Method for manufacturing toner for electrostatic image development

Abstract

This relates to a method for manufacturing a toner for electrostatic image development that has excellent resistance to document offset during high-temperature storage. [Solution] A method for producing electrostatic image developing toner, comprising an external additive step of mixing toner mother particles containing a binder resin and a colorant with an external additive, wherein the binder resin contains amorphous polyester resin A which is a polycondensate of an alcohol component containing an aliphatic diol having 2 to 5 carbon atoms and a carboxylic acid component, and the external additive step comprises at least two mixing steps, the first of which mixing the toner mother particles with inorganic fine particles A having a number average particle diameter of 70 nm to 200 nm, using formula (1): A method for manufacturing toner for electrostatic image developing, comprising a mixing step in which the product of the Froude number (Fr) calculated from TIFF2026142900000007.tif24156 and the mixing time (minutes) is between 20,000 and 125,000, and a second mixing step in which the mixture obtained in the first mixing step is mixed with inorganic fine particles B having a number-average particle size of less than 70 nm.

Description

[Technical Field]

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

[0002] Patent Document 1 describes a method for manufacturing electrostatic image developing toner comprising toner matrix particles containing at least a binder resin and an external additive, Step 1: A step of mixing toner base particles and external additive A, and Step 2: Further mixing with external additive B. A method for manufacturing a toner for electrostatic image development is disclosed, wherein the binder resin contains polyester A having a furan ring, external additive A is hydrophobic silica particles with an average particle diameter of 20 to 80 nm and a carbon content of 2.6 to 6.0% by weight, and external additive B is hydrophobic silica particles with an average particle diameter of 6 nm or more and less than 20 nm, and the difference in average particle diameter between external additive A and external additive B is 10 nm or more.

[0003] Patent Document 2 discloses a method for producing toner, which includes an external additive step of mixing toner particles containing at least a binder resin and a colorant with an external additive, wherein the binder resin contains a polyester resin obtained by polycondensing an alcohol component containing an aliphatic diol having 3 to 5 carbon atoms and a hydroxyl group bonded to a secondary carbon atom, and a carboxylic acid component containing a succinic acid derivative substituted with a hydrocarbon group having 8 to 20 carbon atoms, and the external additive step consists of at least two steps, the first step being carried out under conditions where the stirring Froude number (Fr) is 200 to 550. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-205609 [Patent Document 2] Japanese Patent Publication No. 2019-113791 [Overview of the project] [Problems that the invention aims to solve]

[0005] In recent years, there has been a growing demand for electrophotographic printing in the field of flexible packaging printing, such as food packaging. From the perspective of requiring more stringent safety standards, there is a need for toners containing polyester resin with reduced content of constituent units derived from bisphenol A monomers. However, increasing the content of constituent units derived from aliphatic diol monomers in polyester resin presents a challenge: color transfer (document offset) of printed materials is more likely to occur, especially during high-temperature storage.

[0006] This invention relates to a method for manufacturing a toner for electrostatic image development that has excellent resistance to document offset during high-temperature storage. [Means for solving the problem]

[0007] The present invention relates to a method for producing electrostatic image developing toner, comprising an external addition step of mixing toner matrix particles containing a binder resin and a colorant with an external additive, wherein the binder resin contains amorphous polyester resin A which is a polycondensate of an alcohol component and a carboxylic acid component containing 80 mol% or more of aliphatic diols having 2 to 5 carbon atoms, and the external addition step comprises at least two mixing steps, the first of which mixes the toner matrix particles with inorganic fine particles A having a number average particle diameter of 70 nm to 200 nm, using formula (1):

[0008]

number

[0009] The present invention relates to a method for manufacturing toner for electrostatic image developing, comprising a mixing step in which the product of the Froude number (Fr) calculated from and the mixing time (minutes) is between 20,000 and 125,000, and a second mixing step in which the mixture obtained in the first mixing step is mixed with inorganic fine particles B having a number-average particle size of less than 70 nm. Effects of the Invention

[0010] By the method of the present invention, a toner for developing electrostatic charge images having excellent document offset resistance during high-temperature storage can be obtained. Mode for Carrying Out the Invention

[0011] The present invention is greatly characterized in that, when an electrostatic charge image developing toner (hereinafter also referred to as toner) is obtained by mixing toner base particles and external additives, external additives having a predetermined number-average particle diameter are externally added separately. Although the reason why the effects of the present invention are exhibited is not clear, it is presumed as follows. It should be noted that the following mechanism is an assumption and is not limited thereto.

[0012] When the amount of aliphatic diol used as the alcohol component of a polyester resin is increased, the resin tends to contain a large amount of low-molecular-weight components, which is possibly attributable to the low reactivity of the aliphatic diol. When a printed matter printed with a toner using such a polyester resin having a large amount of low-molecular-weight components is stored at high temperature, the low-molecular-weight components of the resin easily bleed out onto the surface of the printed image, causing adhesion of images between printed matters and resulting in color transfer. In contrast, in the method of the present invention, toner particles containing amorphous polyester resin A, which is a polycondensate of an alcohol component containing 80 mol% or more of an aliphatic diol having 2 to 5 carbon atoms and a carboxylic acid component, are subjected to at least two external addition treatments. First, inorganic fine particles A having a relatively large particle diameter are mixed with toner base particles such that the product of the Froude number (Fr) and the mixing time (minutes) falls within a specific range. Thereby, the inorganic fine particles A can be uniformly and firmly adhered to the surface of the toner particles, and brought into a state where the inorganic fine particles A are partially embedded in the toner base particles. Next, by externally adding inorganic fine particles B having a small particle diameter, the inorganic fine particles B can be sufficiently adhered onto the toner base particles to which the inorganic fine particles A have been externally added, and detachment of the large-diameter inorganic fine particles A from the toner base particles can be suppressed. As a result, a state in which a large amount of inorganic fine particles are present on the surface of a printed image can be formed, the influence of bleed-out of low-molecular-weight components of the resin is suppressed, and adhesion of images between printed matters is suppressed, thereby preventing color transfer of printed matters (document offset) even during high-temperature storage.

[0013] The toner base particles used in the external addition step contain a binder resin and a colorant.

[0014] The binder resin contains amorphous polyester resin A, which is a polycondensate of an alcohol component containing 80 mol% or more of an aliphatic diol having 2 to 5 carbon atoms and a carboxylic acid component.

[0015] Note that whether a resin is amorphous or crystalline is determined based on the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the maximum endothermic peak temperature (softening point (°C) / maximum endothermic peak temperature (°C)) according to the measurement method described in the Examples below. An amorphous resin is one in which no endothermic peak is observed, or when an endothermic peak is observed, the crystallinity index is less than 0.6 or more than 1.4. A crystalline resin is one having a crystallinity index of 0.6 or more and 1.4 or less. 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.

[0016] Examples of aliphatic diols having 2 to 5 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,4-butenediol, neopentyl glycol, and the like.

[0017] From the viewpoint of transferability and electrostatic stability, the content of aliphatic diols having 2 to 5 carbon atoms is 80 mol% or more, preferably 90 mol% or more, more preferably 92 mol% or more, and 100 mol% or less, preferably 98 mol% or less, and more preferably 95 mol% or less, in the alcohol component.

[0018] Other alcohol components include aliphatic diols with 6 or more carbon atoms, aromatic diols such as bisphenol A and alkylene oxide adducts of bisphenol A, hydrogenated bisphenol A, trivalent or higher alcohols such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0019] From the viewpoint of electrostatic stability, the carboxylic acid component preferably contains an aromatic dicarboxylic acid compound.

[0020] 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.

[0021] The content of aromatic dicarboxylic acid compounds is preferably 60 mol% or more, more preferably 75 mol% or more, even more preferably 85 mol% or more, and 100 mol% or less, preferably 95 mol% or less, and more preferably 92 mol% or less, in the carboxylic acid component.

[0022] Other carboxylic acid components besides aromatic dicarboxylic acid compounds include aliphatic dicarboxylic acid compounds and trivalent or higher carboxylic acid compounds.

[0023] Examples of aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid and adipic acid which may be substituted with hydrocarbon groups, anhydrides of these acids, and alkyl esters of alkyl groups with 1 to 3 carbon atoms.

[0024] Examples of carboxylic acid compounds with a valency of 3 or higher include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0025] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monohydric carboxylic acid compound, as appropriate.

[0026] Furthermore, in this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol and carboxylic acid components.

[0027] The equivalent ratio (COOH group / OH group) of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component 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, from the viewpoint of adjusting the softening point of the polyester resin.

[0028] Amorphous polyester resin A can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere, and optionally in the presence of an esterification catalyst, 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.

[0029] 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). 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, and more preferably 1 part by mass or less, per 100 parts by mass of the total amount of alcohol and carboxylic acid components. Examples of co-catalysts for the esterification catalyst include gallic acid. 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 alcohol and carboxylic acid components. Examples of polymerization inhibitors include tert-butylcatechol. 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, based on 100 parts by mass of the total amount of alcohol and carboxylic acid components.

[0030] 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.

[0031] The softening point of amorphous polyester resin A is preferably 80°C or higher, more preferably 90°C or higher, from the viewpoint of electrostatic stability, and preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixability and transferability.

[0032] The glass transition temperature of amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of electrostatic stability, and preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 65°C or lower, from the viewpoint of low-temperature fixability and transferability.

[0033] The content of amorphous polyester resin A in the binder resin is preferably 70% 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.

[0034] Other binder resins include amorphous polyester resins other than amorphous polyester resin A, crystalline polyester resins, vinyl resins such as styrene-acrylic resin, polyamide resins, epoxy resins, polycarbonate resins, polyurethane resins, and composite resins containing two or more of these resins.

[0035] The binder resin content is preferably 60% by mass or more, more preferably 70% by mass or more, and preferably less than 100% by mass, more preferably 98% by mass or less, and even more preferably 95% by mass or less, in the toner mother particles.

[0036] As colorants, dyes, pigments, magnetic materials, etc., used as colorants for toners can be used. Examples 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, isoindoline, disazo yellow, etc. In this invention, the toner may be either black toner or color toner.

[0037] From the viewpoint of improving the image density of the toner and its low-temperature fixability, the amount of colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the binder resin.

[0038] In addition to the binder resin (binder) and colorant, the toner of the present invention may also 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.

[0039] 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, fatty acid metal salts, etc., which can be used individually or in combination of two or more.

[0040] 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.

[0041] 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, per 100 parts by mass of binder resin, from the viewpoint of low-temperature fixation and offset resistance of the toner and dispersibility in the binder resin.

[0042] 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.

[0043] 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.).

[0044] 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.

[0045] 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.

[0046] The toner mother particles may be toner obtained by any conventionally known method such as melt kneading, emulsification agglutination, or suspension polymerization, and may also be toner having a core-shell structure. However, from the viewpoint of the miscibility of the toner raw materials, pulverized toner is preferred, and pulverized toner obtained by the melt kneading method, i.e., pulverized toner obtained by a method including a step of melt kneading at least a binder resin and a colorant and a step of pulverizing the resulting kneaded product, is more preferred. Specifically, for example, the binder resin and colorant, and optionally release agents, charge control agents, and other raw materials, can be uniformly mixed in a mixer such as a Henschel mixer, then melt kneaded in a closed-type kneader, a single-screw or twin-screw extruder, an open-roll type kneader, etc., and then cooled, pulverized, and classified to produce the toner. In the production of toner, if the binder resin consists of two or more types of resins, a binder resin with pre-mixed resins may be used, or these resins may be directly used in the mixing of raw materials when producing the toner.

[0047] Volume median particle size of toner matrix particles (D 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.

[0048] The external additive step, which involves mixing toner base particles containing a binder resin and a colorant with an external additive, comprises at least two mixing steps.

[0049] The first mixing step involves mixing the toner matrix particles with large inorganic fine particles A.

[0050] The number-average particle diameter of inorganic fine particles A is 70 nm or larger, preferably 80 nm or larger, more preferably 90 nm or larger, and even more preferably 100 nm or larger, from the viewpoint of transferability and resistance to document offset during high-temperature storage, and 200 nm or smaller, preferably 180 nm or smaller, more preferably 150 nm or smaller, and even more preferably 125 nm or smaller, from the viewpoint of fluidity and resistance to document offset during high-temperature storage.

[0051] The amount of inorganic fine particles A used is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, even more preferably 1.3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of toner matrix particles.

[0052] The first mixing step involves adjusting the diameter, peripheral speed, and time of the stirring blades of the stirring device used, and formula (1):

[0053]

number

[0054] Toner matrix particles and inorganic fine particles A are mixed under conditions where the product of the Froude number (Fr) calculated from the formula and the mixing time (minutes) (Fr × t) falls within a predetermined range.

[0055] The value of Fr×t is 20,000 or more, preferably 35,000 or more, more preferably 50,000 or more, and 125,000 or less, preferably 100,000 or less, and more preferably 80,000 or less, from the viewpoint of uniformly and firmly adhering inorganic fine particles A to the toner matrix particles.

[0056] The second mixing step involves mixing the mixture obtained in the first mixing step with small inorganic fine particles B.

[0057] The number-average particle diameter of inorganic fine particles B is less than 70 nm from the viewpoint of chargeability and fluidity, preferably 60 nm or less, more preferably 50 nm or less, and even more preferably 40 nm or less, and from the viewpoint of suppressing embedding of external additives, preferably 15 nm or more, more preferably 20 nm or more, and even more preferably 25 nm or more.

[0058] The amount of inorganic fine particles B used is preferably 0.2 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, based on 100 parts by mass of toner matrix particles used in the first mixing step.

[0059] The value of Fr×t in the second mixing step is preferably 1,000 or more, more preferably 3,000 or more, even more preferably 5,000 or more, and preferably 10,000 or less, more preferably 9,000 or less, and even more preferably 8,000 or less.

[0060] The mass ratio (inorganic fine particles A / inorganic fine particles B) of inorganic fine particles A used in the first mixing step to inorganic fine particles B used in the second mixing step is preferably 0.25 or more, more preferably 0.5 or more, and even more preferably 1 or more, from the viewpoint of transferability, and preferably 10 or less, more preferably 8 or less, and even more preferably 4 or less, from the viewpoint of fluidity.

[0061] Examples of inorganic fine particles A and B include silicon dioxide (silica), titanium dioxide, aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide, etc. Among these, from the viewpoint of imparting electrostatic charge, silica or titanium dioxide are preferred, with silica being more preferred. These can be used individually or in combination of two or more.

[0062] It is preferable that the inorganic fine particles A and B are hydrophobized. For example, hydrophobizing agents for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0063] The mixing method in the external additive process is not particularly limited and can be any Henschel mixer, etc., in accordance with conventional methods.

[0064] Within the limits that do not impair the effects of the present invention, inorganic fine particles other than inorganic fine particles A and B, or organic fine particles, may be used as external additives in the first and second mixing steps, and further mixing steps may be performed from the third step onward. However, the total amount of inorganic fine particles A used in the first mixing step and inorganic fine particles B used in the second mixing step is 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, of the total amount of external additives.

[0065] The toner obtained by the method 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]

[0066] 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 the resin and the like were measured by the following methods.

[0067] [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.

[0068] [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, the temperature is increased to 200°C at a rate of 10°C / min and measurements are taken. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature.

[0069] [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 0°C at a rate of 10°C / min. Next, the sample is heated to 150°C at a rate of 10°C / min, and the endothermic peak is measured. The temperature at the intersection of the extension of the baseline 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.

[0070] [Melting point of release agent] 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 at a heating rate of 10°C / min, and then cooled to -10°C at a cooling rate of 5°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min and measured, with the maximum endothermic peak temperature being defined as the melting point.

[0071] [Volume median particle size and CV value of resin particles, colorant particles, and mold release agent particles] (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

[0072] [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 concentration (mass%) = 100-moisture (mass%)

[0073] [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 )

[0074] [Circularity of toner particles] 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

[0075] [Medium volume particle size of toner matrix particles (D 50 )〕 • Measuring instrument: "Coulter Multisizer (Registered Trademark) III" (manufactured by Beckman Coulter, Inc.) • Aperture diameter: 100 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.) • Dispersing liquid: A solution prepared by dissolving polyoxyethylene lauryl ether "Emulgen (Registered Trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) in an electrolyte solution and adjusting the concentration to 5 mass% • Dispersion conditions: 10 mg of a measurement sample is added to 5 mL of the above dispersing liquid, and dispersed for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80 W). Thereafter, 25 mL of the electrolyte solution is added, and further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. • Measurement conditions: The above sample dispersion liquid is added to 100 mL of the above electrolyte solution to adjust the concentration such that the particle diameter of 30,000 particles can be measured in 20 seconds, then 30,000 particles are measured, and the volume-median particle diameter (D 50 ) is determined from the particle size distribution.

[0076] [Number-average particle diameter of external additive] The particle diameter (average value of major axis and minor axis) of 500 particles (primary particles) is measured from a scanning electron microscope (SEM) photograph, and the number average value thereof is taken as the number-average particle diameter.

[0077] Production Example of Alkenyl Succinic Anhydride (1) Using propylene tetramer (manufactured by Nippon Oil Corporation, trade name: "Light Tetramer"), fractional distillation was performed under heating conditions of 183 to 208°C to obtain an alkylene compound (a). The obtained alkylene compound (a) had 40 peaks in gas chromatography-mass spectrometry described later. The distribution of the alkylene compound was measured in accordance with the analysis by mass spectrometry gas chromatography for alkylene compound A in Japanese Patent Application Laid-Open No. 2014-013384, and C9H 18 : 0.5 mass%, C 10 H 20 : 4 mass%, C 11 H 22 : 20 mass%, C 12 H24 :66% by mass, C 13 H 26 :9% by mass, C 14 H 28 The concentration was 0.5% by mass (6 peaks corresponding to alkylene compounds with 9 to 14 carbon atoms).

[0078] (2) 542.4 g of alkylene compound (a), 157.2 g of maleic anhydride, 0.4 g of the antioxidant "Cherex-O" (manufactured by Sakai Chemical Industry Co., Ltd., triisooctyl phosphite), and 0.1 g of butyl hydroquinone as a polymerization inhibitor were charged into a 1 L autoclave manufactured by Nitto High Pressure Co., Ltd., and pressurized nitrogen purging (0.2 MPaG) was repeated three times. After stirring was started at 60°C, the temperature was raised to 230°C over 1 hour and the reaction was carried out for 6 hours. The pressure at the time the reaction temperature was reached was 0.3 MPaG. After the reaction was complete, the mixture was cooled to 80°C and returned to atmospheric pressure (101.3 kPa) and transferred to a 1 L four-necked flask. The temperature was raised to 180°C while stirring, and the remaining alkylene compound was removed by distillation at 1.3 kPa over 1 hour. Subsequently, the mixture was cooled to room temperature (25°C) and then returned to atmospheric pressure (101.3 kPa) to obtain 406.1 g of the target product, alkenyl succinic anhydride A. The average molecular weight of alkenyl succinic anhydride A, calculated from its acid value, was 268.

[0079] Resin manufacturing example 1 The alcohol component, carboxylic acid component, esterification catalyst, and co-catalyst shown in Table 1 were placed in a 5-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 1 was reached to obtain amorphous polyester resins (resins A1 and A2). The physical properties are shown in Table 1.

[0080] Resin manufacturing example 2 The alcohol component, carboxylic acid component other than trimellitic anhydride, esterification catalyst, and co-catalyst shown in Table 1 were placed in a 5-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 reduced to 210°C, trimellitic anhydride as shown in Table 1 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 1 was reached, yielding an amorphous polyester resin (resin A3). The physical properties are shown in Table 1.

[0081] [Table 1]

[0082] Examples 1-15 and Comparative Examples 1-5 100 parts by mass of the binder resin shown in Table 3, 3 parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 75°C), 5 parts by mass of the coloring agent "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd., phthalocyanine blue (PB15:3)), and 0.5 parts by mass of the charge control agent "Bontron E-304" (manufactured by Orient Chemical Industry Co., Ltd.) were mixed for 1 minute using a Henschel mixer, and then melt-kneaded under the conditions shown below.

[0083] Co-rotating twin-screw extruder "PCM-30" (manufactured by Ikegai Co., Ltd., shaft diameter 2.9 cm, shaft cross-sectional area 7.06 cm²) 2 The following was used: barrel set temperature of 100°C, shaft rotation speed of 200 r / min (shaft rotation peripheral speed of 0.30 m / sec), and mixture supply rate of 10 kg / h (mixture supply amount per unit cross-sectional area of ​​the shaft of 1.42 kg / h·cm). 2 ) was.

[0084] The resulting mixture was cooled to approximately 25°C, then coarsely ground using a Rotoplex pulverizer (manufactured by Hosokawa Micron Corporation), and passed through a sieve with a mesh size of 2 mm to obtain coarsely ground material with a maximum diameter of 2 mm or less. The obtained coarsely ground material was then finely ground using an IDS-2 type impact plate jet mill (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) by adjusting the grinding pressure so that the median particle size by volume was 8.0 μm. The obtained finely ground material was then processed using a DS-2 type airflow classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to determine the median particle size by volume (D 50 The static pressure (internal pressure) was adjusted so that the particle size was 8.5 μm, and classification was performed to obtain toner matrix particles.

[0085] Toner was obtained by performing a two-stage external additive process using 100 parts by mass of the obtained toner matrix particles and the external additives shown in Table 3, in a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd., with a stirring blade diameter of 0.206 m) under the processing conditions shown in Table 3.

[0086] Example 16 <Preparation of resin dispersion> In a 3-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 300 g of resin A1 and 300 g of methyl ethyl ketone were placed, and the resin was dissolved at 73°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was removed under reduced pressure to obtain an aqueous dispersion. Then, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (circumferential speed 63 m / min), and deionized water was added to obtain resin dispersion X1 by reducing the solid content concentration to 20% by mass. The median particle size (D) of the resin particles in the obtained dispersion was then measured. 50 The thickness was 0.1 μm, and the CV value was 24%.

[0087] <Preparation of mold release agent dispersion> In a 1L beaker, 120g of deionized water was added, and 167g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution "Neoperex G-15" (anionic surfactant, manufactured by Kao Corporation) was dissolved. Then, 100g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) was added, and the mixture was melted and stirred while maintaining the temperature at 90-95°C to obtain a molten mixture. While maintaining the temperature at 90-95°C, the mixture was dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.), and then cooled to room temperature. Deionized water was added to the obtained dispersion to adjust the solid content concentration to 20% by mass to obtain a release agent dispersion. The median particle size (D) of the release agent particles in the obtained dispersion was measured. 50 The density was 0.22 μm, and the CV value was 27%.

[0088] <Preparation of colorant dispersion> In a 1-liter beaker, 100g of the coloring agent "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd.), 35g of polyoxyethylene (13) distyrenated phenyl ether "Emulgen A-60" (manufactured by Kao Corporation, a nonionic surfactant), and 300g of deionized water were mixed. The mixture was then dispersed for 1 hour at room temperature using a homomixer "TKAGI HOMOMIXER 2M-03" (manufactured by Primix Co., Ltd.) at a stirring blade rotation speed of 8000 rpm. After that, the mixture was subjected to 15 passes at a pressure of 150 MPa using a "Microfluidizer M-110EH" (manufactured by Microfluidics Inc.), and then passed through a 200-mesh filter. Deionized water was added to obtain a coloring agent dispersion with a solid content concentration of 24% by mass. The median particle size (D) of the coloring agent particles in the obtained dispersion was measured. 50 The thickness was 0.15 μm, and the CV value was 25%.

[0089] <Agglomeration process> In a 3-liter four-necked flask equipped with a reflux condenser, stirrer, and thermocouple, 500 g of resin dispersion, 20 g of mold release agent dispersion, 26 g of colorant dispersion, and 10 g of a 10% by mass aqueous solution of polyoxyethylene (50) lauryl ether "Emulgen 150" (manufactured by Kao Corporation, a nonionic surfactant) were mixed at 25°C. Next, while stirring the mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 596 g of deionized water and adding a 4.8% by mass aqueous solution of potassium hydroxide to adjust the pH to 8.0 was added dropwise over 5 minutes at 25°C, and the temperature was raised to 65°C over 2 hours to determine the volume-median particle size (D) of the aggregated particles. 50 The mixture was maintained at 65°C until it reached a size of 8.8 μm, and a dispersion of aggregated particles was obtained.

[0090] <Fusing process> To the resulting dispersion of aggregated particles, an aqueous solution was added, which consisted of 18 g of polyoxyethylene lauryl ether sodium sulfate "Emal E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 429 g of deionized water, and 40 g of 0.1 mol / L aqueous sulfuric acid solution. Subsequently, the temperature was raised to 90°C over 1 hour, and then maintained at 90°C until the circularity reached 0.99, thereby obtaining a dispersion of fused particles in which the aggregated particles had fused together.

[0091] The obtained fused 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, vacuum drying was performed at 33°C for 24 hours using a vacuum constant-temperature dryer to obtain toner matrix particles. The obtained toner matrix particle size D was measured by volume. 50 It was 8.5 μm.

[0092] Toner was obtained by performing a two-stage external additive process using 100 parts by mass of the obtained toner matrix particles and the external additives shown in Table 3, in a Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd., with a stirring blade diameter of 0.206 m) under the processing conditions shown in Table 3.

[0093] Details of the external additives used in the examples and comparative examples are shown in Table 2.

[0094] [Table 2]

[0095] Test example [Document offset resistance during high-temperature storage] Toner was loaded into the non-magnetic single-component developer "OKI MICROLINE 5400" (manufactured by OKI Electric Industry Co., Ltd.), and 8,000 pages were printed at a print density of 1% under conditions of 25°C and 50% relative humidity. Next, the toner deposition amount was measured at 0.40 ± 0.03 mg / cm². 2 The printer was adjusted to print a solid 4.1cm x 4.1cm image. The solid image was removed before passing through the fuser to obtain an unfixed image. The obtained unfixed image was fixed using an external fuser, which was an external fuser unit of an "OKI MICROLINE 3010" (manufactured by Oki Electric Industry Co., Ltd.), with the fuser roll temperature set to 150°C and the fixing speed set to 80mm / s. J-paper (manufactured by Fujifilm Business Innovation Co., Ltd.) was used as the printing medium.

[0096] The resulting fixed image was superimposed onto an unprinted J-paper, and a sample of the two sheets of paper was subjected to a surface pressure of 80 g / cm². 2 The sheets were subjected to a load and left undisturbed for one day at a temperature of 50°C. Afterward, the stacked sheets were removed, and the edges of each sheet were gradually lifted to create a gap between them. A finger was then inserted into this gap to peel them apart. Ten samples were prepared, and the condition of the fixed image area after peeling was visually inspected. Document offset resistance was evaluated according to the following evaluation criteria. The results are shown in Table 3.

[0097] [Evaluation Criteria] A: No peeling sound was heard in any of the 10 samples during peeling, and no image defects were observed. B: During peeling, one or two out of ten samples produced a peeling sound, but no image loss was observed. C: During peeling, peeling sounds were heard in 1 or 2 out of 10 samples, and image defects were observed, or peeling sounds were heard in 3 or more samples, but no image defects were observed. D: During peeling, a peeling sound was heard in 3 or more out of 10 samples, and image defects were observed.

[0098] [Table 3]

[0099] Based on the above results, it can be seen that toners with superior document offset resistance were obtained in Examples 1 to 16, compared to Comparative Example 1, which used two types of external additives at the same time; Comparative Example 2, which did not use large-particle inorganic fine particles; and Comparative Examples 3 to 5, which did not adjust the product of Froude number and time to a predetermined range. [Industrial applicability]

[0100] The electrostatic image developing toner obtained by the method of the present invention is suitably used for developing latent images formed in electrostatic image developing methods, electrostatic recording methods, electrostatic printing methods, and the like.

Claims

1. A method for producing electrostatic image developing toner, comprising at least an external addition step of mixing toner base particles containing a binder resin and a colorant with an external additive, wherein the binder resin contains amorphous polyester resin A which is a polycondensate of an alcohol component and a carboxylic acid component containing 80 mol% or more of aliphatic diol having 2 to 5 carbon atoms, and the external addition step comprises at least two mixing steps, the first of which mixing the toner base particles with inorganic fine particles A having a number average particle diameter of 70 nm to 200 nm, using formula (1): [Math 1] A method for manufacturing toner for electrostatic image developing, comprising: a mixing step in which the product of the Froude number (Fr) calculated from and the mixing time (minutes) is 20,000 or more and 125,000 or less, and a second mixing step in which the mixture obtained in the first mixing step is mixed with inorganic fine particles B having a number average particle diameter of less than 70 nm.

2. A method for producing a toner for electrostatic image developing according to claim 1, wherein the inorganic fine particles A and / or inorganic fine particles B are silica.

3. A method for producing electrostatic image developing toner according to claim 1 or 2, wherein the amount of inorganic fine particles A used in the first mixing step is 0.5 parts by mass or more and 5 parts by mass or less per 100 parts by mass of toner mother particles.

4. A method for manufacturing electrostatic image developing toner according to claim 1 or 2, wherein the mass ratio of inorganic fine particles A used in the first mixing step to inorganic fine particles B used in the second mixing step is 0.25 or more and 10 or less.

5. A method for producing electrostatic image developing toner according to claim 1 or 2, wherein the number-average particle size of inorganic fine particles B is 15 nm or more.

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