Toner

Abstract

To provide a toner that can form an image excellent in image density.SOLUTION: A toner includes toner particles 1. The toner particles 1 include a toner base particle 2 and an external additive attached to a surface of the toner base particle 2. The external additive includes specific external additive particles 3. A number average primary particle diameter of the specific external additive particles 3 is 30 nm or more and 305 nm or less. The specific external additive particles 3 include antimony-doped tin oxide particles or indium tin oxide particles. In the antimony-doped tin oxide particles, the ratio (MSb / (MSn+MSb)) of the mass of antimony atoms (MSb) to the total of the mass of the antimony atoms (MSb) and the mass of tin atoms (MSn) is 4% by mass or more and 46% by mass or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to toner.

Background Art

[0002] In electrophotographic image formation, toner containing toner particles is used. The toner particles include, for example, toner mother particles and external additives attached to the surface of the toner mother particles. As the external additive used for the toner particles, polishing particles may be used for the purpose of polishing the surface of a photoreceptor (for example, an amorphous silicon photoreceptor). As such an external additive, conductive fine particles subjected to a hydrophobization treatment have been proposed (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the toner using the external additive described in Patent Document 1 does not have sufficient image density of the formed image.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a toner capable of forming an image excellent in image density.

Means for Solving the Problems

[0006] The toner according to the present invention includes toner particles. The toner particles include toner base particles and an external additive attached to the surface of the toner base particles. The external additive includes specific external additive particles. The specific external additive particles have a number average primary particle diameter of 30 nm or more and 305 nm or less. The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles. In the antimony-doped tin oxide particles, the mass (M Sb ) and the mass of the tin atom (M Sn ) to the total mass of antimony atoms (M Sb ) ratio (M Sb / (M Sn +M Sb )) is 4 mass % or more and 46 mass % or less. Effect of the Invention

[0007] The toner according to the present invention can form images having excellent image density. [Brief description of the drawings]

[0008]

Figure 1

[0009] A preferred embodiment of the present invention will be described below. The toner is an aggregate (e.g., powder) of toner particles. The external additive is an aggregate (e.g., powder) of external additive particles. Unless otherwise specified, the evaluation results (values ​​indicating shape, physical properties, etc.) of the powder (more specifically, the powder of toner particles, the powder of external additive particles, etc.) are the number averages of values ​​measured for each of a considerable number of particles selected from the powder.

[0010] Volume median diameter of powder (D 50 Unless otherwise specified, the measured values ​​of are values ​​measured based on the Coulter principle (pore electrical resistance method) using a Coulter Counter Multisizer 3 manufactured by Beckman Coulter, Inc.

[0011] If not otherwise specified, the number-average primary particle diameter of the powder is the number-average value of the equivalent circle diameters (Heywood diameters: the diameters of circles having the same area as the projected area of the primary particles) of the primary particles measured using a scanning electron microscope. The number-average primary particle diameter of the powder is, for example, the number-average value of the equivalent circle diameters of 100 primary particles. Unless otherwise specified, the number-average primary particle diameter of the particles refers to the number-average primary particle diameter of the particles in the powder.

[0012] If not otherwise specified, the chargeability means the chargeability in triboelectrification. For example, the measurement target (e.g., toner) is triboelectrically charged by mixing and stirring a standard carrier provided by the Japan Society for Imaging Science and Technology (standard carrier for negatively charged toner: N-01, standard carrier for positively charged toner: P-01) and the measurement target. Before and after triboelectric charging, the charge amount of the measurement target is measured using, for example, a suction-type small charge amount measuring device ("MODEL 212HS" manufactured by Trek), and it shows that the greater the change in the charge amount before and after triboelectric charging of the measurement target, the stronger the chargeability.

[0013] If not otherwise specified, the "main component" of a material means the component most contained in the material on a mass basis.

[0014] Hereinafter, when a "system" is attached after a compound name to comprehensively refer to a compound and its derivatives, it may be the case. When a polymer name is represented by attaching a "system" after a compound name, it means that the repeating unit of the polymer is derived from the compound or its derivative.

[0015] <Toner> The toner according to an embodiment of the present invention includes toner particles. The toner particles include toner mother particles and external additives attached to the surface of the toner mother particles. The external additives include specific external additive particles. The number-average primary particle diameter of the specific external additive particles is 30 nm or more and 305 nm or less. The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles. In the antimony-doped tin oxide particles, the mass of antimony atoms (M Sb ) and the mass of tin atoms (M SnThe mass (M) of antimony atoms relative to the total Sb ) ratio (M Sb / (M Sn +M Sb )) (hereinafter sometimes referred to as the Sb ratio) is 4% by mass or more and 46% by mass or less.

[0016] The toner of the present invention can be suitably used for developing an electrostatic latent image, for example, as a positively chargeable non-magnetic one-component toner.

[0017] By having the above-described configuration, the toner of the present invention can form an image excellent in image density. The reason will be described below. The specific external additive particles contained in the toner of the present invention include antimony-doped tin oxide particles or indium tin oxide particles having an Sb ratio within a certain range. The above-described antimony-doped tin oxide particles and indium tin oxide particles reduce the electric resistance of the toner of the present invention. Therefore, the toner of the present invention is excellent in electric field responsiveness and developability when developing an electrostatic latent image on a photoreceptor drum. Further, the specific external additive particles have a number average primary particle diameter of 30 nm or more and are not overly small particles. Therefore, the specific external additive particles are difficult to be buried in the toner mother particles when continuously forming an image. Furthermore, the specific external additive particles have a number average primary particle diameter of 305 nm or less and are not overly large particles. Therefore, the specific external additive particles are difficult to detach from the toner mother particles when continuously forming an image. Thus, since the specific external additive particles have a number average primary particle diameter of 30 nm or more and 305 nm or less, they stably continue to adhere to the surface of the toner mother particles even when continuously forming an image. As a result, the toner of the present invention can form an image excellent in image density.

[0018] Hereinafter, the details of the toner of the present invention will be further described. Regarding each component described below, unless otherwise specified, it may be used alone or in combination of two or more.

[0019] [Toner particles] FIG. 1 shows an example of toner particles 1 contained in toner. The toner particles 1 shown in FIG. 1 include toner mother particles 2 and external additives attached to the surface of the toner mother particles 2. The external additives include specific external additive particles 3.

[0020] However, the toner particles contained in the toner of the present invention may have a structure different from that of the toner particles 1 shown in FIG. 1. Specifically, the toner particles may contain only specific external additive particles as external additives, or may contain other external additive particles (hereinafter sometimes referred to as other external additive particles). Further, the toner particles may be toner particles having a shell layer (hereinafter sometimes referred to as capsule toner particles). In the case of capsule toner particles, the toner mother particles include, for example, a toner core containing a binder resin and a shell layer covering the surface of the toner core. The details of the toner particles contained in the toner of the present invention have been described above with reference to FIG. 1.

[0021] (Specific external additive particles) The specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles. The number average primary particle diameter of the specific external additive particles is 30 nm or more and 305 nm or less, preferably 60 nm or more and 250 nm or less, and more preferably 100 nm or more and 200 nm or less. By setting the number average primary particle diameter of the specific external additive particles to 30 nm or more, it is possible to suppress the specific external additive particles from being buried in the toner mother particles when continuous image formation is performed. By setting the number average primary particle diameter of the specific external additive particles to 305 nm or less, it is possible to suppress the specific external additive particles from detaching from the toner mother particles when continuous image formation is performed.

[0022] The antimony-doped tin oxide particles are particles containing antimony-doped tin oxide (ATO) as a main component. In the antimony-doped tin oxide particles, the content ratio of antimony-doped tin oxide is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass.

[0023] In the antimony-doped tin oxide particles, the Sb ratio (M Sb / (M Sn +MSb )) is 4% by mass or more and 46% by mass or less, preferably 10% by mass or more and 40% by mass or less, and more preferably 20% by mass or more and 30% by mass or less. Here, tin oxide alone does not exhibit conductivity. Tin oxide with a small amount of antimony added (Sb ratio is 4% by mass or more and 46% by mass or less) is imparted with properties as a semiconductor and exhibits conductivity. Tin oxide with a large amount of antimony added (Sb ratio exceeding 46% by mass) has properties as a mere mixture of tin oxide and antimony and does not exhibit conductivity. From the above, by setting the Sb ratio to 4% by mass or more and 46% by mass or less, the conductivity of the antimony-doped tin oxide particles can be improved. As a result, the toner of the present invention can form an image excellent in image density.

[0024] Indium tin oxide particles are particles containing indium tin oxide (ITO) as a main component. In the indium tin oxide particles, the content ratio of indium tin oxide is preferably 70% by mass or more, more preferably 90% by mass or more, and still more preferably 100% by mass.

[0025] In the indium tin oxide particles, the mass of indium atoms (M In ) and the mass of tin atoms (M Sn ), the ratio of the mass of indium atoms (M In ) to the total (M In / (M Sn + M In )) (hereinafter sometimes referred to as In ratio) is preferably 4% by mass or more and 46% by mass or less, more preferably 10% by mass or more and 40% by mass or less, and still more preferably 20% by mass or more and 30% by mass or less. By setting the In ratio to 4% by mass or more and 46% by mass or less, the conductivity of the indium tin oxide particles can be improved. As a result, the toner of the present invention can form an image even more excellent in image density.

[0026] The specific additive particles are prepared, for example, using tin chloride, antimony chloride, and indium chloride as raw materials. Therefore, chlorine atoms derived from the raw materials may remain in the specific additive particles. Chlorine atoms have a high electronegativity. Therefore, specific additive particles containing a large amount of chlorine atoms tend to reduce the positive chargeability of the toner and slightly reduce the image density of the formed image. From the above, it is preferable that the specific additive particles do not contain chlorine atoms, or contain chlorine atoms and the content ratio of chlorine atoms is more than 0.000 mass% and 0.020 mass% or less.

[0027] However, it is preferable that the specific additive particles contain chlorine atoms in a small amount. Since the toner of the present invention contains specific additive particles, its electrical resistance is relatively low. Therefore, in the toner of the present invention, charge injection may occur due to the positive bias of the developing roller during development, and a phenomenon of an increase in the charge amount may occur. In a normal environment, even if this phenomenon occurs, the toner of the present invention does not become excessively charged. However, when the above phenomenon occurs in a low-temperature and low-humidity environment where the charge amount of the toner is likely to increase, the toner of the present invention may become excessively charged. When the toner of the present invention is a non-magnetic one-component toner, if the toner of the present invention becomes excessively charged, the mirror force between the toner of the present invention and the developing roller becomes excessively high, and the layer thickness of the toner layer on the developing roller increases. On the other hand, when the toner of the present invention contains a small amount of chlorine atoms, the positive chargeability of the toner of the present invention is moderately reduced. As a result, even in a low-temperature and low-humidity environment, it is possible to suppress the toner of the present invention from becoming excessively charged. From the above, it is preferable that the specific additive particles contain chlorine atoms in a small amount. Specifically, in the specific additive particles, the content ratio of chlorine atoms is preferably 0.001 mass% or more and 0.020 mass% or less, and more preferably 0.003 mass% or more and 0.010 mass% or less.

[0028] As the content of the specific additive particles in the toner particles, it is preferably 0.05 parts by mass or more and 5.0 parts by mass or less, more preferably 0.3 parts by mass or more and 1.0 parts by mass or less with respect to 100 parts by mass of the toner base particles. By setting the content of the specific additive particles to 0.05 parts by mass or more and 5.0 parts by mass or less, the image density of the image formed by the toner of the present invention can be further improved.

[0029] An example of a method for preparing the specific additive particles will be described. An acid aqueous solution in which stannous chloride (for example, stannic chloride) and antimony chloride (for example, antimony trichloride) or indium chloride (for example, indium trichloride) are dissolved in hydrochloric acid, and an alkaline aqueous solution (for example, an aqueous ammonia solution) are added to water. Thereby, a suspension containing antimony-doped tin oxide or indium tin oxide is obtained. Thereafter, after performing a washing treatment and a drying treatment on the solid content contained in the suspension, a pulverization treatment is performed to obtain the specific additive particles. When adding the above-mentioned acid aqueous solution and alkaline aqueous solution, it is preferable to maintain the pH and temperature of the suspension within a certain range (for example, pH 6.5 or more and 9.0 or less, and 60°C or more and 80°C or less). In the above-mentioned washing treatment, the content ratio of chlorine atoms in the specific additive particles can be adjusted by adjusting the number of washing times. Specifically, in the above-mentioned washing treatment, by increasing the number of washing times, the content ratio of chlorine atoms in the specific additive particles decreases. Further, in the above-mentioned pulverization treatment, the number average primary particle diameter of the specific additive particles can be adjusted by adjusting the pulverization conditions.

[0030] (Other additive particles) The additive may contain only the specific additive particles, but preferably further contains other additive particles. As the other additive particles, inorganic particles are preferable, more preferably silica particles or particles of a metal oxide (for example, alumina, titanium oxide, magnesium oxide, zinc oxide), and even more preferably silica particles or titanium oxide particles. However, as the other additive particles, particles of an organic acid compound such as a fatty acid metal salt (for example, zinc stearate) or resin particles may be used.

[0031] As the content of other externally added agent particles in the toner particles, from the viewpoint of sufficiently exerting its function while suppressing the detachment from the toner mother particles, it is preferably 0.1 part by mass or more and 15.0 parts by mass or less, more preferably 1.0 part by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the toner mother particles.

[0032] (toner mother particles) The toner mother particles contain, for example, a binder resin as a main component. The toner mother particles may further contain an internal additive (for example, at least one of a colorant, a release agent, a charge control agent, and magnetic powder) as necessary. Examples of the method for producing the toner mother particles include a pulverization method and an aggregation method, and the pulverization method is preferred.

[0033] (binder resin) From the viewpoint of providing a toner excellent in low-temperature fixability, the toner mother particles preferably contain a thermoplastic resin as the binder resin, and more preferably contain the thermoplastic resin at a ratio of 85% by mass or more of the total binder resin. Examples of the thermoplastic resin include styrene resins, acrylic ester resins, olefin resins (for example, polyethylene resins and polypropylene resins), vinyl resins (for example, vinyl chloride resins, polyvinyl alcohol, vinyl ether resins, and N-vinyl resins), polyester resins, polyamide resins, and urethane resins. In addition, copolymers of these resins, that is, copolymers in which arbitrary repeating units are introduced into the above resins (for example, styrene-acrylic ester resins and styrene-butadiene resins) can also be used as the binder resin.

[0034] The content ratio of the binder resin in the toner mother particles is preferably 60% by mass or more and 95% by mass or less, more preferably 75% by mass or more and 90% by mass or less.

[0035] From the viewpoint of improving the low-temperature fixability of the toner of the present invention, a polyester resin is preferable as the binder resin. The polyester resin is obtained by polycondensing one or more polyhydric alcohols and one or more polyvalent carboxylic acids. Examples of the alcohol for synthesizing the polyester resin include dihydric alcohols (for example, diol compounds and bisphenol compounds) and polyhydric alcohols having three or more valences. Examples of the carboxylic acid for synthesizing the polyester resin include divalent carboxylic acids and polyvalent carboxylic acids having three or more valences. Note that instead of the polyvalent carboxylic acid, a polyvalent carboxylic acid derivative capable of forming an ester bond by polycondensation (for example, an anhydride of a polyvalent carboxylic acid and a polyvalent carboxylic acid halide) may be used.

[0036] Examples of the diol compound include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4-diol, 1,5-pentanediol, 2-pentene-1,5-diol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, 1,4-benzenediol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

[0037] Examples of the bisphenol compound include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct (for example, polyoxyethylene(2,2)-2,2-bis(4-hydroxyphenyl)propane), and bisphenol A propylene oxide adduct.

[0038] Examples of alcohols with three or more hydroxyl groups include sorbitol, 1,2,3,6 - hexanetetrol, 1,4 - sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4 - butanetriol, 1,2,5 - pentanetriol, glycerol, diglycerol, 2 - methylpropanetriol, 2 - methyl - 1,2,4 - butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5 - trihydroxymethylbenzene.

[0039] Examples of dibasic carboxylic acids include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, succinic acid, alkyl succinic acids (more specifically, n - butyl succinic acid, isobutyl succinic acid, n - octyl succinic acid, n - dodecyl succinic acid, isododecyl succinic acid), and alkenyl succinic acids (more specifically, n - butenyl succinic acid, isobutenyl succinic acid, n - octenyl succinic acid, n - dodecenyl succinic acid, isododecenyl succinic acid).

[0040] Examples of carboxylic acids with three or more carboxyl groups include 1,2,4 - benzenetricarboxylic acid (trimellitic acid), 2,5,7 - naphthalenetricarboxylic acid, 1,2,4 - naphthalenetricarboxylic acid, 1,2,4 - butanetricarboxylic acid, 1,2,5 - hexanetricarboxylic acid, 1,3 - dicarboxyl - 2 - methyl - 2 - methylenecarboxylpropane, 1,2,4 - cyclohexanetricarboxylic acid, tetra(methylenecarboxyl)methane, 1,2,7,8 - octanetetracarboxylic acid, pyromellitic acid, and Empol trimer acid.

[0041] As the polyester resin, a polycondensate of a bisphenol A ethylene oxide adduct, terephthalic acid, and trimellitic anhydride is preferred.

[0042] (Colorant) The toner mother particles may contain a colorant. As the colorant, known pigments or dyes can be used according to the color of the toner of the present invention. From the viewpoint of forming a high-quality image using the toner of the present invention, 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.

[0043] The toner mother particles may contain a black colorant. Examples of the black colorant include carbon black. Further, the black colorant may be a colorant toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

[0044] The toner mother particles may contain a color colorant. Examples of the color colorant include a yellow colorant, a magenta colorant, and a cyan colorant.

[0045] The toner mother particles preferably contain a black colorant, a magenta colorant, or a cyan colorant.

[0046] As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. Pigment Yellow (3, 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), naphthol yellow S, hansa yellow G, and C.I. Vat Yellow.

[0047] As the magenta colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds can be used. Examples of the magenta colorant include C.I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, and 254).

[0048] As the cyan colorant, for example, one or more compounds selected from the group consisting of copper phthalocyanine compounds, anthraquinone compounds, and basic dye lake compounds can be used. Examples of the cyan colorant include C.I. Pigment Blue (1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66), phthalocyanine blue, C.I. Vat Blue, and C.I. Acid Blue.

[0049] (Release agent) The toner mother particles may contain a release agent. The release agent is used, for example, for the purpose of imparting offset resistance to the toner of the present invention. From the viewpoint of imparting sufficient offset resistance to the toner of the present invention, the content of the release agent 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.

[0050] Examples of the release agent include, for example, aliphatic hydrocarbon waxes, oxides of aliphatic hydrocarbon waxes, plant waxes, animal waxes, mineral waxes, ester waxes mainly composed of fatty acid esters, and waxes in which part or all of the fatty acid esters are deoxidized. Examples of the aliphatic hydrocarbon waxes include, for example, low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymers, polyolefin waxes, microcrystalline waxes, paraffin waxes, and Fischer-Tropsch waxes. Examples of the oxides of aliphatic hydrocarbon waxes include, for example, polyethylene oxide waxes and block copolymers of polyethylene oxide waxes. Examples of the plant waxes include, for example, candelilla wax, carnauba wax, wood wax, jojoba wax, and rice wax. Examples of the animal waxes include, for example, beeswax, lanolin, and spermaceti wax. Examples of the mineral waxes include, for example, ozokerite, ceresin, and petrolatum. Examples of the ester waxes mainly composed of fatty acid esters include, for example, montanic acid ester waxes and castor waxes. Examples of the waxes in which part or all of the fatty acid esters are deoxidized include, for example, deacidified carnauba wax. As the release agent, carnauba wax is preferred.

[0051] When the toner mother particles contain a release agent, a compatibilizer may be added to the toner mother particles in order to improve the compatibility between the binder resin and the release agent.

[0052] (Charge control agent) The toner mother particles may contain a charge control agent. The charge control agent is used, for example, for the purpose of providing a toner having better charging stability or better charging rise characteristics. The charging rise characteristics of the toner are an index as to whether the toner can be charged to a predetermined charging level in a short time. By containing a positively charged charge control agent in the toner mother particles, the cationicity of the toner mother particles can be enhanced.

[0053] Examples of the positively charged charge control agent include azine compounds, direct dyes, acid dyes, alkoxylated amines, alkylamides, quaternary ammonium salt compounds, and resins containing a quaternary ammonium cation group. As the charge control agent, a quaternary ammonium salt is preferred.

[0054] Examples of the azine compound include pyridazine, pyrimidine, pyrazine, 1,2-oxazine, 1,3-oxazine, 1,4-oxazine, 1,2-thiazine, 1,3-thiazine, 1,4-thiazine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6-oxadiazine, 1,3,4-thiadiazine, 1,3,5-thiadiazine, 1,2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1,2,4,6-oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline, and quinoxaline.

[0055] Examples of the direct dye include azine fast red FC, azine fast red 12BK, azine violet BO, azine brown 3G, azine light brown GR, azine dark green BH / C, azine deep black EW, and azine deep black 3RL.

[0056] Examples of the acid dye include nigrosine BK, nigrosine NB, and nigrosine Z.

[0057] Examples of the quaternary ammonium salt include benzyldecylhexylmethylammonium chloride, decyltrimethylammonium chloride, 2-(methacryloyloxy)ethyltrimethylammonium chloride, and dimethylaminopropylacrylamide methyl chloride quaternary salt.

[0058] From the viewpoint of providing a toner having further excellent charge stability, the content of the charge control agent is preferably 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

[0059] [Method for manufacturing toner] The toner of the present invention can be manufactured, for example, by a manufacturing method including a step of preparing toner mother particles and an external addition step.

[0060] (Step of preparing toner mother particles) In the step of preparing toner mother particles, for example, toner mother particles are prepared by an aggregation method or a pulverization method.

[0061] The aggregation method includes, for example, an aggregation step and a unification step. In the aggregation step, fine particles containing components constituting the toner mother particles are aggregated in an aqueous medium to form aggregated particles. In the unification step, the components contained in the aggregated particles are unified in the aqueous medium to form toner mother particles.

[0062] Next, the pulverization method will be described. According to the pulverization method, toner mother particles can be prepared relatively easily and the manufacturing cost can be reduced. When preparing toner mother particles by the pulverization method, the step of preparing toner mother particles includes, for example, a melt-kneading step and a pulverization step. The step of preparing toner mother particles may further include a mixing step before the melt-kneading step. Further, the step of preparing toner mother particles may further include at least one of a fine pulverization step and a classification step after the pulverization step.

[0063] In the mixing step, a binder resin and an internal additive added as necessary are mixed to obtain a mixture. In the melt-kneading step, the toner material is melted and kneaded to obtain a melt-kneaded product. As the toner material, for example, the mixture obtained in the mixing step is used. In the pulverization step, the obtained melt-kneaded product is cooled to, for example, room temperature (25°C) and then pulverized to obtain a pulverized product. When it is necessary to reduce the diameter of the pulverized product obtained in the pulverization step, a step of further pulverizing the pulverized product (fine pulverization step) may be performed. Further, when the particle sizes of the pulverized product are to be made uniform, a step of classifying the obtained pulverized product (classification step) may be performed. Through the above steps, toner mother particles which are pulverized products are obtained.

[0064] (External addition step) In the external addition step, using a mixer, the above-described toner mother particles and an external additive are mixed to attach the external additive to the surface of the toner mother particles. Thereby, the toner of the present invention is obtained. The external additive includes specific external additive particles and other external additive particles used as necessary. Examples of the mixer include an FM mixer (manufactured by Nippon Coke & Engineering Co., Ltd.).

Examples

[0065] Hereinafter, the present invention will be described more specifically using examples. However, the present invention is not limited to the scope of the examples at all.

[0066] [Preparation of External Additive Particles] External additive particles (a) to (n) were prepared by the following method.

[0067] (External Additive Particles (a)) 2 liters of water was charged into a reaction vessel. After heating the reaction vessel and then keeping it warm, the liquid temperature of the water was maintained at 70°C. Separately, 825 g of stannic chloride (SnCl 4 ·5H 2 O) and 5 g of antimony trichloride (SbCl 3)175 g was dissolved in 1 L of hydrochloric acid with a concentration of 2.4 N to prepare an acid solution. An aqueous ammonia solution (ammonia concentration: 1 mol / L) and the above-mentioned acid solution were simultaneously dropped into a reaction vessel filled with water at 70 °C over 1 hour. In the simultaneous dropping, the amount of the aqueous ammonia solution added was adjusted so that the pH of the contents of the reaction vessel was maintained at pH 7 to 8. Due to the simultaneous dropping, the contents of the reaction vessel became a suspension. Next, the suspension in the reaction vessel was suction filtered. In the suction filtration, a Buchner funnel with a capacity of 2 L, a funnel with a capacity of 1.1 L (manufactured by Asahi Seisakusho Co., Ltd.), and filter paper (No. 131 manufactured by Advantec Toyo Co., Ltd.) were used. Next, the residue on the filter paper was washed by pouring 1 L of water from above (washing operation). This washing operation was performed a total of 6 times. When the conductivity of the washed residue was measured using a conductivity meter (ES-51 manufactured by Horiba, Ltd.), it was 10 μS / cm. The washed residue was dried at 110 °C for 12 hours and then fired at 700 °C for 2 hours using an electric furnace. Thereafter, the fired residue was pulverized using a pulverizer (Collision plate type supersonic jet pulverizer CPY + DSF manufactured by Nippon Pneumatic Mfg. Co., Ltd.). In the pulverization of the fired residue, a ceramic flat plate was used as the collision plate, the material supply rate was 7.0 kg / hour, and the pulverization pressure was 0.5 MPa. Thereby, external additive particles (a) were obtained.

[0068] (External additive particles (b) to (l) and (n)) External additive particles (b) to (l) and (n) were prepared by the same method as the preparation of external additive particles (a), except that the following points were changed. In the preparation of external additive particles (b) to (l), the addition amounts of stannic chloride and antimony trichloride, the number of filtrations in the washing operation, and the pulverization conditions were changed as shown in Table 1 below. In the preparation of external additive particles (n), 175 g of indium chloride was used instead of antimony trichloride.

[0069] (External additive particles (m)) 2 liters of water and 100 g of titanium oxide particles ("AEROXIDE (registered trademark) P25" manufactured by Nippon Aerosil Co., Ltd.) were charged into a reaction vessel, and the titanium oxide particles were dispersed in the water. After heating the reaction vessel and then keeping it warm, the liquid temperature of the dispersion was maintained at 70°C. Separately, 13 g of stannic chloride (SnCl 4 ·5H 2 O)4 and 88 g of antimony trichloride (SbCl 3 ) were dissolved in 1 L of 2.4N hydrochloric acid to prepare an acid solution. An aqueous ammonia solution (ammonia concentration 1 mol / L) and the above-mentioned acid solution were simultaneously dropped into the reaction vessel containing the 70°C dispersion over 1 hour. In the simultaneous dropping, the addition amount of the aqueous ammonia solution was adjusted so that the pH of the contents of the reaction vessel was maintained at pH 7 - 8. Due to the simultaneous dropping, the contents of the reaction vessel became a suspension. Next, the suspension in the reaction vessel was suction-filtered. In the suction filtration, a 2 L capacity Buchner funnel, a 1.1 L capacity funnel (manufactured by Asahi Seisakusho Co., Ltd.), and filter paper ("No. 131" manufactured by Advantec Toyo Co., Ltd.) were used. Next, 1 L of water was poured from above to wash the residue on the filter paper (washing operation). This washing operation was performed a total of 6 times. Regarding the residue after washing, when the conductivity was measured using a conductivity meter ("ES-51" manufactured by Horiba, Ltd.), it was 10 μS / cm. The residue after washing was dried at 110°C for 12 hours and then calcined at 700°C for 2 hours using an electric furnace. Then, the calcined residue was pulverized using a pulverizer ("Collision Plate Type Supersonic Jet Pulverizer CPY + DSF" manufactured by Nippon Pneumatic Mfg. Co., Ltd.). In the pulverization of the calcined residue, a ceramic flat plate was used as the collision plate, the material supply rate was 6.0 kg / h, and the pulverization pressure was 0.5 MPa. Thereby, externally added agent particles (m) were obtained.

[0070] (Externally added agent particles (o)) Titanium oxide particles ("AEROXIDE (registered trademark) P25" manufactured by Nippon Aerosil Co., Ltd.) were used as the externally added agent particles (o).

[0071] [Table 1]

[0072] (X-ray fluorescence analysis) The external additive particles (a) to (n) were analyzed by X-ray fluorescence, and based on the analysis results, the "Sb ratio (M Sb / (M Sn +M Sb ))", "In ratio (M In / (M Sn +M In ))" and the content ratio of chlorine atoms were calculated. The results are shown in Table 2 below. The conditions for X-ray fluorescence analysis were as follows. For the preparation of the calibration curve in X-ray fluorescence analysis, a plurality of calibration curve samples were used, which were prepared by mixing tin oxide (SnO 2 ), antimony pentoxide, sodium chloride, and indium oxide in specific mixing ratios.

[0073] (Conditions for X-ray fluorescence analysis) · Sample: Cylindrical pellets obtained by pressure molding the external additive particles under the conditions of a pressure of 20 MPa and a pressurization time of 3 seconds · Analyzer: Scanning X-ray fluorescence analyzer ("ZSX" manufactured by Rigaku Corporation) · X-ray tube (X-ray source): Rh (rhodium) · Excitation conditions: Tube voltage 50 kV, tube current 50 mA · Measurement area (X-ray irradiation range): Diameter 30 mm · Measured elements: Antimony, indium, chlorine, tin

[0074] (Measurement of particle size) A cross-sectional image of the toner (magnification: 30,000 times) was taken using a scanning electron microscope ("JSM-6700F" manufactured by JEOL Ltd.). Based on the taken cross-sectional image, the equivalent circle diameters of 100 external additive particles (specifically, any of the external additive particles (a) to (o)) were analyzed using image analysis software ("WinROOF" manufactured by Mitani Trading Co., Ltd.), and the average value was taken as the number-average primary particle size. The results are shown in Table 2 below.

[0075]

Table 2

[0076] Among the external additive particles (a) to (o), the external additive particles (a), (c), (d), (g), (h), (j), (k), (n) and (l) were specific external additive particles.

[0077] [Examples 1 to 9 and Comparative Examples 1 to 7] (Preparation of Binder Resin) 1.0 mol of polyoxyethylene(2,2)-2,2-bis(4-hydroxyphenyl)propane, 4.5 mol of terephthalic acid, 0.5 mol of trimellitic anhydride, and 4 g of dibutyltin oxide were charged into a reaction vessel. The contents of the reaction vessel were reacted at 230 °C for 8 hours under a nitrogen atmosphere. Thereafter, the unreacted components in the reaction vessel were distilled off under reduced pressure until the pressure in the reaction vessel reached 8.3 kPa. Thereafter, the contents (polyester resin) of the reaction vessel were washed and then dried. Thereby, a polyester resin having a softening point of 120 °C was obtained. This polyester resin was used as the binder resin.

[0078] (Preparation of Toner Mother Particles) Using an FM mixer (FM-20B manufactured by Nippon Coke & Engineering Co., Ltd.), 100 parts by mass of the above-described polyester resin as a binder resin, 4 parts by mass of carbon black (REGAL (registered trademark) 330R manufactured by Cabot Corporation) as a colorant, 10 parts by mass of carnauba wax (Carnauba No. 1 manufactured by Kato Yoko Co., Ltd.) as a wax, and 3 parts by mass of a quaternary ammonium salt compound (FCA210PS manufactured by Fujikura Kasei Co., Ltd.) as a charge control agent were mixed. Thereafter, the obtained mixture was melt-kneaded at 150°C using a twin-screw extruder (TEM45 manufactured by Toshiba Machine Co., Ltd.). Thereafter, the obtained kneaded product was cooled. The cooled kneaded product was coarsely pulverized using a feather mill (registered trademark) (Model 350×600 manufactured by Hosokawa Micron Corporation). The obtained coarsely pulverized product was finely pulverized using a pneumatic classifier mill (Jet Mill IDS-2 type manufactured by Nippon Pneumatic Mfg. Co., Ltd.). The obtained finely pulverized product was classified using an elbow jet classifier (Elbow Jet EJ-LABO type manufactured by Nippon Steel Mining Co., Ltd.). Thereby, toner mother particles having a volume median diameter of 7 μm were obtained. The volume median diameter of the toner mother particles was measured using a particle size analyzer (Coulter Counter Multisizer 3 manufactured by Beckman Coulter, Inc.).

[0079] (External addition treatment) 100.0 parts by mass of toner mother particles, 1.5 parts by mass of silica particles (AEROSIL (registered trademark) REA90 manufactured by Nippon Aerosil Co., Ltd.) as an external additive, and 1.0 part by mass of external additive particles shown in Table 3 below were mixed using an FM mixer (FM-10 manufactured by Nippon Coke & Engineering Co., Ltd.). Thereby, toners (black toners) of Examples 1 to 9 and Comparative Examples 1 to 7 were obtained. In Comparative Example 5, only silica particles were used as the external additive.

[0080] [Examples 10 to 11] In the preparation of the toner mother particles, toners of Examples 10 and 11 were prepared in the same manner as in the preparation of the toner of Example 1, except that the following colorants were used instead of 4 parts by mass of carbon black. Example 10 (Cyan Toner): 4 parts by mass of a cyan colorant ("FASTOGEN (registered trademark) BLUE B-15:3" manufactured by DIC Corporation) Example 11 (Magenta Toner): 4 parts by mass of a magenta colorant ("PR-3" manufactured by Dainichi Seika Chemicals Co., Ltd.)

[0081] <Evaluation> The image density and fixability of the images formed by the toners of Examples 1 to 11 and Comparative Examples 1 to 7 were evaluated by the following method. The evaluation results are shown in Table 3 below.

[0082] [Evaluation Equipment] As the evaluation equipment, a monochrome printer ("HL-1218W" manufactured by Brother Industries, Ltd.) was used. Toner (specifically, any one of the toners of Examples 1 to 11 and Comparative Examples 1 to 7) was loaded into the developing device of the evaluation equipment. The developing device equipped with the evaluation equipment also served as a toner container. That is, the evaluation equipment was a monochrome printer of the developing device replacement type. As the printing paper, "Multi Paper Super White + (registered trademark)" manufactured by Asukuru Co., Ltd. was used.

[0083] [Image Density] Using the evaluation equipment, a pattern image with a printing rate of 5% was continuously formed on 1500 sheets of printing paper under the conditions of a temperature of 23°C and a humidity of 50%. Thereafter, a solid image was formed on the above-mentioned printing paper (toner loading amount: 0.7 mg / cm 2 ). The image density (ID) of the formed solid image was measured with a reflection densitometer ("RD914" manufactured by X-Rite). The image density was evaluated according to the following criteria.

[0084] (Evaluation Criteria for Image Density) A (Extremely Good): ID is 1.3 or more B (Good): ID is 1.1 or more and less than 1.3 C (Poor): ID is less than 1.1

[0085] [Fixability] Using the evaluation equipment, a solid image was formed on the printing paper under the conditions of a temperature of 10°C and a humidity of 10% RH (toner loading amount: 0.7 mg / cm2 ) A rubbing test was performed on the printed paper (evaluation paper) on which the solid image was formed to determine whether or not offset occurred. In the rubbing test, with respect to the evaluation paper, the surface on which the solid image was formed was placed inside, and it was folded so that the center of the solid image passed through the fold line. Next, with respect to the folded evaluation paper, using a brass weight (1 kg) covered with a cotton cloth, it was rubbed 5 times back and forth on the fold line while applying a load of 1 kg. Next, the evaluation paper was spread out, and the length of toner peeling (peeling length) in the portion where the solid image was fixed in the folded portion of the evaluation paper was measured. The fixing property was evaluated according to the following criteria.

[0086] (Evaluation Criteria for Fixing Property) A (Extremely Good): Less than 0.7 mm B (Good): 0.7 mm or more and less than 1.0 mm C (Poor): 1.0 mm or more

[0087]

Table 3

[0088] The toners of Examples 1 to 11 each contained toner particles. The toner particles included toner mother particles and external additives attached to the surface of the toner mother particles. The external additives contained specific external additive particles. The number-average primary particle diameter of the specific external additive particles was 30 nm or more and 305 nm or less. The specific external additive particles contained antimony-doped tin oxide particles or indium tin oxide particles. In the antimony-doped tin oxide particles, the Sb ratio (M Sb / (M Sn +M Sb )) was 4 mass% or more and 46 mass% or less. The toners of Examples 1 to 11 were able to form images excellent in image density and fixing property.

[0089] On the other hand, since the toners of Comparative Examples 1 to 7 did not have the above-described configurations, at least one of the image density and fixing property of the formed images was poor.

[0090] Specifically, the external additive particles (b) and (e) used in the toners of Comparative Examples 1 and 2 were antimony-doped tin oxide particles with an Sb ratio of less than 4% by mass or more than 46% by mass. Since the external additive particles (b) and (e) had a relatively high electrical resistance, it was determined that the image density of the formed image was insufficient.

[0091] The external additive particles (f) and (i) used in the toners of Comparative Examples 3 and 4 had a number-average primary particle diameter of less than 30 nm or more than 305 nm. When continuously forming an image, the external additive particles (f) and (i) were buried in the toner mother particles or detached from the toner mother particles, so it was determined that the image density of the formed image was insufficient.

[0092] No specific external additive particles were used in the toner of Comparative Example 5. The external additive particles (m) and (o) used in the toners of Comparative Examples 6 and 7 were conductive titanium oxide particles or titanium oxide particles. It was determined that the external additive particles (m) and (o) had a relatively high electrical resistance. Also, it was determined that the external additive particle (m) was likely to aggregate on the surface of the toner mother particles and detach from the surface of the toner mother particles because ATO acted like a flocculant. Therefore, it was determined that the toners of Comparative Examples 5 to 7 had insufficient image density of the formed image.

Industrial Applicability

[0093] The toner of the present invention can be used, for example, to form an image in a copying machine, a printer, or a multifunction machine.

Explanation of Symbols

[0094] 1 Toner particle 2 Toner mother particle 3 Specific external additive particle

Claims

1. A non-magnetic one-component toner containing toner particles, wherein the toner particles include toner mother particles and an external additive attached to the surface of the toner mother particles, the external additive includes specific external additive particles, the number-average primary particle diameter of the specific external additive particles is 30 nm or more and 305 nm or less, the specific external additive particles include antimony-doped tin oxide particles or indium tin oxide particles, In the antimony-doped tin oxide particles, the content ratio of antimony-doped tin oxide is 90% by mass or more, and the mass ratio of the antimony atom (M Sb ), and the mass of the tin atom (M Sn ), the ratio of the mass of the antimony atom (M Sb ), (M Sb / (M Sn +M Sb )) is 4% by mass or more and 46% by mass or less, in the indium tin oxide particles, the content ratio of indium tin oxide is 90% by mass or more, and the ratio (MIn / (MSn + MIn)) of the mass (MIn) of indium atoms to the total mass of indium atoms (MIn) and tin atoms (MSn) is 4% by mass or more and 46% by mass or less, the non-magnetic one-component toner.

2. The specific external additive particles, do not contain chlorine atoms, or contain chlorine atoms and the content ratio of chlorine atoms is more than 0.000% by mass and 0.020% by mass or less. The non-magnetic one-component toner according to Claim 1.

3. The specific external additive particles contain chlorine atoms, and the content ratio of chlorine atoms is 0.001% by mass or more and 0.020% by mass or less. The non-magnetic one-component toner according to Claim 2.

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