Toner manufacturing method

Abstract

To provide a toner excellent in scratch resistance.SOLUTION: A toner has a toner particle containing a binder resin and calcium carbonate particles. In X-ray diffraction measurement with a CuKα line on the toner particle with θ as the Bragg angle, as for the calcium carbonate particle, (i) 2θ has peaks at 26.5°±0.5° and 29.5°±0.5°; (ii) the crystallite diameter of crystal attributed to 2θ=29.5°±0.5° is 10 nm or more and 45 nm or less; (iii) the ratio of a peak intensity "a" at 2θ=26.5°±0.5° to a peak intensity "b" at 2θ=29.5°±0.5° (a / b) is 0.15 or more and 0.24 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner used in an electrophotographic image forming method. [Background technology]

[0002] In recent years, electrophotographic full-color copiers have become widely used and are beginning to be applied to the printing market. The printing market is now demanding high speed, high image quality, and high productivity while supporting a wide range of media (paper types). For example, even when the paper type is changed from thick paper to thin paper, there is a demand for media-constant speed capability, meaning that printing can continue without changing the process speed or fuser heating temperature setting to match the paper type.

[0003] From the viewpoint of media uniformity, toners are required to be able to complete fixing properly over a wide range of fixing temperatures, from low to high. For example, toners have been proposed that utilize the internal cohesion of calcium carbonate by adding calcium carbonate to toner particles in order to achieve both low-temperature fixing properties and hot offset resistance (Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 06535988 [Patent Document 2] Patent No. 06089726 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-114828 [Patent Document 4] Japanese Patent Application Publication No. 08-339095 Summary of the Invention [Problem to be solved by the invention]

[0005] Even if low-temperature fixability is improved and the image density is 100%, toner transfer due to rubbing may occur in areas with low image density (hereinafter referred to as "abrasion resistance"). In this case, it has become impossible to improve abrasion resistance simply by improving low-temperature fixability. Furthermore, there is room for further investigation into abrasion resistance from the viewpoint of high image quality.

[0006] An object of the present invention is to provide a toner which can solve the above problems and improve abrasion resistance. [Means for solving the problem]

[0007] The present invention relates to a toner having toner particles containing a binder resin and calcium carbonate particles, characterized in that, in X-ray diffraction measurement of the toner particles using CuKα radiation when the Bragg angle is θ, the calcium carbonate particles (i) have peaks at 2θ of 26.5°±0.5° and 29.5°±0.5°, (ii) the crystallite diameter of crystals assigned to 2θ = 29.5°±0.5° is 10 nm or more and 45 nm or less, and (iii) the ratio (a / b) of the peak intensity "a" at 2θ = 26.5°±0.5° to the peak intensity "b" at 2θ = 29.5°±0.5° is 0.15 or more and 0.24 or less. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a toner that has improved low-temperature fixability and excellent abrasion resistance of images. DETAILED DESCRIPTION OF THE INVENTION

[0009] The preferred toner configurations of the present invention are described in detail below. The expressions "XX or more and YY or less" and "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified.

[0010] The toner of the present invention is a toner having toner particles containing a binder resin and calcium carbonate particles, and is characterized in that, in X-ray diffraction measurement of the toner particles using CuKα radiation when the Bragg angle is θ, the calcium carbonate particles (i) have peaks at 2θ of 26.5°±0.5° and 29.5°±0.5°, (ii) the crystallite diameter of the crystals assigned to 2θ=29.5°±0.5° is 10 nm or more and 45 nm or less, and (iii) the ratio (a / b) of the peak intensity "a" at 2θ=26.5°±0.5° to the peak intensity "b" at 2θ=29.5°±0.5° is 0.15 or more and 0.24 or less.

[0011] By adopting such a configuration, it is possible to provide a toner that has improved low-temperature fixability and excellent abrasion resistance of images.

[0012] The present inventors believe that the mechanism by which the toner having the characteristic structure of the present invention improves the abrasion resistance is as follows. To improve abrasion resistance, it is important to ensure that the toner remains fixed without being destroyed when rubbed. Adding calcium carbonate increased the interaction with the binder resin, improving abrasion resistance, but this was still insufficient in some cases. Therefore, the inventors conducted further research and succeeded in achieving both low-temperature fixability and abrasion resistance by further strengthening the interaction with the binder resin per calcium carbonate particle. Although the specific mechanism has not been established, the following is assumed.

[0013] Calcium carbonate has two crystallite faces: (104) and (112). In X-ray diffraction (XRD) measurements, the (112) face has a crystalline phase peak at 2θ = 26.5° ± 0.5°. In XRD measurements, the (104) face has a crystalline phase peak at 2θ = 29.5° ± 0.5°.

[0014] When the flat (104) plane is crushed, the surface roughness becomes pronounced, and highly active structures called steps appear. Because steps have a strong interaction with organic molecules, it is thought that increasing the number of steps can strengthen the interaction between each calcium carbonate particle and the binder resin. In other words, if the peak intensity at 2θ=29.5°±0.5°, which indicates the amount of (104) planes, decreases compared to the peak intensity at 2θ=26.5°±0.5°, which indicates the amount of (112) planes, this means that the (104) planes have been lost and the number of steps has increased. It is estimated that in this state, the interaction between each calcium carbonate particle and the binder resin will be stronger.

[0015] Any method can be used to increase the number of steps on the (104) plane of calcium carbonate, but it is preferable to apply mechanical stress to the calcium carbonate to break it and expose the steps. For example, methods such as ball milling and solvent milling can be used. Of these, the most preferable method is to increase the number of steps on the (104) plane by melt-kneading calcium carbonate with a binder resin. In this case, it is important to add more calcium carbonate than is conventionally added to toner. This allows the steps on the (104) plane to interact with the binder resin. The manufacturing method will be described later.

[0016] In X-ray diffraction measurement of toner particles using CuKα radiation, calcium carbonate particles must have a crystallite diameter of 10 nm or more and 45 nm or less at 2θ=29.5°±0.5°. When the crystallite diameter is within this range, the number of steps on the (104) plane of calcium carbonate increases, which strengthens the interaction between the steps on the (104) plane and the binder resin, leading to improved abrasion resistance. If the crystallite diameter of the crystals at 2θ=29.5°±0.5° is less than 10 nm, the crystallite diameter is too small and cannot be achieved with calcium carbonate. If the crystallite diameter of the crystals at 2θ=29.5°±0.5° is greater than 45 nm, the number of steps on the (104) plane decreases, preventing the effects of the present invention from being achieved. To further enhance the effects of the present invention, the crystallite diameter is more preferably 20 nm or more and 40 nm or less.

[0017] In X-ray diffraction measurement of toner particles using CuKα radiation, calcium carbonate particles must have a ratio of the crystalline peak intensity at 2θ=26.5±0.5 to the crystalline peak intensity at 2θ=29.5±0.5° of 0.15 or more and 0.24 or less. This ratio refers to the ratio a / b, where "a" is the crystalline peak intensity at 2θ=26.5±0.5° and "b" is the crystalline peak intensity at 2θ=29.5±0.5°. When the intensity ratio is within this range, the steps on the (104) plane of calcium carbonate interact with the binder resin, leading to improved abrasion resistance. The ratio of the peak intensities is more preferably 0.15 or more and 0.20 or less.

[0018] Preferred material configurations are described below. <Calcium carbonate particles> It is important that the toner particles of the present invention contain calcium carbonate particles. The interaction between the (104) plane steps of calcium carbonate and the binder resin increases the toner cohesion force, allowing the toner to maintain a fixed state even when a small amount of calcium carbonate is used. This makes it possible to achieve both low-temperature fixability and abrasion resistance. Calcium carbonate is necessary because the (104) plane steps are necessary.

[0019] As for calcium carbonate, various conventionally known calcium carbonates can be used, such as light calcium carbonate, colloidal calcium carbonate, and heavy calcium carbonate.

[0020] In a cross section of the toner observed with a transmission electron microscope, the number-average particle size of the calcium carbonate particles is preferably 0.1 μm or more and 5.0 μm or less. When the particle size of the calcium carbonate particles is within this range, the interaction between the (104) plane steps and the binder resin increases the cohesive force, improving the abrasion resistance. It is more preferable that the particle size of the calcium carbonate particles is 0.2 μm or more and 0.7 μm or less.

[0021] In the cross section of the toner observed with a transmission electron microscope, the average aspect ratio (major axis / minor axis) of the calcium carbonate particles is preferably 1.5 or more and 6.0 or less. When the average aspect ratio (major axis / minor axis) of the calcium carbonate particles is within this range, the interaction between the steps of the (104) plane of the calcium carbonate and the binder resin increases the cohesive force, improving abrasion resistance. The average aspect ratio (major axis / minor axis) of the calcium carbonate particles is more preferably 2.0 or more and 2.5 or less.

[0022] The content of calcium carbonate particles in the toner particles is preferably 3.0% by mass or more and 40% by mass or less. When the content of calcium carbonate particles in the toner particles is within this range, the interaction between the steps of the (104) plane of the calcium carbonate and the binder resin can be effectively exhibited, thereby improving the abrasion resistance. The content of calcium carbonate particles in the toner particles is more preferably 10 to 33% by mass.

[0023] <Binder resin> The toner particles of the present invention contain a binder resin. As the binder resin, known polymers can be used, and specifically, for example, the following polymers can be used.

[0024] Examples of suitable styrene copolymers include polystyrene, poly-p-chlorostyrene, polyvinyltoluene, and other styrene and substituted styrene homopolymers; styrene-p-chlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylic acid ester copolymers, styrene-methacrylic acid ester copolymers, styrene-α-chloromethyl methacrylate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, and styrene-acrylonitrile-indene copolymers; polyvinyl chloride, phenolic resins, natural resin-modified phenolic resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, polyester resins, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone-indene resins, and petroleum-based resins. These resins may be used alone or in combination. Among these, amorphous polyester resins are preferred from the viewpoint of abrasion resistance, as they readily interact with the steps of the (104) plane of calcium carbonate.

[0025] The binder resin may contain a crystalline polyester resin. Crystalline polyester resins are preferred from the viewpoint of scratch resistance because they readily interact with the (104) plane steps of calcium carbonate. The crystalline polyester resin is preferably a condensation polymer of an alcohol containing an aliphatic diol having 2 to 23 carbon atoms and a carboxylic acid containing an aliphatic dicarboxylic acid having 3 to 24 carbon atoms.

[0026] The crystalline polyester resin is more preferably a condensation polymer of an alcohol containing an aliphatic diol having 4 to 12 carbon atoms in an amount of 80 mol% to 100 mol% (more preferably 85 mol% to 100 mol%) relative to the total alcohol constituting the crystalline polyester resin, and an aliphatic dicarboxylic acid having 4 to 20 carbon atoms in an amount of 80 mol% to 100 mol% (more preferably 85 mol% to 100 mol%) relative to the total carboxylic acid constituting the crystalline polyester resin.

[0027] The aliphatic diol is preferably a straight-chain aliphatic diol, such as 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, or a derivative thereof. The derivative is not particularly limited as long as it can be obtained by condensation polymerization with a similar resin structure. For example, a derivative obtained by esterifying the diol may be used.

[0028] The aliphatic dicarboxylic acid is preferably a straight-chain aliphatic dicarboxylic acid, and examples thereof include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, hexadecanedioic acid, eicosanedioic acid, and derivatives thereof. The derivative is not particularly limited as long as it can obtain a similar resin structure by condensation polymerization. Examples include acid anhydrides of the dicarboxylic acids and derivatives obtained by alkyl esterification or acid chloride of the dicarboxylic acid component.

[0029] On the other hand, the carboxylic acid may be used in combination with a carboxylic acid other than the aliphatic dicarboxylic acid.

[0030] The content of the crystalline polyester resin is preferably 0.1 to 5.0% by mass, more preferably 1.0 to 4.0% by mass, relative to the toner particles. When the content of the crystalline polyester resin is within the above range, interaction with the steps of the (104) plane of calcium carbonate can be effectively exhibited, which can contribute to improving abrasion resistance.

[0031] <Coloring agent> The toner particles may contain a colorant, such as a known organic pigment or oil-based dye, carbon black, or a magnetic material.

[0032] Examples of cyan colorants include copper phthalocyanine compounds and their derivatives, anthraquinone compounds, and basic dye lake compounds. Specific examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0033] Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 254, and CI Pigment Violet 19.

[0034] Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, 191, and 194.

[0035] Examples of black colorants include carbon black, magnetic materials, and those toned to black using the above-mentioned yellow colorants, magenta colorants, and cyan colorants. These colorants can be used alone or in combination. They can also be used in the form of a solid solution.

[0036] The colorant may be selected from the viewpoints of hue angle, saturation, brightness, light resistance, transparency on an overhead projector, and dispersibility in toner particles. The content of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0037] <Release agent> The toner particles may contain a release agent. Examples of the release agent include low-molecular-weight polyolefins such as polyethylene; silicones having a melting point; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; ester waxes such as stearyl stearate; vegetable waxes such as carnauba wax, rice wax, candelilla wax, Japan wax, and jojoba oil; animal waxes such as beeswax; mineral or petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, and ester wax; and modified products thereof. The release agents may be used alone or in combination of two or more.

[0038] The melting point of the release agent is preferably 150°C or lower, more preferably 40°C or higher and 130°C or lower, and even more preferably 40°C or higher and 110°C or lower. The content of the release agent is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0039] <Manufacturing method> The procedure for producing the toner of the present invention will be described. The method for producing the toner is not particularly limited, and known methods such as emulsion aggregation, pulverization, and suspension polymerization can be used. The method for producing the toner of the present invention is characterized by including: Step 1: melt-kneading a first mixture containing a part of the binder resin and calcium carbonate particles in a twin-screw extruder to obtain a molten mixture; and Step 2: melt-kneading a second mixture containing the molten mixture and the remaining binder resin. Specifically, the toner production method of the present invention is preferably a toner production method including the following steps 1 and 2.

[0040] <Process 1> Step 1 is a step of increasing the number of steps on the (104) plane of calcium carbonate. In the raw material mixing process, predetermined amounts of binder resin, calcium carbonate, colorant particles, etc. are weighed, blended, and mixed. The mixing device is not particularly limited, but examples include a Henschel mixer (manufactured by Nippon Coke Company); a Supermixer (manufactured by Kawata Corporation); a Ribocone (manufactured by Okawara Manufacturing Co., Ltd.); a Nauta mixer, a Turbulizer, and a Cyclomix (manufactured by Hosokawa Micron Corporation); a Spiral Pin Mixer (manufactured by Pacific Machinery Works, Ltd.); and a Loedige mixer (manufactured by Matsubo Corporation). The mixture mixed using this mixing device is referred to as the first mixture.

[0041] Next, the first mixture is melt-kneaded in a twin-screw extruder. During this process, the calcium carbonate particles are rubbed against each other or against other materials, such as colorant particles, to reduce the (104) faces of the calcium carbonate particles and increase the number of steps (active surfaces). In addition, a high shear force is required to increase the number of steps. For this reason, high viscosity is required in step 1. This creates an interaction between the steps and the binder resin. Here, the melt-kneaded product produced in step 1 is defined as a "calcium carbonate particle dispersion."

[0042] Based on the mass of the first mixture in step 1, when the content of the binder resin is Mr (mass%) and the content of the calcium carbonate particles is Mi (mass%), the Mr and Mi are 15≦Mr≦75 0.17≦Mi / Mr≦1.3 It is preferable to satisfy the above range because, by rubbing calcium carbonate particles together or calcium carbonate particles and pigment particles together, the (104) faces of the calcium carbonate particles can be reduced and the steps (active faces) can be increased.

[0043] The melt-kneading device is not particularly limited, but examples include batch kneaders such as pressure kneaders and Banbury mixers, TEM extruders (manufactured by Toshiba Machine Co., Ltd.), TEX twin-screw kneaders (manufactured by The Japan Steel Works, Ltd.), PCM kneaders (manufactured by Ikegai Iron Works, Ltd.), and Kneedex (manufactured by Mitsui Mining Co., Ltd.). Continuous kneaders such as single-screw or twin-screw extruders are preferred over batch kneaders due to their advantages, such as continuous production. In addition, the peripheral speed of the outer end of the kneading shaft is preferably 78 mm / s or higher. The peripheral speed is defined as the distance traveled per second by a point on the outer end of the kneading shaft of the extruder. The peripheral speed is calculated by multiplying the shaft diameter (mm) by the circumference of the shaft by the number of revolutions (rpm) / 60. A peripheral speed within the above range reduces the number of (104) faces of the calcium carbonate particles and increases the number of steps (active surfaces).

[0044] The calcium carbonate particle dispersion obtained by melt-kneading is rolled using a two-roll mill or the like after melt-kneading, and then cooled through a cooling step in which the dispersion is cooled using water or the like.

[0045] The cooled calcium carbonate particle dispersion obtained above is then pulverized to a desired particle size in a pulverization step. In the pulverization step, the calcium carbonate particle dispersion is first coarsely pulverized using a crusher, hammer mill, feather mill, or the like, and then finely pulverized using a Kryptron System (manufactured by Kawasaki Heavy Industries, Ltd.), a Super Rotor (manufactured by Nisshin Engineering, Inc.), or the like, to obtain calcium carbonate particle dispersion fine particles. These calcium carbonate particle dispersion fine particles are used as the second mixture.

[0046] <Process 2> Step 2 is a step of obtaining a toner using the second mixture obtained in step 1. In the raw material mixing step, predetermined amounts of the second mixture, binder resin, hydrocarbon wax, and other toner raw materials are weighed, blended, and mixed. The mixing device is not particularly limited, but examples include a Henschel mixer (manufactured by Nippon Coke Company); a Supermixer (manufactured by Kawata Corporation); a Ribocone (manufactured by Okawara Manufacturing Co., Ltd.); a Nauta mixer, a Turbulizer, and a Cyclomix (manufactured by Hosokawa Micron Corporation); a Spiral Pin Mixer (manufactured by Pacific Machinery Works, Ltd.); and a Lödige mixer (manufactured by Matsubo Corporation). In step 2, based on the mass of the second mixture, the content of the remaining binder resin to be added is preferably 30% by mass or more and 75% by mass or less. When within this range, the calcium carbonate, which has many steps, contained in the second mixture and the binder resin interact appropriately, improving abrasion resistance.

[0047] Next, the toner raw materials including the second mixture are melt-kneaded in a twin-screw extruder. In the melt-kneading step, a batch kneader such as a pressure kneader or a Banbury mixer, or a continuous kneader can be used, but a single-screw or twin-screw extruder is preferred because of its advantage of allowing continuous production. The melt-kneading temperature is preferably about 100 to 200°C.

[0048] <Crushing process> The pulverization step is a step in which the kneaded product obtained after steps 1 and 2 is cooled to a pulverizable hardness, and then mechanically pulverized to a toner particle size using a known pulverizer such as an impact plate jet mill, a fluidized bed jet mill, or a rotary mechanical mill. From the viewpoint of pulverization efficiency, it is desirable to use a fluidized bed jet mill as the pulverizer. Examples of grinding machines include counter jet mills, micron jets, and inomizers (manufactured by Hosokawa Micron Corporation); IDS-type mills and PJM jet grinders (manufactured by Nippon Pneumatic Mfg. Co., Ltd.); cross jet mills (manufactured by Kurimoto Iron Works); Urmax (manufactured by Nisso Engineering Co., Ltd.); SK Jet-O-Mill (manufactured by Seishin Enterprise Co., Ltd.); Cryptron (manufactured by Kawasaki Heavy Industries, Ltd.); Turbo Mill (manufactured by Turbo Kogyo Co., Ltd.); and Super Rotor (manufactured by Nisshin Engineering Co., Ltd.).

[0049] <Classification process> The classification step is a step in which the finely pulverized product obtained in the pulverization step is classified to obtain toner particles having a desired particle size distribution. The classifier used for classification may be a known device such as an air classifier, an inertial classifier, or a sieve classifier. Specific examples include Cruseal, Micron Classifier, and Spedic Classifier (manufactured by Seishin Enterprise Co., Ltd.), Turbo Classifier (manufactured by Nisshin Engineering Inc.), Micron Separator, Turboflex (ATP), and TSP Separator (manufactured by Hosokawa Micron Corporation), Elbow Jet (manufactured by Nittetsu Mining Co., Ltd.), Dispersion Separator (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and YM Microcut (manufactured by Yaskawa Corporation).

[0050] If necessary, inorganic fine particles such as silica, alumina, titania, etc., or resin fine particles such as vinyl resin, polyester resin, or silicone resin may be added to the toner particles prepared through the above steps by applying shear force in a dry state. These inorganic fine particles and resin fine particles function as external additives such as a flowability aid or a cleaning aid.

[0051] The weight average particle size of the toner of the present invention is preferably 3.0 μm or more and 20.0 μm or less, and more preferably 4.0 μm or more and 10.0 μm or less. [Example]

[0052] The present invention will be described in more detail below using examples and comparative examples, but these do not limit the present invention in any way. Note that when simply referring to "parts", it means "parts by mass". Various physical properties related to the present invention were measured by the following methods.

[0053] <Method for separating toner particles from toner> Add 160 g of sucrose (Kishida Chemical) to 100 mL of ion-exchange water and dissolve in a hot water bath to prepare a concentrated sucrose solution. Add 31 g of the above concentrated sucrose solution and 6 mL of Contaminon N (a 10% by weight aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) to a centrifuge tube to prepare a dispersion. Add 1.0 g of toner to this dispersion, and break up any toner clumps with a spatula or similar. Next, shake the centrifuge tube in a shaker. After shaking, transfer the solution to a 50 mL glass tube for a swing-out rotor and separate it in a centrifuge at 3500 rpm for 30 minutes. This operation separates the toner particles from the external additives that have come off. After visually confirming that the toner particles and the aqueous solution have been sufficiently separated, the toner particles are collected and filtered using a vacuum filter, and then dried in a dryer for at least one hour to obtain toner particles from which the external additives have been separated (filtrate 1).

[0054] <Method for measuring calcium carbonate content> Filtrate 1 is immersed in 0.1 mol / L hydrochloric acid, treated with ultrasound for 10 minutes, and then left to stand for 3 hours. The resulting liquid is filtered to obtain Filtrate 2. Since calcium carbonate reacts with hydrochloric acid and dissolves, the calcium carbonate content Mc is determined by measuring the mass difference between Filtrate 2 and Filtrate 1.

[0055] <Method for measuring the aspect ratio of calcium carbonate particles> Cross-sectional observation of the toner with a scanning electron microscope and evaluation of the aspect ratio of calcium carbonate particles can be carried out by cross-sectional observation as follows. By observing the cross section of the toner, calcium carbonate particles are observed as a clear contrast. Toner particle cross sections can be prepared by placing toner particles on carbon tape, sputtering PtPd for 60 seconds, and scraping it off with argon ion beam irradiation. Cross-sectional images of toner particles are obtained using a backscattered electron imaging method using a Hitachi ultra-high resolution field emission scanning electron microscope S-4800 (Hitachi High-Technologies Corporation). Calcium carbonate particles in the toner particle cross-sectional images are identified using an energy dispersive X-ray spectrometer (EDAX) or similar. The aspect ratio of calcium carbonate particles is defined as the ratio of the long diameter to the short diameter of the calcium carbonate particles. The long diameter of calcium carbonate particles can be measured as the length in the longitudinal direction (the length of the long side) when the calcium carbonate particles are considered as cubes. The short diameter of calcium carbonate particles can be measured as the length in the lateral direction (the length of the short side) when the calcium carbonate particles are considered as rectangles. The above aspect ratio is measured for 100 calcium carbonate particles, and the average value is taken as the aspect ratio.

[0056] <Method for measuring weight average particle size (D4) of toner particles> The weight-average particle size (D4) of the toner particles is measured with an effective number of 25,000 measurement channels using a precision particle size distribution measuring device equipped with a 50 μm aperture tube and using the narrow-pore electrical resistance method, "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter, Inc.), and the accompanying dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter, Inc.), for setting measurement conditions and analyzing measurement data, and the weight-average particle size (D4) is calculated by analyzing the measurement data. The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in ion-exchanged water to a concentration of approximately 1% by mass, such as "ISOTON II" (manufactured by Beckman Coulter).

[0057] Before carrying out the measurements and analysis, the dedicated software is set up as follows. In the "Change Standard Measurement Method (SOM)" screen of the dedicated software, set the total count in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to the value obtained using "Standard Particle 10.0 μm" (Beckman Coulter). Press the threshold / noise level measurement button to automatically set the threshold and noise level. Also, set the current to 1600 μA, the gain to 2, the electrolyte to ISOTON II, and check "Flush aperture tube after measurement." In the dedicated software's "Pulse to particle size conversion setting screen," set the bin interval to logarithmic particle size, the particle size bin to 256 particle size bins, and the particle size range to 1 μm or more and 30 μm or less.

[0058] The specific measurement method is as follows. (1) Pour approximately 200 ml of the electrolyte solution into a 250 ml round-bottom glass beaker made specifically for the Multisizer 3, set it on the sample stand, and stir the stirrer rod counterclockwise at 24 revolutions per second. Then, use the "aperture flush" function of the analysis software to remove any dirt or air bubbles from inside the aperture tube.

[0059] (2) Approximately 30 ml of the above-mentioned aqueous electrolyte solution is placed in a 100 ml flat-bottom glass beaker, and approximately 0.3 ml of a dilution obtained by diluting "Contaminon N" (a 10% by weight aqueous solution of a neutral detergent for cleaning precision measuring instruments, pH 7, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by weight with ion-exchanged water is added as a dispersant.

[0060] (3) A predetermined amount of ion-exchanged water is placed in the water tank of an ultrasonic disperser "Ultrasonic Dispension System Tetora150" (manufactured by Nikkaki Bios Co., Ltd.) that has two built-in oscillators with an oscillation frequency of 50 kHz and a phase difference of 180 degrees and an electrical output of 120 W, and approximately 2 ml of the Contaminon N is added to this water tank.

[0061] (4) Set the beaker of (2) in the beaker fixing hole of the ultrasonic disperser and operate the ultrasonic disperser. Then, adjust the height position of the beaker so that the resonance state of the liquid surface of the electrolytic aqueous solution in the beaker is maximized.

[0062] (5) With the electrolytic aqueous solution in the beaker of (4) irradiated with ultrasonic waves, add about 10 mg of toner little by little to the electrolytic aqueous solution and disperse it. Then, continue the ultrasonic dispersion treatment for another 60 seconds. In ultrasonic dispersion, appropriately adjust so that the water temperature in the water tank is 10°C or higher and 40°C or lower.

[0063] (6) Drop the electrolyte aqueous solution of (5) in which the toner is dispersed into the round-bottom beaker of (1) installed in the sample stand using a pipette, and adjust so that the measured concentration becomes about 5%. Then, perform the measurement until the number of measured particles reaches 50,000.

[0064] (7) Analyze the measurement data using the dedicated software attached to the device, and calculate the weight average particle diameter (D4). Note that when set to graph / weight% in the dedicated software, the "average diameter" on the analysis / weight statistical value (arithmetic mean) screen is the weight average particle diameter (D4).

[0065] <Measurement method of X-ray diffraction> For X-ray diffraction measurement, use the measurement device "RINT-TTRII" (manufactured by Rigaku Corporation), and the control software and analysis software attached to the device. The measurement conditions are as follows. X-ray: Cu / 50 kV / 300 mA Goniometer: Rotor horizontal goniometer (TTR-2) Attachment: Standard sample holder Divergence slit: Open Divergence vertical limiting slit: 10.00 mm Scattering slit: Open Receiving slit: Open Counter: Scintillation counter Scanning mode: Continuous Scan speed: 4.0000° / min Sampling width: 0.0200° Scanning axis: 2θ / θ Scanning range: 10.0000°~40.0000° Next, the toner particles are placed on the sample plate and the measurement is started. For CuKα characteristic X-rays, the Bragg angle is θ, the diffraction angle is 2θ, and an X-ray diffraction spectrum is obtained with 2θ in the range of 3° to 35°, with the diffraction angle 2θ on the horizontal axis and the X-ray intensity on the vertical axis.

[0066] <Preparation of calcium carbonate particles> Details of the calcium carbonate used in the examples and comparative examples are shown in Table 1. The aspect ratios and major diameters shown in Table 1 were determined from images of the raw material calcium carbonate particles alone observed with a transmission electron microscope.

[0067] [Table 1]

[0068] <Production Example of Crushed Calcium Carbonate Particles 7> Diethylene glycol (DEG) and sodium chloride were kneaded at 40°C in a planetary kneader (TX-15, manufactured by Inoue Seisakusho Co., Ltd.). The kneaded mixture was placed in a mixing vessel with a stirrer containing calcium carbonate particles 7 shown in Table 1 above, and ion-exchanged water was added and stirred to dissolve the diethylene glycol and sodium chloride in the water. The solid content was filtered out, thoroughly washed with ion-exchanged water, and then vacuum-dried at 40°C for 24 hours to obtain crushed calcium carbonate particles 7. Details of the obtained crushed calcium carbonate particles are shown in Table 2. The aspect ratios and major axes shown in Table 2 were determined from images of individual calcium carbonate particles observed with a transmission electron microscope. In the production of the toner 20, the crushed calcium carbonate particles 7 were used.

[0069] [Table 2]

[0070] <Production Example of Calcium Carbonate Particle Dispersion 1> Pigment 30.4 parts by mass (Cyan pigment: Pigment Blue 15:3, weight average particle size 102nm) Calcium carbonate particles 1 (C1) 21.6 parts by mass (Light calcium carbonate Socal P3, number average particle size 0.4 μm) Binder resin 48.0 parts by mass Amorphous polyester A1: composition (molar basis) [polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: isophthalic acid: terephthalic acid = 100:50:50], softening temperature (Tm) = 122°C, glass transition temperature (Tg) = 70°C, SP value = 22.6 (J / cm 3 ) 0.5 ) The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1 After mixing for 5 minutes, the mixture was kneaded at 120°C in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation) (Step 1). The resulting kneaded mixture was cooled and coarsely pulverized in a pin mill to a weight average particle size of 100 μm or less, yielding coarsely pulverized pigment dispersion 1. The melt viscosity of amorphous polyester A1 at 120°C was 2080 Pa sec. The number average particle size of the pigment in the resulting pigment dispersion was 55 nm.

[0071] <Production Examples of Calcium Carbonate Particle Dispersions 2 to 13 and 15 to 29> Coarsely crushed calcium carbonate particle dispersions 2 to 13 and 15 to 29 were obtained in the same manner as in Production Example 1 of Calcium Carbonate Particle Dispersion 1, except that the blending ratios of the binder resin, calcium carbonate particles, and pigment were adjusted as shown in Table 3. In Table 3, Mr is the blending ratio of the binder resin, Mi is the blending ratio of the calcium carbonate particles, and Mp is the blending ratio of the pigment particles.

[0072] [Table 3]

[0073] <Production Example of Calcium Carbonate Particle Dispersion 14> The blending ratio of the binder resin, calcium carbonate particles, and pigment was the same as that of Calcium Carbonate Particle Dispersion 1. These materials were kneaded at 150°C using a planetary kneader (TX-15, manufactured by Inoue Seisakusho Co., Ltd.). The resulting kneaded product was cooled and coarsely pulverized using a pin mill to a weight average particle size of 100 μm or less, thereby obtaining coarsely pulverized calcium carbonate particle dispersion 14.

[0074] <Toner 1 manufacturing example> Amorphous polyester A1 80.0 parts by mass (Composition (molar basis) [polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: isophthalic acid: terephthalic acid = 100:50:50], softening temperature (Tm) = 122 ° C, glass transition temperature (Tg) = 70 ° C, SP value = 22.6 (J / cm 3 ) 0.5 ) Calcium carbonate particle dispersion 1 11.5 parts by mass Synthetic wax 8.0 parts by weight (Hydrocarbon wax, maximum endothermic peak temperature 90℃) The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1 After mixing for 5 minutes, the mixture was kneaded in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation) (Step 2). The resulting kneaded mixture was cooled and coarsely pulverized in a pin mill to a weight average particle size of 100 μm or less to obtain a coarsely pulverized product. The coarsely pulverized product was then finely pulverized in a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.) by adjusting the rotation speed and number of passes to obtain the target particle size. Further, classification was carried out using a rotary classifier (200TSP, manufactured by Hosokawa Micron Corporation) to obtain toner particles. The rotation speed of the rotary classifier (200TSP, manufactured by Hosokawa Micron Corporation) was adjusted to obtain the target particle size and particle size distribution. 100 parts by mass of the resulting toner particles were mixed with 100 parts by mass of a toner having a specific surface area of ​​200 m2 measured by the BET method. 2 1.8 parts by mass of silica fine particles hydrophobized with silicone oil were added, and the mixture was mixed in a Henschel mixer (FM-75, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 30 s -1The mixture was mixed for a rotation time of 10 minutes to obtain Toner 1. The weight average particle size (D4) of the toner was 6.5 μm.

[0075] <Production Examples of Toners 2 to 19, 21 to 24, Comparative Toner 2, and Comparative Toners 4 and 5> Toners 2 to 19, toners 21 to 24, comparative toner 2, and comparative toners 4 and 5 were obtained in the same manner as in the production example of toner 1, except that the conditions for the binder resin, crystalline polyester, and calcium carbonate particles were changed as shown in Table 4.

[0076] [Table 4]

[0077] <Toner 20 manufacturing example> Amorphous polyester A1 82.8 parts by mass (Composition (molar basis) [polyoxypropylene(2.2)-2,2-bis(4-hydroxyphenyl)propane: isophthalic acid: terephthalic acid = 100:50:50], softening temperature (Tm) = 122 ° C, glass transition temperature (Tg) = 70 ° C, SP value = 22.6 (J / cm 3 ) 0.5 ) Crushed calcium carbonate particles C7 4.31 parts by mass Crystalline polyester 0.50 parts by mass Synthetic wax 8.0 parts by weight (Hydrocarbon wax, maximum endothermic peak temperature 90℃) The above materials were mixed in a Henschel mixer (FM-75 model, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 20 s. -1After mixing for 5 minutes, the mixture was kneaded in a twin-screw kneader (PCM-30, manufactured by Ikegai Corporation). The resulting kneaded mixture was cooled and coarsely pulverized in a pin mill to a weight average particle size of 100 μm or less to obtain a coarsely pulverized product. The coarsely pulverized product was then finely pulverized in a mechanical pulverizer (T-250, manufactured by Turbo Kogyo Co., Ltd.) by adjusting the rotation speed and number of passes to obtain the target particle size. Further, classification was performed using a rotary classifier (200TSP, manufactured by Hosokawa Micron Corporation) to obtain toner particles. The operating conditions of the rotary classifier (200TSP, manufactured by Hosokawa Micron Corporation) were such that the rotation speed was adjusted to obtain the target particle size and particle size distribution. 100 parts by mass of the resulting toner particles were mixed with a mixture of 200 parts by mass of toner having a specific surface area of ​​200 m2 measured by the BET method. 2 1.8 parts by mass of silica fine particles hydrophobized with silicone oil were added, and the mixture was mixed in a Henschel mixer (FM-75, manufactured by Mitsui Mining Co., Ltd.) at a rotation speed of 30 s -1 The mixture was mixed at a rotation time of 10 minutes to obtain Toner 20.

[0078] <Production examples of comparative toner 1 and comparative toner 3> Comparative toners 1 and 3 were obtained in the same manner as in the production example of toner 20, except that the conditions for the binder resin, crystalline polyester, and calcium carbonate particles added in the production example of toner 20 were changed as shown in Table 4. The crystallinity of calcium carbonate particles was evaluated in Toners 1 to 24 and Comparative Toners 1 to 5. The results of the toner analysis are shown in Table 5.

[0079] [Table 5]

[0080] <Production example of magnetic core particle 1> Process 1 (weighing and mixing process): Fe2O362.7 parts MnCO329.5 parts Mg(OH)26.8 parts SrCO31.0 parts The ferrite raw materials were weighed so as to achieve the above composition ratio, and then pulverized and mixed for 5 hours in a dry vibration mill using stainless steel beads with a diameter of 1 / 8 inch.

[0081] Step 2 (pre-baking): The resulting pulverized material was made into pellets of approximately 1 mm square using a roller compactor. The pellets were passed through a vibrating sieve with 3 mm openings to remove coarse particles, and then through a vibrating sieve with 0.5 mm openings to remove fine particles. The pellets were then fired in a burner-type firing furnace at 1000°C for 4 hours in a nitrogen atmosphere (oxygen concentration 0.01% by volume) to produce calcined ferrite. The composition of the resulting calcined ferrite was as follows: (MnO) a (MgO) b (SrO) c (Fe2O3) d In the above formula, a=0.257, b=0.117, c=0.007, d=0.393

[0082] Step 3 (Crushing): The obtained calcined ferrite was crushed to about 0.3 mm using a crusher, and then 30 parts of water was added to 100 parts of the calcined ferrite and crushed in a wet ball mill using zirconia beads with a diameter of 1 / 8 inch for 1 hour. The obtained slurry was crushed in a wet ball mill using alumina beads with a diameter of 1 / 16 inch for 4 hours to obtain a ferrite slurry (finely crushed calcined ferrite).

[0083] ·Process 4 (granulation process): To the ferrite slurry, 1.0 part of ammonium polycarboxylate as a dispersant and 2.0 parts of polyvinyl alcohol as a binder were added per 100 parts of calcined ferrite, and the mixture was granulated into spherical particles using a spray dryer (manufacturer: Okawahara Kakoki Co., Ltd.). After adjusting the particle size of the resulting particles, they were heated in a rotary kiln at 650°C for 2 hours to remove the organic components of the dispersant and binder.

[0084] Step 5 (firing): To control the firing atmosphere, the material was heated from room temperature to 1300°C in a nitrogen atmosphere (oxygen concentration 1.00% by volume) in an electric furnace over two hours, and then fired at 1150°C for four hours. The material was then cooled to 60°C over four hours, returned from the nitrogen atmosphere to the air, and removed at a temperature of 40°C or below.

[0085] Step 6 (sorting step): After crushing the agglomerated particles, low magnetic particles were removed by magnetic separation, and coarse particles were removed by sieving through a sieve with a mesh size of 250 μm to obtain magnetic core particles 1 with a volume distribution-based 50% particle size (D50) of 37.0 μm.

[0086] <Preparation of Coating Resin 1> Cyclohexyl methacrylate monomer 26.8% by mass Methyl methacrylate monomer 0.2% by mass Methyl methacrylate macromonomer 8.4% by mass (a macromonomer with a weight-average molecular weight of 5000 and a methacryloyl group at one end) Toluene 31.3% by mass Methyl ethyl ketone 31.3% by mass Azobisisobutyronitrile 2.0% by mass Of the above materials, cyclohexyl methacrylate monomer, methyl methacrylate monomer, methyl methacrylate macromonomer, toluene, and methyl ethyl ketone were placed in a four-neck separable flask equipped with a reflux condenser, thermometer, nitrogen inlet tube, and stirrer, and nitrogen gas was introduced to create a sufficient nitrogen atmosphere. The mixture was then heated to 80°C, azobisisobutyronitrile was added, and the mixture was refluxed for 5 hours to polymerize. Hexane was then poured into the resulting reaction mixture to precipitate the copolymer. The precipitate was then filtered and vacuum dried to obtain Coating Resin 1.

[0087] <Preparation of Coating Resin Solution 1> 33.3% by mass of polymer solution 1 (resin solids concentration 30%) prepared by dissolving 30 parts of coating resin 1 in 40 parts of toluene and 30 parts of methyl ethyl ketone; 66.4% by weight of toluene, and Carbon black Regal 330 (manufactured by Cabot) 0.3% by mass (Primary particle size 25 nm, nitrogen adsorption specific surface area 94 m 2 / g, DBP oil absorption 75mL / 100g) The resulting dispersion was dispersed for 1 hour using zirconia beads with a diameter of 0.5 mm in a paint shaker. The resulting dispersion was filtered through a 5.0 μm membrane filter to obtain coating resin solution 1.

[0088] <Magnetic Carrier 1 Manufacturing Example> (Resin coating process): Magnetic core particles 1 and coating resin solution 1 were added to a vacuum degassing kneader maintained at room temperature (the amount of coating resin solution 1 added was 2.5 parts as a resin component per 100 parts of magnetic core particles 1). After addition, the mixture was stirred at a rotation speed of 30 rpm for 15 minutes, and after a certain amount of the solvent (80% by mass) had evaporated, the mixture was heated to 80°C while mixing under reduced pressure, and the toluene was distilled off over 2 hours, after which it was cooled. The obtained magnetic carrier was separated into low magnetic particles by magnetic separation, passed through a sieve with 70 μm openings, and then classified with an air classifier to obtain magnetic carrier 1 having a 50% particle size (D50) based on volume distribution of 38.2 μm.

[0089] <Production of two-component developer 1> To 92.0 parts of magnetic carrier 1, 8.0 parts of toner 1 were added and mixed in a V-type mixer (V-20, manufactured by Seishin Enterprises) to obtain two-component developer 1.

[0090] <Production of Two-Component Developers 2 to 24 and Comparative Two-Component Developers 1 to 5> In the production example of two-component developer 1, the same procedure was carried out except that the combinations were changed to toners 2 to 24 and comparative toners 1 to 5, to obtain two-component developers 2 to 24 and comparative two-component developers 1 to 5. As the image forming device, a modified Canon imageRUNNER ADVANCE C9075 PRO digital commercial printing printer was used, and a two-component developer was placed in the developer unit in the cyan position. The DC voltage V of the developer carrier was adjusted so that the amount of toner on the electrostatic latent image carrier or paper was as desired. DC, the charging voltage V of the electrostatic latent image carrier D The laser power was adjusted and the evaluation described below was carried out. The modification was made so that the fixing temperature and process speed could be freely set.

[0091] Example 1 Using two-component developer 1, the abrasion resistance and low-temperature fixability were evaluated by the following methods. <Test Example 1: Evaluation of Scratch Resistance> Paper: OK Topcoat+, Oji Paper, 127 g / m 2 Evaluation image: Halftone image (image density: 0.20 to 0.25) The image density was measured using a Macbeth Reflection Densitometer RD918 (manufactured by Macbeth) according to the attached instruction manual by measuring the relative density of the image in the white background area where the image density was 0.00, and the obtained relative density was used as the image density value. On top of the image sample above, paper (OK Topcoat+, Oji Paper, 127 g / m 2 ) and place a 500g weight on top of it with a contact area of ​​12.6cm 2 The paper was then placed on the paper so that it was 12.6 cm thick and rubbed 10 times to perform an abrasion resistance test. 2 The toner adhering to the area (the area where the weight was placed) was measured with a fog meter, and the fog values ​​obtained were evaluated according to the following criteria. The evaluation results are shown in Table 6. [Evaluation criteria] Rank A: Fog is 2% or less Rank B: Fog is 2% or more but less than 5% Rank C: Fog is 5% or more but less than 10% Rank D: Over 10%

[0092] <Test Example 2: Evaluation of low-temperature fixability> Paper: CF-C104 (104.0g / m 2 ) (Sold by Canon Marketing Japan Inc.) Toner amount on paper: 0.90 mg / cm 2 Evaluation image: 25cm from the center of the above A4 paper 2 Place the image Fixing test environment: Low temperature and low humidity environment: Temperature 15°C / Humidity 10% RH (hereinafter referred to as "L / L") After adjusting the DC voltage VDC of the developer carrier, the charging voltage VD of the electrostatic latent image carrier, and the laser power so that the toner loading amount on the paper was as described above, the process speed was set to 300 mm / sec and the fixing temperature to 130°C, and the low-temperature fixability was evaluated. The image density reduction rate was used as an evaluation index for low-temperature fixability. The image density reduction rate was measured using an X-Rite color reflection densitometer (500 series: manufactured by X-Rite Corporation), first measuring the image density at the center. Next, the area where the image density was measured was subjected to pressure of 4.9 kPa (50 g / cm). 2 The fixed image was rubbed (five times back and forth) with Silbon paper under a load of 1000 kJ / cm2, and the image density was measured again. The reduction rate (%) of image density before and after rubbing was then measured. The evaluation results are shown in Table 6. The evaluation criteria were as follows: [Evaluation criteria] Rank A: Concentration reduction rate less than 1.0% Rank B: Density reduction rate 1.0% or more but less than 5.0% Rank C: Density reduction rate 5.0% or more but less than 10.0% Rank D: Density reduction rate 10.0% or more

[0093] <Examples 2 to 24 and Comparative Examples 1 to 5> The evaluation of abrasion resistance and low-temperature fixability was carried out in the same manner as in Example 1, except that the two-component developer 1 used was changed to two-component developers 2 to 24 and comparative two-component developers 1 to 5. The evaluation results are shown in Table 6.

[0094] [Table 6]

[0095] In Comparative Example 1, calcium carbonate was added from step 2 onward to produce the toner. As a result, the number of steps on the (104) plane was small, and the peak intensity ratio was 0.14, which is outside the range for obtaining the effects of the present invention. It is presumed that this resulted in an unacceptable level of abrasion resistance. In Comparative Example 2, the amount of calcium carbonate added in step 1 was small. As a result, it is presumed that the opportunity for calcium carbonate particles to rub against each other in step 1 was extremely reduced, resulting in a toner with a large crystallite size. It is presumed that the area for interaction with the resin was reduced, resulting in an unacceptable level of abrasion resistance. In Comparative Example 3, calcium carbonate C5 was added from step 2. The resulting toner had a small number of steps on the (104) plane and a large crystallite size. As a result, it is presumed that the effects of the present invention were not fully achieved and the abrasion resistance was at an unacceptable level. In Comparative Example 4, calcium carbonate particles are not present in the toner. The interaction between calcium carbonate and resin is not obtained, and the toner cohesion force is reduced. As a result, it is presumed that the effects of the present invention are not fully achieved, and the abrasion resistance is at an unacceptable level. In Comparative Example 5, the peripheral speed during production of the calcium carbonate particle dispersion was as low as 47.1 mm / s. As a result, steps on the (104) plane of the calcium carbonate particles were not easily formed, and the peak intensity ratio between the (104) plane and the (112) plane obtained from XRD measurement was as low as 0.13. This suggests that the interaction with the binder resin was weak, resulting in an unacceptable level of abrasion resistance. Among the examples, some toners were ranked B or C in low temperature fixability. This is thought to be due to the fact that the number of steps on the (104) plane of the calcium carbonate used was too large, resulting in poor low temperature fixability. According to the present invention, it is possible to provide a toner that has improved low-temperature fixability and excellent abrasion resistance of images.

Claims

1. A method for producing a toner, comprising: The method for producing the toner includes: Step 1: Melting and kneading a first mixture containing a portion of the binder resin and calcium carbonate particles in a twin-screw extruder to obtain a molten mixture; Step 2: melt-kneading a second mixture containing the molten mixture and the remaining binder resin; Including, When the content of the binder resin in the first mixture is defined as Mr (mass%) and the content of the calcium carbonate particles in the first mixture is defined as Mi (mass%), based on the mass of the first mixture, the Mr and the Mi satisfy the following conditions: 15≦Mr≦75 0.17≦Mi / Mr≦1.3 Fulfilling The toner produced through the steps 1 and 2 has toner particles containing a binder resin and calcium carbonate particles, In X-ray diffraction measurement of the toner particles using CuKα rays when the Bragg angle is θ, the calcium carbonate particles contained in the toner particles (i) having peaks at 26.5°±0.5° and 29.5°±0.5° in 2θ; (ii) the crystallite diameter of the crystals at 2θ = 29.5 ° ± 0.5 ° is 10 nm or more and 45 nm or less; (iii) the ratio (a / b) of the peak intensity “a” at 2θ=26.5°±0.5° to the peak intensity “b” at 2θ=29.5°±0.5° is 0.15 or more and 0.24 or less; A method for producing a toner comprising the steps of:

2. A method for producing a toner as described in claim 1, wherein the content of the remaining binder resin added in step 2 is 30 mass% or more and 75 mass% or less, based on the mass of the second mixture.

3. 3. The method for producing a toner according to claim 1, wherein the peripheral speed of the outer end of the kneading shaft of the twin-screw extruder in the step 1 is 78 mm / s or more.

4. In X-ray diffraction measurement of the toner particles using CuKα rays when the Bragg angle is θ, the calcium carbonate particles contained in the toner particles are 4. The method for producing a toner according to claim 1, wherein a ratio (a / b) of a peak intensity "a" at 2θ=26.5°±0.5° to a peak intensity "b" at 2θ=29.5°±0.5° is 0.17 or more and 0.20 or less.

Images