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

Abstract

To provide an electrostatic image developing toner which offers superior hot offset resistance.SOLUTION: An electrostatic image developing toner is provided, comprising toner particles containing a silicon phthalocyanine dye and zirconium oxide particles.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toner for electrostatic image development, 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 various fields. In electrophotography, a static charge image is formed as image information on the surface of an image holder through charging and static charge image formation. Then, a toner image is formed on the surface of the image holder using a developer containing toner, and this toner image is transferred to a recording medium and then fixed to the recording medium. Through these processes, the image information is visualized as an image.

[0003] For example, Patent Document 1 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 a yellow pigment selected from at least 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 silicon phthalocyanine represented by the following general formula (2).

[0004] [ka]

[0005] [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 2 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, and Gx5 and Gx6 each independently represent a hydrogen atom or a substituent. Qx1, Qx2, Qx3, Qx4, and Qx5 each independently represent a hydrogen atom or a substituent.]

[0006] [ka]

[0007] [In the formula, R1 and R2 represent a hydrogen atom or an alkyl group, alkenyl group, alkynyl group, aryl group, heterocyclic group, alkoxycarbonyl group, aryloxycarbonyl group, sulfamoyl group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group, cyano group, trifluoroalkyl group, or nitro group, and either R1 or R2 represents an electron-withdrawing group. R3 represents an alkyl group, alkenyl group, alkynyl group, aryl group, or heterocyclic group having 3 or more carbon atoms. X represents a metal atom of copper, nickel, or cobalt.]

[0008] [ka]

[0009] [In the formula, Z independently represents a hydroxyl 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 general formula (IV) shown below. Ra1, Ra2, Ra3, and Ra4 are independent substituents, and na1, na2, na3, and na4 are integers from 0 to 4.]

[0010] [ka]

[0011] [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. Note that R 1 , R 2 , R 3 may be the same group or different groups from each other. ]]

[0012] Further, Patent Document 2 describes an electrophotographic toner obtained by dispersing colored fine particles containing a resin having a composition different from that of the thermoplastic resin and a dye in the thermoplastic resin, wherein the dye is a metal chelate dye represented by the general formula (1). General formula (1) M(L1)(L2)n(X1)m(X2)l·W1 [In the formula, M represents a metal selected from Cu and Zn, X1 and X2 each independently represent a monodentate or bidentate ligand, and X1 and X2 may be linked. L1 and L2 each independently represent a bidentate or tridentate ligand having absorption from visible to infrared, and may be the same or different. n, m, and l represent 0 or 1. W1 represents a counter ion when a counter ion is required to neutralize the charge.]

Prior Art Documents

Patent Documents

[0013]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0014] An object of the present invention is to provide an electrostatic charge image developing toner having excellent hot offset suppression performance as compared with toner particles containing only one of a silicon phthalocyanine dye and zirconium oxide particles.

Means for Solving the Problems

[0015] Means for solving the aforementioned problem include the following embodiments. <1> A toner for electrostatic image development having toner particles containing silicon phthalocyanine dye and zirconium oxide particles. <2> The Net intensity of the element Zr in the aforementioned toner particles, as measured by X-ray fluorescence analysis, is between 0.02 kcps and 25.0 kcps. <1> Toner for developing electrostatic images as described above. <3> The Net intensity of the element Zr in the aforementioned toner particles, as measured by X-ray fluorescence analysis, is between 0.03 kcps and 10.0 kcps. <2> Toner for developing electrostatic images as described above. <4> The toner particles contain the zirconium oxide particles as an internal additive. <1> ~ <3> A toner for developing electrostatic images, as described in one of the following. <5> The silicon phthalocyanine dye is a compound represented by the following formula (I). <1> ~ <4> A toner for developing electrostatic images, as described in one of the following.

[0016] [ka]

[0017] In formula (I), Z independently represents a hydroxyl group, a chlorine atom, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (II). Ra1 to Ra4 are each independently substituents, and na1 to na4 are each independently integers between 0 and 4.

[0018] [ka]

[0019] In formula (II), R 1 ~R 3Each of these independently 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.

[0020] <6> At least a portion of the silicon phthalocyanine dye is dispersed in particulate form within the toner particles. <1> ~ <5> A toner for developing electrostatic images, as described in one of the following. <7> Of the silicon phthalocyanine dyes mentioned above, the number-average particle size of the silicon phthalocyanine dyes dispersed in the toner particles in particulate form is between 10 nm and 1,000 nm. <6> Toner for developing electrostatic images as described above. <8> The number-average particle size of the zirconium oxide particles is between 5 nm and 1.1 μm. <1> ~ <7> A toner for developing electrostatic images, as described in one of the following. <9> The zirconium oxide particles are contained in an amount of 0.001% by mass or more and 0.5% by mass or less, relative to the total mass of the toner particles. <1> ~ <8> A toner for developing electrostatic images, as described in one of the following. <10> The content ratio of the zirconium oxide particles to the silicon phthalocyanine dye is 0.00015 or more and 0.075 or less. <1> ~ <9> A toner for developing electrostatic images, as described in one of the following. <11> The toner particles include a resin with a refractive index of 1.48 or higher as a binder resin. <1> ~ <10> A toner for developing electrostatic images, as described in one of the following. <12> The resin with a refractive index of 1.48 or higher is styrene-acrylic resin. <11> Toner for developing electrostatic images as described above. <13> <1> ~ <12> A electrostatic image developer containing an electrostatic image developing toner as described in any one of the following. <14> <1> ~ <12> A toner cartridge that contains the electrostatic image developing toner described in any one of the above, and is attached to and detached from an image forming apparatus. <15> <13> A process cartridge that contains the electrostatic image developer described above, and includes a developing means for developing an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer, and is attached to and detached from an image forming apparatus. <16> An image holder, a charging means for charging the surface of the image holder, and a static charge image forming means for forming a static charge image on the charged surface of the image holder, <13> An image forming apparatus comprising: a developing means for containing the electrostatic image developer described in [reference] and developing an electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; a transfer means for transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing means for fixing the toner image transferred to the surface of the recording medium. <17> A charging step of charging the surface of the image holder, and a static charge image forming step of forming a static charge image on the charged surface of the image holder, <13> An image forming method comprising: a developing step of developing an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer described in [reference]; a transfer step of transferring the toner image formed on the surface of the image holder 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]

[0021] <1> According to the invention, a toner for electrostatic image development is provided that exhibits superior hot offset suppression compared to toner particles containing only one of silicon phthalocyanine dye or zirconium oxide particles. <2> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to cases where the Net intensity of the element Zr in the toner particles, as measured by X-ray fluorescence analysis, is less than 0.02 kcps or greater than 25.0 kcps. <3> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to cases where the Net intensity of the element Zr in the toner particles, as measured by X-ray fluorescence analysis, is less than 0.03 kcps or greater than 10.0 kcps. <4> According to the invention, a toner for electrostatic image development is provided that exhibits superior hot offset suppression compared to the case in which the toner particles contain only the zirconium oxide particles as an external additive. <5> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to a case where the silicon phthalocyanine dye is a silicon phthalocyanine dye other than the compound represented by formula (I). <6> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to the case in which the silicon phthalocyanine dye is molecularly dispersed in the toner particles. <7> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to cases where the number-average particle size of the silicon phthalocyanine dye, which is dispersed in the toner particles in particulate form, is less than 10 nm or greater than 1,000 nm. <8> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to cases where the number-average particle size of the zirconium oxide particles is less than 5 nm or greater than 1.1 μm. <9> According to the invention, a toner for electrostatic image development is provided that exhibits superior hot offset suppression compared to cases where the zirconium oxide particle content is less than 0.001% by mass or greater than 0.5% by mass relative to the total mass of the toner particles. <10> According to the invention, a toner for developing electrostatic images is provided that exhibits superior hot offset suppression compared to cases where the content ratio of zirconium oxide particles to the silicon phthalocyanine dye is less than 0.00015 or greater than 0.075. <11> According to the invention, a toner for electrostatic image development is provided that exhibits superior hot offset suppression compared to the case in which the toner particles contain only a resin with a refractive index of less than 1.48 as the binder resin. <12> According to the invention, a toner for developing electrostatic images is provided that has superior hot offset suppression properties compared to the case where the resin with a refractive index of 1.48 or higher is an acrylic resin. <13> , <14> , <15> , <16> or <17> According to the invention, an electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, or image forming method is provided that exhibits superior hot offset suppression compared to the case in which an electrostatic image developing toner having toner particles containing only one of silicon phthalocyanine dye and zirconium oxide particles is applied. [Brief explanation of the drawing]

[0022] [Figure 1] This is a schematic diagram showing an example of an image forming apparatus according to this embodiment. [Figure 2] This is a schematic diagram showing an example of a process cartridge according to this embodiment. [Modes for carrying out the invention]

[0023] The following describes in detail an embodiment that is an example of the present invention. Furthermore, in numerical ranges described in stages, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, within a numerical range, the upper or lower limit of a given numerical range may be replaced with the value shown in the example. The amount of each component in the composition refers to the total amount of any multiple substances present in the composition, unless otherwise specified, if multiple substances corresponding to each component are present in the composition. The term "process" includes not only independent processes, but also any process that cannot be clearly distinguished from other processes, as long as its intended purpose is achieved.

[0024] <Toner for developing electrostatic images> The electrostatic image developing toner according to this embodiment has toner particles containing a silicon phthalocyanine dye and zirconium oxide particles. Furthermore, while there are no particular restrictions on the color of the electrostatic image developing toner according to this embodiment, the electrostatic image developing toner according to this embodiment is preferably used as a cyan toner or a black toner.

[0025] The dyes melt (molecularize) during fixing, causing a decrease in melt viscosity, which leads to poor high-temperature fixing and a deterioration in image quality during continuous printing. In particular, the inventors have found that silicon phthalocyanine dyes are poorly compatible, making them prone to appearing on the surface, and their low heat resistance causes image surface roughness and hot offset due to peeling. When using the electrostatic image developing toner according to this embodiment, the presence of zirconium oxide particles causes the surface of the toner particles to become negatively charged. The silicon phthalocyanine dye acts as a nucleating agent, attracting the zirconium oxide particles, and the silicon phthalocyanine dye adheres to or coordinates to the surface of the zirconium oxide particles, forming a particulate structure. This is estimated to result in a greater filler effect than when zirconium oxide particles are not included, suppressing the decrease in melt viscoelasticity and thus providing superior hot offset suppression.

[0026] (Toner particles) The electrostatic image developing toner according to this embodiment contains toner particles containing a silicon phthalocyanine dye and zirconium oxide particles. Preferably, the toner particles also contain a binder resin. The toner particles may also contain colorants, release agents, and other additives.

[0027] -Net strength of the element Zr in toner particles- In the electrostatic image developing toner according to this embodiment, the Net intensity of the Zr element in the toner particles, as measured by X-ray fluorescence analysis, is preferably 0.02 kcps or more and 25.0 kcps or less, and more preferably 0.03 kcps or more and 10.0 kcps or less, from the viewpoint of hot offset suppression and transparency.

[0028] The method for measuring the Net intensity in X-ray fluorescence analysis of the element Zr is as follows: Approximately 0.5 g of toner particles are compressed using a compression molding machine under a load of 10 tons for 60 seconds to create a disc with a diameter of 10 mm and a thickness of 0.5 mm. This disc is used as a sample, and qualitative and quantitative elemental analysis is performed using a scanning X-ray fluorescence analyzer (ZSX Primus II, manufactured by Rigaku Corporation) under the following conditions to determine the Net intensity of the element Zr (unit: kilo counts per second, kcps). • Tube voltage: 40kV ·Tube current: 70mA • Anti-cathode: Rhodium • Measurement time: 15 minutes ·Analysis diameter: 10mm in diameter If the toner contains external additives, the toner (developer) to be measured shall be dispersed in water containing a surfactant, and then ultrasonic treatment shall be performed to obtain toner particles from which the external additives have been removed.

[0029] -Zirconium oxide particles- The toner particles contain zirconium oxide particles, preferably containing two or more zirconium oxide particles. Zirconium oxide particles may be included in toner particles as an internal additive or as an external additive, but from the viewpoint of suppressing hot offset and transparency, it is preferable to include them as an internal additive. The number-average particle size of the zirconium oxide particles is preferably 5 nm to 1.1 μm, more preferably 5 nm to 500 nm, even more preferably 5 nm to 100 nm, particularly preferably 5 nm to 50 nm, and most preferably 5 nm to 30 nm, from the viewpoint of suppressing hot offset and transparency. Furthermore, the ratio PT / PZ, which is the number-average particle size PZ of zirconium oxide particles to the volume-average particle size PT of toner particles, is preferably 5 or more, more preferably 10 or more, even more preferably 20 or more, and particularly preferably 50 to 2,000, from the viewpoint of hot offset suppression and transparency.

[0030] The zirconium oxide particles contained in the toner particles may be of one type or two or more types. From the viewpoint of suppressing hot offset and transparency, the zirconium oxide particle content is preferably 0.001% to 0.5% by mass, more preferably 0.002% to 0.2% by mass, and particularly preferably 0.003% to 0.1% by mass, relative to the total mass of toner particles. The content ratio of zirconium oxide particles to silicon phthalocyanine dye (content of zirconium oxide particles / content of silicon phthalocyanine dye) is preferably 0.00015 to 0.075, more preferably 0.0005 to 0.050, and particularly preferably 0.001 to 0.003, from the viewpoint of suppressing hot offset and transparency.

[0031] - Silicone phthalocyanine dye - The toner particles contain silicon phthalocyanine dye. In toner particles, the silicon phthalocyanine dye may be dispersed in particulate form or molecularly in the binder resin, but from the viewpoint of suppressing hot offset and transparency, it is preferable that at least a portion of the silicon phthalocyanine dye be dispersed in particulate form within the toner particles. Of the silicon phthalocyanine dyes mentioned above, the number-average particle size of the silicon phthalocyanine dyes dispersed in the toner particles in particulate form is preferably 10 nm to 1,000 nm, and more preferably 50 nm to 300 nm, from the viewpoint of suppressing hot offset and transparency. In this embodiment, "pigment" refers to a coloring agent whose solubility in 100g of water at 23°C and 100g of cyclohexanone at 23°C is less than 0.1g, while "dye" refers to a coloring agent whose solubility in 100g of water at 23°C or 100g of cyclohexanone at 23°C is 0.1g or more.

[0032] The number-average particle size of the dye dispersed in the toner particles is measured by staining a cross-section of the toner or toner particles after cutting, and analyzing the image observed with a transmission electron microscope (TEM). Specifically, for example, as follows, the dyeing agent is selected from ruthenium tetroxide, osmium tetroxide, phosphotungstic acid, uranyl acetate, iodine, etc., depending on the type of binder resin and dye, so as to create a difference in the degree of staining between the binder resin and the dye. 7g of bisphenol A type liquid epoxy resin (manufactured by Asahi Kasei Chemicals Corporation) and 3g of the hardening agent ZENAMID250 (manufactured by Henkel Japan) are gently mixed and prepared. Then, 1g of toner is mixed in and left for 24 hours to obtain a cured product. Using a cutting device LEICA ultramicrotome (model number ULTRACUT UCT, manufactured by Hitachi High-Decontours Corporation) equipped with a diamond knife (model number Type Cryo, manufactured by DIATOME Corporation), an embedded cutting sample is cut at -100°C to prepare an observation sample. This observation sample is left in a desiccator under a ruthenium tetroxide atmosphere (manufactured by Soegawa Rika Co., Ltd.) to stain it (the degree of staining is judged by the degree of staining of a tape left at the same time). From the stained observation samples, cross-sectional views of the stained toner are observed at a magnification of 10,000 to 100,000 times using a Hitachi high-resolution electrolytic emission scanning electron microscope (S-4800, manufactured by Hitachi High-Technologies Corporation) equipped with a transmission electron detector. From the observed TEM images, the cross-sections of 300 toner particles are observed, and the dye portion of the toner particles is identified based on the difference in staining degree. The dispersed particle size of the particulate portion is measured, and the number-average particle diameter is calculated. The identification of the dye portion based on the staining degree is performed by comparing the dye alone, a mixture of the dye and binder resin, and the binder resin alone with the aforementioned dye. The number-average particle size of the particulate portion of the stain may be calculated by digitizing the observed image and performing image processing. For example, the TEM image is digitized and imported into image analysis software (Win ROOF) manufactured by Mitani Corporation. The toner cross-sectional area within the embedding material is selected as the target, and the "Automatic Binarization - Discriminant Analysis Method" of the "Binarization Processing" command is used to perform binarization processing, separating the particulate portion of the stain from the binding resin. At this time, the image is compared with the image before binarization to confirm whether the particulate portion of the stain in the binarized image is separated into individual particles. If multiple particles are connected and binarized, the binarization threshold is adjusted so that each particle is binarized independently, or the region is manually divided to correct it so that each region of the particulate portion of the stain is formed as a single particle. The extracted region of the particulate portion of the stain is selected, and the maximum Ferret diameter is determined and used as the particle size of the particulate portion of the stain. If binarization cannot be performed correctly due to the image's density or noise, you may want to sharpen the image by applying a "filter-median" process or edge detection, and then manually set the boundaries.

[0033] There are no particular restrictions on the silicon phthalocyanine dye, but from the viewpoint of suppressing hot offset and transparency, it is preferable to use a silicon phthalocyanine dye having an aromatic ring, more preferably a silicon phthalocyanine dye having both an aromatic ring and a thiophene ring, and particularly preferably a compound represented by the following formula (I). In the compound represented by the following formula (I), a silicon atom (Si) is used as the metal atom located at the center of the phthalocyanine ring (hereinafter also referred to as the central metal atom).

[0034] [ka]

[0035] In formula (I), each Z independently represents a hydroxy group, a chlorine atom, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (II); Ra1 to Ra4 each independently represents a substituent; and na1 to na4 each independently represents an integer of 0 or more and 4 or less.

[0036]

Chemical formula

[0037] In formula (II), R 1 to R 3 each independently 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.

[0038] R 1 , R 2 and R 3 in formula (I) represent 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. Note that R 1 , R 2 , R 3 may be the same group or different groups from each other. Further, R 1 , R 2 and R 3 represent the alkyl group, aryl group, alkoxy group, and aryloxy group having the above number of carbon atoms, and the number of carbon atoms of the alkyl group and alkoxy group is preferably 1 to 10, more preferably 2 to 8.

[0039] The compound represented by formula (I) is a phthalocyanine compound having an axial ligand called a tetraaza porphyrin-based compound represented by formula (I) in which a silicon atom is used as a central metal atom. Here, the axial ligand is what is represented by Z in formula (I).

[0040] Toner containing the compound represented by formula (I) exhibits better color reproduction than toner containing phthalocyanine compounds without axial ligands. This is presumed to be because the compound represented by formula (I) has a more complex structure than phthalocyanine compounds without axial ligands, making aggregation and crystallization of the compound less likely. As a result, it is thought that the high dispersibility of the compound represented by formula (I) is maintained in the toner particles or in the fixed image, thereby improving color reproduction.

[0041] Furthermore, because the compound represented by formula (I) has a structure that is less prone to aggregation and crystallization, it is presumed that it is incorporated into toner particles in a uniformly dispersed state during the toner manufacturing process, and as a result, the formed toner is more likely to exhibit good color reproduction.

[0042] Furthermore, the Z constituting the compound represented by formula (I) is preferably the group represented by formula (II) among the groups mentioned above. And the R in the group represented by formula (II) 1 , R 2 and R 3 These are alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 18 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms. 1 , R 2 , R 3 These may be the same group or different groups.

[0043] In particular, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, and t-butyl groups are preferred. Also, R 1 , R 2 , R 3 These may be the same group or different groups.

[0044] Specific examples of compounds represented by formula (I) are shown in Table 1 below, but it goes without saying that the compounds represented by formula (I) that can be used in this embodiment are not limited to those shown in Table 1.

[0045] [Table 1]

[0046] The structures of I-9, I-10, and I-11 are shown below.

[0047] [ka]

[0048] The toner particles may contain only one type of silicon phthalocyanine dye, or two or more types. From the viewpoint of suppressing hot offset and transparency, the content of silicon phthalocyanine dye is preferably 1% to 30% by mass, and more preferably 2% to 20% by mass, relative to the total mass of toner particles.

[0049] -Binding resin- From the viewpoint of image intensity and suppression of density unevenness in the resulting image, the binder resin preferably contains both amorphous and crystalline resins. The toner particles preferably contain a resin with a refractive index of 1.48 or higher as a binder resin, from the viewpoint of suppressing hot offset and transparency. Furthermore, the resin with a refractive index of 1.48 or higher is preferably a styrene-acrylic resin from the viewpoint of suppressing hot offset and transparency. The refractive index of the binder resin is measured at 25°C using a prism coupler, ellipsometer, or Abbe refractometer.

[0050] Here, amorphous resins refer to materials that, in thermal analysis measurements using differential scanning calorimetry (DSC), exhibit only a stepwise endothermic change rather than a clear endothermic peak, are solid at room temperature, and undergo thermoplasticization at temperatures above their glass transition temperature. On the other hand, crystalline resins are those that exhibit a clear endothermic peak in differential scanning calorimetry (DSC), rather than a stepwise change in endothermic heat. Specifically, for example, a crystalline resin means that the full width at half maximum (FWHM) of the endothermic peak measured at a heating rate of 10°C / min is within 10°C, while an amorphous resin means a resin whose FWHM exceeds 10°C, or a resin in which no clear endothermic peak is observed.

[0051] This section will explain amorphous resins. Examples of amorphous resins include known amorphous resins such as amorphous polyester resin, amorphous vinyl resin (e.g., styrene-acrylic resin), epoxy resin, polycarbonate resin, and polyurethane resin. Among these, amorphous polyester resin and amorphous vinyl resin (particularly styrene-acrylic resin) are preferred from the viewpoint of suppressing density unevenness and whiteout in the resulting image, and amorphous polyester resin is more preferred. Furthermore, it is also preferable to use amorphous polyester resin and styrene acrylic resin in combination as the amorphous resin.

[0052] Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. Commercially available amorphous polyester resins may be used, or synthesized ones may be used.

[0053] 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, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0054] 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, with aromatic diols being more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0055] Amorphous polyester resins can be obtained by known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation. If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point 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 there are monomers with poor miscibility in the copolymerization reaction, it is preferable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them with the main component.

[0056] Examples of binder resins, particularly amorphous resins, include styrene-acrylic resin. Styrene acrylic resin is a copolymer obtained by copolymerizing at least a styrene monomer (a monomer having a styrene skeleton) and a (meth)acrylic monomer (a monomer having (meth)acrylic groups, preferably monomers having (meth)acryloxy groups). Styrene acrylic resin includes, for example, copolymers of styrene monomers and (meth)acrylic acid ester monomers. Furthermore, the acrylic resin portion in styrene-acrylic resin is a substructure formed by polymerizing either an acrylic monomer or a methacrylic monomer, or both. Also, "(meth)acrylic" is an expression that includes both "acrylic" and "methacrylic."

[0057] Examples of styrene 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. Styrene monomers may be used individually or in combination of two or more. Among these, styrene is preferred as the styrene monomer due to its reactivity, ease of reaction control, and availability.

[0058] Examples of (meth)acrylic monomers include, specifically, (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include alkyl (meth)acrylates (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth) Examples 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)acrylates (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 individually or in combination of two or more. Of the (meth)acrylic monomers, among these (meth)acrylic esters, (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 fixation. Among these, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0059] The copolymerization ratio (by mass, styrene monomer / (meth)acrylic monomer) of the styrene monomer and the (meth)acrylic monomer is not particularly limited, but is preferably 85 / 15 to 70 / 30.

[0060] Styrene-acrylic resin may have a crosslinked structure. A preferred example of a styrene-acrylic resin having a crosslinked structure is one obtained by copolymerizing at least a styrene monomer, a (meth)acrylic acid monomer, and a crosslinkable monomer.

[0061] Examples of crosslinkable monomers include crosslinking agents with two or more functionalities. Examples of bifunctional crosslinking agents include divinylbenzene, divinylnaphthalene, di(meth)acrylate compounds (e.g., diethylene glycol di(meth)acrylate, methylenebis(meth)acrylamide, decanediol diacrylate, glycidyl(meth)acrylate, etc.), polyester-type di(meth)acrylate, and 2-([1'-methylpropyleneamino]carboxyamino)ethyl methacrylate. 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 chloridedate, and the like. In particular, as crosslinkable monomers, (meth)acrylate compounds with two or more functions are preferred, more preferably bifunctional (meth)acrylate compounds, even more preferably bifunctional (meth)acrylate compounds having alkylene groups with 6 to 20 carbon atoms, and especially preferably bifunctional (meth)acrylate compounds having linear alkylene groups with 6 to 20 carbon atoms.

[0062] The copolymerization ratio of the crosslinkable monomer to the total monomer (by mass, crosslinkable monomer / total monomer) is not particularly limited, but is preferably 2 / 1,000 to 20 / 1,000.

[0063] There are no particular restrictions on the method for producing styrene-acrylic resin, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) can be applied. Furthermore, known polymerization reactions (e.g., batch, semi-continuous, continuous, etc.) can be used.

[0064] The proportion of 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.

[0065] The amorphous resin is preferably present in proportion to the total binder resin at 60% by mass or more and 98% by mass or less, more preferably at 65% by mass or more and 95% by mass or less, and even more preferably at 70% by mass or more and 90% by mass or less.

[0066] This section explains the properties of amorphous resins. The glass transition temperature (Tg) of amorphous resins is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0067] The weight-average molecular weight (Mw) of the amorphous resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the amorphous resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the amorphous resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0068] This section will explain crystalline resins. Examples of crystalline resins 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 images.

[0069] Examples of crystalline polyester resins include polycondensates of polycarboxylic acids and polyhydric alcohols. Commercially available crystalline polyester resins may be used, or synthesized resins may be used. For crystalline polyester resins, polycondensates using linear aliphatic polymerizable monomers are preferred over polymerizable monomers having aromatic rings, as they readily form a crystalline structure.

[0070] 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., phthalic acid, isophthalic acid, terephthalic acid, dibasic acids such as naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). In addition to these dicarboxylic acids, polycarboxylic acids with sulfonic acid groups and dicarboxylic acids with ethylenic double bonds may also be used in combination. Polycarboxylic acids may be used individually or in combination of two or more.

[0071] Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols with 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-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. Polyhydric alcohols may be used in combination with diols, including trihydric or higher alcohols that have a cross-linked or branched structure. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0072] The polyhydric alcohol often contains 80 mol% or more of aliphatic diols, preferably 90 mol% or more.

[0073] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C. The melting temperature of crystalline polyester resin is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121:1987 "Method for determining the transition temperature of plastics".

[0074] The weight-average molecular weight (Mw) of the crystalline polyester resin is preferably between 6,000 and 35,000.

[0075] Crystalline polyester resins can be obtained, for example, by known manufacturing methods, similar to amorphous polyester resins.

[0076] As for crystalline polyester resins, polymers of α,ω-linear aliphatic dicarboxylic acid and α,ω-linear aliphatic diol are preferred from the viewpoint of easily forming a crystalline structure and having good compatibility with amorphous polyester resins, which in turn improves image fixation.

[0077] As the α,ω-linear aliphatic dicarboxylic acid, an α,ω-linear aliphatic dicarboxylic acid in which the alkylene group connecting the two carboxyl groups has 3 to 14 carbon atoms is preferred, more preferably the alkylene group has 4 to 12 carbon atoms, and even more preferably the alkylene group has 6 to 10 carbon atoms. Examples of α,ω-linear aliphatic dicarboxylic acids 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. Among these, 1,6-hexanedicarboxylic acid, 1,7-heptanedicarboxylic acid, 1,8-octanedicarboxylic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid are preferred. α,ω-linear aliphatic dicarboxylic acids may be used individually or in combination of two or more.

[0078] As the α,ω-linear aliphatic diol, an α,ω-linear aliphatic diol in which the alkylene group connecting the two hydroxyl groups has 3 to 14 carbon atoms is preferred, more preferably the alkylene group has 4 to 12 carbon atoms, and even more preferably the alkylene group has 6 to 10 carbon atoms. Examples of α,ω-linear 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, 1,12-dodecanediol, 1,14-tetradecanediol, and 1,18-octadecanediol, among which 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred. α,ω-linear aliphatic diols may be used individually or in combination of two or more types.

[0079] As a polymer of α,ω-linear aliphatic dicarboxylic acid and α,ω-linear aliphatic diol, from the viewpoint of easily forming a crystalline structure and having good compatibility with amorphous polyester resins, as a result, improving image fixation, 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.

[0080] The crystalline resin is preferably present in an amount of 1% by mass or more and 20% by mass or less of the total binder resin, more preferably 2% by mass or more and 15% by mass or less, and even more preferably 3% by mass or more and 10% by mass or less.

[0081] Other binding 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.), or copolymers of two or more of these monomers. Other examples of binder resins include non-vinyl resins such as epoxy resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin, mixtures of these with the aforementioned vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binding resins may be used individually or in combination of two or more types.

[0082] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total toner particles.

[0083] -Release agent- 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-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these.

[0084] As a release agent, ester waxes are preferred from the viewpoint of suppressing density unevenness and white spots in the resulting image, having good compatibility with amorphous polyester resins, and consequently improving image fixation. Ester waxes of a higher fatty acid having 10 to 30 carbon atoms and a monovalent or polyvalent alcohol component having 1 to 30 carbon atoms are preferred.

[0085] Ester waxes are waxes that contain ester bonds. Ester waxes can be monoesters, diesters, triesters, or tetraesters; known natural or synthetic ester waxes can be used. Examples of ester waxes include ester compounds of higher fatty acids (such as fatty acids with 10 or more carbon atoms) and monohydric or polyhydric aliphatic alcohols (such as aliphatic alcohols with 8 or more carbon atoms), with a melting temperature of 60°C to 110°C (preferably 65°C to 100°C, more preferably 70°C to 95°C). Examples of ester waxes include ester compounds of higher fatty acids (such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and oleic acid) and alcohols (monohydric alcohols such as methanol, ethanol, propanol, isopropanol, butanol, caprylic 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). Specifically, examples include carnauba wax, rice wax, candelilla wax, jojoba oil, wood wax, beeswax, privet wax, lanolin, and montanic acid ester wax.

[0086] The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C. The melting temperature of the release agent is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121:1987 "Method for determining the transition temperature of plastics".

[0087] The release agent content is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less, relative to the total toner particles.

[0088] -Other colorants- The toner particles may contain colorants other than the silicon phthalocyanine dye and the acetylacetone metal compound. Other colorants include, for example, carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene 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, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and Wurth Examples include various pigments such as lamarine blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. Other colorants may be used individually or in combination of two or more.

[0089] Other colorants may include surface-treated colorants as needed, and may be used in combination with dispersants. Furthermore, multiple types of other colorants may be used in combination.

[0090] There are no particular restrictions on the content of other colorants, but it is preferable that the amount is less than the content of the silicon phthalocyanine dye.

[0091] -Other additives- Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0092] -Characteristics of toner particles, etc.- The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core. Here, the core-shell structure of the toner particles may consist of, for example, a core portion comprising a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer comprising a binder resin.

[0093] The volume-average particle size (D50v) of the toner particles is preferably 2 μm to 15 μm, more preferably 4 μm to 8 μm, even more preferably 4 μm to 7 μm, and particularly preferably 5 μm to 6.5 μm.

[0094] The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with a diameter of 2 μm to 60 μm is then measured using a Coulter Multisizer II with an aperture diameter of 100 μm. The number of particles sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0095] The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

[0096] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a still image of the particles is captured by instantaneous strobe flashing. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the average circularity is 3500. If 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.

[0097] (Toner characteristics) In the toner according to this embodiment, the maximum endothermic peak temperature during the first heating cycle measured by a differential scanning calorimeter (DSC) is preferably 58°C to 75°C. Setting the maximum endothermic peak temperature of the toner to 58°C to 75°C improves the low-temperature fixing properties of the toner.

[0098] The maximum endothermic peak temperature during the first heating cycle of the toner, measured using a differential scanning calorimeter (DSC), is determined as follows: A PerkinElmer DSC-7 differential thermal scanning calorimeter is used. 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 up as a control. The temperature is increased from room temperature to 150°C at a heating rate of 10°C / min. The temperature at which the maximum endothermic peak is obtained in the resulting endothermic curve is then determined.

[0099] (Toner manufacturing method) Next, a description of the toner manufacturing method according to this embodiment will be given. The toner according to this embodiment is obtained by manufacturing toner particles and then adding an external additive to the toner particles.

[0100] Toner particles may be manufactured by either a dry process (e.g., kneading and grinding) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension). There are no particular restrictions on these methods, and known methods can be used. Among these, obtaining toner particles by agglomeration is preferable. Examples of agglomeration and aggregation methods include those described in Japanese Patent Publication No. 2010-97101 or Japanese Patent Publication No. 2006-154641. An example of a kneading and grinding method is the method described in Japanese Patent Publication No. 2000-267338. An example of a dissolution and suspension method is the method described in Japanese Patent Publication No. 2000-258950.

[0101] Specifically, for example, when manufacturing resin particles by the agglomeration and coalescence method, toner particles are manufactured through the following steps: preparing a resin particle dispersion in which resin particles that will become the binder are dispersed (resin particle dispersion preparation step); a step of agglomerating resin particles and dye particles or titanium dioxide pigment particles (other particles as needed) in a dispersion after mixing the resin particle dispersion and a colorant dispersion (other particle dispersions as needed) 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).

[0102] The details of each step are explained below. The following description explains a method for obtaining resin particles containing other colorants and release agents, but these other colorants and release agents are used only as needed. Of course, other additives besides colorants and release agents may also be used.

[0103] -Resin particle dispersion preparation process- Along with a resin particle dispersion containing resin particles that will act as a binder, prepare other colorant particle dispersions containing other colorant particles, and a release agent particle dispersion containing release agent particles.

[0104] A resin particle dispersion is prepared, for example, by dispersing resin particles in a dispersion medium using a surfactant.

[0105] Examples of dispersion media used in resin particle dispersions include aqueous media. Examples of aqueous media include water such as distilled water and deionized water, and alcohols. These may be used individually or in combination of two or more.

[0106] Examples of surfactants include anionic surfactants such as sulfate esters, sulfonates, phosphates, and soaps; cationic surfactants such as amine salts and quaternary ammonium salts; and nonionic surfactants such as polyethylene glycol, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly noteworthy. Nonionic surfactants may be used in combination with anionic or cationic surfactants. In particular, the use of nonionic surfactants is preferred, and the use of nonionic surfactants in combination with anionic surfactants or cationic surfactants is preferred. Surfactants may be used individually or in combination of two or more types.

[0107] In resin particle dispersions, common dispersion methods for dispersing resin particles in a dispersion medium include, for example, rotary shear homogenizers, ball mills with media, sand mills, and dyno mills. Depending on the type of resin particles, the resin particles may also be dispersed in the dispersion medium by phase inversion emulsification. Phase inversion emulsification is a method in which the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, a base is added to neutralize the organic continuous phase (O phase), and then an aqueous medium (W phase) is added to perform a phase inversion from W / O to O / W, thereby dispersing the resin in particulate form in the aqueous medium.

[0108] The volume-average particle size of the resin particles dispersed in the resin particle dispersion is preferably 0.01 μm or more and 1 μm or less, more preferably 0.03 μm or more and 0.8 μm or less, and even more preferably 0.05 μm or more and 0.6 μm or less. The volume-average particle size of resin particles is measured using a laser diffraction particle size distribution analyzer (e.g., LA-700, manufactured by Horiba, Ltd.). The particle size distribution is obtained by subtracting the cumulative distribution from the smallest particle size side for each divided particle size range (channel). The particle size at which the cumulative distribution reaches 50% of all particles is measured as the volume-average particle size D50v. The volume-average particle size of particles in other dispersions is measured in the same manner.

[0109] The resin particle content 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.

[0110] Similar to the resin particle dispersion, colorant particle dispersions, such as those for dyes or titanium dioxide pigments, and mold release agent particle dispersions are also prepared. In other words, the volume average particle size, dispersion medium, dispersion method, and particle content of the resin particle dispersion are the same for colorant particles dispersed in the colorant particle dispersion and mold release agent particles dispersed in the mold release agent particle dispersion.

[0111] -Agglomerated particle formation process- Next, the resin particle dispersion, the colorant particle dispersion, and the mold release agent particle dispersion are mixed together. Then, in the mixed dispersion, the resin particles, colorant particles, and release agent particles are heteroaggregated to form aggregated particles containing the resin particles, other colorant particles, and release agent particles, which have a diameter close to the diameter of the target resin particles.

[0112] Specifically, for example, a coagulant is added to a mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 to 5), a dispersion stabilizer is added as needed, and then the mixture is heated to a temperature close to the glass transition temperature of the resin particles (specifically, for example, above -30°C or below -10°C), causing the particles dispersed in the mixed dispersion to coagulate and form coagulated particles. In the agglomerated particle formation process, for example, the mixed dispersion may be stirred in a rotary shear homogenizer, a flocculant may be added at room temperature (e.g., 25°C), the pH of the mixed dispersion may be adjusted to acidic (e.g., pH 2 to 5), a dispersion stabilizer may be added as needed, and then heating may be performed.

[0113] Examples of flocculants include surfactants with opposite polarity to the surfactant contained in the mixed dispersion, inorganic metal salts, and metal complexes with a valency of 2 or higher. When a metal complex is used as a flocculant, the amount of surfactant used is reduced and the electrostatic properties are improved. Along with the flocculant, an additive that forms a complex or similar bond with the metal ions of the flocculant may be used as needed. A chelating agent is preferably used as this additive.

[0114] 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. As a chelating agent, a water-soluble chelating agent may be used. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; and aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA). The amount of flocculant added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less per 100 parts by mass of resin particles, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass.

[0115] -Fusion / unification process- Next, the dispersion of aggregated particles is heated to, for example, a temperature above the glass transition temperature of the resin particles (for example, 30°C to 50°C higher than the glass transition temperature of the resin particles) and above the melting temperature of the release agent, thereby fusing and combining the aggregated particles to form toner particles. In the fusion and coalescence process, the resin and release agent are fused together at temperatures above the glass transition temperature of the resin particles and above the melting temperature of the release agent. Afterward, the mixture is cooled to obtain resin particles. Methods for adjusting the aspect ratio of the release agent in toner particles include promoting crystal growth by holding the release agent at a temperature near its freezing point for a certain period during cooling, or by using two or more types of release agents with different melting points to encourage crystal growth during cooling.

[0116] Toner particles are obtained through the above process. Toner particles may be manufactured by first obtaining an aggregate particle dispersion in which aggregate particles are dispersed, then further mixing the aggregate particle dispersion with a resin particle dispersion in which resin particles are dispersed, and agglomerating the aggregate particles so that more resin particles adhere to the surface of the aggregate particles to form second aggregate particles, and then heating the second aggregate particle dispersion in which the second aggregate particles are dispersed to fuse and combine the second aggregate particles to form core-shell structured resin particles.

[0117] After the fusion and combination process is completed, the toner particles formed in the solution are subjected to known washing, solid-liquid separation, and drying processes to obtain dried toner particles. From the viewpoint of electrostatic properties, the washing process should be performed thoroughly by displacement washing with deionized water. From the viewpoint of productivity, the solid-liquid separation process should be performed by suction filtration, pressure filtration, etc. From the viewpoint of productivity, the drying process should be performed by freeze-drying, air-flow drying, fluidized bed drying, vibratory fluidized bed drying, etc.

[0118] The electrostatic image developing toner according to this embodiment is manufactured, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing is preferably carried out using, for example, a V-blender, a Henschel mixer, a Redigge mixer, etc. Furthermore, if necessary, coarse resin particles may be removed using a vibrating screen separator, wind screen separator, or the like.

[0119] <Electrostatic Image Developer> The electrostatic image developer according to this embodiment includes 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 it may be a two-component developer mixed with the toner and a carrier.

[0120] There are no particular restrictions on the carriers, and known carriers can be used. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0121] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0122] 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 resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, and the like. Furthermore, the coating resin and matrix resin may contain conductive particles or other additives. Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0123] To coat the surface of the core material with a coating resin, one method is to coat it with a coating layer-forming solution in which the coating resin and, if necessary, various additives are dissolved in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for coating, etc. Specific resin coating methods include the immersion method, in which the core material is immersed in a coating layer forming solution; the spray method, in which the coating layer forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer forming solution is sprayed onto the core material while it is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed.

[0124] In a two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100.

[0125] <Image forming device / image forming method> An image forming apparatus / image forming method according to this embodiment will be described. The image forming apparatus according to this embodiment comprises an image holder, a charging means for charging the surface of the image holder, an electrostatic image forming means for forming an electrostatic image on the charged surface of the image holder, a developing means for containing an electrostatic image developer and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, a transfer means for transferring the toner image formed on the surface of the image holder to the surface of a recording medium, and a fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic image developer according to this embodiment is applied as the electrostatic image developer.

[0126] The image forming apparatus according to this embodiment implements an image forming method (image forming method according to this embodiment) comprising: a charging step of charging the surface of an image holder; an electrostatic image forming step of forming an electrostatic image on the charged surface of the image holder; a developing step of developing the electrostatic image formed on the surface of the image holder as a toner image using an electrostatic image developer according to this embodiment; a transfer step of transferring the toner image formed on the surface of the image holder to the surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the recording medium.

[0127] The image forming apparatus according to this embodiment may be a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image holder to a recording medium; an intermediate transfer type apparatus that first transfers a toner image formed on the surface of an image holder to the surface of an intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; an apparatus equipped with cleaning means for cleaning the surface of the image holder before charging after the transfer of the toner image; or an apparatus equipped with static elimination means for irradiating the surface of the image holder with static elimination light before charging after the transfer of the toner image. Among these, an image forming apparatus equipped with a cleaning means for cleaning the surface of the image holder is particularly preferred. Furthermore, a cleaning blade is preferred as the cleaning means. In the case of an intermediate transfer method apparatus, the transfer means may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer means for primaryly transferring the toner image formed on the surface of the image holder to the surface of the intermediate transfer body; and a secondary transfer means for secondary transferring the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium.

[0128] In the image forming apparatus according to this embodiment, for example, the part including the developing means may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge equipped with a developing means containing the electrostatic image developer according to this embodiment is preferably used.

[0129] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will be omitted from the explanation.

[0130] Figure 1 is a schematic diagram showing the image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 is equipped with first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images of 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 at predetermined distances from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may also be process cartridges that can be attached to and detached from the image forming apparatus.

[0131] In the drawings of each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 is extended through each unit as an intermediate transfer body. The intermediate transfer belt 20 is wound around drive rolls 22 and support rolls 24 that are spaced apart from each other from left to right in the drawing and are in contact with the inner surface of the intermediate transfer belt 20, and is configured to travel in the direction from the first unit 10Y to the fourth unit 10K. The support rolls 24 are subjected to a force that moves away from the drive rolls 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both. In addition, an intermediate transfer body cleaning device 30 is provided on the side of the image holder of the intermediate transfer belt 20, facing the drive rolls 22. Furthermore, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K for each unit 10Y, 10M, 10C, and 10K is supplied with toner containing four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0132] Since the first to fourth units 10Y, 10M, 10C, and 10K have equivalent configurations, the first unit 10Y, which forms the yellow image and is located on the upstream side in the direction of travel of the intermediate transfer belt, will be described as a representative example. The descriptions of the second to fourth units 10M, 10C, and 10K will be omitted by assigning reference numerals to parts equivalent to the first unit 10Y, with magenta (M), cyan (C), and black (K) instead of yellow (Y).

[0133] The first unit 10Y has a photoreceptor 1Y that acts as an image holder. Around the photoreceptor 1Y are, in 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 a charge image forming means) 3 that exposes the charged surface with a laser beam 3Y based on a color-separated image signal to form a charge image, a developing device (an example of a developing means) 4Y that supplies charged toner to the charge image to develop the charge image, 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 primary transfer. The primary transfer roll 5Y is positioned inside the intermediate transfer belt 20, facing the photoreceptor 1Y. Furthermore, each of the primary transfer rolls 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) that applies a primary transfer bias. Each bias power supply varies the transfer bias applied to each primary transfer roll through control by a control unit (not shown).

[0134] The following describes the process of forming the yellow image in the first unit 10Y. First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roll 2Y. The photoreceptor 1Y is conductive (e.g., volume resistivity at 20°C: 1 × 10⁻⁶). -6The photosensitive layer is formed by laminating a photosensitive layer on a substrate (less than Ωcm). This photosensitive layer normally has high resistance (resistance of general resin), but when irradiated with a laser beam 3Y, the resistivity of the irradiated area changes. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 according to image data for yellow sent from a control unit (not shown). The laser beam 3Y irradiates the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic image of the yellow image pattern on the surface of the photoreceptor 1Y.

[0135] A static charge image is an image formed on the surface of a photoreceptor 1Y due to charging. It is a so-called negative latent image formed when the resistivity of the irradiated portion of the photoreceptor layer decreases due to the laser beam 3Y, causing the charged material on the surface of the photoreceptor 1Y to flow, while the charge remains in the portion not irradiated by the laser beam 3Y. The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y moves. At this development position, the electrostatic charge image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0136] The developing device 4Y contains, for example, an electrostatic image developer including at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y and is held on the developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the static 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 on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y, on which the yellow toner image has been formed, continues to move at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0137] 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 toward the primary transfer roll 5Y acts on the toner image, transferring the toner image on the photoreceptor 1Y onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity opposite to the toner's polarity (-) (+), and in the first unit 10Y, for example, it is controlled to +10 μA by a control unit (not shown). Meanwhile, any toner remaining on the photoreceptor 1Y is removed and recovered by the photoreceptor cleaning device 6Y.

[0138] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit from 10M onward is also controlled in accordance with the first unit. Thus, the intermediate transfer belt 20, on which the yellow toner image has been transferred in the first unit 10Y, is sequentially transported through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and transferred in multiple layers.

[0139] The intermediate transfer belt 20, on which four-color toner images have been multiple-transferred through the first to fourth units, proceeds to 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 positioned on the image-holding 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 the same polarity (-) as the toner's polarity (-), and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0140] After this, the recording paper P is fed to the contact area (nip area) 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, and a fixed image is formed.

[0141] Examples of recording paper P used to transfer toner images include plain paper used in electrophotographic photocopiers and printers. Other recording media besides recording paper P include OHP sheets. 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, which is plain paper coated with resin or the like, or art paper for printing are suitable for use.

[0142] Once the color image has been fixed onto the recording paper P, it is discharged towards the output section, and the series of color image formation operations is completed.

[0143] <Processor Cartridges / Toner Cartridges> The process cartridge according to this embodiment will be described. The process cartridge according to this embodiment contains the electrostatic image developer according to this embodiment and includes a developing means for developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer, and is a process cartridge that can be attached to and detached from an image forming apparatus.

[0144] The process cartridge according to this embodiment is not limited to the above configuration, and may also include a developing device and, as necessary, at least one other means selected from, for example, an image holder, a charging means, an electrostatic image forming means, and a transfer means.

[0145] The following shows an example of a process cartridge according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will not be explained.

[0146] Figure 2 is a schematic diagram showing the process cartridge according to this embodiment. The process cartridge 200 shown in Figure 2 is constructed by integrally holding a photoreceptor 107 (an example of an image holder), a charging roll 108 (an example of a charging means) provided around the photoreceptor 107, a developing device 111 (an example of a developing means), and a photoreceptor cleaning device 113 (an example of a cleaning means) within a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure, and is then formed into a cartridge. In Figure 2, 109 represents an exposure apparatus (an example of electrostatic image formation means), 112 represents a transfer apparatus (an example of a transfer means), 115 represents a fixing apparatus (an example of a fixing means), and 300 represents recording paper (an example of a recording medium).

[0147] Next, the toner cartridge according to this embodiment will be described. The toner cartridge according to this embodiment is a toner cartridge that contains the toner according to this embodiment and is attached to and detached from an image forming apparatus. The toner cartridge contains replenishment toner for supply to a developing means provided within the image forming apparatus.

[0148] The image forming apparatus shown in Figure 1 is an image forming apparatus with removable toner cartridges 8Y, 8M, 8C, and 8K. The developing units 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to each developing unit (color) by toner supply pipes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced. [Examples]

[0149] The embodiment will be described in more detail below with reference to examples and comparative examples, but this embodiment is not limited to these examples. Unless otherwise specified, "parts" and "%" refer to mass. Furthermore, I-1 to I-27 in this example are the same compounds as those described above.

[0150] <Preparation of Zirconium Oxide Particle Dispersion 1> A dispersion of zirconium oxide particles 1 with a solid content of 0.01% was prepared by mixing zirconia nanoparticles (Daiichi Rare Elements Chemical Industry Co., Ltd. ZSL-10A (number average particle size 80 nm)) with water.

[0151] <Preparation of Zirconium Oxide Particle Dispersion 2> A dispersion of zirconium oxide particles 2 with a solid content of 1% was prepared by mixing zirconia nanoparticles (ZSL-10A, manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd. (number average particle size 80 nm)) with water.

[0152] <Preparation of Zirconium Oxide Particle Dispersion 3> A dispersion of zirconium oxide particles 3 with a solid content of 0.01% was prepared by mixing zirconia nanoparticles (SZR-CW manufactured by Sakai Chemical Industry Co., Ltd. (number average particle size 5 nm)) with water.

[0153] <Preparation of Zirconium Oxide Particle Dispersion 4> A dispersion of zirconium oxide particles 4 with a solid content of 0.01% was prepared by mixing zirconia nanoparticles (TMZ zirconium oxide manufactured by Daiichi Rare Elements Chemical Industry Co., Ltd. (number average particle size 1.1 μm)) with water and a surfactant (5% relative to the zirconia).

[0154] <Preparation of silica particle dispersion> A silica particle dispersion with a solid content of 0.01% was prepared by mixing silica nanoparticles (QSG-100, manufactured by Shin-Etsu Chemical Co., Ltd., with a number-average particle size of 110 nm) with water and a surfactant (5% relative to the silica).

[0155] <Preparation of Titanium Oxide Particle Dispersion> A titanium dioxide particle dispersion with a solid content of 0.01% was prepared by mixing titanium dioxide nanoparticles (MT-600S, manufactured by Teika Co., Ltd., with a number-average particle size of 50 nm) with water and a surfactant (5% relative to the titanium dioxide).

[0156] <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 aforementioned materials were charged into a flask equipped with a stirrer, a nitrogen inlet tube, a temperature sensor, and a rectification column. The temperature was raised to 220°C over 1 hour under a nitrogen gas stream, and 1 part titanium tetraethoxide was added for every 100 parts of the materials. The temperature was raised to 240°C over 0.5 hours while distilling off the generated water, and the dehydration condensation reaction was continued at this temperature for 1 hour. After that, the reactants were cooled. In this way, an amorphous polyester resin with a weight-average molecular weight of 96,000 and a glass transition temperature of 61°C was synthesized. In a container equipped with temperature control and nitrogen purging means, 40 parts of ethyl acetate and 25 parts of 2-butanol were added to form a mixed solvent. Then, 100 parts of amorphous polyester resin were gradually added and dissolved. A 10% aqueous ammonia solution (equivalent to 3 times the molar ratio of the acid value of the resin) was added and stirred for 30 minutes. Next, the container was purged with dry nitrogen, and the temperature was maintained at 40°C. While stirring the mixture, 400 parts of deionized water were added dropwise at a rate of 2 parts / minute to emulsify it. After the dropwise addition was complete, the emulsion was returned to 25°C to obtain a resin particle dispersion in which resin particles with a volume average particle size of 190 nm were dispersed. Deionized water was added to the resin particle dispersion to adjust the solid content to 20% to obtain amorphous polyester resin particle dispersion (A1).

[0157] <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 After placing the aforementioned components into a heated and dried three-necked flask, the air inside the container was removed by a reduced pressure operation to create an inert atmosphere with nitrogen gas, and the mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Subsequently, the temperature was gradually increased to 230°C under reduced pressure and stirred for 2 hours until a viscous state was reached, at which point it was air-cooled to stop the reaction. Molecular weight measurement (polystyrene equivalent) showed that the weight-average molecular weight (Mw) of the obtained "crystalline polyester resin 2" was 13,000, and the melting temperature was 69°C. 90 parts of the obtained resin, 1.5 parts of the ionic surfactant Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 200 parts of ion-exchanged water were heated to 120°C and thoroughly dispersed in an IKA Ultra-Turrax T50. The dispersion treatment was then carried out for 1 hour in a pressure-discharge type Gorin homogenizer to obtain a crystalline polyester resin particle dispersion (B2) with a volume-average particle size of 210 nm and a solid content of 23 parts by mass.

[0158] (Preparation of a dispersion of coloring agent particles) • Silicone phthalocyanine dye I-3: 50 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 5 parts • Ion-exchanged water: 193 parts The aforementioned components were mixed and treated with an ultimateizer (manufactured by Sugino Machine Co., Ltd.) at 240 MPa for 10 minutes to prepare a dispersion of colorant particles (solid content concentration: 20%).

[0159] <Preparation of mold release agent particle dispersion> (Preparation of mold release agent particle dispersion (W1)) • Ester wax (WEP-5, manufactured by NOF Corporation, melting point 85°C): 100 parts • Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1 part • Ion-exchanged water: 350 units The aforementioned materials were mixed and heated to 100°C, dispersed using a homogenizer (IKA Ultra-Turrax T50), and then dispersed again using a Manton-Gorin high-pressure homogenizer (Gorin), 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.

[0160] <Example 1> -Preparation of toner particles 1- • Zirconium oxide particle dispersion 1:7.8 parts by mass • Amorphous polyester resin particle dispersion 1:150 parts by mass • Coloring agent particle dispersion: 25 parts by mass • Release agent particle dispersion: 35 parts by mass • Crystalline polyester resin particle dispersion: 50 parts by mass • Polyaluminum chloride: 0.4 parts by mass • Ion-exchanged water: 100 parts by mass The aforementioned components were thoroughly mixed and dispersed in a round stainless steel flask using IKA's Ultra-Turrax T50. The mixture was then heated in a heating oil bath to 48°C while stirring and held for 60 minutes to produce aggregated particles that would form the core. Subsequently, 100 parts by mass of the same amorphous polyester resin particle dispersion as described above was slowly added to form the shell. After that, the pH of the system was adjusted to 8.0 using a 0.5 mol / L sodium hydroxide aqueous solution. The stainless steel flask was then sealed, the stirring shaft seal was magnetically sealed, and the mixture was heated to 90°C and held for 30 minutes while continuing to stir. After the reaction was complete, the mixture was cooled at a rate of 5°C / min, filtered, thoroughly washed with deionized water, and then solid-liquid separation was performed by Nütsche suction filtration. This was then redispersed using 3,000 parts by mass of deionized water at 30°C and washed by stirring at 300 rpm for 15 minutes. This washing operation was repeated six more times until the filtrate's pH reached 7.54 and its electrical conductivity reached 6.5 μS / cm. At this point, solid-liquid separation was performed using No. 5A filter paper via Nutsche suction filtration. Next, vacuum drying was continued for 24 hours to obtain the toner.

[0161] (Preparation of Toner 1) To 100 parts by mass of the obtained toner particles 1, 1.5 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50, average particle size 140 nm) was mixed and blended using a sample mill at 10,000 rpm for 30 seconds. Subsequently, toner 1 was prepared by sieving with a vibrating sieve with a mesh size of 45 μm. The volume-average particle size of the obtained toner 1 was 5.7 μm.

[0162] (Career creation) 500 parts of spherical magnetite powder particles (volume average particle size: 0.55 μm) were thoroughly mixed in a Henschel mixer, then 5.0 parts of a titanate-based coupling agent were added, and the mixture was heated to 100°C and mixed and stirred for 30 minutes to obtain titanate-based coupling agent-coated spherical magnetite particles. 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 added to a four-necked flask and mixed and stirred. Then, the mixture was reacted at 85°C for 120 minutes while stirring, cooled to 25°C, 500 parts of water were 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.

[0163] (Preparation of electrostatic image developer 1) The obtained carrier and toner 1 were placed in a V blender in a toner:carrier ratio of 5:95 (mass ratio), stirred for 20 minutes, and electrostatic image developer 1 was obtained.

[0164] <Evaluation of Hot Offset Suppression> With the Fuji Xerox DocuCentreColor400, the toner load is 5.2 g / m². 2 The unfixed image was output after adjustments were made to achieve the desired result. OSC127 paper (manufactured by Fuji Xerox Co., Ltd.) was used as the recording medium. The output image was a solid image of 50mm x 50mm with 100% image density. For the fixation evaluation device, we used a modified version of the ApeosPortIV C3370 manufactured by Fuji Xerox Co., Ltd., with the fuser unit removed and the fixation temperature adjustable. The nip width of the fixation evaluation device was 6 mm, and the nip thickness was 1.6 kgf / cm². 2 The process speed was 175 mm / sec. Unfixed images were fixed at fixing temperatures ranging from 160°C to 220°C in 5°C intervals. The presence or absence of hot offset was visually checked, and the lowest temperature at which hot offset occurred was evaluated as the hot offset occurrence temperature. The evaluation criteria are as follows: -Evaluation Criteria- A: Hot offset occurs at temperatures above 210°C B: Hot offset occurs at temperatures between 200°C and 210°C. C: Hot offset occurs at temperatures between 180°C and 200°C. D: Hot offset occurs at a temperature of less than 180°C

[0165] <Image Transparency Evaluation> -Image Formation- The obtained electrostatic image developer was loaded into a modified Fuji Xerox DocuCentre Color 400 machine, the fixing temperature was set to 180°C, and a solid yellow image (40mm x 25mm, toner mass 4.0g / m²) was printed in OHP mode under conditions of 23°C and 55% relative humidity. 2 ) and halftone image (40mm x 25mm, toner weight 0.5g / m²) 2 The following was performed: A black and white OHP sheet manufactured by Fuji Xerox Co., Ltd. was used as the recording medium.

[0166] -Evaluation Method- The ratio of scattered light to total transmitted light was measured using a fully automatic haze meter (TC-HIII DP type, manufactured by Tokyo Denshoku Co., Ltd.) in accordance with JIS K7136:2000 "Plastics - Method for determining haze of transparent materials," and classified into four stages from G1 to G4. G2 to G4 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

[0167] <Examples 2 to 9, and Comparative Examples 1 to 3> As shown in Table 2, toner and electrostatic image developer were prepared and evaluated in the same manner as in Example 1, except that the type and amount of silicon phthalocyanine dye used in the preparation of the colorant particle dispersion, the type and amount of zirconium oxide particle dispersion used in the production of toner particles, and the amorphous polyester resin particle dispersion and crystalline polyester resin particle dispersion (PES) were replaced with styrene acrylic resin particle dispersion (StAC) as described below. The evaluation results are shown in Table 2.

[0168] <Preparation of Styrene Acrylic Resin Particle Dispersion> -Materials for the oil phase- • Styrene (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 30 units • n-butyl acrylate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 10 parts • β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.): 1.3 parts Dodecanethiol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 0.4 parts

[0169] -Materials for aqueous phase 1- • Ion-exchanged water: 17 parts • Anionic surfactant: Dowfax (manufactured by Dow Chemical): 0.4 parts

[0170] -Materials for Aqueous Phase 2- • Ion-exchanged water: 40 parts • Anionic surfactant: Dowfax (manufactured by Dow Chemical): 0.05 parts • Ammonium peroxodisulfate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.): 0.4 parts

[0171] The oil phase materials and the aqueous phase 1 materials were stirred and mixed separately, and then the two were stirred and mixed to obtain a monomer emulsion dispersion. Separately, the aqueous phase 2 materials were added to a reaction vessel, the inside of the reaction vessel was thoroughly purged with nitrogen, and the reaction system was heated in an oil bath while stirring until the temperature reached 75°C. The monomer emulsion dispersion was gradually added dropwise to this reaction vessel over 3 hours to carry out emulsion polymerization. After the dropwise addition was complete, polymerization was continued at 75°C for another 3 hours, and polymerization was completed to obtain a styrene acrylic resin particle dispersion with a solid content of 42% by mass. The volume-average particle size was measured at 250 nm using a particle size distribution analyzer (LA-700, Horiba, Ltd.). The glass transition temperature of the resin was measured at 52°C at a heating rate of 10°C / min using a differential scanning calorimeter (DSC-50, Shimadzu Corporation). The number-average molecular weight (polystyrene equivalent) was measured at 13,000 using GPC.

[0172] [Table 2]

[0173] In addition, the refractive index (25°C) of amorphous polyester resin in PES in Table 2 was 1.50, the refractive index (25°C) of crystalline polyester resin was 1.53, and the refractive index (25°C) of styrene acrylic resin in StAC was 1.57. Furthermore, 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 both the examples and comparative examples were cyan toners.

[0174] From the results above, it can be seen that this embodiment is superior to the comparative example in suppressing hot offset. [Explanation of symbols]

[0175] 1Y, 1M, 1C, 1K photoreceptors (examples of image retainers) 2Y, 2M, 2C, 2K Charging Rolls (Example of Charging Method) 3. Exposure apparatus (an example of electrostatic image formation means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing apparatus (an example of a developing method) 5Y, 5M, 5C, 5K Primary Transfer Rolls (Example of Primary Transfer Method) 6Y, 6M, 6C, 6K Photoreceptor Cleaning Device (Example of Cleaning Method) 8Y, 8M, 8C, 8K Toner Cartridges 10Y, 10M, 10C, 10K Image Forming Units 20. Intermediate transfer belt (an example of an intermediate transfer material) 22 Drive Roll 24 Support Rolls 26. Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate Transfer Body Cleaning Apparatus 107 Photoreceptor (an example of an image-retaining element) 108 Charging Roll (Example of Charging Method) 109 Exposure apparatus (an example of a means for forming electrostatic images) 111 Developing apparatus (an example of a developing means) 112 Transfer device (an example of a transfer means) 113 Photoreceptor cleaning device (an example of a cleaning method) 115 Fixing device (an example of a fixing means) 116 Mounting Rail 118 Aperture for exposure 117 cabinets 200 Process Cartridges 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. The toner particles contain a silicon phthalocyanine dye and zirconium oxide particles, wherein the content ratio of the zirconium oxide particles to the silicon phthalocyanine dye is 0.00015 or more and 0.075 or less. The content of the silicon phthalocyanine dye is 1% by mass or more relative to the total mass of the toner particles. Toner for developing electrostatic images.

2. The toner for developing electrostatic images according to claim 1, wherein the Net intensity of the element Zr in the toner particles, as measured by X-ray fluorescence analysis, is 0.02 kcps or more and 25.0 kcps or less.

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

4. The toner for developing electrostatic images according to claim 2, wherein the Net intensity of the element Zr in the toner particles, as measured by X-ray fluorescence analysis, is 0.031 kcps or more and 25.0 kcps or less.

5. The toner for developing electrostatic images according to any one of claims 1 to 4, wherein the toner particles contain the zirconium oxide particles as an additive.

6. The electrostatic image developing toner according to any one of claims 1 to 5, wherein the silicon phthalocyanine dye is a compound represented by the following formula (I). 【Chemistry 1】 In formula (I), Z independently represents a hydroxyl group, a chlorine atom, an aryloxy group having 6 to 18 carbon atoms, an alkoxy group having 1 to 22 carbon atoms, or a group represented by the following formula (II), Ra １ ~Ra ４ Each of these is an independent substituent, and each of na1 to na4 independently represents an integer between 0 and 4, inclusive. 【Chemistry 2】 In formula (II), R １ ~R ３ Each of these independently 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.

7. The electrostatic image developing toner according to any one of claims 1 to 6, wherein at least a portion of the silicon phthalocyanine dye is dispersed in particulate form within the toner particles.

8. The toner for developing electrostatic images according to claim 7, wherein the number-average particle size of the silicon phthalocyanine dye, which is particulate and dispersed in the toner particles, is 10 nm or more and 1,000 nm or less.

9. The number average particle size of the silicon phthalocyanine dye, which is particulate and dispersed in the toner particles, is 155 nm or more and 1,000 nm or less. The electrostatic image developing toner according to claim 7 or claim 8, wherein the content of the zirconium oxide particles is 0.0013% by mass or more and 0.5008% by mass or less, based on the total mass of the toner particles.

10. The electrostatic image developing toner according to any one of claims 1 to 8, 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. The toner for developing electrostatic images according to any one of claims 1 to 10, wherein the number-average particle size of the zirconium oxide particles is 5 nm or more and 1.1 μm or less.

12. The toner for developing electrostatic images according to any one of claims 1 to 11, wherein the toner particles include a resin with a refractive index of 1.48 or more as a binder resin.

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

14. The electrostatic image developing toner according to any one of claims 1 to 13, wherein the content of the silicon phthalocyanine dye is 1% by mass or more and 30% by mass or less with respect to the total mass of the toner particles.

15. A cyan toner, which is a toner for developing electrostatic images according to any one of claims 1 to 14.

16. A electrostatic image developer comprising the electrostatic image developing toner according to any one of claims 1 to 15.

17. A toner cartridge for containing the electrostatic image developing toner described in any one of claims 1 to 15, which is attached to and detached from an image forming apparatus.

18. A process cartridge that contains the electrostatic image developer described in claim 16, and comprises a developing means for developing an electrostatic image formed on the surface of an image holder as a toner image using the electrostatic image developer, and is detachable from an image forming apparatus.

19. Image holder and, A charging means for charging the surface of the image holder, A means for forming an electrostatic image on the surface of the charged image holder, A developing means comprising: containing the electrostatic image developer described in claim 16; and developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer; A transfer means for transferring a toner image formed on the surface of the image holder to the surface of a recording medium, Fixing means for fixing the toner image transferred to the surface of the recording medium, An image forming apparatus equipped with the following features.

20. A charging step in which the surface of the image holder is charged, A step of forming an electrostatic image on the surface of the charged image holder, A developing step of developing the electrostatic image formed on the surface of the image holder as a toner image using the electrostatic image developer described in claim 16, A transfer step of transferring the toner image formed on the surface of the image holder to the surface of the recording medium, A fixing step for fixing the toner image transferred to the surface of the recording medium, An image forming method having the following characteristics.

Images