Toner for developing electrostatic latent images

Abstract

The present invention provides a toner for developing electrostatic latent images and a method for manufacturing the toner for developing electrostatic latent images. The toner contains a binder resin which contains an amorphous polyester resin A, and a colorant. The amorphous polyester resin A is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate. The colorant contains a naphthol AS-based pigment. The manufacturing method includes a step for melt-kneading at least the binder resin and the colorant, and a step for pulverizing a kneaded substance resulting from the previous step. The toner for developing electrostatic latent images according to the present invention is suitable for developing latent images and the like formed in electrophotography, electrostatic recording, electrostatic printing, or the like.

Description

Toner for developing electrostatic images

[0001] The present invention relates to an electrostatic image developing toner used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like, and a method for manufacturing the same.

[0002] In recent years, toner has come into use in industrial and commercial printing. Because printed materials are often used outdoors in these applications, weather resistance is required. Furthermore, high-resolution images such as photographs are frequently used, and improving image density is essential.

[0003] On the other hand, the use of polyethylene terephthalate as a raw material for the binder resin of toner is being considered (see Patent Document 1).

[0004] Japanese Patent Publication No. 2023-88255

[0005] The present invention relates to: (1) an electrostatic image developing toner containing an amorphous polyester resin A, a binder resin, and a colorant, wherein the amorphous polyester resin A is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, and the colorant contains a naphthol AS-based pigment; and (2) a method for producing the electrostatic image developing toner described in (1), comprising the steps of melting and kneading at least the binder resin and the colorant, and pulverizing the kneaded product obtained in the step. Detailed description of the invention

[0006] Among the magenta pigments used in toners for electrostatic image development, naphthol AS-based pigments are used as colorants due to their excellent balance of coloring power and color gamut, as well as weather resistance. However, there are challenges with their charge stability under high temperature and high humidity conditions, and further improvements are needed.

[0007] The present invention relates to a toner for electrostatic image developing that exhibits excellent charge stability under high temperature and high humidity conditions, and a method for manufacturing the same.

[0008] The electrostatic image developing toner of the present invention exhibits excellent charging stability under high temperature and high humidity conditions.

[0009] The electrostatic image developing toner of the present invention is characterized by containing a binder resin and a colorant, wherein the binder resin is an amorphous polyester resin A which is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate (hereinafter referred to as "PET"), and the colorant is a naphthol AS-based pigment. The reason why the effects of the present invention are achieved is not clear, but it is presumed to be as follows. Note that the mechanism described below is a hypothesis and is not limited thereto.

[0010] Naphthol AS-based pigments are characterized by having a skeleton with a naphthalene structure and a benzene ring structure, which are linked via amide groups. Although naphthalene and benzene ring structures generally have high charge retention capacity, they are thought to have low electrostatic stability because, perhaps due to being linked by hydrophilic amide groups, charge leaks at the amide group portion under high temperature and high humidity conditions. In contrast, the present invention has found that electrostatic stability under high temperature and high humidity conditions is improved by using a polycondensate of an alcohol component, a carboxylic acid component, and PET (amorphous polyester resin A). This is because, in the polycondensation reaction of the alcohol component, carboxylic acid component, and PET, the PET undergoes depolymerization and is incorporated into the polyester resin chain by a transesterification reaction, but it does not become completely randomized, and exists in the resin as units of a certain length that can be called PET segments. It is presumed that the highly polar PET segments, where ester groups are densely packed, interact with the amide groups of the naphthalene AS pigment molecules, thereby stabilizing the structure of the naphthalene AS pigment molecules. This suppresses charge leakage under high temperature and high humidity conditions, resulting in a toner with excellent charge stability.

[0011] The crystalline or amorphous nature of a resin is determined by its crystallinity index. The crystallinity index is defined as the ratio of the resin's softening point to its maximum endothermic peak temperature (softening point (°C) / maximum endothermic peak temperature (°C)) in the measurement method described in the examples below. A crystalline resin is one with a crystallinity index of 0.6 or higher and 1.4 or lower. An amorphous resin is one in which no endothermic peak is observed, or, if observed, has a crystallinity index of less than 0.6 or greater than 1.4. The crystallinity of a resin can be adjusted by the type and ratio of raw material monomers, and manufacturing conditions (e.g., reaction temperature, reaction time, cooling rate). The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In crystalline resins, the maximum endothermic peak temperature is defined as the melting point.

[0012] Amorphous polyester resin A is a polycondensate of an alcohol component, a carboxylic acid component, and PET.

[0013] The alcohol component, from the viewpoint of low-temperature fixation, is formula (I):

[0014]

[0015] It is preferable to include an alkylene oxide adduct of bisphenol A represented by formula (I). Examples of alkylene oxide adducts of bisphenol A represented by formula (I) include an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A. It is preferable to use one or more of these.

[0016] The content of the bisphenol A alkylene oxide adduct represented by formula (I) is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, in the alcohol component. However, the ethylene glycol units of PET are not included in the alcohol component as referred to herein.

[0017] Other alcoholic components include aliphatic diols and trivalent or higher alcohols.

[0018] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol.

[0019] Examples of alcohols with a hydride of 3 or higher include glycerin, trimethylolpropane, and pentaerythritol.

[0020] From the viewpoint of resistance to hot offsetting, the carboxylic acid component preferably includes an aromatic dicarboxylic acid compound.

[0021] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0022] The content of aromatic dicarboxylic acid compounds is preferably 20 mol% or more, more preferably 35 mol% or more, even more preferably 45 mol% or more, even more preferably 55 mol% or more, and 100 mol% or less, of the carboxylic acid component. If the carboxylic acid component includes trivalent or higher carboxylic acid compounds, the content is preferably 90 mol% or less, and more preferably 85 mol% or less. However, the carboxylic acid component as referred to herein does not include terephthalic acid units contained in PET.

[0023] Other carboxylic acid components include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0024] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0025] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol and carboxylic acid components.

[0026] In PET, ethylene glycol and terephthalic acid, produced by the polycondensation reaction of an alcohol component and a carboxylic acid component, and / or by the depolymerization of a portion of PET, are used as raw material monomers in the polycondensation reaction and incorporated into the polyester resin.

[0027] PET can be new virgin PET or recycled PET. Recycled PET refers to PET that has been collected after use and recycled back into PET material. The collected PET is sorted, removed, and washed as needed to remove other chemical substances and foreign matter, and then crushed into flakes or other forms. Recycled PET can be used as is, but it may also be washed and sorted from other materials as needed, then crushed, the crushed material is depolymerized to monomer units, and then resynthesized using these as raw materials.

[0028] In the present invention, it is preferable that the PET has a relatively low IV value, i.e., a low molecular weight, compared to conventionally used PET. By introducing low IV value (low molecular weight) PET into the polyester resin, the depolymerization of the PET proceeds more uniformly.

[0029] From the viewpoint of the above, the IV value of PET is preferably 0.40 or higher, more preferably 0.45 or higher, even more preferably 0.50 or higher, and still more preferably 0.55 or higher. From the viewpoint of low-temperature fixability and homogenization of depolymerization, it is preferably 0.85 or lower, more preferably 0.80 or lower, even more preferably 0.75 or lower, even more preferably 0.70 or lower, and still more preferably 0.65 or lower. The IV value is the intrinsic viscosity and serves as an indicator of molecular weight. The IV value of PET can be adjusted by the polycondensation time, etc.

[0030] Examples of commercially available PET products with an IV value of 0.40 to 0.85 include RAMAPET L1 (manufactured by Indorama Ventures, IV value: 0.60), RAMAPET BF3067 (manufactured by Indorama Ventures, IV value: 0.65), RAMAPET N2G (manufactured by Indorama Ventures, IV value: 0.75), TRN-NTJ (manufactured by Teijin Limited, IV value: 0.53), TRN-RTJC (manufactured by Teijin Limited, IV value: 0.64), RAMAPET S1 (manufactured by Indorama Ventures, IV value: 0.84), and UK-31 (manufactured by Utsumi Recycle Systems Co., Ltd., IV value: 0.67).

[0031] The content of low-IV PET is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and 100% by mass or less, of the total amount of PET subjected to polycondensation.

[0032] The content of PET is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, and preferably 75 mol% or less, more preferably 70 mol% or less, still more preferably 60 mol% or less, still more preferably 50 mol% or less, from the viewpoint of charge stability under high temperature and high humidity, in the total amount of the alcohol component, the carboxylic acid component and PET. Since PET is an equimolar polycondensate of ethylene glycol and terephthalic acid, dimethyl terephthalate, etc., it is converted with 1 mol of the unit of terephthalic acid-ethylene glycol (Mw: 192). Therefore, the number of moles of PET = the number of moles of ethylene glycol units = the number of moles of terephthalic acid units. When the amorphous polyester resin A is composed of two or more resins, the weighted average value of the PET content of each resin is taken as the PET content of the amorphous polyester resin A.

[0033] The equivalent ratio (COOH group / OH group) of the carboxylic acid component (including the terephthalic acid unit in PET) to the alcohol component (including the ethylene glycol unit in PET) is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0034] The amorphous polyester resin A is preferably a polycondensate obtained by reacting an alcohol component, a carboxylic acid component and PET in the presence of an esterification catalyst. For example, in an inert gas atmosphere, the alcohol component, the carboxylic acid component and PET are reacted in the presence of an esterification catalyst, and further, if necessary, in the presence of a cocatalyst, a polymerization inhibitor, etc., preferably at 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower, and can be produced by polycondensation at this temperature.

[0035] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolaminato) and titanium dihydroxybis(triethanolaminato).

[0036] The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component, the carboxylic acid component, and PET.

[0037] Examples of the cocatalyst for the esterification catalyst include gallic acid. The amount of the cocatalyst used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component, the carboxylic acid component, and PET. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component, the carboxylic acid component, and PET.

[0038] In the present invention, the polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, a urethane-modified polyester resin obtained by extending the polyester resin with a polyisocyanate compound is preferred.

[0039] From the viewpoint of hot offset resistance, the softening point of the amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher, and preferably 170°C or lower, more preferably 160°C or lower, still more preferably 150°C or lower.

[0040] From the viewpoint of hot offset resistance, the glass transition temperature of the amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, and preferably 80°C or lower, more preferably 70°C or lower.

[0041] The acid value of amorphous polyester resin A is preferably 1 mg KOH / g or more, more preferably 3 mg KOH / g or more, and more preferably 25 mg KOH / g or less, and more preferably 20 mg KOH / g or less, from the viewpoint of low-temperature fixability and storage properties.

[0042] The content of amorphous polyester resin A in the binder resin is preferably 25% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less.

[0043] Other binder resins include amorphous polyester resins, crystalline polyester resins, vinyl resins such as styrene-acrylic resins, polyamide resins, epoxy resins, polycarbonate resins, polyurethane resins, and composite resins containing two or more of these resins, which are polycondensates of alcohols and carboxylic acid components that do not use PET. Among these, crystalline polyester resins are preferred from the viewpoint of low-temperature fixation.

[0044] The PET content in the binder resin is preferably 2 mol% or more, more preferably 7 mol% or more, even more preferably 12 mol% or more, and preferably 75 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less. If the binder resin consists of two or more resins, the weighted average value of the PET content of each resin is used as the PET content in the binder resin, and the PET content of each resin is the content in the total amount of alcohol component, carboxylic acid component, and PET.

[0045] Furthermore, the binder resin preferably contains two resins with different softening points, from the viewpoint of low-temperature fixability and fixation width. The difference in softening points between the two resins is preferably 10°C or more, more preferably 20°C or more, and preferably 60°C or less, more preferably 40°C or less.

[0046] The softening point of the resin with the higher softening point (resin AH) is preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, and preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, from the viewpoint of resistance to hot offset.

[0047] Furthermore, the softening point of the resin with the lower softening point (resin AL) is preferably 70°C or higher, more preferably 90°C or higher, even more preferably 100°C or higher, and preferably 130°C or lower, more preferably 125°C or lower, and even more preferably 120°C or lower, from the viewpoint of resistance to hot offset.

[0048] The binder resin preferably contains two types of resin AH and resin AL, which have softening points that differ by 10°C or more, and at least one of the two types of resin is amorphous polyester resin A. Either resin AH or resin AL may be amorphous polyester resin A, or both may be amorphous polyester resin A. If either one is amorphous polyester resin A, the other resin is preferably amorphous polyester resin B, which is a polycondensate of alcohol and a carboxylic acid component that does not use PET, and when the binder resin consists of amorphous polyester resin A and amorphous polyester resin B, it is preferable that the weighted average value of the PET content of each resin is within the range of the PET content.

[0049] The mass ratio of resin AH to resin AL (resin AH / resin AL) is preferably 10 / 90 or more, more preferably 20 / 80 or more, even more preferably 30 / 70 or more, and preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 70 / 30 or less.

[0050] The binder resin content in the toner is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and preferably 99% by mass or less, more preferably 97% by mass or less, and even more preferably 95% by mass or less.

[0051] Naphthol AS pigments contain the following compound in their molecules:

[0052]

[0053] This is a pigment having a naphthol AS structure represented by [the formula shown].

[0054] Examples of naphthol AS-based pigments include C.I. Pigment Red 2, 5, 9, 17, 21, 22, 31, 112, 114, 146, 147, 170, 176, 184, 185, 208, 238, and 269. Two or more of these may be used, but among them, C.I. Pigment Red 269 is preferred from the viewpoint of electrostatic stability under high temperature and high humidity conditions.

[0055] The content of naphthol AS-based pigment is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 4 parts by mass or more, per 100 parts by mass of binder resin, and from the viewpoint of low-temperature fixation, preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 12 parts by mass or less.

[0056] The toner of the present invention may contain colorants other than the naphthol AS pigment, to the extent that it does not impair the effects of the present invention. However, the content of the naphthol AS pigment is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, and 100% by mass or less, in the colorant. Other colorants include carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, and the like.

[0057] In addition to the binder resin (binding agent) and colorant, the toner of the present invention may contain additives such as a mold release agent, charge control agent, magnetic powder, flowability improver, conductivity modifier, reinforcing filler such as fibrous material, antioxidant, and cleaning performance improver.

[0058] Examples of mold release agents include hydrocarbon waxes and their oxides, such as polypropylene wax, polyethylene wax, ethylene propylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; ester waxes such as carnauba wax, montane wax and their deoxidizing waxes, and fatty acid ester waxes; and fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These can be used individually or in combination of two or more.

[0059] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of toner transferability, and preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of low-temperature fixation.

[0060] The release agent content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less, from the viewpoint of low-temperature fixing performance and hot offset resistance of the toner, as well as dispersibility in the binder resin, per 100 parts by mass of the binder resin.

[0061] The charge control agent is not particularly limited and may contain either a positively charged charge control agent or a negatively charged charge control agent.

[0062] Positively charged charge control agents include nigrosine dyes, such as "Nigrosine Base EX," "Oil Black BS," "Oil Black SO," "Bontron N-01," "Bontron N-04," "Bontron N-07," "Bontron N-09," "Bontron N-11," and "Bontron N-79" (all manufactured by Orient Chemical Industries, Ltd.); triphenylmethane-based dyes containing a tertiary amine as a side chain; and quaternary ammonium salt compounds, such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX." Examples include VP435 (manufactured by Clariant), polyamine resins such as AFP-B (manufactured by Orient Chemical Industries, Ltd.), imidazole derivatives such as PLZ-2001 and PLZ-8001 (both manufactured by Shikoku Chemicals, Ltd.), and styrene-acrylic resins such as FCA-701PT and FCA-201-PS (manufactured by Fujikura Chemicals, Ltd.).

[0063] Furthermore, negative charge control agents include polymer types such as "FCA-2521NJ" (manufactured by Fujikura Chemical Co., Ltd.); metal-containing azo dyes such as "Barifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Eisenspiron Black TRH", "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); and benzyl Examples include metal compounds of salicylic acid compounds, such as "LR-147" and "LR-297" (both manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, such as "Bontron E-81," "Bontron E-84," "Bontron E-88," and "Bontron E-304" (all manufactured by Orient Chemical Industries, Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; quaternary ammonium salts, such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, etc.; and organometallic compounds.

[0064] From the viewpoint of the charge control agent content, the content is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, per 100 parts by mass of binder resin.

[0065] The toner of the present invention may be obtained by any of the conventionally known methods, such as the melt-kneading method, the emulsification-coagulation method, the suspension polymerization method, or the dissolution-suspension method, and may also be a toner having a core-shell structure. However, from the viewpoint of the miscibility of the toner raw materials, it is preferable to manufacture it by a method that includes at least a step of melt-kneading a binder resin and a colorant (melt-kneading step), and a step of grinding the kneaded product obtained in the step (grinding step).

[0066] In the melt-mixing process, it is preferable to pre-mix the raw materials containing the binder resin and colorant to be melt-mixed using a Henschel mixer or the like before melt-mixing.

[0067] Melt mixing can be carried out using known mixing machines such as closed-type kneaders, single-screw or twin-screw extruders, and open-roll type mixers.

[0068] After the melt-mixing process, the resulting mixture is cooled to a suitable hardness for pulverization and then subjected to the subsequent pulverization process. Here, cooling refers to cooling the mixture to 0°C to 50°C, or to a temperature below the glass transition temperature of the binder resin in the mixture.

[0069] The crushing process is the process of crushing the mixture obtained in the melt-kneading process.

[0070] In the grinding process, the kneaded material may be ground all at once to the desired particle size, or it may be ground in stages. However, from the viewpoint of efficient and more uniform grinding, it is preferable to perform the grinding in two stages: coarse grinding and fine grinding.

[0071] Examples of grinders used for coarse grinding include hammer mills, cutter mills, atomizers, and Rotoplexes.

[0072] Examples of grinders used for fine grinding include counter-jet mills, fluidized bed jet mills, impact plate jet mills, and other types of jet mills, as well as mechanical mills.

[0073] The degree of fine grinding is preferably adjusted as appropriate according to the desired toner particle size.

[0074] After the crushing process, a classification process is performed as needed.

[0075] Classifiers used for classification include air-flow classifiers, inertia classifiers, and sieve classifiers. During the classification process, any pulverized material that is removed due to insufficient pulverization may be subjected to the pulverization process again, and the pulverization and classification processes may be repeated as needed.

[0076] In the toner of the present invention, it is preferable to use an external additive to improve fluidity. Examples of external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more may be used in combination. Among these, silica is preferred, and from the viewpoint of toner fluidity, hydrophobic silica that has been hydrophobicized is more preferred.

[0077] Examples of hydrophobic agents for hydrophobicizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0078] The average particle size of the external additive is preferably 10 nm or larger, more preferably 250 nm or smaller, more preferably 200 nm or smaller, and even more preferably 90 nm or smaller, from the viewpoint of the toner's chargeability, fluidity, and transferability.

[0079] External additive treatment, which involves mixing toner particles with external additives, can be carried out according to conventional methods, and a mixer such as a Henschel mixer can be used.

[0080] From the viewpoint of the toner's electrostatic properties, fluidity, and transferability, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and preferably 5 parts by mass or less, and more preferably 4 parts by mass or less, per 100 parts by mass of toner particles before treatment with the external additive.

[0081] The volume-intermediate particle size (D) of the toner of the present invention ５０ The volume median particle size (D) is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. ５０ ) refers to the particle size at which the cumulative volume frequency, calculated using volume fractions, accounts for 50% when calculated from the smallest particle size. Furthermore, if the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is taken as the volume median particle size of the toner.

[0082] The toner of the present invention can be used as is as a one-component developing toner, or as a two-component developing toner used in combination with a carrier, in image forming apparatuses using either a one-component developing method or a two-component developing method, respectively.

[0083] With respect to the embodiments described above, the present invention further discloses the following electrostatic image developing toner and a method for manufacturing the electrostatic image developing toner.

[0084] <1> A toner for developing electrostatic images, comprising a binder resin containing an amorphous polyester resin A and a colorant, wherein the amorphous polyester resin A is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, and the colorant contains a naphthol AS-based pigment.

[0085] <2> The electrostatic image developing toner according to <1>, wherein the alcohol component contains an alkylene oxide adduct of bisphenol A represented by formula (I). <3> The electrostatic image developing toner according to <2>, wherein the content of the alkylene oxide adduct of bisphenol A represented by formula (I) is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, in the alcohol component. <4> The electrostatic image developing toner according to any one of <1> to <3>, wherein the carboxylic acid component contains an aromatic dicarboxylic acid compound. <5> The electrostatic image developing toner according to <4>, wherein the content of the aromatic dicarboxylic acid compound is 20 mol% or more, preferably 35 mol% or more, more preferably 45 mol% or more, even more preferably 55 mol% or more, and 100 mol% or less, in the carboxylic acid component, preferably 90 mol% or less, and more preferably 85 mol% or less, in the case where the carboxylic acid component contains a trivalent or higher carboxylic acid compound. <6> A toner for developing electrostatic images according to any one of <1> to <5> above, wherein the IV value of polyethylene terephthalate is 0.40 or higher, preferably 0.45 or higher, more preferably 0.50 or higher, even more preferably 0.55 or higher, and 0.85 or lower, preferably 0.80 or lower, more preferably 0.75 or lower, even more preferably 0.70 or lower, and even more preferably 0.65 or lower. <7> A toner for developing electrostatic images according to any one of <1> to <6> above, wherein the content of polyethylene terephthalate having an IV value of 0.40 or higher, preferably 0.45 or higher, more preferably 0.50 or higher, even more preferably 0.55 or higher, and 0.85 or lower, preferably 0.80 or lower, more preferably 0.75 or lower, even more preferably 0.70 or lower, and even more preferably 0.65 or lower is 90% by mass or more, preferably 95% by mass or more, more preferably 98% by mass or more, and 100% by mass or less, of the total amount of polyethylene terephthalate subjected to polycondensation.<8> The electrostatic image developing toner according to any one of <1> to <7> above, wherein the polyethylene terephthalate content is 5 mol% or more, preferably 10 mol% or more, more preferably 20 mol% or more, and 75 mol% or less, preferably 70 mol% or less, more preferably 60 mol% or less, and even more preferably 50 mol% or less, based on 1 mole of terephthalate-ethylene glycol units, in the total amount of alcohol component, carboxylic acid component, and polyethylene terephthalate. <9> The electrostatic image developing toner according to any one of <1> to <8> above, wherein the softening point of amorphous polyester resin A is 70°C or higher, preferably 90°C or higher, more preferably 100°C or higher, and 170°C or lower, preferably 160°C or lower, and more preferably 150°C or lower. <10> The electrostatic image developing toner according to any one of <1> to <9> above, wherein the content of amorphous polyester resin A in the binder resin is 25% by mass or more, preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less. <11> The electrostatic image developing toner according to any one of <1> to <10> above, wherein the content of polyethylene terephthalate in the binder resin is 2 mol% or more, preferably 7 mol% or more, more preferably 12 mol% or more, and 75 mol% or less, preferably 70 mol% or less, and even more preferably 65 mol% or less. <12> The electrostatic image developing toner according to any one of <1> to <11> above, wherein the binder resin contains two resins with different softening points, at least one of the two resins is amorphous polyester resin A, and the difference in softening points of the two resins is 10°C or more, preferably 20°C or more, and 60°C or less, and preferably 40°C or less. <13> The electrostatic image developing toner according to <12> above, wherein the softening point of the resin with the higher softening point is 100°C or more, preferably 110°C or more, more preferably 120°C or more, and 170°C or less, preferably 160°C or less, and more preferably 150°C or less.<14> The electrostatic image developing toner according to <12> or <13>, wherein the softening point of the resin with the lower softening point is 70°C or higher, preferably 90°C or higher, more preferably 100°C or higher, and 130°C or lower, preferably 125°C or lower, and more preferably 120°C or lower. <15> The electrostatic image developing toner according to any one of <12> to <14>, wherein the mass ratio of the resin with the higher softening point to the resin with the lower softening point is 10 / 90 or higher, preferably 20 / 80 or higher, more preferably 30 / 70 or higher, and 90 / 10 or lower, preferably 80 / 20 or lower, and more preferably 70 / 30 or lower. <16> A toner for developing electrostatic images according to any one of <1> to <15>, wherein the content of the binder resin in the toner is 60% by mass or more, preferably 80% by mass or more, more preferably 85% by mass or more, and 99% by mass or less, preferably 97% by mass or less, and more preferably 95% by mass or less. <17> A toner for developing electrostatic images according to any one of <1> to <16>, wherein the naphthol AS pigment is at least one selected from the group consisting of C.I. Pigment Red 2, 5, 9, 17, 21, 22, 31, 112, 114, 146, 147, 170, 176, 184, 185, 208, 238, and 269, preferably C.I. Pigment Red 269. <18> The electrostatic image developing toner according to any one of <1> to <17> above, wherein the content of naphthol AS pigment is 1 part by mass or more, preferably 3 parts by mass or more, more preferably 4 parts by mass or more, and 20 parts by mass or less, preferably 15 parts by mass or less, and more preferably 12 parts by mass or less, per 100 parts by mass of binder resin. <19> The electrostatic image developing toner according to any one of <1> to <18> above, wherein the content of naphthol AS pigment is 60% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less, in the colorant. <20> A method for producing an electrostatic image developing toner according to any one of <1> to <19> above, comprising the steps of melting and kneading at least a binder resin and a colorant, and pulverizing the kneaded product obtained in the step.

[0086] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. The physical properties of resins, etc., can be measured by the following methods.

[0087] [IV value of PET] Dissolve 4 g / L in a mixed solvent of phenol / tetrachloroethane in a 60 / 40 (mass ratio) solution, measure with an Ubbelohde viscometer, and calculate from the following formula: IV = (-1 + √(1 + 4kη)) / (2kC) [wherein k = 0.33, C = 0.004 g / mL, and η = (t １ / t ０ ) - 1 (t ０ : Number of seconds for the solvent to fall, t １ This is the number of seconds it takes for the sample solution to fall.

[0088] [Amine value of ketimine compounds] Measured according to the method of JIS K2501:2003. However, the measurement solvent is changed from chlorobenzene to chloroform as specified in JIS K2501:2003.

[0089] [Resin Softening Point] Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample is heated at a heating rate of 6°C / min while a load of 1.96 MPa is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is defined as the softening point.

[0090] [Maximum Endothermic Peak Temperature of Resin] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan and cooled from room temperature (25°C) to 0°C at a rate of 10°C / min, and maintained at 0°C for 1 minute. Then, measurements are taken at a rate of 10°C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature. For crystalline resins, the maximum endothermic peak temperature is defined as the melting point.

[0091] [Glass Transition Temperature of Resins] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C, and then cooled to -50°C at a rate of 10°C / min. Next, the sample is heated at a rate of 10°C / min and the endothermic peak is measured. The temperature at the intersection of the baseline extension line below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the peak apex is defined as the glass transition temperature.

[0092] [Acid Value of Resins] The acid value of resins shall be measured according to the method of JIS K 0070:1992. However, the measurement solvent shall be changed from the ethanol and ether mixed solvent specified in JIS K 0070 to an acetone and toluene mixed solvent (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a chloroform and dimethylformamide mixed solvent (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0093] [Melting point of release agent] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. Next, the sample is heated at a rate of 10°C / min, the amount of heat is measured, and the maximum endothermic peak temperature is defined as the melting point.

[0094] [Volume median particle size and CV value of resin particles, colorant particles, mold release agent particles, and polymer dispersants] (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: Take the sample dispersion liquid into the measuring cell, add distilled water, and measure the volume median particle size (D) at a temperature where the absorbance is within the appropriate range. ５０ The standard deviation of particle size distribution and the volume-average particle size are measured. The CV value is calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution / volume-average particle size) × 100

[0095] [Solid Content Concentrations of Resin Dispersion, Colorant Dispersion, and Release Agent Dispersion] Using an infrared moisture meter "FD-230" (manufactured by Kett Scientific Laboratories Co., Ltd.), 5 g of the measurement sample is dried under the conditions of a drying temperature of 150°C and a measurement mode of 96 (monitoring time: 2.5 minutes, fluctuation range: 0.05%) to measure the moisture content (mass %) of the dispersion. The solid content concentration is calculated according to the following formula. Solid content concentration (mass %) = 100 - moisture content (mass %)

[0096] [Volume Median Particle Size of Aggregated Particles] - Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) - Aperture diameter: 50 μm - Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.) - Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) - Measurement conditions: After adding the sample dispersion to 100 mL of the electrolyte and adjusting the concentration to a level where the particle sizes of 30,000 particles can be measured in 20 seconds, 30,000 particles are measured, and the volume median particle size (D ５０ ) is determined from the particle size distribution.

[0097] [Volume Median Particle Size (D ５０ ) of Toner] - Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) - Aperture diameter: 50 μm - Analysis software: "Multisizer (registered trademark) III version 3.51" (manufactured by Beckman Coulter, Inc.) - Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) - Dispersion: A solution prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to a concentration of 5 mass % - Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the above dispersion, disperse it for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W), then add 25 mL of the electrolyte, and further disperse it for 1 minute using the ultrasonic disperser to prepare a sample dispersion. - Measurement conditions: After adding the sample dispersion to 100 mL of the electrolyte and adjusting the concentration to a level where the particle sizes of 30,000 particles can be measured in 20 seconds, 30,000 particles are measured, and the volume median particle size (D ５０ ) is determined from the particle size distribution.

[0098] [Toner Circularity] The circularity of toner particles is measured under the following conditions: • Measuring device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) • Dispersion preparation: The toner particle dispersion is prepared by diluting it with deionized water to a solid content concentration of 0.001 to 0.05% by mass. • Measurement mode: HPF measurement mode

[0099] [Average particle size of external additives] The average particle size refers to the number-average particle size. This is determined by measuring the particle size (average value of major and minor axes) of 500 particles (primary particles) from scanning electron microscope (SEM) images and using the number-average value of these measurements.

[0100] Resin Production Example 1 The alcohol component, carboxylic acid component other than trimellitic anhydride, PET, esterification catalyst, and co-catalyst shown in Tables 1 and 2 were placed in a 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 210°C, trimellitic anhydride shown in Tables 1 and 2 was added, and the mixture was reacted at 210°C for 1 hour. The reaction was then carried out at 210°C under reduced pressure of 10 kPa until the softening point shown in Tables 1 and 2 was reached to obtain amorphous polyester resins (resins AH1 to AH5, AH8, AH10 to AH13). The physical properties are shown in Tables 1 and 2.

[0101] Resin Production Example 2: The alcohol component, carboxylic acid component, PET, esterification catalyst, and co-catalyst shown in Tables 1 and 3 were placed in a 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. The mixture was held at 180°C for 1 hour under a nitrogen atmosphere, then the temperature was increased from 180°C to 235°C at a rate of 10°C / h, and polycondensation was carried out at 235°C for 5 hours. After that, the temperature was lowered to 210°C and the reaction was carried out under reduced pressure of 10 kPa until the softening point shown in Tables 1 and 3 was reached to obtain amorphous polyester resins (resins AH6, AH7, resins AL6, AL7). The physical properties are shown in Tables 1 and 3.

[0102] Resin Production Example 3 As shown in Table 2, the alcohol component, carboxylic acid components other than trimellitic anhydride and fumaric acid, PET, esterification catalyst, and co-catalyst were placed in a 10-liter four-necked flask equipped with a drop-flow condenser with a nitrogen inlet tube and dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 180°C, and trimellitic anhydride, fumaric acid, and polymerization inhibitor as shown in Table 2 were added. The mixture was reacted at 180°C for 1 hour, then the temperature was raised from 180°C to 210°C at 10°C / h, and polycondensation was further carried out at 210°C for 1 hour. After that, the reaction was carried out at 210°C under reduced pressure of 10 kPa until the softening point shown in Table 2 was reached to obtain amorphous polyester resin (resin AH9). The physical properties are shown in Table 2.

[0103] Resin Production Example 4: The alcohol component, carboxylic acid component other than trimellitic anhydride, esterification catalyst, and co-catalyst shown in Table 2 were placed in a 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 210°C, trimellitic anhydride shown in Table 2 was added, and the mixture was reacted at 210°C for 1 hour. The reaction was then carried out at 210°C under reduced pressure of 10 kPa until the softening point shown in Table 2 was reached, yielding an amorphous polyester resin (resin AH14). The physical properties are shown in Table 2.

[0104] Resin Production Example 5 As shown in Table 2, the alcohol component, carboxylic acid component other than trimellitic anhydride, esterification catalyst, and co-catalyst were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydration tube fitted with a fractionation tube through which 98°C hot water was passed, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the mixture was held at 180°C for 1 hour, then the temperature was increased from 180°C to 235°C at a rate of 10°C / h, and then polycondensation was carried out at 235°C for 5 hours. After that, the temperature was lowered to 210°C, trimellitic anhydride as shown in Table 2 was added, and the reaction was carried out at 210°C for 1 hour. Then, the reaction was carried out at 210°C under reduced pressure of 10 kPa until the softening point shown in Table 2 was reached to obtain amorphous polyester resin (resin AH15). The physical properties are shown in Table 2.

[0105] Resin Production Example 6: The alcohol component, carboxylic acid component, PET, esterification catalyst, and co-catalyst shown in Tables 3 and 4 were placed in a 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 210°C, and the reaction was carried out under reduced pressure of 10 kPa until the softening point shown in Tables 3 and 4 was reached to obtain amorphous polyester resins (resins AL1 to AL5, AL8, AL10 to AL13). The physical properties are shown in Tables 3 and 4.

[0106] Resin Production Example 7 As shown in Table 4, the alcohol component, carboxylic acid component other than fumaric acid, PET, esterification catalyst, and co-catalyst were placed in a 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 180°C, and the fumaric acid and polymerization inhibitor shown in Table 4 were added. The mixture was reacted at 180°C for 1 hour, then the temperature was raised from 180°C to 210°C at 10°C / h, and polycondensation was further carried out at 210°C for 1 hour. After that, the reaction was carried out at 210°C under reduced pressure of 10 kPa until the softening point shown in Table 4 was reached to obtain amorphous polyester resin (resin AL9). The physical properties are shown in Table 4.

[0107] Resin Production Example 8: The alcohol component, carboxylic acid component, esterification catalyst, and co-catalyst shown in Table 4 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a fall-flow condenser with a dehydration tube, a stirrer, and a thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 210°C, and the reaction was carried out under reduced pressure of 10 kPa until the softening point shown in Table 4 was reached to obtain amorphous polyester resin (resin AL14). The physical properties are shown in Table 4.

[0108] Resin Production Example 9: The alcohol component, carboxylic acid component, esterification catalyst, and co-catalyst shown in Table 4 were placed in a 10-liter four-necked flask equipped with a nitrogen inlet tube, a dehydration tube fitted with a fractionation tube through which 98°C hot water was passed, a stirrer, and a thermocouple. The mixture was held at 180°C for 1 hour under a nitrogen atmosphere, then the temperature was increased from 180°C to 235°C at a rate of 10°C / h, and then polycondensation was carried out at 235°C for 5 hours. Furthermore, the reaction was carried out at 235°C under reduced pressure of 10 kPa until the softening point shown in Table 4 was reached to obtain an amorphous polyester resin (resin AL15). The physical properties are shown in Table 4.

[0109]

[0110]

[0111]

[0112]

[0113] Resin Production Example 10 A 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple was placed in a flask. 3288 g of 1,6-hexanediol and 5712 g of sebacic acid were added and heated to 140°C for 6 hours. The reaction was then continued while increasing the temperature to 200°C at a rate of 10°C / h. After reacting at 200°C for 1 hour, 18 g of tin(II) 2-ethylhexanoate was added as an esterification catalyst, and the reaction was continued at 200°C for another 2 hours. The reaction was further carried out at 8 kPa for another 2 hours to obtain a crystalline polyester resin (resin C1). The softening point of resin C1 was 81°C, the melting point was 69°C, and the crystallinity index was 1.2.

[0114] Preparation Example of Ketimine Compound: 170 parts by mass of isophorone diamine and 75 parts by mass of methyl ethyl ketone were charged into a 1-liter four-necked separable flask equipped with a stirrer and thermometer, and the reaction was carried out at 50°C for 5 hours to obtain ketimine compound K1. The amine value of ketimine compound K1 was 418 mgKOH / g.

[0115] Resin Production Example 11 A 10-liter four-necked flask equipped with a drop-flow condenser having a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple was filled with 2954 g of 3-methyl-1,5-pentanediol, 1697 g of isophthalic acid, and 1825 g of adipic acid. After heating to 100°C, 97 g of trimethylolpropane and 6.6 g of titanium tetraisopropoxide as an esterification catalyst were added. Next, the temperature was raised to 200°C in about 4 hours, then to 230°C in 2 hours, and polycondensation was carried out at 230°C for 6 hours. Furthermore, the reaction was carried out under reduced pressure of 8 kPa for 7 hours to obtain a polyester resin having hydroxyl groups. Next, 410 parts by mass of polyester resin having hydroxyl groups, 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate were placed in a 3-liter four-necked flask equipped with a nitrogen inlet tube, a fall-flow condenser, a stirrer, and a thermocouple, and the mixture was reacted at 100°C for 5 hours to obtain polyester resin b1 having isocyanate groups.

[0116] A 50% by mass ethyl acetate solution of the obtained polyester resin b1 having isocyanate groups is placed in a 3-liter four-necked flask equipped with a nitrogen inlet tube, a fall-flow condenser, a stirrer, and a thermocouple, and while stirring, the equivalent ratio of isocyanate groups to amino groups (NCO groups / NH) is calculated. ２ Ketimine compound K1 was added dropwise until the ratio of the base was 1.0. After stirring at 45°C for 10 hours, the mixture was dried under reduced pressure of 10 kPa at 50°C until the ethyl acetate content was 100 ppm or less, to obtain polyester resin B1. The glass transition temperature of resin B1 was -40°C.

[0117] Examples 1, 4-15, 18, Comparative Examples 1, 2 [Melting and Kneading Method] 100 parts by mass of the binder resin shown in Table 5, 7 parts by mass of the coloring agent "Permanent Carmine 3810" (manufactured by Sanyo Shikiso Co., Ltd., naphthol AS-based pigment, C.I. Pigment Red 269 (PR269)), 3 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), and 0.5 parts by mass of the charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.) were mixed in a Henschel mixer.

[0118] The obtained mixture was melt-kneaded using a co-rotating twin-screw extruder with a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm, at a screw rotation speed of 200 r / min and a barrel set temperature of 100°C to obtain a kneaded product. The mixture was fed at a rate of 20 kg / h, and the average residence time was approximately 18 seconds.

[0119] The resulting mixture is cooled and coarsely ground, then ground in a jet mill, and classified using an air-flow classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain the medium volume particle size (D ５０ This yielded toner particles with a diameter of 7.0 μm.

[0120] 100 parts by mass of the obtained toner particles, along with 1 part by mass of "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 2 parts by mass of "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) as external additives, were mixed in a Henschel mixer at a rotation speed of 3000 r / min (peripheral speed 32 m / sec) for 3 minutes to obtain magenta toner.

[0121] Example 2 A magenta toner was obtained in the same manner as in Example 1, except that 7 parts by mass of "PERMANENT CARMINE FBB02" (manufactured by Heubach, naphthol AS-based pigment, C.I. Pigment Red 146 (PR146)) was used as a coloring agent instead of "Permanent Carmine 3810".

[0122] Example 3 A magenta toner was obtained in the same manner as in Example 1, except that 7 parts by mass of "PERMANENT RUBINE F6B" (manufactured by Heubach, naphthol AS-based pigment, C.I. Pigment Red 184 (PR184)) was used as a coloring agent instead of "Permanent Carmine 3810".

[0123] Example 16 Magenta toner was obtained in the same manner as in Example 1, except that a continuous two-roll open-roll mixer "Nidex" (manufactured by Nippon Coke Industries Co., Ltd.) was used instead of a co-rotating twin-screw extruder during melt-mixing. The continuous two-roll open-roll mixer had a roll outer diameter of 0.14 m and an effective roll length of 0.8 m. The operating conditions were a rotation speed of 75 r / min (peripheral speed 33 m / min) for the high-speed roll (front roll), a rotation speed of 50 r / min (peripheral speed 22 m / min) for the low-speed roll (rear roll), and a roll gap of 0.1 mm. The heating and cooling media temperatures inside the rolls were set to 140°C on the raw material input side and 110°C on the mixed material discharge side of the high-speed roll, and to 65°C on the raw material input side and 30°C on the mixed material discharge side of the low-speed roll. The raw material mixture supply rate was 10 kg / h, and the average residence time was approximately 5 minutes.

[0124] Example 17 [Emulsification and Coagulation Method] <Preparation of Core Resin Dispersion> 600 g of methyl ethyl ketone was placed in a 5-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube. 150 g of resin AH1 was added at 60°C and dissolved. To the obtained solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a neutralization degree of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes to obtain a mixture. Subsequently, 675 g of deionized water was added over 77 minutes. Then, while stirring at 250 r / min under reduced pressure, the methyl ethyl ketone and some of the water were distilled off at a temperature of 50°C or lower. The solid content concentration of the aqueous dispersion was measured, and the solid content concentration of the aqueous dispersion was adjusted to 20% by mass with deionized water to obtain the core resin dispersion. Volume median particle size (D) of resin particles in the dispersion. ５０ The wavelength was 200 nm, and the CV value was 24%.

[0125] <Preparation of resin dispersion for shells> 600 g of methyl ethyl ketone was placed in a 5-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube. 150 g of resin AL1 was added at 60°C and dissolved. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a neutralization degree of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes to obtain a mixture. Subsequently, 675 g of deionized water was added over 77 minutes. Then, while stirring at 250 r / min under reduced pressure, the methyl ethyl ketone and some of the water were distilled off at a temperature of 50°C or lower. The solid content concentration of the aqueous dispersion was then measured, and the solid content concentration of the aqueous dispersion was adjusted to 20% by mass with deionized water to obtain the resin dispersion for shells. The median particle size (D) of the resin particles in the dispersion was measured. ５０ The wavelength was 110 nm, and the CV value was 20%.

[0126] <Preparation of Colorant Dispersion> In a 1-liter beaker, 116.2 g of "Permanent Carmine 3810" (manufactured by Sanyo Shikkei Co., Ltd., naphthol AS-based pigment, PR269), 154.9 g of the anionic surfactant "Neoperex® G-15" (manufactured by Kao Corporation, 15% by mass sodium dodecylbenzenesulfonate aqueous solution), and 260 g of deionized water were mixed and dispersed at room temperature for 3 hours using a homogenizer. Then, deionized water was added to obtain a colorant dispersion to a solid content concentration of 24% by mass. The median particle size (D) of the colorant particles in the dispersion was measured. ５０ The wavelength was 128 nm, and the CV value was 28%.

[0127] <Preparation of Release Agent Dispersion> 50 g of Fischer-Tropsch wax (manufactured by Nippon Seiro Co., Ltd., trade name: FNP0090, melting point: 90°C), 5 g of cationic surfactant (manufactured by Kao Corporation, trade name: Sanizol B50), and 200 g of deionized water were heated to 95°C. The wax was dispersed using a homogenizer, then dispersed again using a pressure-discharge homogenizer, and deionized water was added to obtain a release agent dispersion with a solid content of 20% by mass. The median particle size (D) of the release agent particles in the dispersion was measured. ５０ The wavelength was 550 nm, and the CV value was 26%.

[0128] <Preparation of Toner Particles> In a 3-liter four-necked flask equipped with a reflux condenser, a stirrer, and a thermocouple, 500 g of the core resin dispersion, 58 g of the coloring agent dispersion, 33 g of the mold release agent dispersion, and 3.3 g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant) were mixed at a temperature of 25°C. Next, while stirring the resulting mixture at 25°C, a solution prepared by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8% by mass potassium hydroxide aqueous solution to adjust the pH to 8.2 was added dropwise over 10 minutes, and the temperature was raised to 62°C over 2 hours to determine the volume median particle size (D) of the aggregated particles. ５０ The mixture was maintained at 62°C until it reached a size of 6.9 μm, and a dispersion of aggregated particles (I) was obtained.

[0129] While maintaining the temperature of the dispersion of the obtained aggregated particles (I) at 62°C, 500 g of the shell resin dispersion was added dropwise at a rate of 0.6 mL / min (0.6 g / min) to obtain a dispersion of aggregated particles (II). The median volume particle size (D) of the aggregated particles (II) ５０ The diameter was 7.0 μm.

[0130] To the dispersion of the obtained aggregated particles (II), an aqueous solution was added, which consisted of 20 g of polyoxyethylene lauryl ether sodium sulfate "Emal® E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 280 g of deionized water, and 40 g of 0.1 mol / L sulfuric acid aqueous solution. The mixture was then heated to 80°C over 1 hour, held at 80°C for 30 minutes, and then 10 g of 0.1 mol / L sulfuric acid aqueous solution was added, followed by a further 15 g of 0.1 mol / L sulfuric acid aqueous solution. The mixture was then held at 80°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles (core-shell particles) in which the aggregated particles had fused together.

[0131] The obtained core-shell particle dispersion was cooled to 30°C, and the dispersion was filtered by suction to separate the solid components. The dispersion was then washed with deionized water at 25°C and filtered by suction at 25°C for 2 hours. Subsequently, toner particles were obtained by vacuum drying at 33°C for 24 hours using a vacuum constant-temperature dryer "DRV622DA" (manufactured by ADVANTEC). The median volume particle size (D) of the obtained toner particles was determined.５０ The particle size was 7.0 μm, and the circularity was 0.970. The composition ratio (mass ratio) of the binder resin of the obtained toner particles was resin AH1 / resin AL1 = 50 / 50.

[0132] 100 parts by mass of the obtained toner particles, along with 1 part by mass of "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 2 parts by mass of "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) as external additives, were mixed in a Henschel mixer at a rotation speed of 3000 r / min (peripheral speed 32 m / sec) for 3 minutes to obtain magenta toner.

[0133] Example 19 A magenta toner was obtained in the same manner as in Example 1, except that instead of 50 parts by mass of resin AH1 and 50 parts by mass of resin AL1, 45 parts by mass of resin AH1, 45 parts by mass of resin AL1, and 10 parts by mass of resin C1 were used as the binder resin.

[0134] Example 20 [Dissolution and Suspension Method] <Preparation of Crystalline Polyester Resin Dispersion> 100 g of resin C1 and 400 g of ethyl acetate were placed in a 2-liter metal container and heated to 75°C to dissolve. After that, it was rapidly cooled in an ice bath at a rate of 27°C / min. Glass beads with a diameter of 3 mm were added to achieve a volume filling rate of 60 vol%, and the mixture was ground for 4 hours at a rotation speed of 1300 r / min (peripheral speed of 4.8 m / sec) using a 6-cylinder sand mill "TSG-6" (manufactured by AIMEX Co., Ltd.). The glass beads were removed using a mesh to obtain a crystalline polyester resin dispersion with a solid content concentration of 20% by mass.

[0135] <Preparation of Oil Phase I> 150 parts by mass of the release agent dispersion prepared in Example 17, 150 parts by mass of polyester resin B1, 500 parts by mass of crystalline polyester resin dispersion, 375 parts by mass of resin AH1, 375 parts by mass of resin AL1, and 2 parts by mass of ketimine compound K1 were placed in a container and mixed at 5,000 r / min for 60 minutes using a "TK Homo Mixer" (manufactured by Primix Co., Ltd.) to obtain Oil Phase I.

[0136] <Preparation of Aqueous Phase II> In a flask equipped with a stirrer and thermometer, 683 parts by mass of water, 11 parts by mass of "Eleminol RS-3000" (manufactured by Sanyo Chemical Industries, Ltd.), 138 parts by mass of styrene, 138 parts by mass of methacrylic acid, and 1 part by mass of ammonium persulfate were charged. After stirring at 400 r / min for 15 minutes, the temperature was raised to 75°C and the mixture was reacted for 5 hours. Furthermore, 30 parts by mass of a 1% by mass aqueous solution of ammonium persulfate was added, and the mixture was aged at 75°C for 5 hours to obtain an aqueous dispersion of a polymeric dispersant (polymeric dispersant dispersion) of styrene-methacrylic acid-sodium salt of ethylene oxide methacrylate adduct sulfate. The median particle size (D) of the polymeric dispersant in the dispersion was measured. ５０ The wavelength was 140 nm, and the CV value was 22%.

[0137] 990 parts by mass of water, 83 parts by mass of polymer dispersant dispersion, 38 parts by mass of 50% by mass aqueous solution of alkyldiphenyl ethersulfonate sodium "Perex SS-L" (manufactured by Kao Corporation), and 90 parts by mass of ethyl acetate were placed in a container and stirred to obtain a milky white aqueous phase II.

[0138] <Preparation of Emulsified Slurry III> 146 parts by mass of the colorant dispersion prepared in Example 17 and 100 parts by mass of aqueous phase II were added to a container containing 776 parts by mass of oil phase I. The mixture was then mixed at 13,000 r / min for 20 minutes using a "TK Homomixer" (manufactured by Primix Co., Ltd.) to obtain a dispersed slurry. The dispersed slurry was placed in a 3-liter four-necked flask equipped with a nitrogen inlet tube, a fall-flow condenser, a stirrer, and a thermocouple. The solvent was removed under reduced pressure of 20 kPa at 30°C for 8 hours, and then aged at 45°C for 4 hours to obtain emulsified slurry III.

[0139] <Preparation of Toner Particles> 100 parts by mass of emulsified slurry III was filtered by suction to separate the solid components. The following operations (1) to (4) were repeated twice on the resulting filtered cake.

[0140] (1) Add 100 parts by mass of deionized water to the filtration cake and mix at 12,000 r / min for 10 minutes using a "TK Homo Mixer" (manufactured by Primix Co., Ltd.), then filter by suction. (2) Add 100 parts by mass of 10% sodium hydroxide aqueous solution to the filtration cake from (1) and mix at 12,000 r / min for 30 minutes using a "TK Homo Mixer" (manufactured by Primix Co., Ltd.), then filter by suction. (3) Add 100 parts by mass of 10% hydrochloric acid to the filtration cake from (2) and mix at 12,000 r / min for 10 minutes using a "TK Homo Mixer" (manufactured by Primix Co., Ltd.), then filter by suction. (4) Add 300 parts by mass of deionized water to the filtration cake from (3) and mix at 12,000 r / min for 10 minutes using a "TK Homo Mixer" (manufactured by Primix Co., Ltd.), then filter by suction.

[0141] The obtained filtration cake was dried at 45°C for 48 hours using a vacuum constant-temperature dryer "DRV622DA" (manufactured by ADVANTEC), and then sieved through a mesh with a mesh opening of 75 μm to obtain toner particles. The median volume particle size (D) of the obtained toner particles was determined. ５０ The diameter was 7.0 μm.

[0142] Toner was obtained by mixing 100 parts by mass of the obtained toner particles with 1 part by mass of "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 2 parts by mass of "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) as external additives in a Henschel mixer at a rotation speed of 3000 r / min (peripheral speed 32 m / s) for 3 minutes.

[0143] Test Example [Charge Stability under High Temperature and High Humidity] Under high temperature and high humidity conditions of 32°C and 85% relative humidity, 0.6 g of toner and 19.4 g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size 90 μm) were placed in a 50 mL polyethylene container and mixed at 250 r / min using a ball mill. The charge of the toner was measured using a Q / M meter (manufactured by EPPING) by the following method. After a mixing time of 60 seconds or 600 seconds, a specified amount of toner and carrier mixture was placed in the cell attached to the Q / M meter, and only the toner was aspirated for 90 seconds through a sieve with a mesh size of 32 μm (stainless steel, twill weave, wire diameter: 0.0035 mm). The voltage change on the carrier generated at that time was monitored, and the value of [total electric charge after 90 seconds (μC) / amount of aspirated toner (g)] was defined as the charge amount (μC / g). The charge stability was evaluated by calculating the ratio of the charge amount after 60 seconds of mixing to the charge amount after 600 seconds of mixing (charge amount after 60 seconds of mixing / charge amount after 600 seconds of mixing). A higher value indicates better charge stability under high temperature and high humidity conditions. The results are shown in Tables 5 and 6.

[0144]

[0145]

[0146] From the above results, it can be seen that the toners of Examples 1 to 20 exhibit better electrostatic stability under high temperature and high humidity conditions compared to the toners of Comparative Example 1, which contains an amorphous polyester resin without PET, and Comparative Example 2, which contains an amorphous polyester resin using ethylene glycol and terephthalic acid instead of PET.

[0147] The electrostatic image developing toner of the present invention is suitably used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like.

Claims

1. A toner for developing electrostatic images, comprising a binder resin containing an amorphous polyester resin A and a colorant, wherein the amorphous polyester resin A is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, and the colorant contains a naphthol AS-based pigment.

2. The electrostatic image developing toner according to claim 1, wherein the polyethylene terephthalate content is 5 mol% or more and 75 mol% or less of the total amount of alcohol component, carboxylic acid component and polyethylene terephthalate, with terephthalate-ethylene glycol units considered as 1 mole.

3. The electrostatic image developing toner according to claim 1 or 2, wherein the IV value of polyethylene terephthalate is 0.40 or more and 0.85 or less.

4. The electrostatic image developing toner according to any one of claims 1 to 3, wherein the naphthol AS-based pigment is C.I. Pigment Red 269.

5. The toner for developing electrostatic images according to any one of claims 1 to 4, wherein the content of naphthol AS-based pigment is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of binder resin.

6. The electrostatic image developing toner according to any one of claims 1 to 5, wherein the content of amorphous polyester resin A is 25% by mass or more in the binder resin.

7. The toner for developing electrostatic images according to any one of claims 1 to 6, wherein the softening point of the amorphous polyester resin A is 70°C or higher and 170°C or lower.

8. The toner for developing electrostatic images according to any one of claims 1 to 7, wherein the binder resin contains two resins having softening points that differ by 10°C or more, and at least one of the two resins is amorphous polyester resin A.

9. The toner for developing electrostatic images according to claim 8, wherein the softening point of the resin with the higher softening point is 100°C or higher and 170°C or lower.

10. The toner for developing electrostatic images according to claim 8 or 9, wherein the softening point of the resin with the lower softening point is 70°C or higher and 130°C or lower.

11. The electrostatic image developing toner according to any one of claims 8 to 10, wherein the mass ratio of the resin with the higher softening point to the resin with the lower softening point is 10 / 90 or more and 90 / 10 or less.

12. A method for producing electrostatic image developing toner according to any one of claims 1 to 11, comprising the steps of melting and kneading at least a binder resin and a colorant, and grinding the kneaded product obtained in the step.

Images