Toner

Abstract

The present invention relates to a toner. The toner includes toner particles and an external additive, wherein the external additive comprises composite particles containing organic silicon polymer fine particles covering the surfaces of aluminum oxide particles, the coverage of the surfaces of the aluminum oxide particles by the organic silicon polymer fine particles being 1 to 50 area %, and the following formulas (I) and (II) are satisfied, given A (nm) as the number average particle size of the primary particles of the organic silicon polymer fine particles and B (nm) as the number average particle size of the primary particles of the aluminum oxide particles: A≤90 (I) 100≤B≤1000 (II).

Description

Technical Field

[0001] The present disclosure relates to a toner for use in an image forming method such as an electrophotographic method. Background Art

[0002] Electrophotographic image forming equipment is constantly being demanded for higher speeds, longer lifespans, greater energy savings, and smaller size. Meeting these demands requires further improvements in various performance characteristics. In particular, to achieve longer lifespans, there is a need to improve the quality stability of toners. This is not only necessary to stabilize the properties of the toner itself, but is also crucial for preventing wear and contamination of key components such as the photosensitive member, toner transport member, and charging member. To address this issue, various toners and external additives have been proposed.

[0003] Japanese Patent Application Laid-Open No. 10-326028 proposes a toner that maintains various image characteristics, such as image density and background fogging, while reducing damage to photosensitive members by using aluminum oxide particles exhibiting a specific relationship between BET specific surface area and tap density. Japanese Patent Application Laid-Open No. 2006-201562 proposes a toner that prevents aluminum oxide particles from detaching from the toner particles by limiting the circularity and narrowing the particle size distribution of the toner particles and providing a work function difference between the toner particles and the aluminum oxide particles, thereby reducing member wear while maintaining stable image quality. Japanese Patent Application Laid-Open No. 2016-163866 proposes composite particles with excellent mixing uniformity, obtained by using composite particles containing organic particles and inorganic fine particles partially linked to each other via an organic hydrophobic agent. Summary of the Invention

[0004] However, when the toners disclosed in Japanese Patent Application Laid-Open No. 10-326028 and Japanese Patent Application Laid-Open No. 2006-201562 were evaluated in image forming apparatuses designed to support both high-speed and long-life applications, the following image characteristics were observed at the end of their use: reduced solid image tracking associated with reduced toner fluidity, fogging associated with deterioration in charging characteristics, and contamination of charging components. In the case of the composite particles described in Japanese Patent Application Laid-Open No. 2016-163866, the composite particles are obtained by attaching small-diameter inorganic fine particles to relatively large, submicron-sized organic fine particles. When these composite particles migrate from the toner to key components, they tend to cause wear or contamination of these components.

[0005] That is, it has been found that when the toners described in these prior art documents are used, problems still exist in terms of required performance. The present disclosure provides a toner that has excellent fluidity and charging stability during long-term durable use and causes little wear or contamination to key parts of an image forming apparatus.

[0006] After careful research, the inventors have found that the above-mentioned problems can be solved by using the following toner.

[0007] That is, the present disclosure relates to a toner comprising toner particles and an external additive, wherein

[0008] The external additive comprises composite particles containing organic silicon polymer fine particles covering the surfaces of aluminum oxide particles,

[0009] The coverage of the surfaces of the aluminum oxide particles by the organic silicon polymer fine particles is 1 area % or more and 50 area % or less, and

[0010] Given A (nm) as the number average particle size of the primary particles of the organosilicon polymer fine particles and B (nm) as the number average particle size of the primary particles of the alumina particles, the following formulae (I) and (II) are satisfied:

[0011] A≤90 (I)

[0012] 100≤B≤1000 (II).

[0013] The present disclosure can provide a toner having excellent fluidity and charging stability during long-term durable use and causing little wear or contamination to key components of an image forming apparatus. Other features of the present invention will become apparent from the following description of exemplary embodiments. DETAILED DESCRIPTION

[0014] The toner contains composite particles as an external additive, the composite particles containing fine particles of an organosilicon polymer covering the surface of aluminum oxide particles. Conventionally, it is known that submicron-sized aluminum oxide particles improve the toner charging performance of the toner when used as an external additive. This trend is particularly evident in non-magnetic single-component development systems. This is attributed to the microcarrier effect that imparts charging properties to the toner particles when the aluminum oxide particles are charged to a polarity opposite to that of the toner particles. On the other hand, the hardness of aluminum oxide particles is high and tends to cause wear of various key components such as photosensitive members. In addition, in non-magnetic single-component development systems, the attachment of aluminum oxide to key components such as regulating scrapers tends to result in excessive toner charging at the end of durable use. As a result, during the second half of durable use, charging roller contamination and fogging tend to occur.

[0015] Therefore, the inventors have studied methods for controlling these problems caused by aluminum oxide particles. Specifically, the inventors attempted to control these problems while maintaining the effects of the aluminum oxide particles by partially covering the aluminum oxide particles with a different material. The inventors have thus discovered that silicone polymer fine particles are superior as such a material. It is known that silicone polymer fine particles have a lower hardness than inorganic fine particles such as aluminum oxide and silicon dioxide. By partially covering the aluminum oxide particles with silicone polymer fine particles, the wear of various key components can be suppressed. Because silicone polymer fine particles have excellent mold release properties, it is possible to suppress component contamination while maintaining good toner fluidity.

[0016] Thus, the inventors found that by using composite particles comprising silicone polymer fine particles covering the surfaces of aluminum oxide particles, a toner having excellent fluidity and charging stability with little wear or contamination of key parts of an image forming apparatus can be obtained even during long-term durable use.

[0017] Unless otherwise stated, the description of a numerical range such as "from A to B" or "A to B" means that the numerical range includes the numbers at the upper and lower limits of the range.

[0018] Specifically, the present disclosure relates to a toner comprising toner particles and an external additive, wherein

[0019] The external additive comprises composite particles containing organic silicon polymer fine particles covering the surfaces of aluminum oxide particles,

[0020] The coverage of the surfaces of the aluminum oxide particles by the organic silicon polymer fine particles is 1 area % or more and 50 area % or less, and

[0021] Given A (nm) as the number average particle size of the primary particles of the organosilicon polymer fine particles and B (nm) as the number average particle size of the primary particles of the alumina particles, the following formulae (I) and (II) are satisfied:

[0022] A≤90 (I)

[0023] 100≤B≤1000 (II).

[0024] The toner contains toner particles and an external additive, wherein the external additive includes composite particles containing organosilicon polymer fine particles covering the surfaces of aluminum oxide particles. The term "organosilicon polymer fine particles covering the surfaces of the aluminum oxide particles" refers to a state in which the organosilicon polymer fine particles are attached to the surfaces of the aluminum oxide particles. Whether the organosilicon polymer fine particles are attached or not can be confirmed by observing the toner using an electron microscope or the like.

[0025] The coverage of the surface of the aluminum oxide particles by the organosilicon polymer fine particles is greater than 1 area % and less than 50 area %. If the coverage is less than 1 area %, the inhibitory effect of the organosilicon polymer fine particles on the wear and contamination of key components cannot be obtained. On the other hand, if the coverage is greater than 50 area %, the microcarrier effect of aluminum oxide is suppressed, and therefore the charge-imparting effect of aluminum oxide cannot be fully obtained. By maintaining the coverage within the above range, the problems of wear and contamination of components can be suppressed, while also improving fluidity and charging performance. The coverage is preferably 2 area % to 45 area %, or more preferably 5 area % to 40 area %.

[0026] The specific method for measuring the coverage is described below. The method for controlling the coverage of the composite particles to fall within the above range is not particularly limited, but can be achieved by selecting alumina particles having excellent agglomeration properties or adjusting the mixing conditions of the external additive.

[0027] Alumina particles having excellent aggregability may be alumina particles containing few fine alumina particles generated by a manufacturing method or a deaggregation process, etc. In addition, alumina particles having a high circularity tend to easily aggregate on the toner particle surfaces in an external addition step, whereas alumina particles having a polyhedral structure that is approximately spherical are excellent in forming the most stable aggregates.

[0028] Methods for producing highly rounded alumina particles include an explosion combustion method in which alumina particles are obtained by burning and mixing aluminum in an oxidizing stream; and a method in which particles are obtained by synthesizing and firing aluminum dawsonite.

[0029] Methods for producing aluminum oxide particles having an approximately spherical polyhedral structure include chemical vapor deposition methods in which a hydrated aluminum oxide raw material is fired in a special gas atmosphere to grow single crystal particles in situ.

[0030] The method for forming composite particles is not particularly limited. For example, in a two-stage external addition method, alumina particles are preliminarily mixed with toner particles for external addition and form aggregated particles of the alumina particles. Subsequently, organosilicon polymer fine particles are added and mixed for external addition. Thus, composite particles of organosilicon polymer fine particles and alumina particles can be formed by electrostatic attraction.

[0031] Alternatively, the aluminum oxide particles and the organosilicon polymer fine particles may be mixed in advance to form composite particles of the aluminum oxide particles and the organosilicon polymer fine particles, and then the resultant composite particles may be externally added to the toner particles.

[0032] Composite particles can also be formed by combining other methods such as reducing the kinetics during external addition mixing to promote aggregation of alumina particles or shortening the processing time to maintain aggregated particles.

[0033] Given A (nm) as the number average particle size of the primary particles of the organosilicon polymer fine particles and B (nm) as the number average particle size of the primary particles of the alumina particles, the following formulae (I) and (II) are satisfied:

[0034] A≤90 (I)

[0035] 100≤B≤1000 (II).

[0036] The number average particle size A (nm) of the primary particles of the organosilicon polymer fine particles must be 90 or less. If the number average particle size of the primary particles of the organosilicon polymer fine particles is within this range, it is easier to form composite particles with alumina particles, as described below, and it is easier to control the coverage within a specific range. If A (nm) is greater than 90, the composite particles may break, making the component more susceptible to contamination.

[0037] The number average particle diameter A (nm) is preferably 80 or less, or even more preferably 60 or less. The lower limit is not particularly limited, but is preferably 5 or more, or more preferably 15 or more.

[0038] The number average particle size A (nm) can be controlled by various wet and dry classification processes. In addition, as described below, when the silicone polymer fine particles are prepared by a wet process, the number average particle size A can be controlled by controlling the differences in various reaction conditions during the hydrolysis and condensation reactions.

[0039] The number average particle size B (nm) of the primary particles of the aluminum oxide particles must be 100 or more and 1000 or less. When the number average particle size of the primary particles of the aluminum oxide particles is within this range, the microcarrier effect of the aluminum oxide particles is more easily achieved. If B (nm) is less than 100, the effect of imparting charge to the toner is reduced. If B (nm) is greater than 1000, the fluidity of the toner decreases, and contamination of components may occur.

[0040] The number average particle diameter B (nm) is preferably 150 or more and 900 or less, or more preferably 200 or more and 600 or less.

[0041] The number average particle size B (nm) can be controlled by various wet and dry classification processes, or by controlling differences in production conditions among various alumina production methods discussed below.

[0042] There is a relationship between the number average particle sizes A and B: A<B.

[0043] Making the silicone polymer fine particles smaller than the aluminum oxide particles makes it easy to obtain composite particles in which the silicone polymer fine particles cover the surfaces of the aluminum oxide particles. If A>B, the result is that the aluminum oxide particles cover the surfaces of the silicone polymer fine particles in the composite particles, and the above effect cannot be obtained.

[0044] B-A (nm) is preferably 50 to 700, or more preferably 300 to 650.

[0045] The average projected area of ​​the composite particles of the alumina particles and the organosilicon polymer fine particles is preferably 0.01 μm 2 Above and 1.00μm 2 less than, or more preferably 0.10 μm 2 Above and 0.60μm 2 less, or still more preferably 0.15 μm 2 Above and 0.50μm 2 the following.

[0046] If the average projected area of ​​the composite particles of alumina particles and organosilicon polymer fine particles is 0.01 μm 2 As described above, the rolling properties of the composite particles on the toner particle surfaces are improved, and a more durable charging effect can be obtained.

[0047] If the average projected area is 1.00 μm 2 Then, the detachment of the composite particles from the toner particle surface can be reduced, and member contamination can be further reduced.

[0048] The composition of the organosilicon polymer fine particles is not particularly limited, but fine particles of the following composition are preferred.

[0049] The organic silicon polymer fine particles have a structure in which silicon atoms and oxygen atoms are alternately bonded, and at least a portion of the organic silicon polymer in the organic silicon polymer fine particles has a structure consisting of R a SiO 3 / 2 The T3 unit structure is shown. a Preferably it is a hydrocarbon group, more preferably C 1-6 (Preferred C 1-3 , or more preferably C 1-2 ) alkyl or phenyl.

[0050] In addition, in the silicone polymer fine particles 29 In the Si-NMR measurement, the ratio of the area of ​​the peak derived from silicon having a T3 unit structure to the total area of ​​the peaks derived from all silicon elements contained in the organic silicon polymer fine particles is preferably 0.50 or more and 1.00 or less, or more preferably 0.90 or more and 1.00 or less, or still more preferably 0.97 or more and 1.00 or less.

[0051] There are no particular limitations on the method for producing organosilicon polymer fine particles. For example, they can be obtained by dropping a silane compound into water, hydrolyzing it with a catalyst and causing a condensation reaction, followed by filtering the resulting suspension and drying. The particle size can be controlled by factors such as the type and ratio of the catalyst, the reaction start temperature, and the time of addition.

[0052] Examples of the catalyst include, but are not limited to, acidic catalysts such as hydrochloric acid, hydrofluoric acid, sulfuric acid, and nitric acid, and alkaline catalysts such as aqueous ammonia, sodium hydroxide, and potassium hydroxide.

[0053] The organosilicon compound used for producing the organosilicon polymer fine particles is explained below.

[0054] The organosilicon polymer is preferably a polycondensate of an organosilicon compound having a structure represented by the following formula (Z):

[0055]

[0056] In formula (Z), R a represents an organic functional group, and R 1 、R 2 and R 3 Each independently represents a halogen atom, a hydroxyl group or an acetoxy group, or (preferably C 1-3 ) alkoxy.

[0057] R a is an organic functional group without any particular limitation, but preferred examples include C 1-6 (Preferred C 1-3 , or more preferably C 1-2 ) of a hydrocarbon group (preferably an alkyl group) and an aromatic group (preferably a phenyl group).

[0058] R 1 、R 2 and R 3 Each independently represents a halogen atom, a hydroxyl group, an acetoxy group or an alkoxy group. These are reactive groups that form crosslinking groups by hydrolysis, addition polymerization and condensation. 1 、R 2 and R 3 The hydrolysis, addition polymerization and condensation of can be controlled by reaction temperature, reaction time, reaction solvent and pH. a The three reactive groups (R 1 、R 2 and R 3 The organosilicon compound of alkoxy is also called trifunctional silane. The carbon number of the alkoxy group is preferably 1 to 3, or more preferably 1 or 2.

[0059] Examples of formula (Z) include the following:

[0060] Trifunctional methylsilanes such as p-styryltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyldiethoxymethoxysilane, methylethoxydimethoxysilane, methyltrichlorosilane, methylmethoxydichlorosilane, methylethoxydichlorosilane, methyldimethoxychlorosilane, methylmethoxyethoxychlorosilane, methyldiethoxychlorosilane, methyltriacetoxysilane, methyldiacetoxymethoxysilane, methyldiacetoxyethoxysilane, methylacetoxydimethoxysilane, methylacetoxyformyloxyethoxysilane, methylacetoxydiethoxysilane, methyltrihydroxysilane, methylmethoxydihydroxysilane, methylethoxydihydroxysilane, methyldimethoxyhydroxysilane, methylethoxymethoxyhydroxysilane, and methyldiethoxyhydroxysilane trifunctional ethylsilanes, such as ethyltrimethoxysilane, ethyltriethoxysilane, ethyltrichlorosilane, ethyltriacetoxysilane, and ethyltrihydroxysilane; trifunctional propylsilanes, such as propyltrimethoxysilane, propyltriethoxysilane, propyltrichlorosilane, propyltriacetoxysilane, and propyltrihydroxysilane; trifunctional butylsilanes, such as butyltrimethoxysilane, butyltriethoxysilane, butyltrichlorosilane, butyltriacetoxysilane, and butyltrihydroxysilane; trifunctional hexylsilanes, such as hexyltrimethoxysilane, hexyltriethoxysilane, hexyltrichlorosilane, hexyltriacetoxysilane, and hexyltrihydroxysilane; trifunctional phenylsilanes, such as phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, phenyltriacetoxysilane, and phenyltrihydroxysilane. These organosilicon compounds may be used alone or in combination of two or more.

[0061] The following can also be used in combination with the organosilicon compound having a structure represented by formula (Z): organosilicon compounds having four reactive groups in the molecule (tetrafunctional silanes), organosilicon compounds having two reactive groups in the molecule (difunctional silanes), and organosilicon compounds having one reactive group in the molecule (monofunctional silanes). Examples include:

[0062] Dimethyldiethoxysilane, tetraethoxysilane, hexamethyldisilazane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane and trifunctional vinylsilanes such as vinyltriisocyanatosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyldiethoxymethoxysilane, vinylethoxydimethoxysilane, vinylethoxydihydroxysilane, vinyldimethoxyhydroxysilane, vinylethoxymethoxyhydroxysilane and vinyldiethoxyhydroxysilane.

[0063] The content of the structure represented by formula (Z) in the monomers forming the silicone polymer is preferably 50 mol% or more, or more preferably 60 mol% or more.

[0064] The alumina particles are not particularly limited as long as they can form composite particles with the above-mentioned organosilicon polymer fine particles. Alumina can be produced by methods such as ammonium aluminum carbonate pyrolysis, bauxite pyrolysis, underwater spark discharge, vapor phase oxidation, explosion, Bayer process, and aluminum alkoxide hydrolysis. Alumina can be produced, for example, using transition alumina or an alumina raw material converted to transition alumina by heat treatment.

[0065] Among the alumina forms having a polymorph represented by Al2-O3, transition alumina refers to all aluminas except α-alumina. Specific examples include γ-alumina, δ-alumina, and θ-alumina.

[0066] The desired alpha alumina powder form is obtained through a firing process using alumina raw materials used to obtain transition alumina. Produced by a chemical vapor deposition method that promotes crystal growth by applying heat in a special gas atmosphere during firing, the alumina particles have a polyhedral shape and a uniform particle size distribution with few fine particles, making them particularly suitable for forming composite particles.

[0067] The circularity of the aluminum oxide particles is preferably 0.70 or more and 0.99 or less, or more preferably 0.75 or more and 0.85 or less.

[0068] If the circularity is 0.70 or greater, the alumina particles can better aggregate with each other, making it easier to form composite particles with the organosilicon polymer fine particles. The composite particles also have good rolling properties, and a suitable microcarrier function can be achieved.

[0069] If the circularity is 0.99 or less, the composite particles are resistant to breakage caused by repeated mechanical stress in a developing device and can stably perform the microcarrier function for a long period of time, resulting in excellent durability.

[0070] Alumina particles can also be surface-treated to modify their surface properties and hydrophobicity to impart functionality. However, from the perspective of imparting charge, the alumina particles are preferably strongly positive, and the surface of the alumina particles is preferably left untreated. In other words, the alumina particles are preferably not treated with a hydrophobic agent or the like.

[0071] When carrying out surface treatment, preferably use hydrophobic oil, coupling agent or hydrophobic resin.Wherein, preferably use silicone oil, coupling agent or organic acid resin etc.The example of operable oil comprises silicone oil such as dimethylpolysiloxane and methyl hydrogen polysiloxane and paraffin, mineral oil etc.

[0072] The amount used for treatment is preferably 1 to 50 parts by mass relative to 100 parts by mass of the aluminum oxide particles, and preferably 3 to 40 parts by mass in order to achieve uniform treatment without causing fusion of the particles.

[0073] The method for surface-treating alumina particles with these hydrophobic treatment agents can be a known method. Examples include known methods such as spraying the treatment agent onto the alumina particles in a fluidized state and dropping liquid droplets onto the alumina particles while mechanically stirring the particles. Heat treatment may also be performed after the surface treatment to promote the reaction or remove the solvent.

[0074] There is no particular limitation on the method for adding composite particles comprising organic silicon polymer fine particles covering the surfaces of aluminum oxide particles to toner particles as an external additive. As described above, after forming the composite particles, they can be externally added and mixed with the toner particles, or they can be formed on the toner particles.

[0075] The mixer used for premixing may be, for example, an FM mixer (Nippon Coke & Engineering Co., Ltd.), a super mixer (Kawata Mfg. Co., Ltd.), a Nobilta (Hosokawa Micron Corporation), or a hybridizer (Nara Machinery Co., Ltd.). In addition to the composite particles, silicone polymer fine particles and alumina particles may each independently be present on the toner particles.

[0076] The number ratio of composite particles to toner particles (the number of composite particles per toner particle) is not particularly limited, but is preferably 0.1 or greater, or more preferably 1 or greater. From the viewpoint of toner fluidity, the number ratio is preferably 50 or less, or more preferably 20 or less, or even more preferably 15 or less. These numerical ranges may be arbitrarily combined.

[0077] The content of the composite particles is not particularly limited, but is preferably 0.01 to 3.00 parts by mass, or more preferably 0.10 to 1.00 parts by mass, relative to 100 parts by mass of the toner particles.

[0078] The toner may also contain other external additives to improve toner performance. For example, silica is desirable. In this case, the content of the inorganic and organic fine particles comprising the composite particles is preferably 0.50 to 5.00 parts by mass relative to 100 parts by mass of the toner particles.

[0079] If the total amount of the fine particles is within this range, the fluidity of the toner is further improved, and contamination of the member with the external additive can be further suppressed. Examples of these inorganic and organic fine particles include known particles used in toners.

[0080] The mixer for adding the external additive to the toner particles is not particularly limited, and a known dry or wet mixer can be used. Examples include FM mixer (Nippon Coke & Engineering Co., Ltd.), super mixer (Kawata Mfg. Co., Ltd.), Nobilta (Hosokawa Micron Corporation), and hybrid mixer (Nara Machinery Co., Ltd.).

[0081] The sieving equipment used to separate out coarse particles after external addition can be ultrasonic (Koei Sangyo Co., Ltd.); Resona sieving or Gyro-sieving (Tokuju Co., Ltd.); Vibrasonic system (Dalton Corporation); Soniclean (Sintokogio, Ltd.); Turbo sifter (Freund-Turbo Corporation); or micro sieve (Makino Mfg. Co., Ltd.), etc.

[0082] Here, a method for producing toner particles is described.

[0083] Known methods can be used as methods for producing toner particles, such as kneading and pulverization methods or wet production methods. Wet production methods are preferred from the perspectives of shape control and obtaining uniform particle size. Examples of wet production methods include suspension polymerization, solution suspension methods, emulsion polymerization-aggregation methods, and emulsion aggregation methods, with emulsion aggregation methods being preferred.

[0084] In the emulsion aggregation method, materials such as fine binder resin particles and fine colorant particles are dispersed and mixed in an aqueous medium containing a dispersion stabilizer. A surfactant may also be added to the aqueous medium. A flocculant is then added to aggregate the mixture until the desired toner particle size is achieved. The fine resin particles are also fused together after or during the aggregation process. This method can also be optionally heat-controlled to form toner particles.

[0085] The binder resin fine particles herein may be composite particles formed as multilayer particles comprising two or more layers of resins having different compositions. This can be produced, for example, by emulsion polymerization, microemulsion polymerization, or phase inversion emulsion method, or by a combination of multiple production methods.

[0086] When the toner particles contain an internal additive such as a colorant, the internal additive may be originally contained in the resin fine particles, or a liquid dispersion of internal additive fine particles consisting only of the internal additive may be separately prepared and the internal additive fine particles may be aggregated together when the resin fine particles aggregate.

[0087] Resin fine particles having different compositions may also be added at different times during aggregation and aggregated to prepare toner particles composed of layers having different compositions.

[0088] The following can be used as dispersion stabilizers:

[0089] Inorganic dispersion stabilizers such as tricalcium phosphate, magnesium phosphate, zinc phosphate, aluminum phosphate, calcium carbonate, magnesium carbonate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium metasilicate, calcium sulfate, barium sulfate, bentonite, silicon dioxide, and aluminum oxide.

[0090] Other examples include organic dispersion stabilizers such as polyvinyl alcohol, gelatin, methylcellulose, methylhydroxypropylcellulose, ethylcellulose, carboxymethylcellulose sodium salt, and starch.

[0091] As the surfactant, a known cationic surfactant, anionic surfactant or nonionic surfactant can be used.

[0092] Specific examples of the cationic surfactant include dodecylammonium bromide, dodecyltrimethylammonium bromide, dodecylpyridinium chloride, dodecylpyridinium bromide, hexadecyltrimethylammonium bromide and the like.

[0093] Specific examples of the nonionic surfactant include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, nonylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styrylphenyl polyoxyethylene ether, monodecanoyl sucrose, and the like.

[0094] Specific examples of the anionic surfactant include fatty soaps such as sodium stearate and sodium laurate, as well as sodium lauryl sulfate, sodium dodecylbenzenesulfonate, and sodium polyoxyethylene (2) lauryl ether sulfate.

[0095] Next, the binder resin constituting the toner will be described.

[0096] Preferred examples of the binder resin include vinyl resins, polyester resins, etc. Examples of the vinyl resins, polyester resins, and other binder resins include the following resins and polymers:

[0097] Monomers of styrene and substituted styrene, such as polystyrene and polyvinyltoluene; styrene copolymers, such as styrene-propylene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-methyl acrylate copolymers, styrene-ethyl acrylate copolymers, styrene-butyl acrylate copolymers, styrene-octyl acrylate copolymers, styrene-dimethylaminoethyl acrylate copolymers, styrene-methyl methacrylate copolymers, styrene-ethyl methacrylate copolymers, styrene-butyl methacrylate copolymers, styrene-dimethylaminoethyl methacrylate copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-maleic acid copolymers and styrene-maleic acid ester copolymers; and polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene, polyvinyl butyral, silicone resins, polyamide resins, epoxy resins, polyacrylic resins, rosin, modified rosin, terpene resins, phenolic resins, aliphatic or alicyclic hydrocarbon resins and aromatic petroleum resins. These binder resins may be used alone or in combination.

[0098] The binder resin preferably contains a carboxyl group and is preferably a resin produced using a polymerizable monomer containing a carboxyl group. Examples include vinyl carboxylic acids such as acrylic acid, methacrylic acid, α-ethylacrylic acid, and crotonic acid; unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid, and itaconic acid; and unsaturated dicarboxylic acid monoester derivatives such as monoacryloyloxyethyl succinate, monomethacryloyloxyethyl succinate, monoacryloyloxyethyl phthalate, and monomethacryloyloxyethyl phthalate.

[0099] The polycondensates of the carboxylic acid component and the alcohol component listed below can be used as polyester resins. Examples of the carboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, fumaric acid, maleic acid, cyclohexanedicarboxylic acid, and trimellitic acid. Examples of the alcohol component include bisphenol A, hydrogenated bisphenol, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, glycerol, trimethylolpropane, and pentaerythritol.

[0100] The polyester resin may also be a polyester resin containing urea groups. Preferably, the terminal and other carboxyl groups of the polyester resin are not blocked.

[0101] In order to control the molecular weight of the binder resin constituting the toner particles, a cross-linking agent may also be added during the polymerization of the polymerizable monomer.

[0102] Examples include ethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol dimethacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, divinylbenzene, bis(4-acryloyloxypolyethoxyphenyl)propane, ethylene glycol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,5-pentanediol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, diacrylates of polyethylene glycol #200, #400, and #600, dipropylene glycol diacrylate, polypropylene glycol diacrylate, polyester diacrylate (MANDA, Nippon Kayaku Co., Ltd.), and those in which methacrylates are used instead of acrylates.

[0103] The amount of the cross-linking agent added is preferably 0.001 parts by mass or more and 15.000 parts by mass or less relative to 100 parts by mass of the polymerizable monomer.

[0104] It is preferable to include a releasing agent as one of the materials constituting the toner. In particular, the use of an ester wax having a melting point of 60° C. or higher and 90° C. or lower can easily obtain a plasticizing effect because the wax is highly compatible with the binder resin.

[0105] Examples of the ester wax include waxes having fatty acid esters as main components, such as carnauba wax and montanic acid ester wax; those obtained by deoxygenating part or all of the oxygen components in fatty acid esters, such as deoxygenated carnauba wax; hydroxyl-containing methyl ester compounds obtained by hydrogenation of vegetable oils and fats, etc.; saturated fatty acid monoesters, such as stearyl stearate and behenyl behenate; diester products of saturated aliphatic dicarboxylic acids and saturated fatty alcohols, such as disbehenyl sebacate, distearyl dodecanedioate, and distearyl octadecanediol; and diester products of saturated aliphatic diols and saturated aliphatic monocarboxylic acids, such as nonanediol dibehenate and dodecanediol distearate.

[0106] Among these waxes, it is desirable to include difunctional ester waxes (diesters) having two ester bonds in the molecular structure.

[0107] The difunctional ester wax is an ester compound of a dihydric alcohol and an aliphatic monocarboxylic acid, or an ester compound of a divalent carboxylic acid and an aliphatic monohydric alcohol.

[0108] Specific examples of the aliphatic monocarboxylic acid include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, ligninic acid, cerotic acid, montanic acid, melissic acid, oleic acid, vaccenic acid, linoleic acid, and linolenic acid.

[0109] Specific examples of the aliphatic monohydric alcohol include myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, tetracosanol, hexacosanol, octacosanol, and triacontanol.

[0110] Specific examples of the divalent carboxylic acids include succinic acid (succinic acid), pentanedioic acid (glutaric acid), hexanedioic acid (adipic acid), heptanedioic acid (pimelic acid), octanedioic acid (suberic acid), nonanedioic acid (azelaic acid), decanedioic acid (sebacic acid), dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid, phthalic acid, isophthalic acid, terephthalic acid, and the like.

[0111] Specific examples of the diols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, 1,20-eicosanediol, 1,30-triacontanediol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, spirodiol, 1,4-benzenediol, bisphenol A, hydrogenated bisphenol A, and the like.

[0112] Other release agents that can be used include petroleum waxes such as paraffin wax, microcrystalline wax and petrolatum, and their derivatives; montan wax and its derivatives, hydrocarbon waxes obtained by the Fischer-Tropsch process and their derivatives, polyolefin waxes such as polyethylene and polypropylene and their derivatives, natural waxes such as carnauba wax and candelilla wax and their derivatives, higher fatty alcohols, fatty acids such as stearic acid and palmitic acid, or these compounds.

[0113] The content of the release agent is preferably 5.0 parts by mass or more and 20.0 parts by mass or less relative to 100.0 parts by mass of the binder resin or the polymerizable monomer.

[0114] The toner may contain a colorant. The colorant is not particularly limited, and the following known colorants can be used.

[0115] Examples of yellow pigments include iron oxide yellow, Naples Yellow, Naphthol Yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, quinoline Yellow Lake, Permanent Yellow NCG, condensed azo compounds such as lemon yellow lake, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include:

[0116] CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 155, 168 and 180.

[0117] Examples of red pigments include red iron oxide, permanent red 4R, lycopodium red, pyrazolone red, observation red calcium salt, Lake Red C, Lake Red D, brilliant carmine 6B, brilliant carmine 3B, eosin lake, rhodamine lake B, condensed azo compounds such as alizarin lake, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include:

[0118] 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 and 254.

[0119] Examples of blue pigments include alkali blue lake, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, phthalocyanine blue metachloride, fast sky blue, copper phthalocyanine compounds such as indanthrone blue BG and its derivatives, anthraquinone compounds, and basic dye lake compounds. Specific examples include:

[0120] CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66.

[0121] Examples of black pigments include carbon black and aniline black. These colorants may be used alone, as a mixture, or in the form of a solid solution.

[0122] The content of the colorant is preferably 3.0 parts by mass or more and 15.0 parts by mass or less relative to 100.0 parts by mass of the binder resin.

[0123] The toner particles may further contain a charge control agent. Known charge control agents may be used. Charge control agents that provide a fast charging speed and can stably maintain a uniform charge amount are particularly desirable.

[0124] Examples of the charge control agent for controlling the negative chargeability of toner particles include:

[0125] Organometallic compounds and chelates, including monoazo metal compounds, acetylacetonato metal compounds, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, and metal compounds of hydroxycarboxylic acids and dicarboxylic acids. Other examples include aromatic hydroxycarboxylic acids, aromatic monocarboxylic acids and polycarboxylic acids, and their metal salts, anhydrides, and esters, as well as phenol derivatives such as bisphenol. Further examples include urea derivatives, metal-containing salicylic acid compounds, metal-containing naphthoic acid compounds, boron compounds, quaternary ammonium salts, and calixarenes.

[0126] Meanwhile, examples of charge control agents for controlling the positive chargeability of toner particles include aniline black and aniline black modified with fatty acid metal salts; guanidine compounds; imidazole compounds; quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthalenesulfonate and tetrabutylammonium tetrafluoroborate, onium salts such as phosphonium salts as analogs of these, and lake pigments of these; triphenylmethane dyes and lake pigments thereof (with phosphotungstic acid, phosphomolybdic acid, phosphotungstomolybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide or ferrocyanide as lake agents); metal salts of higher fatty acids; and resin charge control agents.

[0127] The charge control agent may be contained alone or in combination of two or more. The content of the charge control agent is preferably 0.01 parts by mass or more and 10.00 parts by mass or less relative to 100.00 parts by mass of the binder resin or the polymerizable monomer.

[0128] The toner can be suitably used as a two-component developer or a one-component developer. Since one-component developers are particularly susceptible to component contamination and toner degradation during extended operation, the above-mentioned effects can be more fully achieved when the toner is applied to a one-component developer suitable for high-speed development and long life.

[0129] Furthermore, in a one-component development system, the toner can exert a long-term microcarrier effect by both the contact development method and the non-contact development method, so a long-life system can be constructed.

[0130] The measurement methods of various physical properties are described below.

[0131] <Method for Identifying Composite Particles Comprising Silicone Polymer Fine Particles Covering the Surfaces of Alumina Particles>

[0132] Composite particles comprising organic silicon polymer fine particles covering the surfaces of aluminum oxide particles can be identified by a combination of shape observation using a scanning electron microscope (SEM) and elemental analysis using energy dispersive X-ray spectroscopy (EDS). Specifically, identification can be performed using the following method for identifying organic silicon polymer fine particles and aluminum oxide particles.

[0133] <Identification Method of Silicone Polymer Fine Particles>

[0134] The organosilicon polymer fine particles contained in the toner can be identified by a method combining shape observation by SEM and elemental analysis by EDS.

[0135] The toner was observed using a scanning electron microscope (trade name: "S-4800", Hitachi, Ltd.) at a maximum magnification of 50,000x. The microscope was focused on the toner particle surface to observe the external additive. EDS analysis was performed on each particle of the external additive to determine whether the analyzed particle was an organosilicon polymer fine particle based on the presence or absence of a Si element peak.

[0136] When the toner contains both organic silicon polymer fine particles and silica fine particles, the element content (atomic %) ratio of Si and O (Si / O ratio) is compared with that of a standard to identify the organic silicon polymer fine particles.

[0137] Standards of both the organosilicon polymer fine particles and the silica fine particles were subjected to EDS analysis under the same conditions to determine the element contents (atomic %) of Si and O.

[0138] The Si / O ratio of the organosilicon polymer fine particles is A, and the Si / O ratio of the silica fine particles is B. The measurement conditions are selected so that A is significantly greater than B.

[0139] Specifically, the standard was measured 10 times under the same conditions, and the arithmetic mean was obtained for both A and B. The measurement conditions were selected so that the arithmetic mean yielded an A / B ratio greater than 1.1.

[0140] If the Si / O ratio of the evaluated fine particle is closer to A than to [(A+B) / 2], the fine particle is judged to be an organosilicon polymer fine particle.

[0141] Tospearl 120A (Momentive Performance Materials Japan LLC) was used as a standard substance for silicone polymer fine particles, and HDK V15 (Asahi Kasei Corporation) was used as a standard substance for silica fine particles.

[0142] <Method for Identifying the Composition and Ratio of the Constituent Compounds of Silicone Polymer Fine Particles>

[0143] The composition and ratio of the constituent compounds of the organosilicon polymer fine particles contained in the toner are identified by NMR.

[0144] When the toner contains silica fine particles in addition to the silicone polymer fine particles, 1 g of the toner is dissolved and dispersed in 31 g of chloroform in a vial, and dispersed for 30 minutes using an ultrasonic homogenizer to prepare a liquid dispersion.

[0145] Ultrasonic processing unit: VP-050 ultrasonic homogenizer (Taitec Corporation)

[0146] Microchip: Stepper microchip, tip diameter

[0147] Microchip tip position: center of glass vial and 5 mm above the vial bottom

[0148] Ultrasonic conditions: 30% intensity, 30 minutes

[0149] Ultrasonic waves were applied while cooling the vial with ice water so that the temperature of the dispersion did not rise.

[0150] The dispersion was transferred to a swing rotor glass tube (50 mL) and the precipitate was added at 58.33 S- 1 The solution was centrifuged for 30 minutes in a centrifuge (H-9R; Kokusan Co., Ltd.) under 40°C conditions. The lower layer of the glass tube contained high-density silica fine particles. The upper layer, a chloroform solution containing organosilicon polymer fine particles, was collected and vacuum-dried (40°C / 24 hours) to remove the chloroform, thereby preparing a sample.

[0151] Use the sample or silicone polymer fine particles, through the solid 29 The abundance ratio of the constituent compounds of the organosilicon polymer fine particles and the ratio of the T3 unit structure in the organosilicon polymer fine particles were measured and calculated by Si-NMR.

[0152] The above is by R a The hydrocarbon group represented by 13 C-NMR confirmation.

[0153] 13 C-NMR (solid) measurement conditions

[0154] Unit: JNM-ECX500II (JEOL RESONANCE Inc.)

[0155] Sample tube:

[0156] Sample: Sample or silicone polymer fine particles

[0157] Measurement temperature: room temperature

[0158] Pulse mode: CP / MAS

[0159] Determined core frequency: 123.25MHz( 13 C)

[0160] Standard substance: Adamantane (external standard: 29.5ppm)

[0161] Sample rotation: 20kHz

[0162] Contact time: 2ms

[0163] Delay time: 2 seconds

[0164] Number of points: 1024

[0165] In this method, the presence or absence of methyl (Si-CH3), ethyl (Si-C2H5), propyl (Si-C3H7), butyl (Si-C4H9), pentyl (Si-C5H 11 ), hexyl (Si-C6H 13 ) or phenyl (Si-C6H5) signals to confirm the above R a Represents a hydrocarbon group.

[0166] On the other hand, in solid 29 In Si-NMR, peaks are detected in different shift regions depending on the structure of the functional group bonded to Si in the constituent compound of the organic silicon polymer fine particles.

[0167] The structure bound to Si can be specified by specifying the position of each peak using a standard sample. The abundance ratio of each constituent compound can also be calculated from the obtained peak area. The ratio of the peak area of ​​the T3 unit structure to the total peak area can also be determined by calculation.

[0168] solid 29 The measurement conditions of Si-NMR are as follows, for example.

[0169] Unit: JNM-ECX5002 (JEOL RESONANCE Inc.)

[0170] Temperature: Room temperature

[0171] Determination method: DDMAS method, 29 Si 45°

[0172] Sample tube: Zirconia

[0173] Sample: Filled in the sample tube in powder form

[0174] Sample rotation: 10kHz

[0175] Relaxation delay: 180s

[0176] Scans: 2000

[0177] After this measurement, the peaks of various silane components with different substituents and linking groups in the organosilicon polymer fine particles were separated into the following X1, X2, X3, and X4 structures by curve fitting, and the peak areas of each were calculated.

[0178] The X3 structure below is the T3 unit structure.

[0179] X1 structure: (Ri)(Rj)(Rk)SiO 1 / 2 (A1)

[0180] X2 structure: (Rg)(Rh)Si(O 1 / 2 )2 (A2)

[0181] X3 structure: RmSi(O 1 / 2 )3 (A3)

[0182] X4 structure: Si(O 1 / 2 )4 (A4)

[0183]

[0184] In formulae (A1), (A2) and (A3), Ri, Rj, Rk, Rg, Rh and Rm represent halogen atoms, hydroxyl groups, acetoxy groups, alkoxy groups or organic groups, such as C 1-6 Hydrocarbon group.

[0185] When more detailed confirmation of the structure is required, in addition to the above 13 C-NMR and 29 In addition to Si-NMR measurement results, 1 The results of H-NMR determination were used for identification.

[0186] <Identification Method of Alumina Particles>

[0187] The aluminum oxide particles can be identified by a combination of shape observation by a scanning electron microscope (SEM) and elemental analysis by energy dispersive X-ray spectroscopy (EDS).

[0188] The toner was observed using an S-4800 (trade name: Hitachi Inc.) scanning electron microscope at a magnification of 50,000x. The microscope was focused on the surface of the toner particles to observe the external additive to be identified. The external additive to be identified was analyzed by EDS, and the aluminum oxide particles could be identified based on the presence or absence of elemental peaks.

[0189] When an Al element peak is observed as an element peak, the presence of aluminum oxide particles can be inferred.

[0190] Prepare a standard sample of alumina particles identified by EDS analysis, perform SEM morphology observation and EDS analysis, and then determine whether the particle being identified is alumina based on whether the analysis results match those of the standard sample.

[0191] <Method for Determining the Coverage of the Surfaces of Alumina Particles in Composite Particles with Silicone Polymer Fine Particles>

[0192] The coverage of the aluminum oxide particle surfaces with the organosilicon polymer fine particles in the composite particles was measured using an S-4800 (trade name) scanning electron microscope (Hitachi, Ltd.). 100 random composite particles were photographed in a field of view magnified up to 50,000 times.

[0193] In the captured image, the area "A" of the region without adhered silicone polymer fine particles and the area "B" of the region with adhered particles in each composite particle were measured, and the ratio of the area covered by the silicone polymer fine particles [B / (A+B)] was calculated. The coverage was measured for 100 composite particles, and the arithmetic average was used as the coverage (area %).

[0194] <Method for Determining the Number Average Particle Size of Primary Particles of Silicone Polymer Fine Particles and Alumina Particles>

[0195] This was measured using an "S-4800" (trade name) scanning electron microscope (Hitachi, Ltd.) combined with elemental analysis by energy dispersive X-ray analysis (EDS). 100 random composite particles were photographed in a field of view magnified up to 50,000 times.

[0196] Randomly select 100 silicone polymer fine particles and alumina particles from the captured image, measure the major diameter of the primary particles, and calculate the average value as the number average particle size. The observation magnification is appropriately adjusted according to the size of the silicone polymer fine particles and alumina particles.

[0197] <Method for measuring circularity of alumina particles>

[0198] To measure the circularity of aluminum oxide particles, images of aluminum oxide particles taken with a Hitachi S-4800 ultra-high resolution field emission scanning electron microscope (Hitachi High Technologies) were analyzed using ImageJ image analysis software (developed by Wayne Rashand) to calculate the circularity. The measurement procedure is as follows.

[0199] (1) Sample preparation

[0200] A thin layer of conductive paste was applied to a sample stage (15 mm x 6 mm aluminum sample stage), and aluminum oxide particles were attached to the sample stage. Excess aluminum oxide particles were blown out with a blower, and the particles were thoroughly dried. The sample stage was set in the sample holder.

[0201] When highly aggregated aluminum oxide particles are measured, the aluminum oxide particles are first mixed with methanol and dispersed by ultrasonic wave, and then the solvent is removed to obtain a measurement sample.

[0202] (2) S-4800 observation conditions

[0203] The observation conditions are as follows.

[0204] Accelerating voltage: 0.8 kV

[0205] Emission current: 20μA

[0206] Detector: [SE top(U)], [+BSE(LA100)]

[0207] Probe current: [Normal]

[0208] Focus mode: [UHR]

[0209] WD: [3.0mm]

[0210] (3) Image preservation

[0211] Adjust the brightness in ABC mode, capture, and save a 640 x 480 pixel image. Use this file for the following analysis. Adjust the magnification appropriately based on the size of the fine particles being observed.

[0212] (4) Image analysis

[0213] The circularity was calculated from the obtained SEM images using ImageJ image analysis software (developed by Wayne Rashand). The calculation steps are as follows.

[0214] [1] Use [Analysis] – [Set Scale] to set the scale.

[0215] [2] The threshold value can be set through [Image]-[Adjustment]-[Threshold].

[0216] (Set to a value that eliminates noise and leaves the aluminum oxide particles to be measured)

[0217] [3] Use [Image]-[Crop] to select the image portion of the aluminum oxide particles to be measured.

[0218] [4] Eliminate overlapping particles through image editing.

[0219] [5] Invert the black and white image using [Edit] - [Invert].

[0220] [6] Select [Area] and [Shape Description] under [Analysis]-[Set Measurement]. Set [Redirect To] to [None] and [Decimal Places (0-9)] to 3.

[0221] [7] Analyzed using [Analyze] – [Analyze Particles], the indicated particle area is at least 0.0005 μm 2 .

[0222] [8] The circularity value of each particle was obtained.

[0223] [9] The circularity was measured for 100 observed particles, and the arithmetic mean of the observed circularity was calculated and used as the circularity.

[0224] The formula for circularity is 4π×(area) / (circumference 2 ). A circularity value of 1 indicates a perfect circle.

[0225] (Separation of Alumina Particles from Toner)

[0226] The circularity can also be measured using aluminum oxide particles separated from toner by the following method.

[0227] The toner was ultrasonically dispersed in methanol to separate the aluminum oxide particles and other external additives in the composite particles, and then allowed to stand for 24 hours. The aluminum oxide particles and other external additives were separated from the toner particles by centrifugation, collected, and thoroughly dried to separate the aluminum oxide particles from the toner particles.

[0228] <Measurement of Average Projected Area of ​​Composite Particles>

[0229] To measure the projected area of ​​the composite particles, the toner surface was observed using a scanning electron microscope and image analysis software. A Hitachi S-4800 ultra-high-resolution field-emission scanning electron microscope (Hitachi High Technologies) was used as the scanning electron microscope, and backscattered electron images were captured using the S-4800. The observation magnification was 20,000x, the accelerating voltage was 10 kV, and the working distance was 3 mm. At 20,000x magnification, the observation area was approximately 30 μm x 20 μm.

[0230] The composite particles on the toner surface are captured in an image, which can then be binarized using image analysis software to define the outlines of the composite particles in the field of view. The projected area of ​​the composite particles can then be calculated by particle analysis of the resulting outline image. ImageJ (developed by Wayne Rasband) was used as the image analysis software.

[0231] The projected areas of 100 composite particles present on the toner particle surfaces are determined by this observation, and the average projected area is calculated by the following formula.

[0232] (Average projected area) = (Total projected area) / (Total number of particles)

[0233] <Method for measuring the number ratio of composite particles to toner particles>

[0234] The number ratio of the composite particles to the toner particles was determined using an S-4800 scanning electron microscope (Hitachi, Inc.) combined with elemental analysis by energy dispersive X-ray spectroscopy (EDS).

[0235] Observe the toner containing composite particles and capture images of 100 randomly selected fields of view at a magnification of 1000. Count the number of composite particles in the toner and the number of toner particles, and calculate the number ratio. If the number ratio of composite particles to toner particles is N, this means that N is the average number of composite particles attached to each toner particle.

[0236] <Method for measuring average circularity of toner>

[0237] The average circularity of the toner is measured using an "FPIA-3000" flow particle image analyzer (Sysmex Corporation) under measurement and analysis conditions of a calibrated operation.

[0238] The specific measurement method is as follows.

[0239] First, approximately 20 mL of ion-exchanged water from which solid impurities had been removed was placed in a glass container. Then, approximately 0.2 mL of a dilution solution of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision instruments, containing a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted approximately three times its mass with the ion-exchanged water was added to serve as a dispersant.

[0240] Then, about 0.02 g of a measurement sample was added and dispersed for 2 minutes using an ultrasonic disperser to obtain a dispersion liquid for measurement. During this process, cooling was performed appropriately so that the temperature of the dispersion liquid was 10°C to 40°C.

[0241] Using a table-top ultrasonic cleaner and disperser (e.g., "VS-150" manufactured by Velvo-Clear) having an oscillation frequency of 50 kHz and an electrical output of 150 W as an ultrasonic disperser, a predetermined amount of ion-exchanged water was placed on a water tank, and then about 2 mL of Contaminon N was added to the water tank.

[0242] The measurement was performed using a flow particle image analyzer equipped with a "LUCPLFLN" objective lens (magnification 20x, aperture 0.40), and a particle sheath "PSE-900A" (Sysmex Corporation) as the sheath liquid. The liquid dispersion obtained through the above steps was introduced into the flow particle image analyzer, and 2,000 toner particles were measured in the HPF measurement mode and total count mode.

[0243] The average circularity of the toner is then determined during particle analysis using a binarization threshold of 85%, and the analyzed particle size is limited to an equivalent circle diameter of 1.977 μm or more and less than 39.54 μm.

[0244] Before starting the measurement, perform automatic focus adjustment using standard latex particles (e.g., "RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A" manufactured by Duke Scientific Corporation, diluted with ion-exchanged water). Then, perform automatic focus adjustment again every two hours after the start of the measurement.

[0245] <Method for measuring weight average particle size (D4) of toner>

[0246] The weight-average particle size (D4) of the toner is calculated as follows. A "Multisizer 3 Coulter Counter" precision particle size distribution analyzer (registered trademark, Beckman Coulter, Inc.) equipped with a 100 μm pore diameter tube and equipped with the dedicated accessory "Beckman Coulter Multisizer 3 Version 3.51" software (Beckman Coulter, Inc.) for setting measurement conditions and analyzing measurement data is used as the measurement unit. Measurements are performed using 25,000 effective measurement channels.

[0247] The electrolytic aqueous solution used in the measurement may be a solution in which special grade sodium chloride is dissolved in ion exchange water to a concentration of about 1% by mass, such as "ISOTON II" (Beckman Coulter, Inc.).

[0248] Before measurement and analysis, the following settings were made on the dedicated software.

[0249] On the "Change Standard Measurement Method (SOMME)" screen in the dedicated software, set the total count number in control mode to 50,000 particles, the number of measurements to 1, and the Kd value to that obtained using "Standard Particles 10.0 μm" (Beckman Coulter, Inc.). Press the "Threshold / Noise Level Determination" button to automatically set the threshold and noise level. Set the current to 1,600 μA, the gain to 2, the electrolyte to ISOTON II, and check the "Post-Measurement Aperture Flushing" button.

[0250] On the "Pulse to Size Conversion Settings" screen of the dedicated software, the element spacing was set to logarithmic size, the size elements were set to 256, and the particle size range was set to 2 to 60 μm.

[0251] The specific measurement method is as follows.

[0252] (1) Place approximately 200 mL of the electrolyte solution in a 250 mL round-bottom glass beaker designed for the Multisizer 3. Place the beaker on the sample stage and stir counterclockwise at 24 rps using a stirring rod. Then, use the "Aperture Tube Rinse" function in the dedicated software to remove contaminants and bubbles from the aperture tube.

[0253] (2) 30 mL of the same electrolytic aqueous solution was placed in a 100 mL glass flat-bottom beaker, and about 0.3 mL of a diluent of "Contaminon N" (a 10% by mass aqueous solution of a pH 7 neutral detergent for cleaning precision instruments, containing a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) diluted 3 times by mass with ion-exchanged water was added.

[0254] (3) Prepare an ultrasonic disperser "Ultrasonic Dispersion System Tetra 150" (Nikkaki Bios Co., Ltd.) with an electrical output of 120 W and equipped with two built-in oscillators with an oscillation frequency of 50 kHz and a phase shift of 180°. Add approximately 3.3 L of ion-exchanged water to the water tank of the ultrasonic disperser and add approximately 2 mL of Contaminon N to the water tank.

[0255] (4) Place the beaker of (2) above in the beaker fixing hole of the ultrasonic disperser, operate the ultrasonic disperser, and adjust the height of the beaker to maximize the resonance condition of the liquid surface of the electrolytic aqueous solution in the beaker.

[0256] (5) Expose the electrolytic aqueous solution in the beaker of (4) above to ultrasonic waves, and simultaneously add approximately 10 mg of the toner little by little to the electrolytic aqueous solution and disperse it. Then, continue ultrasonic dispersion for 60 seconds. During ultrasonic dispersion, adjust the water temperature in the water tank appropriately to between 10°C and 40°C.

[0257] (6) The electrolytic aqueous solution of (5) above, in which the toner is dispersed, is dropped into the round-bottom beaker of (1) above, which is set on the sample stage, using a pipette and adjusted to a measurement concentration of about 5%. The measurement is then continued until the number of particles measured reaches 50,000.

[0258] (7) Analyze the measured data using the dedicated software included with the equipment and calculate the weight-average particle size (D4). The weight-average particle size (D4) is the "Average diameter" displayed on the "Analysis / Volume Statistics (Arithmetic Mean)" screen when setting Graph / Volume % in the dedicated software.

[0259] <Measurement of Glass Transition Point (Tg) of Toner>

[0260] The Tg of the toner was measured by differential scanning calorimetry (DSC) as follows. Measurements were performed using a Q2000 differential scanning calorimeter (TA Instruments) in accordance with ASTM D3418-82. The melting points of indium and zinc were used for temperature calibration of the instrument's detection unit, and the heat of fusion of indium was used for calorific value calibration.

[0261] Specifically, 3 mg of the sample toner was accurately weighed and placed in an aluminum pan. An empty aluminum pan was used as a reference and the measurement was conducted under the following conditions. The glass transition point was determined by the midpoint method from the DSC curve during the first heating process.

[0262] Measurement conditions

[0263] Keep at 20℃ for 5 minutes

[0264] Apply a modulation of 1.0°C / min and increase the temperature to 140°C at 1°C / min

[0265] Maintain equilibrium at 140°C for 5 minutes

[0266] Temperature drops to 20°C

[0267] Example

[0268] The present invention will be described in more detail below based on Examples and Comparative Examples, but the present invention is by no means limited to these Examples. Unless otherwise specified, the parts in the examples are all by mass.

[0269] Description of Toner Production Example.

[0270] <Preparation of Binder Resin Particle Dispersion>

[0271] 89.5 parts of styrene, 9.2 parts of butyl acrylate, 1.3 parts of acrylic acid and 3.2 parts of n-lauryl mercaptan were mixed and dissolved. An aqueous solution of 1.5 parts of Neogen RK (DKS Co., Ltd.) in 150 parts of ion-exchanged water was added and dispersed in the mixed solution.

[0272] Then, an aqueous solution of 0.3 parts of potassium persulfate and 10 parts of ion-exchanged water was added, and the mixture was gently stirred for 10 minutes.

[0273] After nitrogen purging, emulsion polymerization was carried out at 70°C for 6 hours. After completion of the polymerization, the reaction solution was cooled to room temperature and ion-exchanged water was added to obtain a binder resin particle dispersion having a volume-based median particle size of 0.2 μm and a solid content concentration of 12.5% ​​by mass.

[0274] <Preparation of Release Agent Dispersion>

[0275] 100 parts of a release agent (behenyl behenate, melting point: 72.1°C) and 15 parts of Neogen RK were mixed with 385 parts of ion-exchanged water and dispersed using a JN100 wet jet mill (Jokoh Co., Ltd.) for about 1 hour to obtain a release agent dispersion. The solid concentration of the release agent dispersion was 20% by mass.

[0276] <Preparation of Colorant Dispersion>

[0277] 100 parts of carbon black "Nipex35 (Orion Engineered Carbons)" and 15 parts of Neogen RK were mixed with 885 parts of ion-exchanged water and dispersed in a JN100 wet jet mill for about 1 hour to obtain a colorant dispersion.

[0278] <Preparation of Toner Particles 1>

[0279] 265 parts of the binder resin particle dispersion, 10 parts of the release agent dispersion, and 10 parts of the colorant dispersion were dispersed using a homogenizer (IKA Japan KK: Ultra-Turrax T50).

[0280] While stirring, the container temperature was adjusted to 30°C, and 1 mol / L hydrochloric acid was added to adjust the pH to 5.0. The mixture was allowed to stand for 3 minutes before heating, and then the temperature was raised to 50°C to produce aggregated particles. Under these conditions, the particle size of the aggregated particles was measured using a "Multisizer 3 Coulter Counter" (registered trademark, Beckman Coulter, Inc.). Once the weight-average particle size reached 6.2 μm, 1 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 8.0 and arrest particle growth.

[0281] The temperature was then raised to 95° C. to fuse and spheroidize the aggregated particles. When the average circularity reached 0.980, the temperature was lowered to 30° C. to obtain a toner particle dispersion 1.

[0282] Hydrochloric acid was added to adjust the pH of the obtained Toner Particle Dispersion Liquid 1 to 1.5 or less, and the dispersion liquid was stirred for 1 hour, left to stand, and then subjected to solid-liquid separation in a pressure filter to obtain a toner cake.

[0283] The toner was slurried with ion-exchanged water, redispersed, and subjected to solid-liquid separation in the previous filtration unit. Reslurrying and solid-liquid separation were repeated until the conductivity of the filtrate was below 5.0 μS / cm, at which point a final solid-liquid separation was performed to obtain a toner filter cake.

[0284] The resulting toner cake was dried using a Flash Jet air dryer (Seishin Enterprise Co., Ltd.). Drying conditions included a blast temperature of 90°C and a dryer outlet temperature of 40°C. The toner cake feed rate was adjusted according to the toner cake's moisture content to maintain the outlet temperature at 40°C. Fine and coarse powders were then separated using a multi-division classifier using the Coanda effect to obtain Toner Particles 1. Toner Particles 1 had a weight-average particle size (D4) of 6.3 μm, an average circularity of 0.980, and a glass transition temperature (Tg) of 57°C.

[0285] <Production Example of Silicone Polymer Fine Particles A1>

[0286] (Step 1)

[0287] 360.0 parts of water were placed in a reactor equipped with a thermometer and a stirrer, and 15.0 parts of 5.0% by mass hydrochloric acid were added to obtain a homogeneous solution. This solution was stirred at 25°C, 136.0 parts of methyltrimethoxysilane were added, and stirred for 5 hours. The mixture was then filtered to obtain a clear reaction solution containing a silanol compound or a partial condensate thereof.

[0288] (Step 2)

[0289] 440.0 parts of water were placed in a reactor equipped with a thermometer, a stirrer, and a dripping mechanism, and 15.0 parts of 10.0% by mass ammonia water were added to obtain a uniform solution.

[0290] 100.0 parts of the reaction solution obtained in step 1 was added dropwise over 1.00 hour, and the mixture was stirred at 40° C. for 6 hours to obtain a suspension.

[0291] The resulting suspension was centrifuged to precipitate particles, which were then taken out and dried in a dryer at 200° C. for 24 hours to obtain silicone polymer fine particles A1.

[0292] The number average particle diameter of primary particles of the obtained silicone polymer fine particles A1 was 50 nm.

[0293] <Production Example of Silicone Polymer Fine Particles A2 to A6>

[0294] Silicone polymer fine particles A2 to A6 were obtained according to the production example of silicone polymer fine particle A1, except that the silane compound, reaction starting temperature, amount of ammonia water added, and reaction solution dropwise addition time were changed as shown in Tables 1-1 and 1-2. The physical properties of the obtained silicone polymer fine particles A2 to A6 are shown in Tables 1-1 and 1-2.

[0295] [Table 1-1]

[0296]

[0297] [Table 1-2]

[0298]

[0299] In Tables 1-1 and 1-2, T represents the ratio of the peak area derived from silicon having a T3 unit structure to the total area of ​​peaks derived from all silicon elements contained in the organosilicon polymer fine particles.

[0300] <Examples of Alumina Particles>

[0301] Alumina particles will be described.

[0302] The alumina particles used were shown in Table 2. The physical properties of the alumina particles 1 to 10 are shown in Table 2. The alumina particles 4 to 6 were prepared by the following production method.

[0303] The surfaces of aluminum oxide particles 1 to 5 and 7 to 10 were untreated. The surface of aluminum oxide particle 6 had been treated with calcium stearate.

[0304] <Production Example of Alumina Particles 4>

[0305] Alumina particles 2 (AKP-53, Sumitomo Chemical Co., Ltd.) with a number average particle size of 150 nm were dispersed in the solution, centrifuged to remove coarse particles, and then dried to obtain alumina particles 4 with a number average particle size of 100 nm. The physical properties of alumina particles 4 are shown in Table 2.

[0306] <Production Example of Alumina Particles 5>

[0307] Fine particles were removed from alumina particles 3 (AA-07, Sumitomo Chemical Co., Ltd.) having a number average particle size of 590 nm using an air classifier to obtain alumina particles 5 having a number average particle size of 950 nm.

[0308] <Production Example of Alumina Particles 6>

[0309] Alumina particles (AES-11, Sumitomo Chemical Co., Ltd.) having a number average particle size of 240 nm were surface-treated with 0.5% by mass of calcium stearate to obtain alumina particles 6.

[0310] The physical properties of the aluminum oxide particles 6 are shown in Table 2.

[0311] [Table 2]

[0312]

[0313] <Production Example of Composite Particles 1>

[0314] The silicone polymer fine particles A1 and the aluminum oxide particles 1 were mixed in a 500 ml glass container at the ratio shown in Table 3, and then mixed with a blender-mixer (Oster Co.) at an output of 450 W for 1 minute to obtain composite particles 1 .

[0315] <Production Examples of Composite Particles 2 to 19>

[0316] Composite particles 2 to 19 were obtained according to the production example of composite particle 1 except that the conditions were changed as shown in Table 3.

[0317] <Production Example of Composite Particles 20>

[0318] Composite particles 20 were obtained according to the production example of composite particles 1, except that 8 parts of sol-gel silica (X24-9600A, Shinetsu Chemical Co., Ltd.) having a number average particle diameter of 110 nm was used instead of 3.5 parts of organosilicon polymer fine particles A1.

[0319] [Table 3]

[0320]

[0321] <Manufacturing Example of Toner 1>

[0322] <External addition steps>

[0323] 0.30 parts of the composite particles 1 and 1.00 parts of hydrophobic silica fine particles [indicated as C1 in the table, with a BET specific surface area of ​​300 m 2 / g, hydrophobically treated with 30 parts of hexamethyldisilazane (HMDS) and 10 parts of dimethyl silicone oil relative to 100 parts of silica fine particles, was added to 100.00 parts of the obtained toner particles 1 in an FM mixer (FM10C, Nippon Coke and Engineering Co., Ltd.) while flowing water at 7° C. in the jacket.

[0324] Once the water temperature in the jacket stabilized at 7°C ± 1°C, it was mixed at a circumferential speed of 38 m / sec for 5 minutes to obtain Toner Mixture 1. During this process, the amount of water flowing through the jacket was appropriately adjusted so that the temperature within the tank of the FM mixer did not exceed 25°C. The resulting Toner Mixture 1 was sieved with a 75 μm mesh to obtain Toner 1.

[0325] Table 4 shows the toner preparation conditions and physical properties. The coverage of the surfaces of the aluminum oxide particles in the composite particles with the organosilicon polymer fine particles, the average projected area of ​​the composite particles, and the ratio of the number of composite particles to the toner particles were also measured for the resulting toner. The results are shown in Table 4.

[0326] <Manufacturing Examples of Toners 2 to 19 and Comparative Toners 1 to 7>

[0327] Toners 2 to 19 and Comparative Toners 1 to 7 were obtained according to the production example of Toner 1 except that the conditions were changed as shown in Table 4. The physical properties of Toners 2 to 19 and Comparative Toners 1 to 7 are shown in Table 4.

[0328] [Table 4]

[0329]

[0330] In the table, "CE" means "Comparative Example", "C." means "Comparison", X means the coverage of the surface of the aluminum oxide particles by the silicone polymer fine particles (area %), Y means the average projected area of ​​the composite particles, Z means the number ratio of the composite particles to the toner particles, and A3 is the silicone polymer fine particles A3.

[0331] <Example 1>

[0332] Toner 1 was evaluated as follows. The evaluation results are shown in Table 5.

[0333] A modified LBP 712Ci (Canon) was used as the evaluation instrument. The main machine's processing speed was modified to 300 mm / sec. Under these conditions, necessary adjustments were made to enable image formation. Toner was also removed from the black cartridge, and then 200 g of Toner 1 was loaded.

[0334] (Image Evaluation)

[0335] (1) Fogging on the drum

[0336] To test the charging stability of the toner, fogging in a high temperature and high humidity environment (30° C. / 80% RH) (HH fogging) and fogging in a low temperature and low humidity environment (15° C. / 10% RH) (LL fogging) were evaluated by the following methods.

[0337] Every day under various environments on Canon color laser copy paper (A4: 81.4g / m 2 (Unless otherwise specified, this is also used below.) 2,000 sheets of an image with a 1.0% print rate were output, with a 2-second pause after each 2-sheet print, for a total of 20,000 sheets. Fogging on the drum in the box was collected by taping at the start, after 10,000 sheets were output, and after 20,000 sheets were output, and evaluation was performed.

[0338] Fogging was measured using a reflection densitometer (Tokyo Denshoku, TC-6DS reflectometer). The worst value of the white background reflection on the web portion was designated Ds, the average reflection density on the web portion was Dr, and the fog density (%) was calculated as (Ds – Dr). A green filter was used as the filter. Evaluation was performed using the following criteria. In this evaluation method, the fog density on the drum increases as the toner's charging performance decreases.

[0339] (fog)

[0340] Evaluation criteria

[0341] A: Fogging concentration is less than 0.5%

[0342] B: Fogging concentration is 0.5% or more and less than 2.0%

[0343] C: Fogging concentration is 2.0% or more and less than 4.0%

[0344] D: Fogging concentration is 4.0% or more

[0345] (2) Solid image tracking

[0346] To test the toner's fluidity and durability, solid image tracking was evaluated in a high-temperature, high-humidity environment (30°C / 80% RH, HH). In this environment, 2,000 images with a 1.0% print rate were printed on Canon color laser copy paper per day, with a 2-second pause between each two prints, for a total of 20,000 prints.

[0347] At the beginning, after 10,000 sheets were output, and after 20,000 sheets were output, three solid images were continuously output as sample images using the cartridge. The solid image followability of the three solid images obtained was visually evaluated. The greater the fluidity of the toner, the better the result of this evaluation.

[0348] (Solid image tracking)

[0349] Evaluation criteria

[0350] A: The image density is uniform and there are no irregularities

[0351] B: Image density is somewhat irregular

[0352] C: Image density is irregular but still good

[0353] D: Image density is irregular, and a uniform solid image cannot be obtained

[0354] (3) LL charging roller pollution

[0355] To test the degree of toner wear and contamination of key components, the charging roller contamination was evaluated using the following method. Under a low-temperature, low-humidity environment (15°C / 10% RH, LL), 2,000 images with a 1.0% print rate were printed on Canon color laser copy paper per day. A 2-second pause was performed after every two prints, for a total of 20,000 prints.

[0356] Next, the charging roller was removed from the toner cartridge and replaced with the one from a new (commercially available) process cartridge after 20,000 sheets had been output. A halftone image was then output. The uniformity of the halftone image was visually evaluated to assess charging roller contamination. Because the charging roller is likely to be contaminated if the photoreceptor or cleaning blade is worn, a lower rating indicates a greater degree of toner wear and contamination of key components.

[0357] (Contamination of live components)

[0358] Evaluation criteria

[0359] A: The image density is uniform and there are no irregularities

[0360] B: Image density is somewhat irregular

[0361] C: Image density is irregular but still good

[0362] D: Image density is irregular, and a uniform solid image cannot be obtained

[0363] <Examples 2 to 19, Comparative Examples 1 to 7>

[0364] The same evaluation as in Example 1 was performed using Toners 2 to 19 and Comparative Toners 1 to 7. The evaluation results are shown in Table 5.

[0365] [Table 5]

[0366]

[0367] In the table, "CE" stands for "Comparative Example" and "C." stands for "Comparative".

[0368] Examples 1 to 19 achieved good results in all evaluation items. However, Comparative Examples 1 to 7 did not perform well in some evaluation items. These results demonstrate that the present disclosure can provide toners that exhibit excellent fluidity and charging stability during long-term, durable use and exhibit little wear or contamination of key components of image forming apparatuses.

[0369] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A toner, characterized in that: Contains toner particles and external additives, wherein The external additive comprises composite particles containing organic silicon polymer fine particles covering the surfaces of aluminum oxide particles, The coverage of the surfaces of the aluminum oxide particles by the organic silicon polymer fine particles is 1 area % or more and 50 area % or less, and Given A as the number average particle size of the primary particles of the silicone polymer fine particles and B as the number average particle size of the primary particles of the alumina particles, with the units of A and B being nm, the following formulae (I) and (II) are satisfied: A≤90(I) 100≤B≤1000(II), in The organic silicon polymer fine particles have a structure in which silicon atoms and oxygen atoms are alternately bonded, and At least a portion of the organosilicon polymer in the organosilicon polymer fine particles comprises a SiO 3 / 2 The T3 unit structure represented by R a It is C 1-6 Alkyl or phenyl, wherein the organic silicon polymer fine particles 29 In Si-NMR measurement, the ratio of the area of ​​the peak derived from silicon having the T3 unit structure to the total area of ​​the peaks derived from all silicon elements contained in the organosilicon polymer fine particles is 0.50 or more and 1.00 or less. 2 . The toner according to claim 1 , wherein the circularity of the aluminum oxide particles is 0.70 or more and 0.99 or less.

3. The toner according to claim 1, wherein the average projected area of ​​the composite particles is 0.01 μm 2 Above and 1.00μm 2 the following, The average projected area is obtained by observing the surface of the toner with a scanning electron microscope, capturing the composite particles on the toner surface in an image, binarizing the image with image analysis software to define the outline of the composite particles in the field of view, calculating the projected area of ​​the composite particles by particle analysis of the resulting outline image, and calculating the average projected area by the following formula: (Average projected area) = (total projected area) / (total number of particles). 4 . The toner according to claim 1 , wherein a ratio of the number of composite particles attached to the toner particles to the number of the toner particles is 0.1 or more. 5 . The toner according to claim 1 , wherein the content of the composite particles is 0.01 to 3.00 parts by mass relative to 100 parts by mass of the toner particles.

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