Toner for developing electrostatic images, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method

Abstract

To provide an electrostatic image developing toner which offers a superior property to prevent color transfer of formed images.SOLUTION: An electrostatic image developing toner is provided, comprising toner particles containing a pyrazolotriazole dye and zirconium oxide particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] 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 liquid developer in which toner particles containing a pigment and a resin are dispersed in an insulating liquid by a dispersant, and the pigment contains a compound represented by the following general formula (I) and a compound represented by the following general formula (II).

[0004] [ka]

[0005] (In general 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. Qx1, Qx2, Qx3, Qx4, and Qx5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.) (In general formula (II), R1 and R2 each independently represent 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. Either R1 or 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. X represents a metal atom of copper, nickel, or cobalt.)

[0006] Furthermore, Patent Document 2 discloses a full-color toner kit for forming a full-color image from at least yellow toner, magenta toner, cyan toner, and black toner, characterized in that the yellow toner contains at least a yellow pigment selected from CI Pigment Yellow 74, CI Pigment Yellow 139, CI Pigment Yellow 155, CI Pigment Yellow 180, and CI Pigment Yellow 185, the magenta toner contains at least a dye represented by the following general formula (X-1) and a metal compound represented by the following general formula (1), and the cyan toner contains a silicon phthalocyanine represented by the following general formula (2).

[0007] [ka]

[0008] [In the formula, Rx1 and Rx2 each independently represent an alkyl group, Lx represents a hydrogen atom or an alkyl group, Gx1 represents an alkyl group having two or more carbon atoms, Gx2 represents an alkyl group or an aromatic hydrocarbon group, Gx3 represents a hydrogen atom, a halogen atom, Gx4-CO-NH-, or Gx5-N(Gx6)-CO-, Gx4 represents a substituent, Gx5 and Gx6 each independently represent a hydrogen atom or a substituent, and Qx1, Qx2, Qx3, Qx4, and Qx5 each independently represent a hydrogen atom or a substituent.]

[0009] [ka]

[0010] [In the formula, R1 and R2 represent a hydrogen atom or an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a 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, and one of R1 and R2 represents an electron-withdrawing group. R3 represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, or a heterocyclic group having 3 or more carbon atoms. X represents a metal atom of copper, nickel, or cobalt.]

[0011] [ka]

[0012] [In the formula, each Z independently represents a hydroxy group, a chlorine 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 general formula (IV). Ra1, Ra2, Ra3, and Ra4 each independently represent a substituent, and na1, na2, na3, and na4 each represent an integer of 0 to 4.]

[0013] [ka]

[0014] [In the formula, R 1 , R 2 , R 3 represents an alkyl group having 1 to 22 carbon atoms, an aryl group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or an aryloxy group having 6 to 18 carbon atoms. 1 , R 2 , R 3 may be the same group or different groups. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-234128 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-002897 Summary of the Invention [Problem to be solved by the invention]

[0016] An object of the present invention is to provide a toner for developing electrostatic images which is superior in color transfer suppression properties of the resulting images compared to toner particles containing only one of a pyrazolotriazole dye and zirconium oxide particles. [Means for solving the problem]

[0017] Means for solving the above problems include the following aspects. <1> A toner for developing electrostatic images, comprising toner particles containing a pyrazolotriazole dye and zirconium oxide particles. <2> The net intensity of Zr element in the toner particles measured by fluorescent X-ray analysis is 0.02 kcps or more and 25.00 kcps or less. <1> 2. The toner for developing electrostatic images according to claim 1. <3> The net intensity of Zr element in the toner particles measured by fluorescent X-ray analysis is 0.03 kcps or more and 10.00 kcps or less. <2> 2. The toner for developing electrostatic images according to claim 1. <4> The toner particles contain the zirconium oxide particles as an internal additive. <1> ~ <3> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <5> The pyrazolotriazole dye is a compound represented by the following formula (I): <1> ~ <4> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images.

[0018] [ka]

[0019] 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.

[0020] <6> The toner particles further contain an acetylacetonate metal compound. <1> ~ <5> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <7> The acetylacetonate metal compound is a compound represented by the following formula (II): <6> 2. The toner for developing electrostatic images according to claim 1.

[0021] [ka]

[0022] In formula (II), R1 and R2 each independently represent 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 copper, nickel, or cobalt.

[0023] <8> At least a part of the pyrazolotriazole dye is dispersed in the toner particles in a particulate form. <1> ~ <7> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <9> Among the pyrazolotriazole dyes, the pyrazolotriazole dyes dispersed in the toner particles in particulate form have a number average particle size of 10 nm or more and 1,000 nm or less. <8> 2. The toner for developing electrostatic images according to claim 1. <10> The number average particle size of the zirconium oxide particles is 5 nm or more and 1.1 μm or less. <1> ~ <9> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <11> The content of the zirconium oxide particles is 0.001% by mass or more and 0.5% by mass or less with respect to the total mass of the toner particles. <1> ~ <10> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <12> The content ratio of the zirconium oxide particles to the pyrazolotriazole dye is 0.00015 or more and 0.075 or less. <1> ~ <11> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <13> The toner particles contain a resin having a refractive index of 1.48 or more as a binder resin. <1> ~ <12> 10. The toner for developing electrostatic images according to claim 9, wherein the toner is a toner for developing electrostatic images. <14> The resin having a refractive index of 1.48 or more is a styrene acrylic resin. <13> 2. The toner for developing electrostatic images according to claim 1. <15> <1> ~ <14> 10. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 9. <16> <1> ~ <14> 10. A toner cartridge containing the toner for developing electrostatic images according to any one of claims 1 to 9, which is detachably mounted on an image forming apparatus. <17> <15> and a developing means for developing an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image, the process cartridge being detachably mountable to an image forming apparatus. <18> an image carrier; a charging means for charging the surface of the image carrier; and an electrostatic image forming means for forming an electrostatic image on the charged surface of the image carrier; <15> and developing means for developing an electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer; transferring means for transferring the toner image formed on the surface of the image carrier to a surface of a recording medium; and fixing means for fixing the toner image transferred to the surface of the recording medium. <19> a charging step of charging the surface of an image carrier; and an electrostatic image forming step of forming an electrostatic image on the charged surface of the image carrier. <15> a developing step of developing an electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer described in claim 1; a transferring step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium. [Effects of the Invention]

[0024] <1> According to the invention, there is provided a toner for developing electrostatic images which has excellent color transfer suppression properties for the resulting images compared to toner particles containing only one of a pyrazolotriazole dye and zirconium oxide particles. <2> According to the invention related to (1), there is provided a toner for developing electrostatic images, which has better color transfer suppression properties in the obtained images than when the net intensity of Zr element in the toner particles, as measured by fluorescent X-ray analysis, is less than 0.02 kcps or more than 25.00 kcps. <3> According to the invention related to (1), there is provided a toner for developing electrostatic images, which has better color transfer suppression properties in the obtained images than when the net intensity of Zr element in the toner particles, as measured by fluorescent X-ray analysis, is less than 0.03 kcps or more than 10.00 kcps. <4> According to the invention, there is provided a toner for developing electrostatic images, which has superior color transfer suppression properties in the resulting images compared to when the toner particles contain the zirconium oxide particles only as an external additive. <5> According to the invention, there is provided a toner for developing electrostatic images, which has better color transfer suppression properties for the resulting images than when the pyrazolotriazole dye is a pyrazolotriazole compound other than the compound represented by formula (I). <6> According to the invention, there is provided a toner for developing electrostatic images, which has superior color transfer suppression properties in the resulting images compared to when the toner particles do not contain an acetylacetone metal compound. <7> According to the invention, there is provided a toner for developing electrostatic images, which has better color transfer suppression properties for the obtained images than when the acetylacetone metal compound is an acetylacetone metal compound other than the compound represented by the following formula (II): <8> According to the invention, there is provided a toner for developing electrostatic images which is superior in color transfer suppression properties of the resulting images compared to when the pyrazolotriazole dye is molecularly dispersed in the toner particles. <9> According to the invention related to (1), there is provided a toner for developing electrostatic images, which has better color transfer suppression properties in the obtained images than when the number average particle diameter of the pyrazolotriazole dye, which is particulate and dispersed in the toner particles, is less than 10 nm or more than 1,000 nm. <10> According to the invention, there is provided a toner for developing electrostatic images which exhibits superior color transfer suppression properties in the resulting images compared to when the number average particle size of the zirconium oxide particles is less than 5 nm or exceeds 1.1 μm. <11> According to the invention, there is provided a toner for developing electrostatic images which exhibits superior color transfer suppression properties in the resulting images compared to when the content of the zirconium oxide particles is less than 0.001% by mass or more than 0.5% by mass relative to the total mass of the toner particles. <12> According to the invention, there is provided a toner for developing electrostatic images, which has better color transfer suppression properties in the obtained images than when the content ratio of the zirconium oxide particles to the pyrazolotriazole dye is less than 0.00015 or more than 0.075. <13> According to the invention, there is provided a toner for developing electrostatic images, which has better color transfer suppression properties in the resulting images than when the toner particles contain only a resin having a refractive index of less than 1.48 as a binder resin. <14> According to the invention, there is provided a toner for developing electrostatic images which is superior in the color transfer suppression properties of the resulting images compared to when the resin having a refractive index of 1.48 or more is an acrylic resin. <15> , <16> , <17> , <18> or <19> According to the invention, there are provided an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method, which have excellent color transfer suppression properties for the resulting image compared to when a toner for developing electrostatic images having toner particles containing only one of a pyrazolotriazole dye and zirconium oxide particles is used. [Brief explanation of the drawings]

[0025] [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

[0026] 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 composition contains a plurality of substances corresponding to each component, the amount of each component in the composition means the total amount of the 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.

[0027] <Toner for developing electrostatic images> The electrostatic image developing toner according to this exemplary embodiment has toner particles containing a pyrazolotriazole dye and zirconium oxide particles. The color of the electrostatic image developing toner according to this embodiment is not particularly limited, but the electrostatic image developing toner according to this embodiment is particularly suitable for use as a magenta toner or a black toner.

[0028] The dye may melt (molecularize) into the binder resin of the toner due to the heat generated during fixation or transfer onto fabric using a transfer sheet (such as iron printing), or the dye may bleed (migrate) onto the surface of the toner image, resulting in color transfer to objects that come into contact with the dye when the dye is stored at or above the glass transition temperature Tg. The inventors have found that pyrazolotriazole dyes, which contain a large number of nitrogen atoms in particular, are less compatible with the binder resin of the toner and therefore more likely to come out onto the surface, resulting in color transfer. When the toner for developing electrostatic images according to this embodiment is used, it contains zirconium oxide particles. When zirconium oxide particles are present in the toner particles, their surfaces become negatively charged, and the pyrazolotriazole dye containing many nitrogen atoms gathers around the zirconium oxide particles, acting as a nucleating agent during cooling after toner fixation, and it is believed that this suppresses color transfer by suppressing bleeding to the surface.

[0029] (toner particles) The electrostatic image developing toner according to this embodiment contains toner particles containing a pyrazolotriazole dye and zirconium oxide particles. The toner particles preferably contain a binder resin. The toner particles may also contain a colorant, a release agent, and other additives.

[0030] -Net intensity of Zr element in toner particles- In the toner for developing electrostatic images according to the present embodiment, from the viewpoints of the net intensity of Zr element in the toner particles measured by fluorescent X-ray analysis, and the color transfer suppression and transparency of the resulting image, the zirconium saturation is preferably 0.02 kcps or more and 0.30 kcps or less, and more preferably 0.03 kcps or more and 0.20 kcps or less.

[0031] The method for measuring the net intensity in the X-ray fluorescence analysis of Zr element is as follows. Approximately 0.5 g of toner particles are compressed using a compression molding machine under a load of 1 ton for 60 seconds to produce a disk with a diameter of 10 mm and a thickness of 0.5 mm. This disk is used as a sample for qualitative and quantitative elemental analysis using a scanning X-ray fluorescence analyzer (Rigaku Corporation ZSX Primus II) under the following conditions to determine the net intensity of Zr element (unit: kilocounts per second, kcps). Tube voltage: 40kV ·Tube current: 70mA Anticathode: Rhodium Measurement time: 15 minutes ·Analysis diameter: 10mm in diameter In addition, 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.

[0032] -Zirconium oxide particles- The toner particles contain zirconium oxide particles, and preferably contain two or more zirconium oxide particles. The zirconium oxide particles may be contained in the toner particles as an internal additive or an external additive, but from the viewpoint of the color transfer suppression and transparency of the resulting image, it is preferable to contain the zirconium oxide particles as an internal additive. From the viewpoint of color transfer suppression and transparency of the resulting image, the number average particle size of the zirconium oxide particles is preferably 5 nm or more and 1.1 μm or less, more preferably 5 nm or more and 500 nm or less, even more preferably 5 nm or more and 100 nm or less, particularly preferably 5 nm or more and 50 nm or less, and most preferably 5 nm or more and 30 nm or less. Furthermore, from the viewpoint of color transfer suppression and transparency of the resulting image, the ratio PT / PZ of the number average particle diameter PZ of the zirconium oxide particles to the volume average particle diameter PT of the toner particles is preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, and particularly preferably 50 or more and 2,000 or less.

[0033] The toner particles may contain only one type of zirconium oxide particles, or two or more types of zirconium oxide particles. From the viewpoint of color transfer suppression and transparency of the resulting image, the content of the zirconium oxide particles is preferably from 0.001% by mass to 0.5% by mass, more preferably from 0.0013% by mass to 0.2% by mass, and particularly preferably from 0.002% by mass to 0.050% by mass, relative to the total mass of the toner particles. The content ratio of zirconium oxide particles to pyrazolotriazole dye (content of zirconium oxide particles / content of pyrazolotriazole dye) is preferably 0.00015 or more and 0.075 or less, more preferably 0.0002 or more and 0.05 or less, and particularly preferably 0.0003 or more and 0.01 or less, from the viewpoint of color transfer suppression and transparency of the resulting image.

[0034] -Pyrazolotriazole dyes- The toner particles contain a pyrazolotriazole dye. In the toner particles, the pyrazolotriazole dye may be dispersed in the binder resin in a particulate form or in a molecular form. However, from the viewpoint of the color transfer suppression and transparency of the resulting image, it is preferable that at least a part of the pyrazolotriazole dye is dispersed in the toner particles in a particulate form. Of the pyrazolotriazole dyes, the number average particle size of the pyrazolotriazole dye dispersed in the toner particles in particulate form is preferably 10 nm or more and 1,000 nm or less, and more preferably 50 nm or more and 300 nm or less, from the viewpoint of color transfer suppression and transparency of the resulting image. 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.

[0035] 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.

[0036] The pyrazolotriazole dye is not particularly limited, but from the viewpoint of the color transfer suppression and transparency of the resulting image, it is preferably a pyrazolotriazole dye having an aromatic ring, more preferably a pyrazolotriazole dye having an aromatic ring and a thiophene ring, and particularly preferably a compound represented by the following formula (I):

[0037] [ka]

[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 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] The linear alkyl group is, for example, 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] The branched alkyl group is, for example, 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 preferable that it is an alkyl group represented by the above Rx1 and Rx2.

[0076] <<Gx5 and Gx6>> Each of Gx5 and Gx6 may independently 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 preferable that it is an alkyl group represented by the above Rx1 and Rx2.

[0077] <<Qx1~Qx5>> Each of Qx1~Qx5 may independently 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, each of Qx1~Qx5 is independently any one of a hydrogen atom, an alkyl group, a halogen atom, and an alkoxy group. More preferably, all of Qx1~Qx5 are hydrogen atoms.

[0078] Specific examples of the compound represented by the above formula (I) include (I-1)~(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] Note: There may be some inaccuracies in the original text, especially the repeated tags like which might be incorrect. The above translation is based on the best understanding and following the translation rules. [ka]

[0082] [ka]

[0083] The toner particles may contain only one type of pyrazolotriazole dye, or two or more types of dyes. From the viewpoint of color transfer suppression and transparency of the resulting image, the content of the pyrazolotriazole dye is preferably 0.5% by mass or more and 30% by mass or less, more preferably 0.5% by mass or more and 20% by mass or less, and particularly preferably 1% by mass or more and 15% by mass or less, relative to the total mass of the toner particles.

[0084] -Acetylacetone metal compounds- From the viewpoint of color transfer suppression and transparency of the resulting image, the toner particles preferably further contain an acetylacetonate metal compound. It is believed that in the toner particles, the pyrazolotriazole dye and the acetylacetone metal compound partially form a complex, which acts as a nucleating agent during cooling after toner fixation, inhibiting migration to the surface and resulting in superior color transfer inhibition and transparency of the resulting image.

[0085] The acetylacetone metal compound is not particularly limited, but from the viewpoint of the color transfer suppression property and transparency of the obtained image, an acetylacetone metal compound having an electron-withdrawing group is preferred, an acetylacetone copper, nickel or cobalt compound having an electron-withdrawing group is more preferred, and a compound represented by the following formula (II) is particularly preferred.

[0086] [ka]

[0087] In formula (II), 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.

[0088] In the compound represented by formula (II), the total number of carbon atoms in one molecule of the acetylacetone ligand is preferably 25 or less.

[0089] <<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 haloalkyl 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 amide 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 one of R1 and R2 is an electron-withdrawing group.

[0090] The alkyl group may be any of a straight-chain alkyl group, a branched alkyl group, and a cycloalkyl group, and examples thereof include 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] Examples of the cycloalkoxy group include a cyclopentyloxy group and a cyclohexyloxy group.

[0097] 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.

[0098] Examples of the cycloalkylthio group include a cyclopentylthio group and a cyclohexylthio group.

[0099] 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.

[0100] The aryloxycarbonyl group includes, for example, a phenyloxycarbonyl group or a naphthyloxycarbonyl group.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] Examples of the arylsulfonyl group include a phenylsulfonyl group, a naphthylsulfonyl group, and a 2-pyridylsulfonyl group.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] < <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.

[0115] < <x>> X is, for example, any one of a metal atom of copper, nickel, and cobalt, and is preferably copper.

[0116] Specific examples of the compound represented by formula (II) 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.

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] [ka]

[0122] [ka]

[0123] [ka]

[0124] 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 color transfer suppression and transparency of the resulting image, 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 (content of acetylacetone metal compound / content of pyrazolotriazole dye) 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 viewpoint of color transfer suppression and transparency of the resulting image.

[0125] -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. The toner particles preferably contain, as a binder resin, a resin having a refractive index of 1.48 or more, from the viewpoint of color transfer suppression and transparency of the resulting image. The resin having a refractive index of 1.48 or more is preferably a styrene acrylic resin from the viewpoint of the color transfer suppression and transparency of the resulting image. The refractive index of the binder resin is measured at 25° C. using a prism coupler, an ellipsometer, or an Abbe refractometer.

[0126] 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.

[0127] The amorphous resin will be described. Examples of the amorphous resin include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin), epoxy resin, polycarbonate resin, polyurethane resin, etc. Among these, from the viewpoint of suppressing uneven density and white spots in the obtained image, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred, and amorphous polyester resin is more preferred. In addition, it is also a preferred embodiment to use an amorphous polyester resin and a styrene-acrylic resin in combination as the amorphous resin.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] Examples of binder resins, particularly amorphous resins, include styrene-acrylic resins. 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."

[0133] 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.

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] 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.).

[0140] 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.

[0141] 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.

[0142] 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."

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] 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.

[0148] The polyhydric alcohol may have an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

[0149] 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."

[0150] The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

[0151] The crystalline polyester resin can be obtained by a known production method, for example, in the same manner as the amorphous polyester resin.

[0152] 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.

[0153] 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.

[0154] 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.

[0155] 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.

[0156] The proportion of the crystalline resin in the total binder resin is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, and even more preferably 3% by mass to 10% by mass.

[0157] 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.

[0158] 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.

[0159] -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.

[0160] As the release agent, from the viewpoint of suppressing uneven density and white spots in the obtained image and having good compatibility with the amorphous polyester resin, thereby improving the fixability of the image, an ester wax is preferred, and an ester wax of a higher fatty acid having from 10 to 30 carbon atoms and a monovalent or polyvalent alcohol component having from 1 to 30 carbon atoms is preferred.

[0161] 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.

[0162] 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."

[0163] The content of the release agent is preferably from 1% by mass to 20% by mass, and more preferably from 5% by mass to 15% by mass, based on the total mass of the toner particles.

[0164] -Other colorants- The toner particles may contain a colorant other than the pyrazolotriazole dye and the acetylacetone metal compound. 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.

[0165] 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.

[0166] The content of the other coloring agent is not particularly limited, but it is preferably an amount smaller than the content of the pyrazolotriazole dye.

[0167] -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.

[0168] -Characteristics of toner particles, etc.- The toner particles may be toner particles of a single layer structure, or may be toner particles of a so-called core-shell structure composed of a core part (core particle) and a coating layer (shell layer) that coats the core part. Here, the toner particles having a core-shell structure may 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.

[0169] The volume average particle size (D50v) of the toner particles is preferably from 2 μm to 15 μm, more preferably from 4 μm to 8 μm, even more preferably from 4 μm to 7 μm, and particularly preferably from 5 μm to 6.5 μm.

[0170] 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:

[0171] The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

[0172] 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.

[0173] (Toner characteristics) In the toner according to this embodiment, the maximum endothermic peak temperature during the first temperature rise measured by a differential scanning calorimeter (DSC) is preferably 58° C. or more and 75° C. or less. By setting the maximum endothermic peak temperature of the toner to 58° C. or more and 75° C. or less, the low-temperature fixability of the toner is improved.

[0174] The maximum endothermic peak temperature of the toner during the first temperature rise is measured by a differential scanning calorimeter (DSC) as follows. A PerkinElmer DSC-7 differential scanning calorimeter is used, and the melting points of indium and zinc are used to correct the temperature of the detector, and the heat of fusion of indium is used to correct the heat quantity. An aluminum pan is used for the sample, and an empty pan is set as a control. The temperature is raised from room temperature to 150°C at a rate of 10°C / min. The temperature at which the maximum endothermic peak occurs is then determined in the resulting endothermic curve.

[0175] (Toner manufacturing method) Next, a method for producing the toner according to this embodiment will be described. The toner according to this exemplary embodiment is obtained by producing toner particles and then externally adding an external additive to the toner particles.

[0176] 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.

[0177] 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).

[0178] 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.

[0179] -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.

[0180] The resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0181] 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.

[0182] 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.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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.

[0187] -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.

[0188] 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.

[0189] 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.

[0190] 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.

[0191] -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.

[0192] 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: a step of 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 a step of 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.

[0193] 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.

[0194] The toner for developing electrostatic images according to this embodiment 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.

[0195] <Electrostatic image developer> The electrostatic image developer according to this embodiment contains at least the toner according to this embodiment. The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer containing the toner mixed with a carrier.

[0196] 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.

[0197] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0198] 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 ester 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.

[0199] 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.

[0200] 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.

[0201] <Image forming device / image forming method> An image forming apparatus and an image forming method according to this embodiment will be described. The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, a developing unit that contains an electrostatic image developer and develops the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer, a transfer unit that transfers the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing unit that fixes the toner image transferred to the surface of the recording medium. The electrostatic image developer according to the present embodiment is used as the electrostatic image developer.

[0202] The image forming apparatus according to this embodiment carries out an image forming method (the image forming method according to this embodiment) that includes a charging step of charging the surface of an image carrier, an electrostatic image forming step of forming an electrostatic image on the surface of the charged image carrier, a developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image using the electrostatic image developer according to this embodiment, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0203] The image forming apparatus according to the present embodiment may be any of known image forming apparatuses, such as a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; an intermediate transfer type apparatus that primarily transfers a toner image formed on the surface of an image carrier to the surface of an intermediate transfer medium, and then secondarily transfers the toner image transferred to the surface of the intermediate transfer medium to the surface of a recording medium; an apparatus equipped with a cleaning means that cleans the surface of the image carrier after the transfer of the toner image but before charging; and 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. Among these, an image forming apparatus equipped with a cleaning means for cleaning the surface of the image carrier is preferred, and a cleaning blade is preferred as the cleaning means. 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.

[0204] In the image forming apparatus according to the present embodiment, for example, a portion including the developing means may have a cartridge structure (process cartridge) that is detachably attached to the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with developing means that accommodates the electrostatic image developer according to the present embodiment is preferably used.

[0205] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. Note that only the main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0206] FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 includes first through fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images in the colors yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side horizontally spaced a predetermined distance apart from one another. Note that these units 10Y, 10M, 10C, and 10K may also be process cartridges that are detachable from the image forming apparatus.

[0207] Above each of the units 10Y, 10M, 10C, and 10K in the drawing, an intermediate transfer belt 20 serving as an intermediate transfer body extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24 that are spaced apart from each other and arranged from left to right in the drawing, and is configured to run in a direction from the first unit 10Y to the fourth unit 10K. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), thereby applying tension to the intermediate transfer belt 20 wound around them. In addition, an intermediate transfer body cleaning device 30 is provided on the image carrier side of the intermediate transfer belt 20, facing the drive roll 22. In addition, the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K are supplied with toner including four colors of toner, yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K, respectively.

[0208] Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, the first unit 10Y, which forms a yellow image and is disposed upstream in the direction of travel of the intermediate transfer belt, will be described here as a representative. Note that parts equivalent to those of the first unit 10Y are given reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y), and descriptions of the second to fourth units 10M, 10C, and 10K will be omitted.

[0209] The first unit 10Y has a photoreceptor 1Y that acts as an image carrier. Around the photoreceptor 1Y, there are arranged in this order: a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential; an exposure device (an example of an electrostatic image forming means) 3 that exposes the charged surface to a laser beam 3Y based on a color-separated image signal to form an electrostatic image; a developing device (an example of a developing means) 4Y that supplies charged toner to the electrostatic image to develop it; a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20; and a photoreceptor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20 and is positioned opposite the photoreceptor 1Y. Furthermore, a bias power supply (not shown) that applies a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

[0210] The operation of forming a yellow image in first unit 10Y will be described below. First, prior to operation, the surface of the photosensitive member 1Y is charged to a potential of −600V to −800V by the charging roll 2Y. The photoconductor 1Y has conductivity (for example, volume resistivity at 20°C: 1×10 -6 The photosensitive layer is formed by laminating a photosensitive layer on a substrate with a resistivity of Ωcm or less. This photosensitive layer normally has a high resistance (the resistance of ordinary resins), but when irradiated with a laser beam 3Y, the resistivity of the irradiated portion changes. Therefore, a laser beam 3Y is output to the charged surface of the photosensitive element 1Y via an exposure device 3 in accordance with image data for yellow sent from a control unit (not shown). The laser beam 3Y is irradiated onto the photosensitive layer on the surface of the photosensitive element 1Y, thereby forming an electrostatic charge image of a yellow image pattern on the surface of the photosensitive element 1Y.

[0211] An electrostatic image is an image formed on the surface of the photosensitive element 1Y by charging it; the laser beam 3Y reduces the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photosensitive element 1Y to flow, while the charges remain in the portions not irradiated by the laser beam 3Y, forming a so-called negative latent image. The electrostatic image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0212] The developing device 4Y contains an electrostatic image developer containing, for example, at least yellow toner and a carrier. The yellow toner is frictionally charged by being stirred inside the developing device 4Y, and is held on a developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. The photoreceptor 1Y on which the yellow toner image has been formed continues to travel at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0213] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoreceptor 1Y to the primary transfer roll 5Y acts on the toner image, causing the toner image on the photoreceptor 1Y to be transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a (+) polarity opposite to the (-) polarity of the toner, and in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

[0214] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit 10M and subsequent units is also controlled in accordance with the first unit. In this way, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is conveyed sequentially through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are transferred onto the intermediate transfer belt 20 in a superimposed manner.

[0215] The intermediate transfer belt 20, onto which the four-color toner images have been multiplex-transferred through the first to fourth units, reaches a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 arranged on the image bearing surface side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has a negative polarity, the same as the negative polarity of the toner. Electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to resistance detected by resistance detection means (not shown) that detects resistance in the secondary transfer section, and is voltage-controlled.

[0216] Thereafter, the recording paper P is sent to the pressure contact portion (nip portion) of a pair of fixing rolls in a fixing device (an example of fixing means) 28, where the toner image is fixed onto the recording paper P, forming a fixed image.

[0217] Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copying machines, printers, etc. In addition to the recording paper P, examples of the recording medium include overhead projector sheets and the like. To further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. For example, coated paper in which the surface of plain paper is coated with resin or the like, or art paper for printing, etc., is preferably used.

[0218] 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.

[0219] <Process cartridges / toner cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that is detachably attached to an image forming apparatus and that contains the electrostatic image developer according to this embodiment and is equipped with a developing means that develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

[0220] 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.

[0221] 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.

[0222] 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 transfer device (an example of a transfer means), 115 denotes a fixing device (an example of a fixing means), and 300 denotes recording paper (an example of a recording medium).

[0223] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to the present embodiment is a toner cartridge that contains the toner according to the present embodiment and is detachably attached to an image forming apparatus. The toner cartridge contains replenishment toner to be supplied to a developing unit provided in the image forming apparatus.

[0224] 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and developing devices 4Y, 4M, 4C, and 4K are connected to the toner cartridges corresponding to each developing device (color) by toner supply pipes (not shown). When the toner stored in a toner cartridge runs low, the toner cartridge is replaced. [Example]

[0225] 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) and (II-1) to (II-85) in this example are the same compounds as the above-mentioned (I-1) to (I-23) and (II-1) to (II-85), respectively.

[0226] <Preparation of Zirconium Oxide Particle Dispersion Liquid 1> Zirconia nanoparticles (ZSL-10A (number average particle size 80 nm) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were mixed with water to prepare zirconium oxide particle dispersion 1 with a solid content of 0.01%.

[0227] <Preparation of Zirconium Oxide Particle Dispersion Liquid 2> Zirconia nanoparticles (ZSL-10A (number average particle size 80 nm) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were mixed with water to prepare zirconium oxide particle dispersion 2 with a solid content of 1%.

[0228] <Preparation of Zirconium Oxide Particle Dispersion 3> Zirconia nanoparticles (SZR-CW (number average particle size 5 nm) manufactured by Sakai Chemical Industry Co., Ltd.) were mixed with water to prepare zirconium oxide particle dispersion 3 with a solid content of 0.01%.

[0229] <Preparation of Zirconium Oxide Particle Dispersion Liquid 4> Zirconia nanoparticles (TMZ zirconium oxide (number average particle size 1.1 μm) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) were mixed with water and a surfactant (5% relative to the zirconia) to prepare zirconium oxide particle dispersion 4 with a solid content of 0.01%.

[0230] <Preparation of Silica Particle Dispersion> Silica nanoparticles (Shin-Etsu Chemical Co., Ltd., QSG-100 (number average particle size 110 nm)) were mixed with water and a surfactant (5% based on silica) to prepare a silica particle dispersion with a solid content of 0.01%.

[0231] <Preparation of titanium oxide particle dispersion> Titanium oxide nanoparticles (MT-600S (number average particle size 50 nm) manufactured by Teika Corporation) were mixed with water and a surfactant (5% based on titanium oxide) to prepare a titanium oxide particle dispersion with a solid content of 0.01%.

[0232] <Preparation of amorphous resin particle dispersion> (Preparation of amorphous polyester resin particle dispersion (A1)) Terephthalic acid: 70 parts Fumaric acid: 30 parts Ethylene glycol: 41 parts 1,5-pentanediol: 48 parts The above materials were placed in a flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and distillation column, and the temperature was raised to 220°C over 1 hour under a nitrogen gas stream. Then, 1 part of titanium tetraethoxide was added per 100 parts of the materials. The temperature was raised to 240°C over 0.5 hours while distilling off the resulting water. The dehydration condensation reaction continued at that temperature for 1 hour, and the reaction mixture was then cooled. This resulted in the synthesis of an amorphous polyester resin with a weight-average molecular weight of 96,000 and a glass transition temperature of 61°C. A vessel equipped with a temperature control device and a nitrogen purge device was charged with 40 parts of ethyl acetate and 25 parts of 2-butanol to form a mixed solvent, followed by gradual addition of 100 parts of amorphous polyester resin to dissolve therein. A 10% aqueous ammonia solution (equivalent to three times the molar amount of the resin's acid value) was then added and stirred for 30 minutes. The atmosphere inside the vessel was then purged with dry nitrogen, the temperature was maintained at 40°C, and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / min while stirring the mixed solution, resulting in emulsification. After the addition was completed, the emulsion was returned to 25°C, yielding a resin particle dispersion containing dispersed resin particles with a volume average particle size of 190 nm. Ion-exchanged water was added to the resin particle dispersion to adjust the solids content to 20%, yielding amorphous polyester resin particle dispersion (A1).

[0233] <Preparation of Crystalline Polyester Resin Particle Dispersion> (Preparation of Crystalline Polyester Resin Particle Dispersion (B2)) 1,10-decanedicarboxylic acid: 265 parts 1,6-Hexanediol: 168 parts Dibutyltin oxide (catalyst): 0.4 parts The above components were placed in a heated and dried three-neck flask, and the air in the vessel was evacuated to an inert atmosphere with nitrogen gas. The mixture was then mechanically stirred and refluxed at 180°C for 5 hours. The temperature was then gradually increased to 230°C under reduced pressure and stirred for 2 hours. When the mixture reached a viscous state, it was air-cooled to terminate the reaction. Molecular weight measurement (polystyrene equivalent) revealed that the weight-average molecular weight (Mw) of the resulting "crystalline polyester resin 2" was 13,000 and the melting temperature was 69°C. 90 parts of the resulting resin, 1.5 parts of the ionic surfactant NEOGEN RK (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and 200 parts of ion-exchanged water were heated to 120°C and thoroughly dispersed using an IKA Ultra-Turrax T50. The mixture was then dispersed for 1 hour using a pressure-discharge Gaulin homogenizer to obtain crystalline polyester resin particle dispersion (B2) with a volume average particle size of 210 nm and a solids content of 23 parts by mass.

[0234] (Preparation of Colorant 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%).

[0235] <Preparation of Release Agent Particle Dispersion> (Preparation of Release Agent Particle Dispersion (W1)) Ester wax (NOF Corporation WEP-5, melting temperature 85°C): 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 (Ultra Turrax T50 manufactured by IKA), and then dispersed using a Manton-Gaulin high-pressure homogenizer (manufactured by Gaulin) to obtain a release agent particle dispersion (solid content 20%) in which release agent particles with a volume average particle size of 220 nm were dispersed.

[0236] Example 1 -Preparation of toner particles 1- Zirconium oxide particle dispersion liquid 1:7.8 parts by mass Amorphous polyester resin particle dispersion 1:150 mass parts Colorant particle dispersion: 25 parts by weight Release agent particle dispersion: 35 parts by weight Crystalline polyester resin particle dispersion: 50 parts by weight Polyaluminum chloride: 0.4 parts by weight Ion-exchanged water: 100 parts by weight The above components were thoroughly mixed and dispersed in a round stainless steel flask using an IKA Ultra-Turrax T50. The flask was then heated to 48°C with stirring in a heating oil bath and held for 60 minutes to produce aggregated particles that would become the core particles. To this mixture, 100 parts by mass of the same amorphous polyester resin particle dispersion as above was slowly added to form the shell particles. The pH of the system was then adjusted to 8.0 using a 0.5 mol / L aqueous sodium hydroxide solution. The stainless steel flask was then sealed, the stirring shaft was magnetically sealed, and the mixture was heated to 90°C with continued stirring and held for 30 minutes. After the reaction was complete, the mixture was cooled at a rate of 5°C / min, filtered, thoroughly washed with ion-exchanged water, and then subjected to solid-liquid separation using a Nutsche suction filtration. This mixture was then redispersed in 3,000 parts by mass of 30°C ion-exchanged water and stirred and washed for 15 minutes at 300 rpm. This washing procedure was repeated six more times, and when the pH of the filtrate reached 7.54 and the electrical conductivity reached 6.5 μS / cm, solid-liquid separation was carried out using No. 5A filter paper by Nutsche suction filtration, followed by vacuum drying for 24 hours to obtain a toner.

[0237] (Preparation of Toner 1) 100 parts by mass of the obtained toner particles 1 were mixed and blended with 1.5 parts by mass of hydrophobic silica (RY50, manufactured by Nippon Aerosil Co., Ltd., number average particle size 140 nm) using a sample mill at 10,000 rpm for 30 seconds. The mixture was then sieved using a vibrating sieve with 45 μm openings to prepare toner 1. The volume average particle size of the obtained toner 1 was 5.7 μm.

[0238] (Carrier production) 500 parts of spherical magnetite powder particles (volume average particle diameter: 0.55 μm) were thoroughly stirred in a Henschel mixer, and then 5.0 parts of a titanate coupling agent were added, heated to 100°C, and mixed and stirred for 30 minutes to obtain spherical magnetite particles coated with a titanate coupling agent. Next, 6.25 parts of phenol, 9.25 parts of 35% formalin, 500 parts of the magnetite particles, 6.25 parts of 25% aqueous ammonia, and 425 parts of water were mixed and stirred in a four-neck flask. Next, the mixture was reacted at 85°C for 120 minutes while stirring, then cooled to 25°C, 500 parts of water was added, the supernatant was removed, and the precipitate was washed with water. This was dried under reduced pressure at 150°C to 180°C to obtain a carrier with an average particle size of 35 μm.

[0239] (Preparation of electrostatic image developer 1) The obtained carrier and Toner 1 were placed in a V blender in a ratio of toner:carrier=5:95 (mass ratio), and stirred for 20 minutes to obtain Electrostatic Image Developer 1.

[0240] <Evaluation of color transfer prevention> -Image formation- The obtained electrostatic image developer was loaded into a modified DocuCentre Color 400 machine manufactured by Fuji Xerox Co., Ltd., and the fixing temperature was set to 180°C. A yellow solid image (40 mm x 25 mm, toner mass 4.0 g / m) was printed in OHP mode in an environment of a temperature of 23°C and a relative humidity of 55%. 2 ) and halftone image (40mm x 25mm, toner mass 0.5g / m 2 As a recording medium, OS coated paper manufactured by Fuji Xerox Co., Ltd. was used.

[0241] -Evaluation method- The fixed images were superimposed on each other and subjected to a pressure of 80 g / cm 2 The sheets were left in an atmosphere of 70°C under a load of 1000 kJ / cm2 for 10 days, and after 10 days, they were peeled off and visually evaluated for the presence or absence of document offset to evaluate the color transfer suppression ability. The results are shown in Table 1. A: No color transfer is observed. B: Very slight color transfer is observed C: A little color transfer is observed D: Color transfer is clearly visible

[0242] <Image transparency evaluation> -Image formation- The obtained electrostatic image developer was loaded into a modified DocuCentre Color 400 machine manufactured by Fuji Xerox Co., Ltd., and the fixing temperature was set to 180°C. A yellow solid image (40 mm x 25 mm, toner mass 4.0 g / m) was printed in OHP mode in an environment of a temperature of 23°C and a relative humidity of 55%. 2 ) and halftone image (40mm x 25mm, toner mass 0.5g / m 2 As a recording medium, a black and white OHP sheet manufactured by Fuji Xerox Co., Ltd. was used.

[0243] -Evaluation method- The ratio of scattered light to total transmitted light was measured using a fully automatic haze meter (TC-HIII DP model, manufactured by Tokyo Denshoku Co., Ltd.) in accordance with JIS K7136:2000 "Determination of haze for plastics - transparent materials" and classified into four levels, G1 to G4, as shown below. G1 to G3 are within the acceptable range. G1: Less than 15% G2: 15% to less than 20% G3: 20% to less than 30% G4: 30% or more

[0244] <Examples 2 to 9 and Comparative Examples 1 to 3> Toners and electrostatic image developers were prepared and evaluated in the same manner as in Example 1, except that the types and amounts of the pyrazolotriazole dye and acetylacetone metal compound used in preparing the colorant particle dispersion, the type and amount of the zirconium oxide particle dispersion used in preparing the toner particles, and the amorphous polyester resin particle dispersion and crystalline polyester resin particle dispersion (PES) were changed to the following styrene acrylic resin particle dispersion (StAC), as shown in Table 1. The evaluation results are shown in Table 1.

[0245] <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

[0246] -Ingredients for aqueous phase 1- Ion-exchanged water: 17 parts Anionic surfactant: Dowfax (Dow Chemical Company): 0.4 parts

[0247] -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

[0248] The oil phase materials and aqueous phase 1 materials were mixed and stirred separately, and the two were mixed to form an emulsified dispersion of monomer. Separately, the aqueous phase 2 materials were added to a reaction vessel, the atmosphere in 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 the reaction vessel over a period of 3 hours, and emulsion polymerization was carried out. After the addition was completed, the polymerization was continued at 75°C and terminated after 3 hours, yielding a styrene acrylic resin particle dispersion with a solids content of 42% by mass. 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.

[0249] [Table 1]

[0250] In Table 1, the refractive index (25°C) of the amorphous polyester resin in PES was 1.50, the refractive index (25°C) of the crystalline polyester resin was 1.53, and the refractive index (25°C) of the styrene acrylic resin in StAC was 1.57. The numerical value in the column for the amount of zirconium oxide particles in Comparative Example 2 represents the amount of silica particles, and the numerical value in the column for the amount of zirconium oxide particles in Comparative Example 3 represents the amount of titanium oxide particles. Furthermore, the toners obtained in the examples and comparative examples were all magenta toners.

[0251] From the above results, it can be seen that the present example is superior to the comparative example in terms of color transfer suppression in the obtained images. [Explanation of symbols]

[0252] 1Y, 1M, 1C, 1K Photoconductor (an example of an image carrier) 2Y, 2M, 2C, 2K Charging roll (an example of charging means) 3. Exposure device (an example of an electrostatic image forming means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (an example of developing means) 5Y, 5M, 5C, 5K Primary transfer roll (an example of a primary transfer means) 6Y, 6M, 6C, 6K: Photoconductor cleaning device (an example of a cleaning means) 8Y, 8M, 8C, 8K toner cartridges 10Y, 10M, 10C, 10K image forming units 20 Intermediate transfer belt (an example of an intermediate transfer body) 22 Drive Roll 24 Support Roll 26 Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate transfer body cleaning device 107 Photoconductor (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. The toner particles contain a pyrazolotriazole dye and zirconium oxide particles, The pyrazolotriazole dye is a compound represented by the following formula (I): Toner for developing electrostatic images. 【Chemical 1】 In formula (I), Rx 1 and Rx 2 represent a methyl group, Lx represents a hydrogen atom or an alkyl group which may have a substituent, Gx 1 represents an alkyl group having 2 or more carbon atoms, Gx 2 represents an aryl group or an alkyl group which may have a substituent, Gx 3 represents a hydrogen atom, a halogen atom, Gx 4 -CO-NH-, or Gx 5 -N(Gx 6 )-CO-, Gx 4 represents an aryl group or an alkyl group which may have a substituent, Gx 5 and Gx 6 each independently represent a hydrogen atom or an alkyl group which may have a substituent, and Qx 1 to Qx 5 each independently represent a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the net intensity of Zr element in the toner particles measured by fluorescent X-ray analysis is 0.02 kcps or more and 25.00 kcps or less.

3. 3. The toner for developing electrostatic images according to claim 2, wherein the net intensity of Zr element in the toner particles measured by fluorescent X-ray analysis is 0.03 kcps or more and 10.0 kcps or less.

4. 4. The toner for developing electrostatic images according to claim 1, wherein the toner particles contain the zirconium oxide particles as an internal additive.

5. 5. The toner for developing electrostatic images according to claim 1, wherein the toner particles further contain a metal acetylacetone compound.

6. 6. The toner for developing electrostatic images according to claim 5, wherein the metal acetylacetone compound is a compound represented by the following formula (II): 【Chemistry 2】 In formula (II), R １ and R ２ each independently represents 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; R １ and R ２ At least one of R is an electron-withdrawing group, ３ represents an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an aliphatic heterocyclic group, or an aromatic heterocyclic group; R ２ and R ３ may be bonded to each other to form a ring, and X represents a metal atom of copper, nickel, or cobalt.

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

8. 8. The electrostatic image developing toner according to claim 7, wherein the number average particle size of the pyrazolotriazole dye dispersed in the toner particles in particulate form is 10 nm or more and 1,000 nm or less.

9. 9. The toner for developing electrostatic images according to claim 1, wherein the number average particle size of the zirconium oxide particles is 5 nm or more and 1.1 μm or less.

10. 10. The toner for developing electrostatic images according to claim 1, wherein the content of the zirconium oxide particles is 0.001% by mass or more and 0.5% by mass or less with respect to the total mass of the toner particles.

11. 11. The toner for developing electrostatic images according to claim 1, wherein a content ratio of the zirconium oxide particles to the pyrazolotriazole dye is 0.00015 or more and 0.075 or less.

12. 12. The toner for developing electrostatic images according to claim 1, wherein the toner particles contain, as a binder resin, a resin having a refractive index of 1.48 or more.

13. 13. The toner for developing electrostatic images according to claim 12, wherein the resin having a refractive index of 1.48 or more is a styrene-acrylic resin.

14. An electrostatic image developer comprising the toner for developing electrostatic images according to any one of claims 1 to 13.

15. A toner cartridge containing the toner for developing electrostatic images according to any one of claims 1 to 13, and being detachably mountable on an image forming apparatus.

16. 15. A process cartridge detachably mountable to an image forming apparatus, comprising: a developing unit that contains the electrostatic image developer according to claim 14 and develops an electrostatic image formed on the surface of an image carrier using the electrostatic image developer into a toner image.

17. 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; a developing unit containing the electrostatic image developer according to claim 14 and developing the electrostatic image formed on the surface of the image carrier into a toner image by the electrostatic image developer; a transfer means for transferring the toner image formed on the surface of the image carrier to the surface of a recording medium; a fixing means for fixing the toner image transferred onto the surface of the recording medium; An image forming apparatus comprising:

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

Images