Toner for developing electrostatic images

Abstract

This invention relates to a toner for developing electrostatic images that exhibits excellent charge stability under high temperature and high humidity conditions, and to a method for manufacturing the same. [Solution] A toner for developing electrostatic images 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; and a method for producing the toner for developing electrostatic images, comprising the steps of melting and kneading at least the binder resin and the colorant, and grinding the kneaded product obtained in the step.

Description

[Technical Field]

[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. [Background technology]

[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). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-88255 [Overview of the project] [Problems that the invention aims to solve]

[0005] 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 their weather resistance. However, they have issues with charge stability under high temperature and high humidity conditions, and further improvements are needed.

[0006] 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. [Means for solving the problem]

[0007] The present invention [1] A toner for developing electrostatic images containing an amorphous polyester resin A and 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 electrostatic image developing toner according to [1], comprising the steps of melting and kneading at least a binder resin and a colorant, and grinding the kneaded material obtained in the first step. Regarding. [Effects of the Invention]

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

[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 following mechanism is a hypothesis and is not limited thereto.

[0010] Naphthol AS pigments are characterized by having a skeleton in which naphthalene and benzene ring structures 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, possibly 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 using a polycondensate of an alcohol component, a carboxylic acid component, and PET (amorphous polyester resin A) improves the electrostatic stability under high temperature and high humidity conditions. This is because, in the polycondensation reaction of the alcohol component, carboxylic acid component, and PET, the amorphous polyester resin A obtained using PET undergoes depolymerization and is incorporated into the polyester resin chain by transesterification, 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 with densely packed ester groups interact with the amide groups of the naphthalene AS-based pigment molecules, thereby stabilizing the structure of the naphthalene AS-based pigment molecules, which suppresses charge leakage under high temperature and high humidity conditions, resulting in a toner with excellent electrostatic 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 in which the crystallinity index is between 0.6 and 1.4. An amorphous resin is one in which no endothermic peak is observed, or if observed, the crystallinity index is 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, as well as the 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 standpoint of low-temperature fixation, is formula (I):

[0014] [ka]

[0015] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are each a positive number. The value of the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and still more preferably 4 or less) It preferably contains an alkylene oxide adduct of bisphenol A represented by the formula. Examples of the alkylene oxide adduct of bisphenol A represented by the formula (I) include an ethylene oxide adduct of bisphenol A, a propylene oxide adduct of bisphenol A, and the like. It is preferable to use one or more of these.

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

[0017] Examples of other alcohol components include aliphatic diols and alcohols with three or more valences.

[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, neopentyl glycol, and the like.

[0019] Examples of alcohols with three or more valences include glycerin, trimethylolpropane, pentaerythritol, and the like.

[0020] From the viewpoint of hot offset resistance, the carboxylic acid component preferably contains an aromatic dicarboxylic acid-based 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, more preferably 85 mol% or less. However, the terephthalic acid units contained in PET are not included in the carboxylic acid component as referred to herein.

[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 subjected to a polycondensation reaction as raw material monomers and incorporated into the polyester resin.

[0027] The PET can be either new virgin PET or recycled PET. Recycled PET refers to PET that has been collected from used materials and recycled into new 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 in its crushed form, but it may also be obtained by washing and sorting it from other materials, crushing the crushed material, depolymerizing it to monomer units, and then resynthesizing it using these as raw materials.

[0028] In this 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 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] Commercially available PET products with an IV value between 0.40 and 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 PET content is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, and preferably 75 mol% or less, more preferably 70 mol% or less, even more preferably 60 mol% or less, and even more preferably 50 mol% or less, from the viewpoint of electrostatic stability under high temperature and high humidity, relative to the total amount of alcohol component, carboxylic acid component, and PET. Since PET is an equimolar polycondensate of ethylene glycol, terephthalic acid, dimethyl terephthalate, etc., the terephthalic acid-ethylene glycol unit (Mw: 192) is considered as 1 mole. Therefore, the number of moles of PET = the number of moles of ethylene glycol units = the number of moles of terephthalic acid units. If amorphous polyester resin A consists of two or more resins, the weighted average value of the PET content of each resin shall be used as the PET content of amorphous polyester resin A.

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

[0034] 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, it can be produced by polycondensing an alcohol component, a carboxylic acid component, and PET in an inert gas atmosphere, in the presence of an esterification catalyst, and optionally in the presence of a co-catalyst, polymerization inhibitor, etc., at a temperature preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

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

[0036] The amount of 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 alcohol component, carboxylic acid component, and PET.

[0037] Furthermore, gallic acid and the like can be used as co-catalysts for the esterification catalyst. The amount of co-catalyst 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, and more preferably 0.1 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component, carboxylic acid component and PET. Tert-butylcatechol and the like can be used as polymerization inhibitors. The amount of 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, and more preferably 0.1 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component, carboxylic acid component and PET.

[0038] In this invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins that have been grafted or blocked with phenol, urethane, epoxy, etc., by methods described in Japanese Patent Publication No. 11-133668, Japanese Patent Publication No. 10-239903, Japanese Patent Publication No. 8-20636, etc. Among modified polyester resins, urethane-modified polyester resins obtained by urethane elongation of polyester resin with a polyisocyanate compound are preferred.

[0039] The softening point of amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, even more preferably 100°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.

[0040] The glass transition temperature of 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, from the viewpoint of resistance to hot offset.

[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 preferably 25 mg KOH / g or less, 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 types of resins with different softening points, from the viewpoint of low-temperature fixability and fixation width. The difference in softening points between the two types of 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 with softening points differing 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. 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 molecule:

[0052] [ka]

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

[0054] Examples of naphthol AS-based pigments include CI 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, CI Pigment Red 269 is preferred from the viewpoint of electrostatic stability under high temperature and high humidity conditions.

[0055] The content of naphthol AS 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 (binder) 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 the toner's low-temperature fixing performance, hot offset resistance, and 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 tertiary amines as side chains; 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, as negative charge control agents, polymer types such as "FCA-2521NJ" (manufactured by Fujikura Chemical Co., Ltd.), etc.; 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.), etc.; metal compounds of benzyl acid compounds such as "LR-147", "LR-297" (both manufactured by Nippon Carlit Co., Ltd.), etc.; metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", "Bontron E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE Examples include "NX VP434" (manufactured by Clariant), nitroimidazole derivatives, organometallic compounds, etc.

[0064] From the viewpoint of the charge stability of the toner, the content of the charge control agent 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 the 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 used to hydrophobize 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% of the total volume frequency, starting 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 considered 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 mixed with a carrier, in image forming apparatuses using either a one-component developing method or a two-component developing method, respectively. [Examples]

[0083] 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.

[0084] [PET IV value] The phenol / tetrachloroethane is dissolved at a concentration of 4 g / L in a 60 / 40 (mass ratio) mixed solvent, and the concentration is measured using an Ubbelohde viscometer and calculated using the following formula. IV = (-1 + √(1 + 4kη)) / (2kC) [In the formula, k = 0.33, C = 0.004 g / mL, and η = (t1 / t0) - 1 (t0: number of seconds for the solvent to fall, t1: number of seconds for the sample solution to fall).]

[0085] [Amine value of ketimine compounds] The measurement will be performed according to the method of JIS K2501:2003. However, the measurement solvent will be changed from chlorobenzene to chloroform as specified in JIS K2501:2003.

[0086] [Softening point of resin] 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 the sample is 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 temperature, and the temperature at which half of the sample has flowed out is defined as the softening point.

[0087] [Maximum peak temperature of endothermic 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.

[0088] [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 below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rise of the peak to the peak apex is defined as the glass transition temperature.

[0089] [Acid value of resins] Measurements will be performed according to the method of JIS K 0070:1992. However, the measurement solvent will be changed from the ethanol and ether mixed solvent specified in JIS K 0070 to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a mixed solvent of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0090] [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 again at a rate of 10°C / min, the amount of heat is measured, and the maximum peak temperature of endothermic heating is defined as the melting point.

[0091] [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 into a measuring cell, add distilled water, and measure the volume mid-particle size (D) at a temperature where the absorbance is within the appropriate range. 50 The volume-average particle size is measured. The CV value is calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume-average particle size) × 100

[0092] [Solid content concentration of resin dispersion, colorant dispersion, and mold release agent dispersion] Using the infrared moisture meter "FD-230" (manufactured by Kett Scientific Research Institute Co., Ltd.), 5g of the sample to be measured was dried at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, variation range 0.05%), and the moisture content (mass%) of the dispersion was measured. The solid content concentration was calculated according to the following formula. Solid content concentration (mass%) = 100-moisture (mass%)

[0093] [Medium particle size by volume 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: The sample dispersion was added to 100 mL of the electrolyte solution to adjust the concentration to one that could measure the particle size of 30,000 particles in 20 seconds. Then, the 30,000 particles were measured, and the volume median particle size (D) was determined from the particle size distribution. 50 )

[0094] [Toner volume medium particle size (D 50 )〕 • 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: Prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust the concentration to 5% by mass. • Dispersion conditions: Add 10 mg of the sample to 5 mL of the dispersion and disperse for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80W). Then, add 25 mL of electrolyte and disperse for another minute using the ultrasonic disperser to prepare the sample dispersion. • Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, the 30,000 particles are measured, and the volume median particle size (D) is determined from the particle size distribution. 50 )

[0095] [Toner circularity] The circularity of the toner particles will be measured under the following conditions. • Measurement device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) • Preparation of dispersion: Prepare the dispersion of toner particles by diluting it with deionized water so that the solid content concentration is 0.001 to 0.05% by mass. • Measurement mode: HPF measurement mode

[0096] [Average particle size of external additives] The average particle diameter refers to the number-average particle diameter, which is calculated by measuring the particle size (average of the major and minor axes) of 500 particles (primary particles) from scanning electron microscope (SEM) images and using the number-average value of these measurements.

[0097] Resin manufacturing example 1 The alcohol components, carboxylic acid components 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 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 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, yielding amorphous polyester resins (resins AH1-AH5, AH8, AH10-AH13). The physical properties are shown in Tables 1 and 2.

[0098] Resin manufacturing 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 with a nitrogen inlet tube and 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.

[0099] Resin manufacturing example 3 The alcohol components, carboxylic acid components other than trimellitic anhydride and fumaric acid shown in Table 2, 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 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.

[0100] Resin manufacturing example 4 The alcohol components, carboxylic acid components 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 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 210°C, trimellitic anhydride as 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.

[0101] Resin manufacturing example 5 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 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 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, yielding an amorphous polyester resin (resin AH15). The physical properties are shown in Table 2.

[0102] Resin manufacturing 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 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 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-AL5, AL8, AL10-AL13). The physical properties are shown in Tables 3 and 4.

[0103] Resin manufacturing example 7 The alcohol component, carboxylic acid component other than fumaric acid, PET, esterification catalyst, and co-catalyst shown in Table 4 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 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 a rate of 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.

[0104] Resin manufacturing 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 drop-flow condenser with 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 Table 4 was reached to obtain amorphous polyester resin (resin AL14). The physical properties are shown in Table 4.

[0105] Resin manufacturing 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.

[0106] [Table 1]

[0107] [Table 2]

[0108] [Table 3]

[0109] [Table 4]

[0110] Resin manufacturing example 10 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, 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.

[0111] Examples of ketimine compound production In a 1-liter four-necked separable flask equipped with a stirrer and thermometer, 170 parts by mass of isophorone diamine and 75 parts by mass of methyl ethyl ketone were charged, 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.

[0112] Resin manufacturing example 11 2954 g of 3-methyl-1,5-pentanediol, 1697 g of isophthalic acid, and 1825 g of adipic acid were added to a 10-liter four-necked flask equipped with a drop-flow condenser with a nitrogen inlet tube and a dehydration tube, a stirrer, and a thermocouple. After raising the temperature 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 over about 4 hours, then to 230°C over 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 containing 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.

[0113] A 50% by mass ethyl acetate solution of the obtained polyester resin b1 having isocyanate groups was placed in a 3-liter four-necked flask equipped with a nitrogen inlet tube, a drop-through condenser, a stirrer, and a thermocouple. Ketimine compound K1 was added dropwise while stirring so that the equivalent ratio of isocyanate groups to amino groups (NCO groups / NH2 groups) was 1.0. After stirring at 45°C for 10 hours, the solution was dried under reduced pressure at 50°C under 10 kPa 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.

[0114] Examples 1, 4-15, 18, Comparative Examples 1, 2 [Melting 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 Shikkei Co., Ltd., naphthol AS-based pigment, CI Pigment Red 269 (PR269)), 3 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83℃), 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.

[0115] 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.

[0116] 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 ) yielded toner particles with a size of 7.0 μm.

[0117] 100 parts by mass of the obtained toner particles and 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.

[0118] Example 2 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, CI Pigment Red 146 (PR146)) was used as a coloring agent instead of "Permanent Carmine 3810".

[0119] Example 3 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, CI Pigment Red 184 (PR184)) was used as a coloring agent instead of "Permanent Carmine 3810".

[0120] 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.

[0121] Example 17 [Emulsification and Coagulation Method] <Preparation of resin dispersion for core> 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 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 at a temperature below 50°C, the methyl ethyl ketone and some of the water were distilled off. 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 a resin dispersion for the core. The median particle size (D) of the resin particles in the dispersion was measured. 50 The wavelength was 200 nm, and the CV value was 24%.

[0122] <Preparation of resin dispersion for shells> 600 g of methyl ethyl ketone was charged into a 5-liter container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and 150 g of resin AL1 was added and dissolved at 60 °C. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to a neutralization degree of 60 mol% with respect 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, methyl ethyl ketone and a part of the water were distilled off under reduced pressure at a temperature of 50 °C or lower, and the solid content concentration of the aqueous dispersion was measured. The solid content concentration of the aqueous dispersion was adjusted to 20% by mass with deionized water to obtain a resin dispersion for the shell. The volume median diameter (D 50 ) of the resin particles in the dispersion was 110 nm, and the CV value was 20%.

[0123] <Preparation of Colorant Dispersion> 116.2 g of "Permanent Carmine 3810" (manufactured by Sanyo Pigment Co., Ltd., naphthol AS-based pigment, PR269), 154.9 g of an anionic surfactant "Neoperex (registered trademark) G-15" (manufactured by Kao Corporation, 15% by mass aqueous sodium dodecylbenzenesulfonate solution), and 260 g of deionized water were mixed in a 1-liter beaker and dispersed at room temperature for 3 hours using a homogenizer. Then, deionized water was added so that the solid content concentration became 24% by mass to obtain a colorant dispersion. The volume median diameter (D 50 ) of the colorant particles in the dispersion was 128 nm, and the CV value was 28%.

[0124] <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 a cationic surfactant (manufactured by Kao Corporation, trade name: Sanisol B50), and 200 g of deionized water were heated to 95 °C, and the wax was dispersed using a homogenizer. Then, it was subjected to a dispersion treatment with a pressure discharge type homogenizer, and deionized water was added to obtain a release agent dispersion with a solid content concentration of 20% by mass. The volume median diameter (D 50 ) of the release agent particles in the dispersion was 550 nm, and the CV value was 26%.

[0125] <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.

[0126] 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.

[0127] 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.

[0128] 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 particle size (D) of the obtained toner particles was measured. 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.

[0129] 100 parts by mass of the obtained toner particles and 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.

[0130] Example 19 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.

[0131] Example 20 [Dissolution and Suspension Method] <Preparation of crystalline polyester resin dispersion> 100g of resin C1 and 400g of ethyl acetate were placed in a 2-liter metal container, heated to 75°C to dissolve, and then 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 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.

[0132] <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.

[0133] <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.), sodium salt of ethylene oxide adduct sulfate methacrylate, 138 parts by mass of styrene, 138 parts by mass of methacrylic acid, and 1 part by mass of ammonium persulfate were charged. The mixture was stirred at 400 r / min for 15 minutes, then the temperature was raised to 75°C and the mixture was allowed to react 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 adduct sulfate methacrylate). The median particle size (D) of the polymeric dispersant in the dispersion was measured. 50 The wavelength was 140nm, and the CV value was 22%.

[0134] 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.

[0135] <Preparation of Emulsified Slurry III> To a container containing 776 parts by mass of oil phase I, 146 parts by mass of the colorant dispersion prepared in Example 17 and 100 parts by mass of aqueous phase II were added. The mixture was then mixed for 20 minutes at 13,000 r / min using a "TK Homomixer" (manufactured by Primix Co., Ltd.) to obtain a dispersion slurry. The dispersion slurry was placed in a 3-liter four-necked flask equipped with a nitrogen inlet tube, a drop-through condenser, a stirrer, and a thermocouple. The slurry was desolvated 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.

[0136] <Preparation of toner particles> 100 parts by mass of the 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.

[0137] (1) 100 parts by mass of deionized water was added to the filtration cake and mixed at 12,000 r / min for 10 minutes using a "TK Homomixer" (manufactured by Primix Co., Ltd.), and then filtered by suction. (2) 100 parts by mass of 10% sodium hydroxide aqueous solution was added to the filtration cake from (1), and the mixture was mixed at 12,000 r / min for 30 minutes using a "TK Homomixer" (manufactured by Primix Co., Ltd.), and then filtered by suction. (3) 100 parts by mass of 10% hydrochloric acid was added to the filtration cake from (2), and the mixture was mixed at 12,000 r / min for 10 minutes using a "TK Homomixer" (manufactured by Primix Co., Ltd.), and then filtered by suction. (4) 300 parts by mass of deionized water were added to the filtration cake from (3), and the mixture was mixed at 12,000 r / min for 10 minutes using a "TK Homomixer" (manufactured by Primix Co., Ltd.), and then filtered by suction.

[0138] 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 particle size (D) of the obtained toner particles was determined. 50 The diameter was 7.0 μm.

[0139] 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.

[0140] Test example [Charge stability under high temperature and high humidity conditions] Under high temperature and high humidity conditions of 32°C and 85% relative humidity, 0.6g of toner and 19.4g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size 90μm) were placed in a 50mL polyethylene container and mixed at 250r / min using a ball mill. The charge level of the toner was then measured using a Q / M meter (manufactured by EPPING) by the following method. After a mixing time of 60 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 drawn through a 32 μm mesh sieve (stainless steel, twill weave, wire diameter: 0.0035 mm) for 90 seconds. The voltage change on the carrier that occurred at that time was monitored, and the value of [total electric charge after 90 seconds (μC) / amount of toner drawn (g)] was defined as the charge amount (μC / g). 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) was calculated to evaluate the charge stability. A larger value indicates better charge stability under high temperature and high humidity conditions. The results are shown in Tables 5 and 6.

[0141] [Table 5]

[0142] [Table 6]

[0143] Based on these 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. [Industrial applicability]

[0144] 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, wherein the IV value of polyethylene terephthalate is 0.40 or more and 0.85 or less.

4. The toner for developing electrostatic images according to claim 1, wherein the naphthol AS-based pigment is C.I. Pigment Red 269.

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

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

9. The electrostatic image developing toner 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 electrostatic image developing toner according to claim 8, 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 claim 8, 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 pulverizing the kneaded product obtained in the step.

Images