mixed with 8 parts of the toner B1 to obtain a developer B1 (electrostatic image developer).

[0271] The resulting developer set of Developer A1 and Developer B1 was used to carry out the following evaluations.

[0272] The following operations, image formation, and measurements were carried out in an environment of a temperature of 35°C (±5°C) and humidity of 70%. Two DocuCentre Color 400 CPs manufactured by Fujifilm Business Innovation Co., Ltd. were prepared as image forming apparatuses for forming evaluation images. The first apparatus was used for forming a base image using white toner B, and the developer for each example and comparative example was placed in a developing unit at the K engine position, and the toner was placed in a toner cartridge. The second apparatus was used for forming a YMCK color image using toner A, and the developer for each example and comparative example was placed in a developing unit at the engine position corresponding to the example and comparative example, and the toner was placed in a toner cartridge.

[0273] <Evaluation of color fading prevention under high temperature and humidity conditions> A 100% density image of white toner B monochrome (full solid image, toner coverage 12 g / m) is printed on the bottom layer of a clear A4 PPC laser OHP film manufactured by Fujifilm Business Innovation Co., Ltd. 2 ) on the top layer, a 100% density image of a single color of toner A (size 5cm x 5cm, toner amount 5g / m 2 ) was formed. The formed image was subjected to ultraviolet irradiation (illuminance 99,000 lux) for 50 hours in an environment of temperature 35°C (±5°C) / humidity 70% using an accelerated weather resistance tester (ATLAS Ci4000). Using an X-Rite Spectrophotometer 939 (manufactured by X-Rite Corporation), the solid image density SAD(1) ​​before UV irradiation and the solid image density SAD(2) before UV irradiation were measured, and the density retention ratio SAD(2) / SAD(1) ​​was calculated for the C value for cyan toner, the M value for magenta toner, the Y value for yellow toner, and the K value for black toner. The color fading resistance under high temperature and high humidity conditions was then evaluated according to the following criteria. The results are shown in Table 2.

[0274] -Judgment criteria- AA: Concentration residual ratio SAD(2) / SAD(1) ​​is 90% or more and 100% or less A: Concentration residual ratio SAD(2) / SAD(1) ​​is 80% or more but less than 90% B: Concentration residual ratio SAD(2) / SAD(1) ​​is 70% or more but less than 80% C: Concentration residual ratio SAD(2) / SAD(1) ​​is 60% or more but less than 70% D: Concentration residual ratio SAD(2) / SAD(1) ​​is 50% or more but less than 60% E: Concentration residual ratio SAD(2) / SAD(1) ​​is 30% or more and less than 50% F: Concentration residual ratio SAD(2) / SAD(1) ​​is 10% or more and less than 30% G: Concentration residual ratio SAD(2) / SAD(1) ​​is less than 10%

[0275] <Halftone reproducibility evaluation> In the same environment as the evaluation of color fading suppression under high temperature and high humidity, two similar machines were used to print a 100% density image (full solid image, toner coverage of 12 g / m) of white toner B on the bottom layer of a clear A4 OHP film for PPC laser manufactured by Fujifilm Business Innovation Co., Ltd. 2 ) and Toner A as the upper layer, and the Electrophotographic Society Test Chart No. 5-1 was printed. After that, without irradiating ultraviolet light with an accelerated weathering tester, 10 points of the +0.1 multi-color halftone image part of the output image were measured using an X-Rite 939 (aperture diameter 4 mm) manufactured by X-Rite Corporation according to CIE1976L * a * b * Color coordinates (L * value, a * value and b * The coordinate values ​​obtained were used to calculate the color difference ΔE. Then, halftone reproducibility under high temperature and high humidity conditions was judged according to the following criteria. The results are shown in Table 2.

[0276]

number

[0277] L1, a1, and b1 are the L values ​​measured using X-Rite939 for the images output in each example and comparative example. * value, a * value, b * L2, a2, and b2 are the L values ​​measured using the test chart published by the Imaging Society of Japan (Electrophotography Society Test Chart No. 5-1) with an X-Rite 939. * value, a * value, b * value.

[0278] -Evaluation criteria- A: The difference between the maximum and minimum ΔE values ​​at 10 points is less than 1.0. B: The difference between the maximum and minimum ΔE values ​​at 10 points is 1.0 or more and less than 2.0. C: The difference between the maximum and minimum ΔE values ​​at 10 points is 2.0 or more.

[0279] <Example 2> In the preparation of toner particles (A1), 60 parts of the 390 parts of styrene acrylic resin particle dispersion liquid (1) initially placed in a round stainless steel flask was replaced with amorphous polyester resin particle dispersion liquid (1), In the preparation of toner particles (B1), 120 parts of the 250 parts of amorphous polyester resin dispersion (1) initially placed in the round stainless steel flask was replaced with styrene acrylic resin particle dispersion (1), In the same manner as in Example 1, toner A, white toner B and electrostatic image developers thereof were prepared and evaluated.

[0280] Example 3 Toner particles (B3) were produced in the same manner as in Example 1, except that in the production of toner particles (B1), 250 parts of the amorphous polyester resin dispersion liquid (1) initially placed in the round stainless steel flask was replaced with 250 parts of the amorphous polyester resin dispersion liquid (2), and 30 parts of the 50 parts of the release agent dispersion liquid (1) was replaced with the amorphous polyester resin dispersion liquid (2). Toner A, white toner B, and electrostatic image developers thereof were produced and evaluated.

[0281] Example 4 Toner A, white toner B, and electrostatic image developers thereof were prepared and evaluated in the same manner as in Example 3, except that in the preparation of toner particles (B3), 60 parts of the 250 parts of amorphous polyester resin dispersion (2) initially placed in the round stainless steel flask was replaced with release agent dispersion (1).

[0282] <Example 5> Toner A, white toner B and electrostatic image developers thereof were prepared and evaluated in the same manner as in Example 1, except that white toner B was prepared by the kneading and pulverization method described below.

[0283] -Toner particle production / kneading and pulverization method- A mixture of 44 parts of the amorphous polyester resin (1), 13 parts of the crystalline polyester resin (1), 38 parts of titanium oxide (CR-60-2: manufactured by Ishihara Sangyo Kaisha), and 5 parts of paraffin wax (HNP-9 manufactured by Nippon Seiro Co., Ltd.) was premixed in a 75 L Henschel mixer, and then kneaded in a twin-screw continuous mixer having a screw configuration under the following conditions to obtain a kneaded product. Specifically, the kneading was performed under the conditions of a kneading temperature of 160°C, a rotation speed of 280 rpm, and a kneading speed of 90 kg / h. The resulting kneaded product was pulverized using a 400AFG-CR pulverizer (manufactured by Hosokawa Micron Corporation), and then fine and coarse powders were removed using an air-type elbow jet classifier (manufactured by Matsubo Corporation) to obtain toner particles. Next, heating (post-annealing) was carried out under conditions of 73°C for 120 minutes to obtain toner particles (B5) with a volume average particle size of 15 μm. 100 parts of the toner particles (B5) and 0.7 parts of dimethylsilicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer to obtain white toner B5 (toner for developing electrostatic images). A toner was prepared in the same manner as in Example 1 except for using the white toner particles B5, to obtain developer B5.

[0284] Example 6 Toner A, white toner B, and their electrostatic image developers were prepared and evaluated in the same manner as in Example 1, except that in the preparation of toner A, pyrazolotriazole dye I-3 was changed to phthalocyanine dye c1. The phthalocyanine dye c1 is the compound shown below.

[0285] [ka]

[0286] Example 7 Toner A, white toner B, and electrostatic image developers thereof were prepared and evaluated in the same manner as in Example 1, except that in the preparation of toner A, pyrazolotriazole dye I-3 was changed to Basic Red 1.

[0287] Example 8 In preparing the dye particle dispersion of Toner A, Acetylacetone metal compound II-34 was changed from 34.2 parts to 30 parts, The amount of anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was increased from 5 parts to 8 parts. Except for changing the processing time of the Ultimizer (manufactured by Sugino Machine Co., Ltd.) to 15 minutes, In the same manner as in Example 1, toner A, white toner B and electrostatic image developers thereof were prepared and evaluated.

[0288] Example 9 Toner A, white toner B, and their electrostatic image developers were prepared and evaluated in the same manner as in Example 1, except that the processing time in the Ultimizer (manufactured by Sugino Machine Co., Ltd.) was changed to 2 minutes when preparing the dye particle dispersion of toner A.

[0289] Example 10 In the preparation of toner particles (A1), all of the styrene acrylic resin particle dispersion liquid (1) was replaced with amorphous polyester resin particle dispersion liquid (1), Toner A, white toner B, and their electrostatic image developers were prepared and evaluated in the same manner as in Example 1, except that in the preparation of toner particles (B1), the amorphous polyester resin dispersion (1) and the crystalline polyester resin dispersion (1) were all replaced with styrene acrylic resin particle dispersion (1).

[0290] <Comparative Example 1> In the preparation of toner particles (B1), the amorphous polyester resin dispersion (1) and the crystalline polyester resin dispersion (1) are all replaced with styrene acrylic resin particle dispersion (1). Except for the substitution, toner A, white toner B and electrostatic image developers thereof were prepared in the same manner as in Example 1, and evaluated.

[0291] <Comparative Example 2> In the preparation of toner particles (A1), 210 parts of the 390 parts of styrene acrylic resin particle dispersion liquid (1) initially placed in a round stainless steel flask was replaced with amorphous polyester resin particle dispersion liquid (1), In the preparation of toner particles (B1), 180 parts of the 250 parts of amorphous polyester resin dispersion (1) initially placed in the round stainless steel flask was replaced with styrene acrylic resin particle dispersion (1), In the same manner as in Example 1, toner A, white toner B and electrostatic image developers thereof were prepared and evaluated.

[0292] [Table 2]

[0293] In Table 2, St / Ac represents a styrene-acrylic resin, and Pes represents a polyester resin.

[0294] From the above results, it is apparent that the present example provides images that are superior in terms of preventing fading under high temperature and high humidity conditions compared to the comparative example. [Explanation of symbols]

[0295] 15Y, 15M, 15C, 15K, 15B cleaning device 17Y, 17M, 17C, 17K, 17B Primary transfer roll 19Y, 19M, 19C, 19K, 19B exposure equipment 20Y, 20M, 20C, 20K, 20B developing device 21Y, 21M, 21C, 21K, 21B photoconductor 22 Drive Roll 23 Support Roll 24 bias roll 26 Belt cleaner 28Y, 28M, 28C, 28K, 28B charging roll 33 Intermediate transfer belt 34 Secondary transfer roll 35 Fixing unit 40Y, 40M, 40C, 40K, 40B toner cartridges 50Y, 50M, 50C, 50K, 50B Image forming units 107 Photosensitive body (an example of an image carrier) 108 Charging roll (an example of charging means) 109 Exposure device (an example of electrostatic image forming means) 111 Developing device (an example of developing means) 112 Transfer device (an example of transfer means) 113 Photosensitive drum cleaning device (an example of cleaning means) 115 Fixing device (an example of fixing means) 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)< / x> < / lx>

Claims

1. a toner A containing a binder resin A and a dye; a white toner B containing a binder resin B and a titanium oxide pigment, the content of the binder resin A is 51% by mass or more with respect to the total mass of the binder resin contained in the toner A, the content of the binder resin B is 51% by mass or more with respect to the total mass of the binder resin contained in the white toner B, The absolute value (ΔSP value) of the difference in solubility parameter between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is 0.5 or more. Toner set for developing electrostatic images.

2. a toner A containing a binder resin A and a dye; a white toner B containing a binder resin B and a titanium oxide pigment, the content of the binder resin A is 51% by mass or more with respect to the total mass of the binder resin contained in the toner A, the content of the binder resin B is 51% by mass or more with respect to the total mass of the binder resin contained in the white toner B, The binder resin A is a styrene acrylic resin, and the binder resin B is a polyester resin. Toner set for developing electrostatic images.

3. 2. The toner set for developing electrostatic images according to claim 1, wherein the binder resin A is a styrene-acrylic resin, and the binder resin B is a polyester resin.

4. 4. The toner set for developing electrostatic images according to claim 1, wherein the dye comprises at least one of a pyrazolotriazole dye and a phthalocyanine dye.

5. 4. The toner set for developing electrostatic images according to claim 1, wherein the dye comprises a pyrazolotriazole compound represented by the following formula (I): 【Chemistry 1】 In formula (I), Rx １ and Rx ２ each independently represents an alkyl group which may have a substituent, Lx represents a hydrogen atom or an alkyl group which may have a substituent, Gx １ represents an alkyl group having two or more carbon atoms, and Gx ２ represents an aryl group or an alkyl group which may have a substituent; Gx ３ is a hydrogen atom, a halogen atom, Gx ４ —CO—NH— or Gx ５ -N(Gx ６ )-CO-, and Gx ４ represents an aryl group or an alkyl group which may have a substituent; Gx ５ and Gx ６ each independently represents a hydrogen atom or an alkyl group which may have a substituent; Qx １ ~Qx ５ each independently represents a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.

6. 4. The toner set for developing electrostatic images according to claim 1, wherein the dye comprises a phthalocyanine compound represented by the following formula (II): 【Chemistry 2】 In the formula (II), M represents a silicon atom, a germanium atom, or a tin atom; １ ~Ra ４ each independently represents an electron-withdrawing group; na1 to na4 each independently represent an integer of 0 to 4; Z １ and Z ２ each independently represents a hydroxy group, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (III): 【Transformation 3】 In the formula (III), R ３ ~R ５ each independently represents an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.

7. 7. The toner set for developing electrostatic images according to claim 1, wherein an absolute value of a difference in solubility parameter (ΔSP value) between the binder resin A and the binder resin B is 0.5 or more and 3.0 or less.

8. 8. The toner set for developing electrostatic images according to claim 7, wherein the absolute value of the difference in solubility parameter ([Delta]SP value) between the binder resin A and the binder resin B is 1.0 or more and 3.0 or less.

9. 9. The toner set for developing electrostatic images according to claim 1, wherein at least a part of the dye is dispersed in the toner in the form of particles.

10. 10. The toner set for developing electrostatic images according to claim 9, wherein the particulate dyes among the dyes have a number average particle size of 10 nm or more and 1,000 nm or less.

11. a toner A containing a binder resin A and a dye; a white toner B containing a binder resin B and a titanium oxide pigment, The dye contains a pyrazolotriazole compound represented by the following formula (I): The absolute value (ΔSP value) of the difference in solubility parameter between the binder resin A contained in the toner A and the binder resin B contained in the white toner B is 0.5 or more. Toner set for developing electrostatic images. 【Chemistry 4】 In formula (I), Rx １ and Rx ２ each independently represents an alkyl group which may have a substituent, Lx represents a hydrogen atom or an alkyl group which may have a substituent, Gx １ represents an alkyl group having two or more carbon atoms, and Gx ２ represents an aryl group or an alkyl group which may have a substituent; Gx ３ is a hydrogen atom, a halogen atom, Gx ４ —CO—NH— or Gx ５ -N(Gx ６ )-CO-, and Gx ４ represents an aryl group or an alkyl group which may have a substituent; Gx ５ and Gx ６ each independently represents a hydrogen atom or an alkyl group which may have a substituent; Qx １ ~Qx ５ each independently represents a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.

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

13. a first toner cartridge containing the toner A of the toner set for developing an electrostatic image according to any one of claims 1 to 11; a second toner cartridge containing the white toner B of the toner set for developing an electrostatic image 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 means containing the first electrostatic image developer of the electrostatic image developer set according to claim 12; a second developing means 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 for forming a color image using the toner A of the toner set for developing electrostatic images according to any one of claims 1 to 11; a second image forming unit for forming a white image using the white toner B of the toner set for developing an electrostatic image according to any one of claims 1 to 11; a transfer means for transferring the color image and the white image onto a recording medium; a fixing means for fixing the color image and the white image on the recording medium; An image forming apparatus comprising:

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

Images