Non-magnetic one-component developing toner

Abstract

To provide nonmagnetic one-component development toner in which the fluidity is controlled, with which a printed matter with the high initial image density is obtained, which suppresses the occurrence of fogging in printing of an image under a high-temperature and high-humidity environment and can obtain the image with the high quality.SOLUTION: There is provided nonmagnetic one-component development toner by externally adding sol-gel silica particles to toner base particles whose circularity is equal to or greater than 0.940. The sol-gel silica particles have the average particle size of the primary particles equal to or greater than 60 nm and equal to or less than 130 nm. The association degree being a ratio of the average particle size of the secondary particles to the average particle size of the primary particles obtained from a specific surface area [average particle size of the secondary particles / average particle size of the primary particles] is equal to or greater than 1.3 and equal to or less than 2.5.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for non-magnetic one-component development. [Background technology]

[0002] In image forming devices such as electrophotographic devices, electrostatic recording devices, and electrostatic printing devices, a technology for forming a desired image by developing an electrostatic latent image formed on a photoreceptor with a toner for developing an electrostatic image is widely used. Such a technology is applied to copying machines, printers, facsimiles, and combination machines thereof. In recent years, with the demand for higher definition and higher quality image formation, electrostatic image developing toners in which external additives are added to toner base particles having a high degree of circularity have been used.

[0003] Patent Document 1 describes a toner for developing electrostatic images that has excellent cleaning properties as well as development maintenance, and includes a toner produced by a chemical method and an external additive that is silica particles having an average diameter of 100 nm or more and 500 nm or less, an average circularity of 0.5 or more and 0.8 or less, and an average ratio of the circle-equivalent diameter to the maximum height of more than 1.5 and less than 1.9. Furthermore, Patent Document 2 describes an electrostatic image developing toner that has the objective of providing a toner for preventing fluctuations in image density even with use over time, and that includes toner particles containing a binder resin, a release agent, and a colorant, and an external additive having a volume average particle diameter d of 70 nm or more and 400 nm or less, a ratio of the volume average particle diameter d to the volume-based particle diameter standard deviation σ (d / σ) of 2.0 or more and 12 or less, and an average circularity of 0.5 or more and 0.9 or less. Furthermore, Patent Document 3 describes a toner for the purpose of providing a toner that has sufficient low-temperature fixability and bottle dischargeability and is capable of forming high-quality images over a long period of time, the toner comprising toner base particles containing a crystalline polyester resin and an amorphous polyester resin and external additives attached to the surfaces thereof, the toner having an average circularity of 0.945 or more and less than 0.965, the external additives comprising silica particles having a volume-average particle size of 70 nm or more and 300 nm or less and an average circularity of 0.5 or more and 0.9 or less, and fatty acid metal salt particles having a volume-based median diameter of 0.50 μm or more and 2.00 μm or less. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-156591 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-128195 [Patent Document 3] Japanese Patent Application Laid-Open No. 2017-90489 Summary of the Invention [Problem to be solved by the invention]

[0005] Toners containing toner base particles with high circularity and nearly spherical shape, such as those produced by chemical processes, are advantageous for achieving high image quality, but they also have high fluidity and are easily charged. Therefore, in non-magnetic single-component development systems, the toner has high fluidity and is excessively charged, which can easily cause fogging. Here, by using sol-gel silica particles produced by a wet process, as described in Patent Documents 1 to 3, as an external additive, these sol-gel silica particles contain an appropriate amount of moisture, which makes it easier for the charge on the toner surface to be released, thereby suppressing the occurrence of fogging. However, even toners containing sol-gel silica particles as an external additive did not achieve sufficient fogging suppression effects in harsh environments such as increased print counts or high-temperature, high-humidity environments. The present invention relates to a non-magnetic single-component developing toner that has controlled fluidity, can produce printed matter with high initial image density, can suppress the occurrence of fog when printing images in a high-temperature, high-humidity environment, and can produce high-quality images. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by externally adding sol-gel silica particles having a specific particle size and a specific degree of association to toner base particles having a high degree of circularity.

[0007] That is, the present invention relates to the following [1]. [1] A toner base particle having a circularity of 0.940 or more to which sol-gel silica particles are externally added, The sol-gel silica particles have an average particle size of primary particles of 60 nm or more and 130 nm or less, and a degree of association, which is the ratio of the average particle size of secondary particles to the average particle size of primary particles calculated from the specific surface area [average particle size of secondary particles / average particle size of primary particles], of 1.3 or more and 2.5 or less. Non-magnetic single-component developer toner. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a non-magnetic one-component developing toner that has controlled fluidity, can produce printed matter with high initial image density, can suppress the occurrence of fog when printing images in a high-temperature, high-humidity environment, and can produce high-quality images. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Non-magnetic single-component developing toner] The non-magnetic one-component developing toner of the present invention (hereinafter simply referred to as "toner") is composed of toner base particles having a circularity of 0.940 or more, and sol-gel silica particles having an average primary particle size of 60 nm or more and 130 nm or less, and an association degree, which is the ratio of the average secondary particle size to the average primary particle size calculated from the specific surface area [average secondary particle size / average primary particle size], of 1.3 or more and 2.5 or less, which are externally added to the toner base particles having a circularity of 0.940 or more. In the following description, the non-magnetic one-component toner contains toner base particles and an external additive, and preferably consists of the toner base particles and the external additive. Also, each particle of the non-magnetic one-component toner is also referred to as a "toner particle."

[0010] In the non-magnetic one-component development method, the friction of toner particles between the charging blade and the developing roller is reduced with toner having a high degree of circularity, which results in less toner being placed on the developing roller, making it impossible to ensure a stable amount of toner being transported, and making it prone to fogging.In addition, the toner becomes excessively charged by the charging blade, which also creates the problem of not being able to guarantee image density. In the present invention, it has been discovered that while sol-gel silica particles, which do not aggregate and have an aggregation degree of close to 1, are normally used as external additives, by setting the particle size and aggregation degree of the primary particles of the sol-gel silica particles within a specific range, it is possible to provide a non-magnetic one-component developing toner that controls fluidity, produces printed matter with high initial image density, and suppresses the occurrence of fogging when printing images under high-temperature, high-humidity environments, thereby producing high-quality images. The reason why the above effect is obtained is not clear, but is thought to be as follows. Highly circular toner particles, in which excessive charging is suppressed by sol-gel silica particles with a moderate moisture content, have a moderately large average particle size of the primary particles of the sol-gel silica particles and a moderately high degree of association, thereby controlling fluidity. As a result, it is believed that the toner transportability between the developing roll and the charging blade is improved, and the toner is not excessively charged, resulting in printed matter with high initial image density. Furthermore, it is believed that the improved toner transportability ensures a stable transport amount and suppresses the occurrence of fog. Furthermore, the external addition of sol-gel silica particles with a moderate moisture content, a relatively large primary particle size, and a moderate degree of association suppresses aggregation of toner particles even under high temperature and high humidity conditions, thereby suppressing image quality degradation and resulting in high-quality images. The above-mentioned mechanism regarding the effects of the present invention is only a supposition, and the present invention is not limited to this.

[0011] The definitions of various terms used in this specification are shown below. Whether a resin is crystalline or amorphous is determined by its crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the endothermic maximum peak temperature (softening point (°C) / endothermic maximum peak temperature (°C)) measured by the method described in the Examples below. A crystalline resin is one with a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or, if an endothermic peak is observed, one with a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be adjusted appropriately by adjusting the types and ratios of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. In the specification, the carboxylic acid component of the polyester resin includes not only the compound itself, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). Volume median particle size (D 50 )" is the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size. The coefficient of variation of particle size distribution (hereinafter also simply referred to as "CV value") is a value expressed by the following formula: The volume average particle size in the formula is the particle size obtained by multiplying the particle size of all measured particles by the volume of that particle, and then dividing the sum by the total volume of the measured particles. CV value (%) = [Standard deviation of particle size distribution (μm) / Volume average particle size (μm)] x 100

[0012] <Toner base particles> In the present invention, the circularity of the toner base particles is 0.940 or more. When the circularity is 0.940 or more, images with excellent quality can be obtained even under high temperature and high humidity conditions. The circularity of the toner base particles is, from the viewpoint of obtaining images of excellent quality, 0.940 or more, preferably 0.950 or more, more preferably 0.960 or more, and, from the viewpoint of further suppressing the occurrence of fogging, is preferably 0.995 or less, more preferably 0.990 or less, even more preferably 0.985 or less, and still more preferably 0.980 or less. The circularity of the toner base particles is measured by the method described in the examples.

[0013] The toner base particles contain a binder resin, and preferably contain a colorant and a release agent in addition to the binder resin. The toner base particles may be obtained by any known method such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, or an aggregation fusion method. From the viewpoint of obtaining a desired circularity, however, toner base particles obtained by an aggregation fusion method are preferred, and toner base particles having a core-shell structure are more preferred. Preferred embodiments of the toner base particles will be described below, but in the present invention, the toner base particles are not particularly limited as long as they have the above-mentioned circularity.

[0014] [Binder resin] From the viewpoint of achieving excellent low-temperature fixing properties and a desired degree of circularity, the toner base particles preferably contain a polyester resin as a binder resin, more preferably contain an amorphous polyester resin A, and even more preferably contain an amorphous polyester resin A and a crystalline polyester resin C.

[0015] <Amorphous polyester resin A> In the present invention, the toner base particles preferably contain an amorphous polyester resin A as a binder resin, and more preferably the core contains the amorphous polyester resin A. The amorphous polyester resin A is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of amorphous polyester resins include polyester resins and modified polyester resins. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition-polymerized resin segments. Among these, amorphous composite resins containing polyester resin segments that are polycondensates of alcohol components and carboxylic acid components and addition-polymerized resin segments that are addition-polymerized products of raw material monomers containing styrene-based compounds are preferred.

[0016] Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of obtaining a toner with excellent low-temperature fixability. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I):

[0017] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 are each independently an ethylene group or a propylene group, x and y are each a positive number that represents the average number of moles of alkylene oxide added, and the sum of x and y is 1 or more and 16 or less.

[0018] Examples of alkylene oxide adducts of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination. Among these, the propylene oxide adduct of bisphenol A is preferred. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0019] Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and alkylene oxide adducts of hydrogenated bisphenol A having 2 to 4 carbon atoms (average number of moles added: 2 to 12). Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0020] Examples of the carboxylic acid component include dicarboxylic acids and trivalent or higher polycarboxylic acids. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 45 mol% or more, and is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less.

[0021] The linear or branched aliphatic dicarboxylic acid preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 30 or less, more preferably 20 or less carbon atoms. Examples of linear or branched aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms. Examples of succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, fumaric acid, sebacic acid, and succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms are preferred, with fumaric acid, sebacic acid, and dodecenylsuccinic acid being more preferred. The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and is preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less.

[0022] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, for example, trimellitic acid, and preferably trimellitic acid or its anhydride. When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0023] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0024] The addition polymerized resin segment is, for example, an addition polymer of raw material monomers containing a styrene-based compound. Examples of styrene compounds include unsubstituted or substituted styrene. Examples of the substituent substituted on styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group, or a salt thereof. Examples of styrene compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene is preferred. The content of styrene-based compounds in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 65% by mass or more, even more preferably 75% by mass or more, and is 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0025] Examples of raw material monomers other than styrene-based compounds include (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyl compounds such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylates are more preferred. The number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and is preferably 24 or less, more preferably 22 or less, even more preferably 20 or less. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate. Preferred are 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate, more preferred are 2-ethylhexyl acrylate and stearyl methacrylate, and even more preferred are stearyl methacrylate. In addition, "(iso or tertiary)" and "(iso)" refer to both the presence and absence of these prefixes, and the absence of these prefixes indicates normal. In addition, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[0026] The content of (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, even more preferably 25% by mass or less. The total amount of the styrene compound and (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 100% by mass.

[0027] The amorphous polyester resin A preferably has a constitutional unit derived from a bireactive monomer bonded to a polyester resin segment and an addition polymerization resin segment via a covalent bond. The term "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of a functional group and an addition polymerizable group of a bireactive monomer. An example of the addition polymerizable group is a carbon-carbon unsaturated bond (ethylenically unsaturated bond). Examples of the bireactive monomer include addition-polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, addition-polymerizable monomers having at least one functional group selected from a hydroxyl group and a carboxyl group are preferred, and addition-polymerizable monomers having a carboxyl group are more preferred. Examples of addition-polymerizable monomers having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of reactivity in both polycondensation reactions and addition polymerization reactions, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. When the bireactive monomer is an addition-polymerizable monomer having a carboxy group, the amount of the constitutional units derived from the bireactive monomer is preferably 1 mol part or more, more preferably 5 mol parts or more, even more preferably 8 mol parts or more, and preferably 30 mol parts or less, more preferably 25 mol parts or less, even more preferably 20 mol parts or less, relative to 100 mol parts of the alcohol component of the polyester resin segment of the amorphous polyester resin A.

[0028] The amorphous polyester resin A may further contain a structural unit derived from a hydrocarbon wax having at least one of a carboxyl group and a hydroxyl group (a structural unit derived from a hydrocarbon wax) in addition to the polyester resin segment and the addition polymerization resin segment. When the amorphous polyester resin A contains the structural unit derived from a hydrocarbon wax via a covalent bond, the releasability of the toner can be improved.

[0029] The content of the polyester resin segment in the amorphous polyester resin A is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 55% by mass or more, and is preferably 95% by mass or less, more preferably 85% by mass or less, and even more preferably 75% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment. The structural unit derived from a bireactive monomer is referred to as a polyester resin segment.

[0030] The content of the addition polymerization resin segment in the amorphous polyester resin A is preferably 5% by mass or more, more preferably 15% by mass or more, even more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 45% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0031] The amount of the bireactive monomer-derived structural units in the amorphous polyester resin A is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and is preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 4% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0032] The amount of hydrocarbon wax-derived structural units in the amorphous polyester resin A is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 6 parts by mass or less, per 100 parts by mass of the total amount of the polyester resin segment and the addition polymerization resin segment.

[0033] The above amounts are calculated based on the ratios of the amounts of the polyester resin segment, raw material monomers for the addition polymerization resin segment, bireactive monomer, and radical polymerization initiator, and the mass of the polyester resin segment, etc. is based on the mass excluding the mass of water produced by polycondensation. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated by including it in the addition polymerization resin segment. Furthermore, when the amorphous polyester resin A contains structural units derived from hydrocarbon wax, the above amounts are based on the mass excluding the mass of the structural units derived from hydrocarbon wax.

[0034] The amorphous polyester resin A may be produced, for example, by a method including step A of polycondensing an alcohol component and a carboxylic acid component. When the amorphous polyester resin A is a composite resin, it may be produced by a method including step A and step B of addition-polymerizing raw material monomers of the addition-polymerized resin segment and a bireactive monomer. When the amorphous polyester resin A further contains a structural unit derived from a hydrocarbon wax, in the above-mentioned step A, for example, a polycondensation reaction of an alcohol component and a carboxylic acid component is carried out in the presence of a hydrocarbon wax having at least one of a hydroxyl group and a carboxyl group. Step B may be carried out after step A, step B may be carried out after step A, or step A and step B may be carried out simultaneously. A preferred method is to subject a part of the carboxylic acid component to a polycondensation reaction in step A, then carry out step B, and then add the remainder of the carboxylic acid component to the polymerization system to further promote the polycondensation reaction of step A and the polycondensation reaction with the carboxy group of the bireactive monomer or the constituent moiety derived from the bireactive monomer.

[0035] In step A, if necessary, polycondensation may be carried out using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxybis(triethanolaminate) in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, and more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0036] Examples of the radical polymerization initiator for the addition polymerization in step B include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator used is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the raw material monomer of the addition polymerization resin segment. The temperature of the addition polymerization is preferably 110°C or higher, more preferably 130°C or higher, and preferably 230°C or lower, more preferably 220°C or lower, and even more preferably 210°C or lower.

[0037] (Physical properties of amorphous polyester resin A) The softening point of the amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 125°C or lower. The glass transition temperature of the amorphous polyester resin A is preferably 30°C or higher, more preferably 35°C or higher, and even more preferably 40°C or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower.

[0038] The acid value of the amorphous polyester resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less. The softening point, glass transition temperature, and acid value of the amorphous polyester resin A can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values can be determined by the methods described in the examples. When two or more kinds of amorphous polyester resins A are used in combination, the softening point, glass transition temperature and acid value of the mixture thereof preferably fall within the above-mentioned ranges.

[0039] The content of the amorphous polyester resin A is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 65% by mass or more, relative to the total amount of the resin components of the core portion, and is 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 87% by mass or less.

[0040] <Crystalline polyester resin C> In the present invention, the toner base particles preferably contain crystalline polyester resin C, more preferably the toner base particles have a core-shell structure and contain crystalline polyester resin C in the core portion, and even more preferably the toner base particles contain crystalline polyester resin C only in the core portion.

[0041] The crystalline polyester resin C is, for example, a crystalline polyester resin that is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol preferably has 2 or more carbon atoms, more preferably 4 or more carbon atoms, and even more preferably 6 or more carbon atoms, and preferably has 16 or less carbon atoms, more preferably 14 or less carbon atoms, and even more preferably 12 or less carbon atoms. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, and 1,10-decanediol is more preferred.

[0042] The amount of α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0043] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols, such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0044] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 8 or more carbon atoms, and even more preferably 10 or more carbon atoms, and preferably has 14 or less carbon atoms, more preferably 12 or less carbon atoms. Examples of aliphatic dicarboxylic acids include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid and tetradecanedioic acid are preferred, and sebacic acid is more preferred. These carboxylic acid components may be used alone or in combination.

[0045] The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0046] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and polycarboxylic acids having three or more carboxylic acids. These carboxylic acid components may be used alone or in combination.

[0047] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0048] The crystalline polyester resin C is produced, for example, by a method of polycondensing an alcohol component and a carboxylic acid component. During polycondensation, if necessary, an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxybis(triethanolaminate) may be used in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, and more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0049] (Physical properties of crystalline polyester resin C) The softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 150°C or lower, more preferably 120°C or lower, even more preferably 100°C or lower, and even more preferably 95°C or lower, from the viewpoint of further improving the low-temperature fixability. The melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 100°C or lower, more preferably 90°C or lower, even more preferably 85°C or lower, and even more preferably 80°C or lower, from the viewpoint of further improving the low-temperature fixability.

[0050] The acid value of the crystalline polyester resin C is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and is preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less, even more preferably 20 mgKOH / g or less.

[0051] The softening point, melting point, and acid value of the crystalline polyester resin C can be appropriately adjusted by the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the Examples below. When two or more crystalline polyester resins C are used in combination, it is preferable that the softening point, melting point, and acid value of the mixture thereof each fall within the above-mentioned ranges.

[0052] When amorphous polyester resin A and crystalline polyester resin C are used in combination, the mass ratio of amorphous polyester resin A to crystalline polyester resin C [amorphous polyester resin A / crystalline polyester resin C] is preferably 40 / 60 or more, more preferably 50 / 50 or more, even more preferably 60 / 40 or more, even more preferably 65 / 35 or more, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, even more preferably 85 / 15 or less, even more preferably 75 / 25 or less.

[0053] [Core-shell structure] The toner of the present invention preferably has a core-shell structure, and the core portion preferably contains the crystalline polyester resin C and the amorphous polyester resin A. The core portion preferably contains a colorant and a release agent in addition to the crystalline polyester resin C and the amorphous polyester resin A.

[0054] In the present invention, from the viewpoint of obtaining a high-resolution image, the content of the shell in the toner particles is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, relative to 100 parts by mass of the toner base particles. The shell in the toner preferably contains an amorphous polyester resin B described below, and more preferably the shell is made of an amorphous polyester resin B. From the viewpoint of obtaining a high-resolution image, the amount of the shell binder resin in 100 parts by mass of the toner binder resin is 5 parts by mass or more, preferably 7 parts by mass or more, more preferably 10 parts by mass or more, and is 30 parts by mass or less, preferably 25 parts by mass or less, more preferably 20 parts by mass or less.

[0055] <Amorphous polyester resin B> In the present invention, the toner base particles preferably contain, as binder resins, amorphous polyester resin B in addition to crystalline polyester resin C and amorphous polyester resin A, and it is more preferable that the shell contains amorphous polyester resin B. The amorphous polyester resin B is preferably an amorphous polyester resin containing, for example, a polycondensate of an alcohol component and a carboxylic acid component. Examples of polyester-based resins include polyester resins and modified polyester resins. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition-polymerized resin segments. Among these, amorphous polyester resins, which are polycondensates of alcohol components and carboxylic acid components, are preferred.

[0056] The alcohol component may be an alkylene oxide adduct of an aromatic diol, a linear or branched aliphatic diol, an alicyclic diol, or a trihydric or higher polyhydric alcohol, similar to the alcohol component of the polyester resin segment of the amorphous polyester resin A described above. Among these, from the viewpoint of obtaining a toner with excellent low-temperature fixability, an alkylene oxide adduct of an aromatic diol is preferred, an alkylene oxide adduct of bisphenol A is more preferred, and a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] or an ethylene oxide adduct of bisphenol A is even more preferred. These may be used alone or in combination of two or more. Among these, an ethylene oxide adduct of bisphenol A is more preferred.

[0057] Examples of the carboxylic acid component include the same dicarboxylic acids and trivalent or higher polycarboxylic acids as the carboxylic acid component of the polyester resin segment of the amorphous polyester resin A described above. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, and is preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less.

[0058] The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 5 mol% or more, and is preferably 60 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 15 mol% or less.

[0059] When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and is preferably 30 mol% or less, more preferably 25 mol% or less, even more preferably 20 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0060] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0061] The polyester resin B may be produced, for example, by the step A of polycondensing an alcohol component and a carboxylic acid component. Step A is the same as step A described in the method for producing amorphous polyester resin A, and the preferred ranges are also the same.

[0062] (Physical properties of amorphous polyester resin B) The softening point of the amorphous polyester resin B is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 125°C or lower. The glass transition temperature of the amorphous polyester resin B is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower.

[0063] The acid value of the amorphous polyester resin B is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, even more preferably 25 mgKOH / g or less. The softening point, glass transition temperature, and acid value of the amorphous polyester resin B can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values can be determined by the methods described in the examples. When two or more kinds of amorphous polyester resins B are used in combination, the softening point, glass transition temperature and acid value of the mixture thereof preferably fall within the above-mentioned ranges.

[0064] The content of the amorphous polyester resin B is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, even more preferably 100% by mass, relative to the total amount of the resin components of the resin particles Y for the shell layer.

[0065] [Coloring Agent] In the present invention, the toner base particles preferably contain a colorant, and the core preferably contains the colorant. As the colorant, any dye, pigment, etc. that is used as a colorant for toner can be used. Examples of colorants include carbon black, phthalocyanine blue (e.g., pigment blue 15:3), permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow. The toner may be either black toner or a color toner other than black. The content of the colorant in the toner base particles is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less.

[0066] [Release agent] In the present invention, the toner base particles preferably contain a release agent, and more preferably contain a release agent in the core portion. Examples of release agents include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and Sasol wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination.

[0067] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 100°C or lower. The content of the release agent in the toner base particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

[0068] <Method of manufacturing toner base particles> The method for producing the toner base particles is not particularly limited as long as it can produce toner base particles with the desired circularity. From the viewpoint of obtaining the desired circularity of 0.940 or more, it is preferable to employ a chemical method such as emulsion polymerization, suspension polymerization, or aggregation and fusion (emulsion aggregation). Furthermore, from the viewpoint of obtaining a toner having excellent toner physical properties such as low-temperature fixability, it is preferable to obtain the toner base particles by an aggregation and fusion method including the following steps 1 and 2. Step 1: A step of aggregating resin particles X containing an amorphous polyester resin A in an aqueous medium to obtain aggregated particles 1; Step 1': a step of aggregating resin particles Y containing an amorphous polyester-based resin B to the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2; Step 2: A step of heating and fusing the aggregated particles 1 obtained in step 1 or the aggregated particles 2 obtained in step 1' to obtain fused particles. In step 1, the resin particles X may contain the crystalline polyester resin C and the amorphous polyester resin A in the same or different particles. As a method for producing toner base particles by steps 1 and 2, reference may be made to, for example, steps 1, 1', and 2 described in JP 2021-012242 A, and steps 1, 1', and 2 described in JP 2021-026129 A.

[0069] In step 1, it is preferable to aggregate colorant particles containing a colorant and release agent particles containing a release agent together with the resin particles X. The dispersion of resin particles X is preferably obtained by a phase inversion emulsification method. Furthermore, the colorant particles are preferably mixed with resin particles to form a dispersion of colorant particles, followed by aggregating the colorant particles, and are incorporated into aggregated particles, and the dispersion is preferably obtained by dispersing the colorant and aqueous medium using a disperser such as a homogenizer or an ultrasonic disperser. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of an addition polymer (hereinafter, the addition polymer used to disperse the colorant is also referred to as "addition polymer E") or a surfactant. Examples of the surfactant include a nonionic surfactant, an anionic surfactant, and a cationic surfactant. The addition polymer E preferably has a constituent unit derived from an addition polymerizable monomer a having an aromatic group, and preferably further contains at least one selected from the group consisting of an addition polymerizable monomer b having an ionic group, an addition polymerizable monomer c having a polyalkylene oxide group, and a macromonomer d. For details of the colorant particle dispersion and the addition polymer E, reference is made to the addition polymer E described in JP 2021-026129 A. Furthermore, it is preferable that the release agent particles are mixed with the resin particle dispersion and the colorant particle dispersion as a dispersion of the release agent particles, and then aggregated, so that the release agent particles are contained in the aggregated particles. The dispersion of release agent particles can be obtained using a surfactant, but is preferably obtained by mixing the release agent with resin particles Z. By preparing the release agent particles using the release agent and resin particles Z, the release agent particles are stabilized by the resin particles Z, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is believed that the dispersion of release agent particles has a structure in which a large number of resin particles Z adhere to the surfaces of the release agent particles. The resin constituting the resin particles Z in which the release agent is dispersed is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition polymerization resin segment. For details about the release agent particle dispersion and the composite resin D, see JP 2021-026129 A. Furthermore, a post-treatment step may be carried out after step 2, and it is preferable to obtain toner base particles by isolation. Since the particles obtained in step 2 are present in an aqueous medium, it is preferable to first carry out solid-liquid separation, and then wash and dry them as necessary.

[0070] [Volume average particle diameter D of toner base particles 50 〕 It is preferable to add an external additive, which will be described later, to the surface of the toner base particles obtained by drying or the like, and use the resultant as a toner for non-magnetic one-component development. The volume median particle size of the toner base particles (D 50 ) is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 9 μm or less, even more preferably 8 μm or less, from the viewpoint of improving toner productivity, obtaining a desired circularity, and improving low-temperature fixability of the toner. The CV value of the toner base particles is preferably 12% or more, more preferably 14% or more, and even more preferably 16% or more from the viewpoint of improving toner productivity, and is preferably 32% or less, more preferably 30% or less, and even more preferably 27% or less from the viewpoint of obtaining high-quality images.

[0071] <Sol-gel silica particles> In the present invention, the non-magnetic one-component developing toner comprises toner base particles having a circularity of 0.940 or more, and sol-gel silica particles having an average primary particle size of 60 nm or more and 130 nm or less and an association degree of 1.3 or more and 2.5 or less externally added thereto.

[0072] When the average particle size of the primary particles of the sol-gel silica particles is 60 nm or more, the fluidity of the toner is controlled, the toner charge level is prevented from increasing too much, and the occurrence of fogging is suppressed. Furthermore, aggregation of the toner particles is suppressed even under high temperature and high humidity conditions, thereby suppressing image quality degradation and resulting in high-quality images. Furthermore, when the average particle size of the primary particles is 130 nm or less, detachment of the sol-gel silica particles from the toner particles is suppressed, improving image quality. The average particle size of the primary particles is preferably 65 nm or more, more preferably 70 nm or more, and preferably 120 nm or less, more preferably 110 nm or less, and even more preferably 100 nm or less. When two or more types of sol-gel silica particles are used in combination, it is preferable that the average particle size of the primary particles of each sol-gel silica particle falls within the above range. The average particle size of the primary particles of the sol-gel silica particles is measured by the method described in the Examples.

[0073] When the degree of association of sol-gel silica particles is 1.3 or more, the toner fluidity is controlled, friction with the developing roller is moderate, and the required transport amount is obtained, thereby suppressing the occurrence of fogging. Furthermore, the improved toner transportability by the developing roller prevents the toner from being excessively charged by the charging blade, resulting in printed matter with high image density. Furthermore, when the degree of association of sol-gel silica particles is 2.5 or less, the friction between the charging blade and the non-magnetic single-component developing toner is not excessively high, and the toner is appropriately charged, resulting in printed matter with high image density. The degree of association of sol-gel silica particles is preferably 1.4 or more, more preferably 1.5 or more, and preferably 2.4 or less, more preferably 2.3 or less. When two or more types of sol-gel silica particles are used in combination, it is preferable that the degree of association of each of the sol-gel silica particles satisfies the above range. The degree of association of sol-gel silica particles is the ratio of the average particle size of secondary particles to the average particle size of primary particles of the sol-gel silica particles, which is determined from the specific surface area [average particle size of secondary particles / average particle size of primary particles], and the average particle size of primary particles of the sol-gel silica particles is measured by the method described in the examples.

[0074] The amount of sol-gel silica particles added relative to 100 parts by mass of toner base particles is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 2 parts by mass or more, from the viewpoints of controlling the fluidity of the toner, obtaining printed matter with high initial image density, and suppressing the occurrence of fog when printing images in a high-temperature, high-humidity environment, thereby obtaining images of high image quality, and is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, even more preferably 5 parts by mass or less.

[0075] Sol-gel silica particles can be obtained by a method of obtaining an aqueous dispersion by hydrolysis of alkoxysilane, and specifically, they can be produced by the method described in the claims and the related specifications of JP-A-2005-60217 and JP-A-2005-60219, or a method similar thereto. The degree of association of the sol-gel silica particles can be adjusted to the above range by selecting the average particle size of the secondary particles according to the average particle size of the primary particles, or by adjusting the degree of association by a method such as using a sol-gel method to produce silica particles, as exemplified in the above publications.

[0076] The sol-gel silica particles may be commercially available sol-gel silica particles, such as "HSP-6A" and "HSP-7S" manufactured by Fuso Chemical Co., Ltd.

[0077] The sol-gel silica particles are preferably hydrophobic silica that has been subjected to a hydrophobic treatment, from the viewpoint of improving toner transferability. Examples of hydrophobic treatment agents that hydrophobize the surfaces of silica particles include silane coupling agents and silicone oils. Silane coupling agents include disilazanes such as hexamethyldisilazane (HMDS); cyclic silazanes; trimethylsilane; trimethylchlorosilane; dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, benzyldimethylchlorosilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylmethoxysilane, octyltriethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-octadecyltrimethoxysilane, vinyltrimethysilane, alkylsilane compounds such as hydroxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and vinyltriacetoxysilane; and aminosilane compounds such as γ-aminopropyltriethoxysilane, γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, and N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane. Examples of the silicone oil include polydimethylsiloxane, polymethylhydrogensiloxane, polymethylphenylsiloxane, and amino-modified silicone oil. Among these, hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), polydimethylsiloxane, octyltriethoxysilane (OTES), and polydimethylsiloxane are preferred. These may be used alone or in combination of two or more.

[0078] <Polymer beads> In the non-magnetic one-component developing toner of the present invention, polymer beads may be further added externally to the toner base particles in addition to the sol-gel silica particles. The polymer beads preferably have a charge polarity different from that of the toner base particles. When the toner base particles are positively chargeable, it is preferable to externally add negatively chargeable polymer beads, and when the toner base particles are negatively chargeable, it is preferable to externally add positively chargeable polymer beads. Here, when the toner base particles are those having the above-mentioned polyester resin as a binder resin, it is preferable to externally add positively chargeable polymer beads since the toner base particles are negatively chargeable.

[0079] The number average primary particle size of the polymer beads is preferably 0.1 μm or more, more preferably 0.15 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less. The external addition of such polymer beads to the toner base particles is preferable because it improves transfer efficiency throughout continuous use. This is thought to be because the polymer beads have the above particle size, allowing them to roll on the toner particle surface, promoting toner charging and ultimately suppressing the decrease in charge due to the application of a transfer bias.

[0080] Examples of positively charged polymer beads include benzoguanamine resin particles, benzoguanamine-melamine resin particles, melamine resin particles, melamine-formaldehyde resin particles, etc. Among these, melamine-formaldehyde resin particles are particularly preferred. Examples of negatively charged particles include polytetrafluoroethylene particles, trifluoroethylene particles, vinylidene fluoride particles, and fluoroethylene resin particles.

[0081] The amount of polymer beads added relative to 100 parts by mass of toner base particles is preferably 0.05 parts by mass or more, more preferably 0.15 parts by mass or more, even more preferably 0.2 parts by mass or more, and is preferably 2 parts by mass or less, more preferably 1 part by mass or less, even more preferably 0.5 parts by mass or less.

[0082] The non-magnetic one-component developing toner of the present invention may contain external additives other than the sol-gel silica particles and polymer beads, and from the viewpoint of transferability, inorganic particles are preferred. Examples of inorganic particles include silica other than sol-gel silica particles, alumina, titania, zirconia, tin oxide, zinc oxide, etc.

[0083] A mixer such as a Henschel mixer can be used to mix the toner base particles, the sol-gel silica particles, and, if necessary, the polymer beads and / or other external additives.

[0084] <Non-magnetic single-component developing toner> The non-magnetic one-component developing toner obtained as described above can be used as a one-component developer. [Example]

[0085] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods. In expressions such as "alkylene oxide (X)", the number X in parentheses means the average number of moles of alkylene oxide added.

[0086] [measurement] [Acid value of resin] Measurement was carried out in accordance with JIS K0070:1992, except that the measurement solvent was chloroform.

[0087] [Resin softening point, crystallinity index, melting point, glass transition temperature] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while a load of 1.96 MPa was applied by the plunger, and the sample was extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[0088] (2) Crystallinity index Using a differential scanning calorimeter "Q100" (TA Instruments Japan), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, after which it was heated to 180°C at a rate of 10°C / min and the calorific value was measured. The temperature of the endothermic peak with the largest area was defined as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C)) / (endothermic maximum peak temperature (1) (°C)).

[0089] (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the calorific value was measured. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the maximum endothermic peak temperature (2). For crystalline resins, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak is observed, the temperature of the peak is taken as the glass transition temperature. When a step is observed instead of a peak, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step is taken as the glass transition temperature.

[0090] [Weight average molecular weight of addition polymer] The measurements were performed by gel permeation chromatography (GPC) using a Tosoh HLC-8320GPC gel permeation chromatography system with Tosoh TSKgel SuperAWM-H, Tosoh SuperAW3000, and Tosoh TSKgel guardcolumn Super AW-H columns at a flow rate of 0.5 mL / min. The eluent was a solution of 60 mmol / L phosphoric acid and 50 mmol / L lithium bromide dissolved in N,N-dimethylformamide. The standard samples were monodisperse polystyrene kits with known molecular weights (PStQuick B (F-550, F-80, F-10, F-1, A-1000), PStQuick C (F-288, F-40, F-4, A-5000, A-500), Tosoh PStQuick C).

[0091] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the calorific value was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0092] [Volume median particle diameter D of resin particles, release agent particles, and colorant particles 50 and CV value) (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Add distilled water to the measurement cell and measure the volume median particle size D at a concentration that brings the absorbance into the appropriate range. 50 The volume average particle size was measured, and the CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0093] [Solid Content Concentration of Resin Particle Dispersion, Release Agent Particle Dispersion, and Colorant Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture content (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 min / fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0094] [Volume median particle size of agglomerated particles D 50 and CV value) Volume median particle size of agglomerated particles D 50 was measured as follows: Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured, and the volume median particle size D is calculated from the particle size distribution. 50 The volume average particle size was calculated. The CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0095] [Circularity of Fused Particles and Toner Base Particles] The circularity of the fused particles and the toner base particles was measured under the following conditions. Measurement equipment: Flow particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: A dispersion of fused particles or toner base particles was prepared by diluting it with deionized water so that the solid content concentration was 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0096] [Volume median particle size D of toner particles 50 and CV value) Volume median particle size D of toner particles 50 was measured as follows: The measuring instrument, aperture diameter, analysis software, and electrolyte are all set to the volume median particle diameter D of the agglomerated particles. 50 The same was used. Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB: 13.6) was dissolved in the electrolyte solution to obtain a dispersion with a concentration of 5% by mass. Dispersion conditions: 10 mg of the toner measurement sample was added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of electrolyte was added, and the mixture was further dispersed for 1 minute using an ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 and the volume average particle size were determined. The CV value (coefficient of variation of particle size distribution, %) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0097] [Primary particle size of silica particles] The primary particle size of the silica particles is determined by assuming that the particle shape of the silica particles is perfectly spherical, and the density of the sol-gel silica particles is 2.0 g / cm 3 The density of fumed silica is 2.2 g / cm 3 The specific surface area was calculated according to the following formula: Particle size (m)=6 / (specific surface area (m 2 / g) x density (g / m 3 )) The specific surface area (m 2 The specific surface area (p / g) was obtained using the BET multipoint method with a specific surface area analyzer. In the BET multipoint method, the adsorption amount was measured at three or more points within the equilibrium relative pressure range of the adsorbed gas (nitrogen) of 0.05 to 0.30, and the specific surface area was calculated. Specifically, the analysis was carried out under the following measurement conditions. Measuring instrument: Multi-sample high-performance specific surface area / pore distribution measuring device 3Flex-3MP (Micromeritics) Dispersed adsorbate: Nitrogen Pretreatment: 40°C, 4 hours or more Equilibrium relative pressure: 0.05 to 0.30 (in 0.05 increments) Equilibrium interval: 10 seconds

[0098] [Secondary particle size of silica particles] The secondary particle size of the silica particles was measured as follows. Measurement equipment: Zeta potential and particle size measurement system "ELSZ-2" (Otsuka Electronics Co., Ltd.) Measurement conditions: Cumulant analysis. The dispersion of particles to be measured was placed in a measurement cell, and measurements were taken at a temperature of 25°C, with an angle of 90° between the incident light and the detector, 100 accumulations, and the refractive index of ethanol (1.3611) entered as the refractive index of the dispersion solvent. The dispersion liquid was prepared by placing 5 g of ethanol and 0.05 g of sample in a 50 mL screw tube, stirring at 200 rpm for 5 minutes in a ball mill, and then dispersing for 5 minutes in an ultrasonic disperser (Citizen ultrasonic cleaner SW5800). The particle diameter was measured so that the particle concentration was approximately 5 × 10 -3 The solution was diluted with ethanol to a mass %.

[0099] [Evaluation method] [Liquidity evaluation] Sieves with 150 μm, 75 μm, and 45 μm openings were stacked in this order on a powder tester (manufactured by Hosokawa Micron Corporation), and 4 g of toner was placed on the top sieve with 150 μm openings and vibrated at a vibration amplitude of 1 mm for 10 seconds. After vibration, the amount of toner remaining on the sieve was evaluated for fluidity using the following formula. A fluidity of 80 or higher was evaluated as excellent fluidity. Liquidity=100-(a+b+c) In the above formula, a, b, and c are calculated by the following formula. a = (mass of toner remaining on the sieve with 150 μm openings / mass of toner used) × 100 b = (mass of toner remaining on the sieve with 75 μm openings / mass of toner used) × 100 × 3 / 5 c = (mass of toner remaining on the sieve with 45 μm openings / mass of toner used) × 100 × 1 / 5

[0100] [Measurement of initial image density] The toner was loaded into a commercially available printer, "COREFIDO C712dnw" (manufactured by Oki Electric Industry Co., Ltd.), and the image density was measured at the three center points of the first full-page solid image printed on high-quality paper, "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.), in an environment of 25°C and 50% humidity (NN environment), and the average value was calculated. The image density was measured using a colorimeter, "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). An initial image density of 1.3 or higher was evaluated as excellent initial image density.

[0101] [Fogging test conditions] The toner was loaded into a commercially available printer, "COREFIDO C712dnw" (manufactured by Oki Electric Industry Co., Ltd.), and 2,000 consecutive prints were made on high-quality paper, "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.), at a temperature of 25°C and humidity of 50% (NN environment) with a print density of 0.3%. The prints were then left to stand for 12 hours at a temperature of 30°C and humidity of 80% (HH environment), after which another 2,000 consecutive prints were made in the HH environment, for a total of 4,000 prints in the NN and HH environments. Fog measurements were taken under five conditions: the first print (2,001st print), the 2,500th print, the 3,000th print, the 3,500th print, and the 4,000th print in the HH environment.

[0102] [Measurement of fogging under high temperature and humidity conditions] Fog was measured as follows. First, blank paper was printed, and the printer was stopped midway through printing. The developing unit was removed from the printer, and Scotch (registered trademark) Mending Tape 810 (manufactured by 3M Japan Ltd., width: 18 mm) was attached to the photoreceptor, and the toner on the photoreceptor was peeled off with the tape. The tape peeled off from the photoreceptor and unused tape were attached to high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.), and the tape peeled off from the photoreceptor and unused tape were each measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The color difference (ΔE) between the tape peeled off from the photoreceptor and unused tape was defined as fog. The smaller the fog value, the better the image without fog. If the average fog value when printing under the above five conditions was 2.0 or less, it was evaluated that the occurrence of fog under high temperature and high humidity was suppressed.

[0103] [Evaluation of image quality under high temperature and humidity conditions] The toner was loaded into a commercially available printer, "COREFIDO C712dnw" (manufactured by Oki Electric Industry Co., Ltd.), and left to stand for 12 hours in an environment with a temperature of 30°C and humidity of 80% (HH environment). Then, in the HH environment, 2,000 sheets were continuously printed on high-quality paper, "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.), with a print density of 0.3%. Subsequently, printing was repeated every 500 sheets until 4,000 sheets were printed. Images printed at the 2,000th, 2,500th, 3,000th, 3,500th, and 4,000th sheets were visually evaluated according to the following criteria, and the rank in the HH environment was calculated as the average. An average value of 4.0 or higher was considered to indicate good image quality under high temperature and high humidity. 5: No print defects 4: Slightly faded 3: There is some fading 2: Many scratches 1: There are a lot of scratches

[0104] [Resin manufacturing] [Production of Polyester Resin A] Production Example A1 (Production of Resin A-1) A 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 3356 g of propylene oxide (2.2) adduct of bisphenol A, 955 g of terephthalic acid, 385 g of Paracol 6490 (manufactured by Nippon Seiro Co., Ltd.), 25 g of tin(II) di(2-ethylhexanoate), and 2.5 g of 3,4,5-trihydroxybenzoic acid were added. The mixture was heated to 235°C under a nitrogen atmosphere with stirring, maintained at 235°C for 5 hours, and then the pressure in the flask was reduced and maintained at 8 kPa for 1 hour. The mixture was then returned to atmospheric pressure, cooled to 160°C, and a mixture of 2198 g of styrene, 550 g of stearyl methacrylate, 110 g of acrylic acid, and 330 g of dibutyl peroxide was added dropwise over 1 hour while maintaining the temperature at 160°C. After that, the temperature was maintained at 160°C for 30 minutes, then increased to 200°C, and the pressure inside the flask was further reduced and maintained at 8 kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the mixture was cooled to 190°C. 200 g of fumaric acid, 194 g of sebacic acid, 184 g of trimellitic anhydride, and 2.5 g of 4-tert-butylcatechol were added, and the temperature was increased to 210°C at 10°C / hr. Then, the mixture was reacted at 4 kPa until the desired softening point was reached, yielding Resin A-1. The physical properties are shown in Table 1.

[0105] Production Example A2 (Production of Resin A-2) A 10 L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3558 g of propylene oxide (2.2) adduct of bisphenol A, 1416 g of ethylene oxide (2.2) adduct of bisphenol A, 1229 g of terephthalic acid, 1518 g of dodecenylsuccinic anhydride, and 40 g of tin(II) di(2-ethylhexanoate) were added. The mixture was heated to 230°C under nitrogen atmosphere with stirring. After 6 hours at 230°C, the pressure in the flask was further reduced and maintained at 8.3 kPa for 1 hour. The mixture was then cooled to 215°C and returned to atmospheric pressure. 279 g of trimellitic anhydride was added. After 1 hour at 215°C, the pressure in the flask was further reduced and maintained at 8.3 kPa for 3 hours to obtain Resin A-2. The physical properties are shown in Table 1.

[0106] [Production of Polyester Resin B] Manufacturing Example B1 (Manufacturing of Resin B-1) A 10 L four-neck flask equipped with a nitrogen inlet, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3265 g of ethylene oxide (2.2) adduct of bisphenol A, 1334 g of terephthalic acid, 25 g of tin(II) di(2-ethylhexanoate), and 2.5 g of 3,4,5-trihydroxybenzoic acid were added. The mixture was heated to 235°C under nitrogen atmosphere with stirring. After 6 hours at 235°C, the pressure in the flask was reduced to 8.3 kPa and maintained at 8.3 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 180°C. 73 g of adipic acid, 135 g of dodecenylsuccinic anhydride, and 193 g of trimellitic anhydride were added. The temperature was increased at 10°C / hr to 220°C. The pressure in the flask was then reduced to 10 kPa and the reaction was continued until the desired softening point was reached, yielding Resin B-1. The physical properties are shown in Table 1.

[0107] [Production of Composite Resin D] Manufacturing Example D1 (Manufacturing of Resin D-1) A 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 4313 g of a propylene oxide (2.2) adduct of bisphenol A, 818 g of terephthalic acid, 30 g of tin(II) di(2-ethylhexanoate), and 3.0 g of 3,4,5-trihydroxybenzoic acid were placed in the flask. The contents were heated to 235°C under a nitrogen atmosphere with stirring and maintained at 235°C for 5 hours. The pressure in the flask was then reduced to 8 kPa and maintained at 8 kPa for 1 hour. The contents were then returned to atmospheric pressure, cooled to 160°C, and, while maintaining the temperature at 160°C, a mixture of 2756 g of styrene, 689 g of stearyl methacrylate, 142 g of acrylic acid, and 413 g of dibutyl peroxide was added dropwise over 1 hour. The mixture was then maintained at 160°C for 30 minutes, then heated to 200°C. The pressure inside the flask was then reduced and maintained at 8 kPa for 1 hour. The mixture was then returned to atmospheric pressure, cooled to 190°C, and 727 g of succinic acid was added. The mixture was heated to 210°C at a rate of 10°C / hr. The mixture was then heated to the desired softening point at 4 kPa to obtain Resin D-1. The physical properties are shown in Table 1.

[0108] [Table 1] *1: BPA-PO means a propylene oxide (2.2) adduct of bisphenol A. BPA-EO means an ethylene oxide (2.2) adduct of bisphenol A. *2: This refers to the molar parts of each monomer constituting the raw material monomer (P) and the bireactive monomer when the alcohol component of the raw material monomer (P) is taken as 100 molar parts. *3: This refers to the content (mass%) of each monomer constituting the raw material monomer (V) in the total amount of the raw material monomer (V). *4: Paracol 6490: Manufactured by Nippon Seiro Co., Ltd., Mn800, melting point 76°C, acid value 18mgKOH / g, hydroxyl value 97mgKOH / g *5: This refers to the amount (% by mass) relative to 100 parts by mass of the total amount of polyester resin segment, addition polymerization resin segment, and structural units derived from bireactive monomers.

[0109] [Production of crystalline polyester resin] Manufacturing Example C1 (Manufacturing of Resin C-1) A 10 L four-neck flask equipped with a nitrogen inlet, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3,416 g of 1,10-decanediol and 4,084 g of sebacic acid were added and heated to 135°C with stirring. The mixture was then held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. 23 g of tin(II) di(2-ethylhexanoate) was then added and the mixture was held at 200°C for another hour. The pressure inside the flask was then reduced and the mixture was held under a reduced pressure of 8.3 kPa for 1 hour, yielding Resin C-1. The physical properties are shown in Table 2.

[0110] [Table 2]

[0111] [Production of resin particle dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 210 g of Resin A-1, 90 g of Resin C-1, and 360 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resins were dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion X-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values are shown in Table 3.

[0112] Production Example X2 (Production of Resin Particle Dispersion X-2) 300 g of Resin A-2, 360 g of methyl ethyl ketone, and 59 g of deionized water were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (circumferential speed 63 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion X-2. The volume median particle diameter D of the resulting resin particles was 50 and CV values are shown in Table 3.

[0113] Production Example Y1 (Production of Resin Particle Dispersion Y-1) 300 g of Resin B-1 and 360 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved over 2 hours at 40° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 40°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min), resulting in phase inversion emulsification. The temperature was raised to 73°C, and methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (circumferential speed 88 m / min), and deionized water was added to obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion Y-1. The volume median particle diameter D of the obtained resin particles was 50 and CV values are shown in Table 3.

[0114] Production Example Z1 (Production of Resin Particle Dispersion Z-1) 200 g of Resin D-1 and 200 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of Resin D-1 was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min (circumferential speed 88 m / min), resulting in phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion Z-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values are shown in Table 3.

[0115] [Table 3]

[0116] [Production of release agent particle dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) 120 g of deionized water, 86 g of resin particle dispersion Z-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added to a 1 L beaker, and the mixture was melted by maintaining the temperature at 90 to 95°C and stirred to obtain a molten mixture. The obtained molten mixture was further dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content to 20% by mass, thereby obtaining release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles in the dispersion was 50 The particle size was 0.47 μm and the CV value was 27%.

[0117] Production Example W2 (Production of Release Agent Particle Dispersion W-2) A release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent used was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). 50 The particle size was 0.45 μm and the CV value was 28%.

[0118] [Production of addition polymers] Production Example E1 (Synthesis of Addition Polymer E-1) 16 parts by mass of methacrylic acid (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 44 parts by mass of styrene (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.), 30 parts by mass (15 parts by mass as solids) of styrene macromonomer "AS-6S" (manufactured by Toagosei Co., Ltd., number average molecular weight 6,000, solids content 50%), and 25 parts by mass of methoxypolyethylene glycol methacrylate "BLEMMER PME-200" (NOF Corporation) were mixed to prepare 115 parts by mass of a monomer mixture. 18 parts by mass of methyl ethyl ketone, 0.03 parts by mass of 2-mercaptoethanol as a chain transfer agent, and 10% (11.5 parts by mass) of the monomer mixture were placed in a reaction vessel and mixed, followed by thorough nitrogen gas replacement. Separately, the remaining 90% (103.5 parts by mass) of the monomer mixture was mixed with 0.27 parts by mass of the chain transfer agent, 42 parts by mass of methyl ethyl ketone, and 3 parts by mass of the polymerization initiator 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and placed in a dropping funnel. The mixed solution in the reaction vessel was heated to 75°C under a nitrogen atmosphere while stirring, and the mixed solution in the dropping funnel was added dropwise over 3 hours. After 2 hours at 75°C after the completion of the dropping, a solution of 3 parts by mass of the polymerization initiator in 5 parts by mass of methyl ethyl ketone was added, and the mixture was further aged at 75°C for 2 hours and then at 80°C for 2 hours. The methyl ethyl ketone was then distilled off under reduced pressure to obtain addition polymer E-1. The weight-average molecular weight of the resulting addition polymer is shown in Table 4.

[0119] [Table 4]

[0120] [Production of colorant particle dispersion] Production Example F1 (Production of Colorant Particle Dispersion F-1) In a 5L vessel equipped with a stirrer equipped with a disperser blade, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 75 g of addition polymer E-1 was dissolved in 620 g of methyl ethyl ketone. Then, 96 g of a 5% by weight aqueous solution of sodium hydroxide as a neutralizing agent and 942 g of deionized water were added, and the mixture was stirred with a disperser blade at 20°C for 10 minutes. Next, 300 g of copper phthalocyanine pigment "ECB-301" (Dainichiseika Color & Chemicals Mfg. Co., Ltd., Pigment Blue 15:3) was added, and the mixture was stirred with a disperser blade at 6400 rpm for 2 hours at 20°C. The mixture was then passed through a 200-mesh filter and subjected to 15 passes at 150 MPa using a homogenizer "Microfluidizer M-110EH" (Microfluidics). While stirring the resulting dispersion, the methyl ethyl ketone and some of the water were removed under reduced pressure at 70°C. The mixture was then passed through a 200 mesh filter, and deionized water was added to the mixture so that the solid content was 20% by mass, thereby obtaining a colorant particle dispersion F-1. 50 The particle size was 0.12 μm and the CV value was 21%.

[0121] [Toner manufacturing] Production Example 1 (Preparation of Toner Base Particles 1) In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 500 g of resin particle dispersion X-1, 35 g of release agent particle dispersion W-1, 35 g of release agent particle dispersion W-2, 63 g of colorant particle dispersion F-1, 10 g of a 10 mass% aqueous solution of polyoxyethylene (50) lauryl ether "EMULGEN 150" (Kao Corporation, nonionic surfactant), and 10 g of a 15 mass% aqueous solution of sodium dodecylbenzenesulfonate "NEOPELEX G-15" (Kao Corporation, anionic surfactant) were mixed at 25°C. Next, while stirring the mixture, a solution prepared by dissolving 35 g of ammonium sulfate in 519 g of deionized water and adding 26 g of a 4.8 mass% aqueous solution of potassium hydroxide was added dropwise at 25°C over 10 minutes, and the mixture was then heated to 65°C over 2 hours to measure the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 65° C. until the particle size reached 5.9 μm, thereby obtaining a dispersion of aggregated particles 1. Next, the dispersion of aggregated particles 1 was cooled to 59°C, and while maintaining the temperature at 59°C, 75 g of resin particle dispersion Y-1 was added over 90 minutes to obtain a dispersion of aggregated particles 2 in which resin particles were aggregated to aggregated particles 1. To the resulting dispersion of aggregated particles 2, an aqueous solution containing 41 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (Kao Corporation, anionic surfactant, effective concentration 27% by mass), 1,396 g of deionized water, and 26 g of 0.1 mol / L aqueous sulfuric acid solution was added. The mixture was then heated to 75°C over 1 hour and maintained at 75°C for 30 minutes. After that, 75 g of 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 75°C for 15 minutes. Another 25 g of 0.1 mol / L aqueous sulfuric acid solution was then added, and the mixture was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30°C, and the solid matter was separated by suction filtration, washed with deionized water at 25°C, and vacuum dried at 30°C for 48 hours to obtain toner base particles 1. The physical properties of the obtained toner base particles 1 are shown in Table 5.

[0122] Production Example 2 (Preparation of Toner Base Particles 2) Toner base particles 2 were produced in the same manner as in Production Example 1, except that the circularity of the fused particles was changed as shown in Table 5. Table 5 shows the physical properties of the obtained toner base particles 2.

[0123] Production Example 3 (Preparation of Toner Base Particles 3) In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 500 g of resin particle dispersion X-2, 84 g of release agent particle dispersion W-1, 72 g of colorant particle dispersion F-1, 15 g of a 10 mass % aqueous solution of polyoxyethylene (50) lauryl ether "EMULGEN 150" (Kao Corporation, nonionic surfactant), and 17 g of a 15 mass % aqueous solution of sodium dodecylbenzenesulfonate "NEOPELEX G-15" (Kao Corporation, anionic surfactant) were mixed at 25°C. Next, while stirring the mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 568 g of deionized water and adding 4.8 mass % aqueous potassium hydroxide to adjust the pH to 8.6 was added dropwise over 10 minutes at 25°C, and the mixture was then heated to 63°C over 2 hours to measure the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 63° C. until the particle size reached 5.9 μm, thereby obtaining a dispersion of aggregated particles 1. Subsequently, the dispersion of aggregated particles 1 was cooled to 59°C, and while maintaining the temperature at 59°C, 75 g of resin particle dispersion Y-1 was added over 90 minutes to obtain a dispersion of aggregated particles 2 in which resin particles were aggregated to aggregated particles 1. To the resulting dispersion of aggregated particles 2, an aqueous solution containing 48 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (Kao Corporation, anionic surfactant, effective concentration 27% by mass), 600 g of deionized water, and 50 g of 0.1 mol / L aqueous sulfuric acid solution was added. The mixture was then heated to 75°C over 1 hour and maintained at 75°C for 30 minutes. After that, 10 g of 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 75°C for 15 minutes. Thereafter, 10 g of 0.1 mol / L aqueous sulfuric acid solution was added again, and the mixture was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30°C, and the solid matter was separated by suction filtration, washed with deionized water at 25°C, and vacuum dried at 30°C for 48 hours to obtain toner base particles 3. The physical properties of the obtained toner base particles 3 are shown in Table 5.

[0124] [Table 5]

[0125] Example 1 (Preparation of Toner 1) 100 parts by mass of toner base particles 1 and 3 parts by mass of sol-gel silica particles "HSP-6A" (manufactured by Fuso Chemical Co., Ltd.) as an external additive were placed in a 5 L Henschel mixer and stirred at 3800 r / min for 3 minutes, and then passed through a 150 mesh sieve to obtain toner 1. The evaluation results of the obtained toner 1 are shown in Table 6.

[0126] Examples 2 to 5 and Comparative Examples 1 to 5 (Preparation of Toners 2 to 5 and Toners 11 to 15) Toners 2 to 5 and toners 11 to 15 were prepared in the same manner as in Example 1, except that the type of toner base particles used, the type and amount of external additives added were changed as shown in Table 6, and polymer beads shown in Table 6 were added. The evaluation results of the obtained toners are shown in Table 6.

[0127] The sol-gel or fumed silica particles and polymer beads shown in Table 6 are as follows: HSP-6A: Sol-gel silica particles (manufactured by Fuso Chemical Co., Ltd., degree of association 2.2, average primary particle size 74 nm) HSP-7S: Sol-gel silica particles (manufactured by Fuso Chemical Co., Ltd., degree of association 1.6, average primary particle size 87 nm) X24-9600A-80: Sol-gel silica particles (Shin-Etsu Chemical Co., Ltd., degree of association 1.1, average primary particle size 112 nm) RY50: AEROSYL (trademark) RY 50, fumed silica particles (manufactured by Nippon Aerosil Co., Ltd., degree of association 2.2, average primary particle size 124 nm) R972: AEROSYL (trademark) R 972, fumed silica particles (manufactured by Nippon Aerosil Co., Ltd., degree of association 10.7, average primary particle size 16 nm) X24-9404-30: Sol-gel silica particles (manufactured by Shin-Etsu Chemical Co., Ltd., degree of association 1.5, average primary particle size 27 nm) Eposter S: Melamine-formaldehyde condensate (manufactured by Nippon Shokubai Co., Ltd., average primary particle size 0.2 μm (catalog value))

[0128] [Table 6]

[0129] From the results of the Examples and Comparative Examples, it is clear that the non-magnetic one-component developing toner of the present invention has controlled fluidity and can produce printed matter with high initial image density. It is also clear that when an image is printed using the non-magnetic one-component developing toner of the present invention under a high-temperature and high-humidity environment, the occurrence of fog is suppressed and high-quality images can be produced. In Examples 2 to 5, in which toners 2 to 5 having polymer beads were used, fogging was further suppressed. When toner 11 of Comparative Example 1, which contains sol-gel silica particles with an association degree of less than 1.3, was used, fog occurred and image quality deteriorated when printing images under a high-temperature, high-humidity environment. Furthermore, when toner 15 of Comparative Example 5, which contains sol-gel silica particles with a particle size of less than 60 nm, fog also occurred and image quality deteriorated. Furthermore, the fluidity of toners 12 and 13 of Comparative Examples 2 and 3, which used fumed silica particles, was reduced. In addition, when an image was printed using toner 14 of Comparative Example 4, which used fumed silica particles, the initial image density was low, and fogging occurred when the image was printed in a high-temperature, high-humidity environment.

Claims

1. Sol-gel silica particles are externally added to toner base particles having a circularity of 0.940 or more, The sol-gel silica particles have an average particle size of primary particles of 60 nm or more and 130 nm or less, and a degree of association, which is the ratio of the average particle size of secondary particles to the average particle size of primary particles calculated from the specific surface area [average particle size of secondary particles / average particle size of primary particles], of 1.3 or more and 2.5 or less, the amount of the sol-gel silica particles added relative to 100 parts by mass of the toner base particles is 2 parts by mass or more and 15 parts by mass or less; Polymer beads exhibiting a chargeability different from that of the toner base particles are further externally added, the polymer beads comprise a melamine-formaldehyde resin; Non-magnetic single-component developer toner.

2. Volume median particle size D of toner base particles ５０ The toner for non-magnetic one-component development according to claim 1, wherein the particle size is 2 μm or more and 10 μm or less.

3. 3. The toner for non-magnetic one-component development according to claim 1, wherein the circularity of the toner base particles is 0.995 or less.

4. 4. The toner for non-magnetic one-component development according to claim 1, wherein the toner base particles contain a polyester resin.

5. 5. The toner for non-magnetic one-component development according to claim 1, wherein the toner base particles have a core-shell structure.

6. 6. The toner for non-magnetic one-component development according to claim 1, wherein the polymer beads have an average particle size of 0.1 μm or more and 0.5 μm or less.

Images