Image forming method

Abstract

To provide an image forming method on a polypropylene film or a polyethylene film, the image forming method excellent in image density of an image to be obtained and excellent in scratch resistance of an image.SOLUTION: An image forming method is a method for forming an image on a polypropylene film or a polyethylene film with a toner containing a crystalline polyester resin C in a binder resin. The SP value of the crystalline polyester resin C is 9.0 or more and 10.1 or less. The content of the crystalline polyester resin C in the binder resin is 10% by mass or more and 60% by mass or less. The surface tension on a printing surface of the polypropylene film or the polyethylene film is 35 mN / m or more and 49 mN / m or less. A fixing temperature is equal to or lower than a temperature 5°C higher than the melting point of the polypropylene film or the polyethylene film.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an image forming method.

Background Art

[0002] Due to the diversification of printing media, electrophotographic printing on printing media other than paper has begun to be demanded. One of the main media is polypropylene film (hereinafter also referred to as "PP film") and polyethylene film (hereinafter also referred to as "PE film"), which are used for pet bottle labels and various packages. On the other hand, paper, polypropylene, and polyethylene have greatly different characteristics as printing media, such as the polarity of the material and the state of the surface. Patent Document 1 describes a binder resin composition for electrostatic charge image developing toner containing a polyester resin and a polypropylene wax, and having an endothermic ratio ΔH represented by the following formula (1). CW / W is 0.10 or more and 0.80 or less. Endothermic ratio ΔH CW / W = ΔH CW / ΔH W (1) ΔH CW : The endothermic amount of the melting endothermic peak per 1 g of the polypropylene wax when measured as the binder resin composition. ΔH W : The endothermic amount of the melting endothermic peak per 1 g of the polypropylene wax when the polypropylene wax is measured alone. According to the binder resin composition, it is described that a toner excellent in fixability to a PP (polypropylene) film can be obtained. Patent Document 2 describes an electrostatic charge image developing toner containing an amorphous polyester resin A and a crystalline polyester resin C. The amorphous polyester resin A has a constituent part derived from a polyester resin and a constituent part derived from a modified polyolefin polymer A having a reactive functional group. The constituent part derived from the polyester resin and the constituent part derived from the modified polyolefin polymer A are linked via a covalent bond, and the amount of the constituent part derived from the modified polyolefin polymer A is 5% by mass or more and 30% by mass or less based on the total amount of the resin components in the toner. According to the toner, it is described that it has excellent fixability to a polypropylene film and excellent rubbing resistance of the printed image.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In existing copying systems, the fixing temperature of the toner is higher than the heat resistance temperature of the film, and the film is likely to shrink during toner fixing. Therefore, for example, conventionally developed toners have had the problem that they cannot be fixed to PP films or PE films. Also, even for the toners disclosed in Patent Document 1 and Patent Document 2, there is a limit to the fixing strength, and better fixability to PP films and PE films has been desired. In particular, perhaps because the films are subjected to various surface treatments, when printed with toner, there has been a problem that it is easily scratched with a fingernail. Therefore, considering the usage modes such as labels for PET bottles, a printing method capable of obtaining an image with excellent rubbing resistance so that the printed image does not peel off even if the printed matter is rubbed after printing on a PP film or PE is required. The present invention relates to a method for forming an image on a polypropylene film or a polyethylene film, and provides an image forming method that is excellent in the image density of the obtained image and further excellent in the rubbing resistance of the image. [Means for Solving the Problems]

[0005] The present inventors have found that the above problems can be solved by forming an image at a specific fixing temperature on a PP film or a PE film having a specific surface tension on the printing surface using a toner containing a crystalline polyester resin in a specific amount or more.

[0006] That is, the present invention relates to the following [1]. [1] A method for forming an image on a polypropylene film or a polyethylene film with a toner containing a crystalline polyester resin C in a binder resin, wherein the SP value of the crystalline polyester resin C is 9.0 or more and 10.1 or less, and the content of the crystalline polyester resin C in the binder resin is 10% by mass or more and 60% by mass or less, and the surface tension of the printing surface of the polypropylene film or the polyethylene film is 35 mN / m or more and 49 mN / m or less, and the fixing temperature is equal to or lower than a temperature 5°C higher than the melting point of the polypropylene film or the polyethylene film. [Advantages of the Invention]

[0007] According to the present invention, it is possible to provide an image forming method for a PP film or a PE film, which is excellent in the image density of the obtained image and further excellent in the rubbing resistance of the image. [Embodiments for Carrying Out the Invention]

[0008] [Image Forming Method] The image forming method of the present invention is a method of forming an image on a polypropylene film or a polyethylene film with a toner containing a crystalline polyester resin C in a binder resin, wherein the SP value of the crystalline polyester resin C is 9.0 or more and 10.1 or less, the content of the crystalline polyester resin C in the binder resin is 10% by mass or more and 60% by mass or less, the surface tension of the printing surface of the polypropylene film or the polyethylene film is 35 mN / m or more and 49 mN / m or less, and the fixing temperature is 5 °C higher than the melting point of the polypropylene film or the polyethylene film or lower. In the following description, the toner used in the image forming method of the present invention is also simply referred to as "toner" or "the toner of the present invention".

[0009] In the image forming method of the present invention, by printing a toner containing a specific amount or more of a crystalline polyester resin C having a specific SP value on a PP film or a PE film having a printing surface in a specific surface tension range, the image density of the obtained image is high and the abrasion resistance is significantly improved. The detailed reason for obtaining the above effects is unknown, but part of it is considered as follows. In a toner containing a crystalline polyester resin, the component that first melts due to the fixing heat during fixing is the crystalline polyester resin, and it is considered that it bleeds out from the toner surface and exists on the interface with the film. Therefore, when examining by focusing on the properties of the crystalline polyester resin, it was found that the printing properties on the film are remarkably improved when the SP value of the crystalline polyester resin C and the surface tension of the printed surface of the film are within specific ranges respectively. That is, when using a toner containing 10% by mass or more of a crystalline polyester resin having an SP value of 9.0 or more and 10.1 or less, if the surface tension of the printed surface of the film is 35 mN / m or more and 49 mN / m or less, the compatibility between the toner and the film is high. Furthermore, the surface tension of the toner containing a large amount of the crystalline polyester resin instantaneously decreases greatly during fixing (fusion), and the surface tension of the toner can be made lower than the surface tension of the printed surface of the film in a short time during fixing. Therefore, the wet spreading property of the toner is improved, the adhesiveness between the toner and the film is high, and since the image surface becomes smooth, it is considered that the abrasion resistance is improved. Also, as described above, since the wet spreading property of the toner is good, it is considered that the hiding property is high and the image density is high. When the toner is a white toner, "image density" means "whiteness". In the following description, "image density" is used as a concept including "whiteness" unless otherwise specified. Note that the above mechanism regarding the effects of the present invention is an estimation and is not limited thereto.

[0010] The definitions of various terms in this specification are shown below. Whether the resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the maximum peak temperature of endotherm in the measurement method described in the examples below (softening point (°C) / maximum peak temperature of endotherm (°C)). A crystalline resin has 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, the crystallinity index is less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted according to the type and ratio of the raw material monomers, and manufacturing 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 generate acids, and alkyl esters of each carboxylic acid (alkyl group having 1 to 3 carbon atoms). “Volume median diameter (D 50 )” means the particle diameter at which the cumulative volume frequency calculated by volume fraction becomes 50% when calculated from the smaller particle diameter. The coefficient of variation of the particle size distribution (hereinafter, also simply referred to as “CV value”) is a value represented by the following formula. The volume average particle diameter in the following formula is the particle diameter obtained by dividing the total value of the product of each particle diameter and the volume of the particle for all the measured particles by the total volume of the measured particles. CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle diameter (μm)] × 100

[0011] <Image forming method> As the image forming method of the present invention, similar to the image forming method using a conventionally known toner (toner for developing an electrostatic latent image), an electrostatic latent image forming step of forming an electrostatic latent image on an electrostatic latent image carrier, a developing step of developing the electrostatic latent image formed on the electrostatic latent image carrier using toner to form a toner image, a transfer step of transferring the toner image formed on the electrostatic latent image carrier to the surface of a recording medium, and a fixing step of fixing the toner image transferred to the surface of the recording medium are exemplified. In the present invention, as the recording medium, a polypropylene film or a polyethylene film having a surface tension of the printing surface of 35 mN / m or more and 49 mN / m or less is used, and the fixing temperature during the fixing step is 5°C higher than the melting point of the polypropylene film or the polyethylene film or lower.

[0012] The melting point of the polypropylene film varies depending on the presence or absence of stretching and the like, but is approximately in the range of 135°C or more and 170°C or less. On the other hand, the melting point of the polyethylene film varies depending on the density and the like, but is approximately in the range of 105°C or more and 150°C or less. The melting points of the polypropylene film and the polyethylene film are measured by the method described in the examples. In the present invention, the fixing temperature during the fixing step is 5°C higher than the melting point of the polypropylene film or the polyethylene film or lower, preferably at or below the melting point, more preferably 5°C lower than the melting point or lower, still more preferably 10°C lower than the melting point or lower, and preferably 100°C lower than the melting point or higher, more preferably 85°C lower than the melting point or higher, still more preferably 70°C lower than the melting point or higher. Also, from the viewpoint of utilizing the low-temperature fixing performance of the toner, the fixing temperature during the fixing step is preferably 120°C or lower, more preferably 115°C or lower, still more preferably 110°C or lower, and preferably 70°C or higher, more preferably 80°C or higher, still more preferably 90°C or higher.

[0013] <Polypropylene film or polyethylene film> In the image forming method of the present invention, an image is formed on a polypropylene film or a polyethylene film with the toner of the present invention. Polypropylene films and polyethylene films are used for various labels, packages, etc., and among these, those used as polypropylene labels and polyethylene labels are preferably exemplified. The surface tension of the printing surface of the polypropylene film or polyethylene film to be used is 35 mN / m or more, preferably 36 mN / m or more, more preferably 37 mN / m or more, still more preferably 40 mN / m or more, and 49 mN / m or less, preferably 48 mN / m or less, more preferably 47 mN / m or less, still more preferably 46 mN / m or less, from the viewpoint of obtaining an image with high image density and excellent abrasion resistance. The surface tension of the printing surface of the polypropylene film and the polyethylene film is measured by the method described in the examples.

[0014] The polypropylene film and the polyethylene film may be appropriately surface-treated so as to satisfy the above surface tension. Also, the polypropylene film and the polyethylene film may be a transparent film, may contain a pigment or the like in the film, may have an arbitrary color such as white, or may have a toner receiving layer formed on the surface.

[0015] Among the polypropylene film and the polyethylene film, it is possible to form an image even on the polyethylene film with lower heat resistance.

[0016] <Toner> The toner used in the image forming method of the present invention (hereinafter, also simply referred to as "toner" or "toner of the present invention") contains 10% by mass or more of a crystalline polyester resin C having an SP value of 9.0 or more and 10.1 or less in the binder resin. Note that the "binder resin" means the entire resin component contained in the toner. The "resin component" is a polymer component excluding the release agent, and preferably has a weight average molecular weight of 1,000 or more. The toner of the present invention preferably further contains an amorphous polyester resin A in addition to the crystalline polyester resin C. Further, the toner of the present invention may be a toner obtained by any known method such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, an aggregation fusion method, etc., but preferably has a core-shell structure. From the viewpoint of manufacturing toner particles having a core-shell structure, a chemical toner by an aggregation fusion method is preferable. In the toner having a core-shell structure, it is preferable that the core portion contains a crystalline polyester resin C, and it is preferable that the core portion contains an amorphous polyester resin A in addition to the crystalline polyester resin C. Further, it is preferable that the core portion contains a colorant and a release agent in addition to the crystalline polyester resin C and the amorphous polyester resin A. Also, it is preferable that the shell portion contains an amorphous polyester resin B.

[0017] 〔Binder resin〕 ≪Crystalline polyester resin C≫ The toner of the present invention contains 10% by mass or more and 60% by mass or less of a crystalline polyester resin C in the binder resin. From the viewpoints of low-temperature fixability, image rub resistance, and image density improvement, the content of the crystalline polyester resin in the binder resin is 10% by mass or more, preferably 12% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, still more preferably 23% by mass or more, and 60% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 27% by mass or less. Further, the toner of the present invention preferably has a core-shell structure and contains a crystalline polyester resin C in the core portion, and more preferably contains a crystalline polyester resin only in the core portion.

[0018] The crystalline polyester resin C is, for example, a crystalline polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component. The crystalline polyester resin is a polycondensate of an alcohol component and a carboxylic acid component. As the alcohol component, α,ω-aliphatic diol is preferable. The number of carbon atoms of the α,ω-aliphatic diol is preferably 2 or more, more preferably 4 or more, still more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, still more preferably 12 or less. Examples of the α,ω-aliphatic diol 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, from the viewpoint of obtaining a desired SP value, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred.

[0019] The amount of the α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, and still more preferably 100 mol%.

[0020] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of the 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 of two or more.

[0021] As the carboxylic acid component, an aliphatic dicarboxylic acid is preferred, and a linear aliphatic dicarboxylic acid is more preferred. The number of carbon atoms of the aliphatic dicarboxylic acid is preferably 4 or more, more preferably 8 or more, still more preferably 10 or more, and preferably 14 or less, more preferably 12 or less. Examples of the aliphatic dicarboxylic acid 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 of two or more.

[0022] The amount of the aliphatic dicarboxylic acid is preferably 80 mol% or more, more preferably 85 mol% or more, still more preferably 90 mol% or more, and even more preferably 95 mol% or more, and 100 mol% or less, and more preferably 100 mol% in the carboxylic acid component.

[0023] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of the other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; polyvalent carboxylic acids having a valency of 3 or more. These carboxylic acid components may be used alone or in combination of two or more.

[0024] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component [COOH group / OH group] is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0025] (Method for producing crystalline polyester resin C) The crystalline polyester resin C is produced, for example, by a method of polycondensing an alcohol component and a carboxylic acid component. During the polycondensation, if necessary, an esterification catalyst such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxybis(triethanolamineate) may be used in an amount of 0.01 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; an esterification co-catalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component for polycondensation. Also, when using a monomer having an unsaturated bond such as fumaric acid in polycondensation, a radical polymerization inhibitor may be used, preferably in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, if necessary. 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, still more preferably 180°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0026] (Physical properties of crystalline polyester resin C) From the viewpoint of the storage stability of the toner, the softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, still more preferably 80°C or higher, and from the viewpoint of further improving the low-temperature fixability, it is preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, and still more preferably 95°C or lower. From the viewpoint of the storage stability of the toner, the melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, still more preferably 65°C or higher, and still more preferably 70°C or higher, and from the viewpoint of further improving the low-temperature fixability, it is preferably 100°C or lower, more preferably 90°C or lower, still more preferably 85°C or lower, and still more preferably 80°C or lower.

[0027] The acid value of the crystalline polyester resin C is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, still more preferably 15 mgKOH / g or more, and preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less, still more preferably 22 mgKOH / g or less.

[0028] The solubility parameter (SP value) of the crystalline polyester resin C is 9.0 or more, preferably 9.2 or more, more preferably 9.4 or more, still more preferably 9.6 or more, from the viewpoint of improving the rubbing resistance and image density of the image, and is 10.1 or less, preferably 10 or less, more preferably 9.9 or less, still more preferably 9.7 or less. Here, the "solubility parameter" and "SP value" are calculated by the method described in [POLYMER ENGINEERING AND SCIENCE, FEBRUARY, 1974, Vol.14, No.2, ROBERT F. FEDORS. (pages 147 to 154)], and are expressed in the unit of "(cal / cm 3 ) 1 / 2 ".

[0029] The softening point, melting point, acid value, and SP value of the crystalline polyester resin C can be appropriately adjusted by the types and amounts of raw material monomers used, and 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 kinds of the crystalline polyester resin C are used in combination, it is preferable that the values of the softening point, melting point, and acid value obtained as a mixture thereof are within the above ranges, respectively.

[0030] ≪Amorphous polyester resin A≫ In the present invention, the toner preferably contains an amorphous polyester resin A in addition to the crystalline polyester resin C as a binder resin. 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 the amorphous polyester resin include a polyester resin and a modified polyester resin. Examples of the modified polyester resin include a urethane-modified polyester resin, an epoxy-modified polyester resin, and a composite resin including a polyester resin segment and an addition polymer resin segment. Among these, an amorphous polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component, or an amorphous composite resin including a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component and an addition polymer resin segment which is an addition polymer of a raw material monomer containing a styrene-based compound is preferable.

[0031] Examples of the alcohol component include an alkylene oxide adduct of an aromatic diol, a linear or branched aliphatic diol, an alicyclic diol, and a polyhydric alcohol having a valence of 3 or more. Among these, an alkylene oxide adduct of an aromatic diol is preferable from the viewpoint of obtaining a toner excellent in low-temperature fixability. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably represented by the formula (I):

[0032]

Chemical formula

[0033] Examples of the alkylene oxide adduct of bisphenol A include an adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] with propylene oxide and an adduct of bisphenol A with ethylene oxide. One or more of these may be used. Among these, an adduct of bisphenol A with propylene oxide or an adduct of bisphenol A with ethylene oxide is preferable, and it is more preferable to use the adduct of bisphenol A with propylene oxide alone or to use the adduct of bisphenol A with propylene oxide and the adduct of bisphenol A with ethylene oxide in combination. 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, still more preferably 95 mol% or more, and is 100 mol% or less, and more preferably 100 mol%.

[0034] Examples of the linear or branched aliphatic diol 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 the alicyclic diol include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and an alkylene oxide adduct (average number of moles added: 2 or more and 12 or less) of hydrogenated bisphenol A having 2 or more and 4 or less carbon atoms. Examples of the polyhydric alcohol having a valence of 3 or more include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. One or more of these alcohol components may be used.

[0035] Examples of the carboxylic acid component include dicarboxylic acid and polyvalent carboxylic acid having a valence of 3 or more. Examples of the dicarboxylic acid 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 preferable. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable. The amount of the aromatic dicarboxylic acid is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more in the carboxylic acid component, and is preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less.

[0036] The number of carbon atoms of the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and is preferably 30 or less, more preferably 20 or less. Examples of the linear or branched aliphatic dicarboxylic acid 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 acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, fumaric acid, sebacic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferable. The amount of the linear or branched aliphatic dicarboxylic acid is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 10 mol% or more in the carboxylic acid component, and is preferably 80 mol% or less, more preferably 50 mol% or less, still more preferably 40 mol% or less, still more preferably 30 mol% or less.

[0037] As the polyvalent carboxylic acid having a valence of 3 or more, a trivalent carboxylic acid is preferable, and examples thereof include trimellitic acid. Trimellitic acid or its anhydride is preferable. When containing a polyvalent carboxylic acid having a valence of 3 or more, the amount of the polyvalent carboxylic acid having a valence of 3 or more is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 8 mol% or more in the carboxylic acid component, and preferably 30 mol% or less, more preferably 25 mol% or less, still more preferably 20 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0038] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component [COOH group / OH group] is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0039] When the amorphous polyester resin A is an amorphous composite resin, the addition polymerization resin segment is, for example, an addition polymer of a raw material monomer containing a styrene-based compound. Examples of the styrene-based compound include unsubstituted or substituted styrene. Examples of the substituent substituted for 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 the styrene-based compound include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrene sulfonic acid or a salt thereof. Among these, styrene is preferable. In the raw material monomer of the addition polymerization resin segment, the content of the styrene-based compound is preferably 50% by mass or more, more preferably 65% by mass or more, still more preferably 75% by mass or more, and 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 85% by mass or less.

[0040] Examples of raw material monomers other than styrene 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; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; 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. (meth)acrylic acid alkyl preferably has 1 or more carbon atoms in the alkyl group, more preferably 4 or more carbon atoms, still more preferably 6 or more carbon atoms, and preferably 24 or less carbon atoms, more preferably 22 or less carbon atoms, still more preferably 20 or less carbon atoms. (meth)acrylic acid alkyl includes, for example, 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)palmitoyl (meth)acrylate, (iso)stearyl (meth)acrylate, (iso)behenyl (meth)acrylate, etc. Preferred are 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate, more preferred is 2-ethylhexyl acrylate or stearyl methacrylate, and still more preferred is stearyl methacrylate. Note that “(iso or tertiary)” and “(iso)” mean both the case where these prefixes are present and the case where they are not present. When these prefixes are not present, it indicates normal. Also, “(meth)acrylic acid” indicates acrylic acid or methacrylic acid.

[0041] In the raw material monomers of the addition polymerization resin segment, the content of (meth)acrylic acid ester is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less. In the raw material monomers of the addition polymerization resin segment, the total amount of the styrene-based compound and the (meth)acrylic acid ester is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass.

[0042] When the amorphous polyester resin A is an amorphous composite resin, the amorphous polyester resin A preferably has structural units derived from both reactive monomers bonded via a covalent bond to the polyester resin segment and the addition polymerization resin segment. The "structural units derived from both reactive monomers" means units in which the functional groups and addition polymerizable groups of the both reactive monomers have reacted. Examples of the addition polymerizable group include a carbon-carbon unsaturated bond (ethylenic unsaturated bond). Examples of the both reactive monomers include addition polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxy 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 carboxy group are preferable, and addition polymerizable monomers having a carboxy group are more preferable. Examples of the addition polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of the reactivity of both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferable, and acrylic acid is more preferable. When the both-reactive monomer is an addition polymerizable monomer having a carboxy group, the amount of the structural unit derived from the both-reactive monomer is preferably 1 mol part or more, more preferably 5 mol parts or more, still more preferably 8 mol parts or more, and preferably 30 mol parts or less, more preferably 25 mol parts or less, still more preferably 20 mol parts or less, based on 100 mol parts of the alcohol component of the polyester resin segment of the amorphous polyester resin A.

[0043] When the amorphous polyester resin A is an amorphous composite resin, the amorphous polyester resin A preferably further contains a structural unit derived from a hydrocarbon wax having at least one of a carboxy group and a hydroxy group (structural unit derived from the hydrocarbon wax) in addition to the polyester resin segment and the addition polymer resin segment. The structural unit derived from the hydrocarbon wax is, for example, a part of the hydrocarbon wax in which a hydroxy group or a carboxy group has reacted and is covalently bonded to the polyester resin segment. The hydrocarbon wax has at least one of a carboxy group and a hydroxy group. The hydrocarbon wax may have either one or both of a hydroxy group and a carboxy group, but preferably has a hydroxy group and a carboxy group from the viewpoint of improving the image density of the printed matter. The hydrocarbon wax can be obtained, for example, by modifying an unmodified hydrocarbon wax by a known method. Examples of the raw material of the hydrocarbon wax include paraffin wax, Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, and polypropylene wax. Among these, paraffin wax and Fischer-Tropsch wax are preferable.

[0044] Examples of commercially available products of the hydrocarbon wax having a hydroxy group include "Unilin 700", "Unilin 425", and "Unilin 550" (manufactured by Baker Petrolite). Examples of the hydrocarbon wax having a carboxy group include acid-modified hydrocarbon wax. Examples of commercially available hydrocarbon waxes having a carboxy group include, for example, maleic anhydride-modified ethylene-propylene copolymer "Hiwax 1105A" (manufactured by Mitsui Chemicals, Inc.). Examples of commercially available hydrocarbon waxes having a hydroxyl group and a carboxy group include, for example, "Paracol 6420", "Paracol 6470", "Paracol 6490" (all manufactured by Nippon Seiro Co., Ltd.).

[0045] From the viewpoint of improving the image density of the printed matter, the hydroxyl value of the hydrocarbon wax is preferably 35 mgKOH / g or more, more preferably 50 mgKOH / g or more, still more preferably 70 mgKOH / g or more, and preferably 180 mgKOH / g or less, more preferably 150 mgKOH / g or less, still more preferably 120 mgKOH / g or less. From the viewpoint of improving the image density of the printed matter, the acid value of the hydrocarbon wax is preferably 1 mgKOH / g or more, more preferably 5 mgKOH / g or more, still more preferably 10 mgKOH / g or more, and preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, still more preferably 20 mgKOH / g or less.

[0046] From the viewpoint of improving the image density of the printed matter, the total of the hydroxyl value and the acid value of the hydrocarbon wax is preferably 35 mgKOH / g or more, more preferably 40 mgKOH / g or more, still more preferably 60 mgKOH / g or more, still more preferably 80 mgKOH / g or more, still more preferably 90 mgKOH / g or more, and preferably 210 mgKOH / g or less, more preferably 175 mgKOH / g or less, still more preferably 140 mgKOH / g or less, still more preferably 120 mgKOH / g or less.

[0047] From the viewpoint of improving the image density of the printed matter, the number average molecular weight of the hydrocarbon wax is preferably 500 or more, more preferably 600 or more, still more preferably 700 or more, and preferably 2000 or less, more preferably 1700 or less, still more preferably 1500 or less. The methods for measuring the hydroxyl value and acid value of the hydrocarbon wax are in accordance with the methods described in the examples. The number average molecular weight of the hydrocarbon wax is measured by gel permeation chromatography using chloroform as a solvent and polystyrene as a standard substance.

[0048] When the amorphous polyester resin A is an amorphous composite resin, the content of the polyester resin segment in the amorphous polyester resin A is preferably 35% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, and preferably 90% by mass or less, more preferably 85% by mass or less, still 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 units derived from both reactive monomers are regarded as the polyester resin segment.

[0049] When the amorphous polyester resin A is an amorphous composite resin, the content of the addition polymerization resin segment in the amorphous polyester resin A is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 25% by mass or more, and preferably 65% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment. The structural units derived from both reactive monomers are regarded as the polyester resin segment.

[0050] When the amorphous polyester resin A is an amorphous composite resin, the amount of the structural units derived from both reactive monomers in the amorphous polyester resin A is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, still more preferably 4% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0051] When the amorphous polyester resin A is an amorphous composite resin, the amount of the structural unit derived from hydrocarbon wax in the amorphous polyester resin A is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, still more preferably 1 part by mass or more, based on 100 parts by mass of the total amount of the polyester resin segment and the addition polymerized resin segment, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 6 parts by mass or less.

[0052] When the amorphous polyester resin A is an amorphous composite resin, the total amount of the polyester resin segment, the addition polymerized resin segment, and the structural unit derived from hydrocarbon wax in the amorphous polyester resin A is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and is 100% by mass or less, and still more preferably 100% by mass.

[0053] The above amounts are calculated based on the ratios of the amounts of the polyester resin segment, the raw material monomers of the addition polymerized resin segment, both reactive monomers, the radical polymerization initiator, and the structural unit derived from hydrocarbon wax, and are based on the mass excluding the amount of water removed by polycondensation in the polyester resin segment and the like. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated including it in the addition polymerized resin segment.

[0054] The amorphous polyester resin A may be produced, for example, by a step A of polycondensing an alcohol component and a carboxylic acid component. When the amorphous polyester resin A is an amorphous composite resin, it may also be produced by a method including the step A and a step B of addition polymerizing the raw material monomers of the addition polymerized resin segment and both reactive monomers. When the amorphous polyester resin A is an amorphous composite resin and further has a structural unit derived from hydrocarbon wax, in the above 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 carboxy group. When the method for producing the amorphous polyester resin A has steps A and B, step B may be carried out after step A, step A may be carried out after step B, or steps A and B may be carried out simultaneously. In step A, a part of the carboxylic acid component is subjected to a polycondensation reaction, and then after step B is carried out, the remainder of the carboxylic acid component is added to the polymerization system, and the polycondensation reaction of step A and the polycondensation reaction with the carboxy groups of both reactive monomers or the structural sites derived from both reactive monomers are further advanced. A method is preferred.

[0055] In step A, if necessary, an esterification catalyst such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, titanium diisopropoxybis(triethanolamine) is used in an amount of 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; an esterification co-catalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) is used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, and polycondensation may be carried out. Also, when using a monomer having an unsaturated bond such as fumaric acid in the polycondensation, if necessary, a radical polymerization inhibitor is preferably used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 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, still more preferably 180 °C or higher, and preferably 250 °C or lower, more preferably 240 °C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0056] 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 based on 100 parts by mass of the raw material monomers of the addition polymerization resin segment. The temperature of the additional superposition is preferably 110°C or higher, more preferably 130°C or higher, and preferably 230°C or lower, more preferably 220°C or lower, still more preferably 210°C or lower.

[0057] (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, still more preferably 100°C or higher, and from the viewpoint of further improving the low-temperature fixing property, it is preferably 150°C or lower, more preferably 140°C or lower, still 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, still more preferably 40°C or higher, and from the viewpoint of further improving the low-temperature fixing property, it is preferably 80°C or lower, more preferably 70°C or lower, still more preferably 60°C or lower.

[0058] The acid value of the amorphous polyester resin A is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, and preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower. The softening point, glass transition temperature, and acid value of the amorphous polyester resin A can be appropriately adjusted according to the types and amounts of the raw material monomers used, and the production conditions such as the reaction temperature, reaction time, and cooling rate. Moreover, those values are determined by the method described in the examples. In addition, when two or more kinds of the amorphous polyester resin A are used in combination, it is preferable that the values of the softening point, glass transition temperature, and acid value obtained as their mixture are respectively within the above-mentioned ranges.

[0059] The content of the amorphous polyester resin A is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and still more preferably 65% by mass or more, based on the total amount of the resin components of the resin particles X, and is preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 85% by mass or less, and still more preferably 82% by mass or less.

[0060] The mass ratio of the amorphous polyester resin A to the crystalline polyester resin C [amorphous polyester resin A / crystalline polyester resin C] is preferably 40 / 60 or more, more preferably 50 / 50 or more, still more preferably 60 / 40 or more, and still more preferably 65 / 35 or more, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, still more preferably 85 / 15 or less.

[0061] ≪Amorphous polyester resin B≫ In the present invention, the toner preferably contains an amorphous polyester resin B in addition to the above-mentioned crystalline polyester resin C and amorphous polyester resin A as a binder resin. It is more preferable that the toner has a core-shell structure and the shell portion contains the 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 the polyester resin include polyester resins and modified polyester resins. Examples of the modified polyester resin include, for example, a urethane-modified product of a polyester resin, an epoxy-modified product of a polyester resin, and a composite resin containing a polyester resin segment and an addition polymerized resin segment. Among these, an amorphous polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component is preferable.

[0062] As the alcohol component, for example, from the viewpoint of obtaining a desired aromatic ring concentration, an alkylene oxide adduct of an aromatic diol can be mentioned. Among these, from the viewpoint of obtaining a toner excellent in low-temperature fixability, an alkylene oxide adduct of an aromatic diol is preferable. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably of the formula (I):

[0063] [Chemical formula] (In the formula, OR 1 and R 2 O is an oxyalkylene group, R 1 and R 2 are each independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are each a positive number. The value of the sum of x and y is 1 or more, preferably 1.5 or more, more preferably 1.8 or more, and 16 or less, preferably 8 or less, more preferably 4 or less, still more preferably 3 or less, and still more preferably 2.5 or less), which is an alkylene oxide adduct of bisphenol A.

[0064] Examples of the alkylene oxide adduct 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 of two or more. Among these, an ethylene oxide adduct of bisphenol A is more preferable. 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, still more preferably 95 mol% or more, and 100 mol% or less, and still more preferably 100 mol%.

[0065] In addition to the alkylene oxide adduct of bisphenol A, the amorphous polyester resin A may contain a linear or branched aliphatic diol, an alicyclic diol, a polyhydric alcohol having a trivalent or higher valence, etc. as described above. These alcohol components may be used alone or in combination of two or more.

[0066] Examples of the carboxylic acid component include dicarboxylic acids and polyvalent carboxylic acids having a trivalent or higher valence. Examples of the dicarboxylic acid 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 preferable. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferable, and terephthalic acid is more preferable. The amount of the aromatic dicarboxylic acid is preferably 40 mol% or more, more preferably 50 mol% or more, still more preferably 60 mol% or more, still more preferably 70 mol% or more, and preferably 90 mol% or less, more preferably 85 mol% or less, still more preferably 80 mol% or less, still more preferably 75 mol% or less in the carboxylic acid component from the viewpoint of obtaining a desired aromatic ring concentration.

[0067] The number of carbon atoms of the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of the linear or branched aliphatic dicarboxylic acid 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 acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, fumaric acid and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred. The amount of the linear or branched aliphatic dicarboxylic acid is preferably 60 mol% or less, more preferably 30 mol% or less, and still more preferably 20 mol% or less in the carboxylic acid component.

[0068] The polyvalent carboxylic acid having a valence of 3 or more is preferably a trivalent carboxylic acid, and examples thereof include trimellitic acid. Preferably, it is trimellitic acid or its anhydride. When the polyvalent carboxylic acid having a valence of 3 or more is included, the amount of the polyvalent carboxylic acid having a valence of 3 or more is preferably 3 mol% or more, more preferably 5 mol% or more, and still more preferably 8 mol% or more in the carboxylic acid component, and is preferably 30 mol% or less, more preferably 25 mol% or less, and still more preferably 20 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0069] The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component [COOH group / OH group] 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.

[0070] The polyester resin B may be produced, for example, by a 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 the amorphous polyester resin A, and the preferred ranges are also the same. In Project A, if necessary, esterification catalysts such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, and titanium diisopropoxybis(triethanolaminato) may be used in an amount of 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; esterification cocatalysts such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component for polycondensation. When using a monomer having an unsaturated bond such as fumaric acid in polycondensation, if necessary, a radical polymerization inhibitor may be used in an amount of preferably 0.001 parts by mass or more and 0.5 parts by mass or less based on 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, still more preferably 180 °C or higher, and is preferably 250 °C or lower, more preferably 240 °C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0071] (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, still 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, still 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, still more preferably 50 °C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 90 °C or lower, more preferably 80 °C or lower, still more preferably 70 °C or lower.

[0072] The acid value of the amorphous polyester resin B is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, still more preferably 15 mg KOH / g or more, and preferably 40 mg KOH / g or less, more preferably 30 mg KOH / g or less, still more preferably 25 mg KOH / g or less. The softening point, glass transition temperature, and acid value of the amorphous polyester resin B can be appropriately adjusted according to the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate. These values are determined by the methods described in the examples. When two or more kinds of the amorphous polyester resin B are used in combination, it is preferable that the values of the softening point, glass transition temperature, and acid value obtained as a mixture thereof are each within the aforementioned ranges.

[0073] 〔Colorant〕 The toner of the present invention preferably contains a colorant, and it is more preferable that the toner has a core-shell structure and the colorant is contained in the core part. As the colorant, all dyes, pigments, etc. used as colorants for toners can be used. Examples of the colorant include carbon black, phthalocyanine blue, 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 (for example, pigment yellow 155). The toner may be either a black toner or a color toner other than black.

[0074] When the toner of the present invention is a white toner, it preferably contains a white pigment as the colorant, and the white pigment is preferably titanium oxide. As the titanium oxide, rutile-type titanium oxide or anatase-type titanium oxide can be used, but from the viewpoints of stability and availability, rutile-type titanium oxide is preferable. From the perspective of obtaining good dispersibility in the toner, surface-treated titanium oxide is preferred. The surface treatment of titanium oxide is not particularly limited, and either surface treatment with an organic substance or surface treatment with an inorganic substance may be applied. From the perspective of avoiding the influence of photocatalytic properties, titanium oxide surface-treated with an inorganic substance is preferred, titanium oxide surface-treated with at least one of silica and alumina is more preferred, and titanium oxide surface-treated with silica and alumina is even more preferred. The powder of surface-treated titanium oxide can also suppress sintering between particles and improve the fluidity and dispersibility of titanium oxide by firing at 800 °C or higher and 1000 °C or lower. Examples of the particle shape of titanium oxide include granular and acicular shapes, but it is not particularly limited.

[0075] From the perspective of obtaining high whiteness, the average primary particle size of titanium oxide is preferably 100 nm or more, more preferably 150 nm or more, even more preferably 200 nm or more, and even more preferably 220 nm or more. From the perspective of dispersibility, it is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 350 nm or less. The average primary particle size of titanium oxide can be measured using a transmission electron microscope. Specifically, 500 titanium oxide primary particles are extracted by image analysis using a transmission electron microscope, their particle sizes are measured, and the average is calculated as the number average particle size. When titanium oxide has a major axis and a minor axis, the major axis is used for calculation. Examples of commercially available products of titanium oxide used in the present invention include product names: JR, JR-300, JR-605, JR-701 manufactured by Teika Corporation, and product names: Typepeke CR-93, CR-90, CR-80 manufactured by Ishihara Sangyo Co., Ltd.

[0076] When the colorant is other than a white pigment, the content of the colorant in the toner particles is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less. When the colorant is a white pigment, the content of the colorant (white pigment) in the toner particles is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, still more preferably 45% by mass or less, from the viewpoint of enhancing whiteness.

[0077] 〔Release agent〕 The toner of the present invention preferably contains a release agent, and it is more preferable that the toner has a core-shell structure and the release agent is contained in the core part. Examples of the release agent include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, Sasol wax or their oxides; ester waxes such as carnauba wax, montan wax or their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

[0078] 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, still more preferably 120°C or lower, still more preferably 100°C or lower. The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less.

[0079] <Method for manufacturing toner> In the present invention, the toner preferably has a core-shell structure, and the toner having a core-shell structure is preferably obtained by a method having the following steps 1 to 3. Step 1: A step of aggregating resin particles X containing a crystalline polyester resin C and an amorphous polyester resin A in the same or different particles in an aqueous medium to obtain aggregated particles 1. Step 2: A step of aggregating resin particles Y containing an amorphous polyester resin B with the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2. Step 3: A step of heating and fusing the aggregated particles 2 obtained in Step 2 to obtain fused particles. In Step 1, in an aqueous medium, resin particles X are aggregated to obtain aggregated particles 1. Here, it is preferable that the resin particles X contain a crystalline polyester resin C and an amorphous polyester resin A. Further, in addition to the resin particles X, it is preferable to aggregate colorant particles and mold release agent particles, and it is more preferable to mix a resin particle dispersion containing the resin particles X, a colorant particle dispersion containing the colorant particles, and a mold release agent particle dispersion containing the mold release agent particles to aggregate these particles. Hereinafter, each step will be described.

[0080] 〔Step 1〕 In Step 1, it is preferable to mix the resin particles X containing the crystalline polyester resin C and the amorphous polyester resin A in the same or different particles and the colorant particles in an aqueous medium, and aggregate the resin particles X and the colorant particles to obtain aggregated particles. The mixing of the resin particles X and the colorant particles is preferably performed by mixing a resin particle dispersion containing the resin particles X and a colorant particle dispersion containing the colorant particles. Further, the resin particle dispersion is preferably an aqueous dispersion of the resin particles, and the colorant particle dispersion is preferably an aqueous dispersion of the colorant particles. In Step 1, it is preferable to aggregate the mold release agent particles together with the resin particles X and the colorant particles. Further, in Step 1, the aggregated particles 1 may also contain other additives such as charge control agents, magnetic powders, fluidity improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleaning property improvers.

[0081] ≪Resin Particles X≫ The resin particle dispersion used in Project 1 contains resin particles X. In order to obtain excellent low-temperature fixability, the resin particles X preferably contain the amorphous polyester resin A and the crystalline polyester resin C in the same or different resin particles. From the viewpoint of further improving the low-temperature fixability of the resulting toner and widening the non-offset temperature range, preferably, the amorphous polyester resin A and the crystalline polyester resin C are contained in the same resin particles.

[0082] (Preparation of resin particle dispersion) The preparation of the resin particle dispersion containing the resin particles X, preferably the resin particle dispersion containing the amorphous polyester resin A and the crystalline polyester resin C in the same or different resin particles, can be carried out using a known method, but it is preferably dispersed by the phase inversion emulsification method. Examples of the phase inversion emulsification method include a method in which an aqueous medium is added to an organic solvent solution of a resin or a molten resin to cause phase inversion emulsification.

[0083] The organic solvent used for phase inversion emulsification is not particularly limited as long as it can dissolve the resin. From the viewpoint of facilitating phase inversion, for example, alcohol solvents such as ethanol, isopropanol, and isobutanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and diethyl ketone; ether solvents such as dibutyl ether, tetrahydrofuran, and dioxane; and acetate ester solvents such as ethyl acetate and isopropyl acetate can be mentioned. Among these, from the viewpoint of easy removal from the mixed solution after adding the aqueous medium, ketone solvents and acetate ester solvents are preferred, and methyl ethyl ketone, ethyl acetate, and isopropyl acetate are more preferred. It is preferable to add a neutralizing agent to the organic solvent solution. Examples of the neutralizing agent include basic substances. Examples of the basic substances include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The equivalent amount (mol%) of the neutralizing agent with respect to the acid groups of the resin contained in the resin particles X is preferably 10 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, and preferably 90 mol% or less, more preferably 70 mol% or less, from the viewpoint of obtaining fine resin particles and improving the dispersion stability. Note that the equivalent amount (mol%) of the neutralizing agent can be determined by the following formula. When the equivalent amount of the neutralizing agent is 100 mol% or less, it is synonymous with the degree of neutralization. Equivalent amount (mol%) of neutralizing agent = [{mass of neutralizing agent added (g) / equivalent of neutralizing agent} / [{weight average acid value (mgKOH / g) of the resin constituting the resin particles X × mass of the resin constituting the resin particles X (g)} / (56 × 1000)]] × 100

[0084] While stirring the organic solvent solution or the molten resin, an aqueous medium is gradually added to cause phase inversion. The temperature of the organic solvent solution when adding the aqueous medium is preferably at or above the glass transition temperature of the resin constituting the resin particles X, more preferably 50°C or above, still more preferably 60°C or above, and preferably 85°C or below, more preferably 80°C or below, from the viewpoint of improving the dispersion stability of the resin particles X. The contents of the amorphous polyester resin A and the crystalline polyester resin C are as described above.

[0085] After phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation or the like. In this case, the remaining amount of the organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, still more preferably substantially 0% by mass.

[0086] The volume median diameter (D 50 ) of the resin particles X in the dispersion is preferably 0.05 μm or more, more preferably 0.08 μm or more, still more preferably 0.12 μm or more, and preferably 0.8 μm or less, more preferably 0.4 μm or less, still more preferably 0.3 μm or less, from the viewpoint of obtaining a toner that can provide high-quality images. The CV value of the resin particles X in the dispersion is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, from the viewpoint of obtaining a toner capable of obtaining a high-quality image. The volume median particle diameter (D 50 ) of the resin particles X and the CV value are determined by the method described in the examples below.

[0087] When resin particles Xa containing the amorphous polyester resin A and resin particles Xc containing the crystalline polyester resin C are mixed and used, the resin particles Xa and Xc can be obtained by the same method as described above. The addition amounts of the resin particles Xa and the resin particles Xc are preferably amounts that result in the contents of the amorphous polyester resin A and the crystalline polyester resin C described above.

[0088] - Aqueous medium - In the present invention, the aqueous medium is a medium mainly composed of water. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and 100% by mass or less. As the water, deionized water, ion-exchanged water, or distilled water is preferable. As components other than water that can constitute the aqueous medium together with water, alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having 3 to 5 carbon atoms such as acetone and methyl ethyl ketone; organic solvents soluble in water such as cyclic ethers such as tetrahydrofuran are used. Among these, alkyl alcohols having 1 to 5 carbon atoms are preferable, and methanol or ethanol is more preferable.

[0089] ≪Colorant particles≫ The colorant is preferably contained in the aggregated particles by mixing and aggregating with the resin particles as a dispersion of the colorant particles. The colorant particle dispersion is preferably obtained by dispersing a colorant and an aqueous medium using a disperser such as a homogenizer or an ultrasonic disperser. From the viewpoint of improving the dispersion stability of the colorant, it is preferable to perform the dispersion in the presence of an addition polymer (hereinafter, the addition polymer used for dispersing the colorant is also referred to as "addition polymer E") or a surfactant. Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. From the viewpoint of improving the dispersion stability of the colorant particles, an anionic surfactant is preferable. Examples of the anionic surfactant include dodecylbenzenesulfonate, dodecyl sulfate, lauryl ether sulfate, and alkenyl succinate. Among these, dodecylbenzenesulfonate is preferable. From the viewpoint of improving the dispersion stability of the colorant, the content of the surfactant in the colorant particle dispersion is preferably 1 part by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, based on 100 parts by mass of the colorant.

[0090] When the colorant is a colorant other than a white pigment, the addition polymer E (hereinafter, the addition polymer E when the colorant is a colorant other than a white pigment is also referred to as "addition polymer E1") is preferably an addition polymer of a raw material monomer containing an addition polymerizable monomer a having an aromatic group (hereinafter, simply referred to as "monomer a"). And it is more preferable that the addition polymer E1 contains a structural unit derived from the addition polymerizable monomer a having an aromatic group in the main chain. The raw material monomer of the addition polymer E1 contains, in addition to the addition polymerizable monomer a having an aromatic group, more preferably an addition polymerizable monomer b having an ionic group (hereinafter, simply referred to as "monomer b"). In addition to the monomer b, the raw material monomer of the addition polymer E1 more preferably further contains at least one selected from an addition polymerizable monomer c having a polyalkylene oxide group (hereinafter, simply referred to as "monomer c") or a macromonomer d (hereinafter, simply referred to as "monomer d").

[0091] The addition-polymerizable monomer a having an aromatic group is preferably nonionic. Examples of the addition-polymerizable monomer a having an aromatic group include styrene-based compounds a-1 and aromatic group-containing (meth)acrylates a-2. Examples of the styrene-based compound a-1 include substituted or unsubstituted styrene. Examples of the substituent for styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, or a salt thereof. The molecular weight of the styrene-based compound a-1 is preferably 1,000 or less, more preferably 800 or less, still more preferably 500 or less, still more preferably 300 or less, and is preferably 80 or more, more preferably 90 or more, still more preferably 100 or more. Examples of the styrene-based compound a-1 include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, or a salt thereof. Among these, styrene is preferred. From the viewpoint of further improving the image quality, the amount of the styrene-based compound a-1 in the raw material monomers of the addition polymer E1 is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 35% by mass or more, and is preferably 98% by mass or less, more preferably 80% by mass or less, still more preferably 65% by mass or less, still more preferably 50% by mass or less.

[0092] Examples of the aromatic group-containing (meth)acrylate a-2 include benzyl (meth)acrylate and phenoxyethyl (meth)acrylate. The molecular weight of the aromatic group-containing (meth)acrylate a-2 is preferably 1,000 or less, more preferably 800 or less, still more preferably 500 or less, still more preferably 300 or less, and is preferably 160 or more. When using the aromatic group-containing (meth)acrylate a-2, from the viewpoint of further improving the image quality, the content of the aromatic group-containing (meth)acrylate a-2 in the raw material monomers of the addition polymer E1 is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.

[0093] From the viewpoint of further improving the image density, the amount of the addition polymerizable monomer a having an aromatic group in the raw material monomers of the addition polymer E1 is preferably 1% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, still more preferably 20% by mass or more, still more preferably 30% by mass or more, still more preferably 35% by mass or more, and preferably 98% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass or less, still more preferably 80% by mass or less, still more preferably 65% by mass or less, still more preferably 50% by mass or less.

[0094] The ionic group in the monomer b means a group that dissociates into ions in water. Examples of the ionic group include a carboxy group, a sulfo group, a phosphoric acid group, an amino group, or salts thereof. From the viewpoint of improving the dispersion stability of the colorant particles, the ionic group is preferably an anionic group. As the anionic group, an acidic group or salts thereof are preferable, a carboxy group, a sulfo group, or salts thereof are more preferable, and a carboxy group or salts thereof are still more preferable. Examples of the addition polymerizable monomer having a carboxy group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and 2-methacryloyloxymethyl succinic acid. Among these, an addition polymerizable monomer having an anionic group is preferable, (meth)acrylic acid is more preferable, and methacrylic acid is still more preferable. When monomer b is contained, the amount of monomer b is preferably 2% by mass or more, more preferably 5% by mass or more, still more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less in the raw material monomers of the addition polymer E1.

[0095] The average number of moles of alkylene oxide added to the polyalkylene oxide group of monomer c is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, still more preferably 10 or less. Monomer c is preferably nonionic. Examples of monomer c include polyalkylene glycol (meth) acrylates such as polyethylene glycol (meth) acrylate and polypropylene glycol (meth) acrylate; alkoxypolyalkylene glycol (meth) acrylates such as methoxypolyethylene glycol (meth) acrylate; and aryloxypolyalkylene glycol (meth) acrylates such as phenoxy (ethylene glycol - propylene glycol copolymer) (meth) acrylate. When monomer c is contained, the amount of monomer c is preferably 3% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less in the raw material monomers of the addition polymer E1.

[0096] Examples of monomer d include styrene - based compound polymers having an addition - polymerizable functional group at one end (hereinafter also referred to as "styrene - based macromonomers"). Examples of the addition - polymerizable functional group include a vinyl group, an allyl group, and a (meth) acryloyl group. Among these, the (meth) acryloyl group is preferred. In monomer d, as the styrene - based compound, styrene is preferred. The number average molecular weight of monomer d is preferably 1,000 or more and 10,000 or less. The number average molecular weight is measured by gel permeation chromatography using chloroform containing 1 mmol / L of dodecyl dimethylamine as a solvent and polystyrene as a standard substance. Examples of commercially available styrene-based macromonomers include "AS-6", "AS-6S", "AN-6", "AN-6S", "HS-6", "HS-6S" (manufactured by Toagosei Co., Ltd., etc.). When monomer d is contained, the amount of monomer d is preferably 3% by mass or more, more preferably 6% by mass or more, still more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less in the raw material monomers of the addition polymer E1.

[0097] Furthermore, as the raw material monomers of the addition polymer E1, addition polymerizable monomers (other monomers) other than monomers a to d may be contained. Examples of other monomers include alkyl (meth) acrylates having an alkyl group with 1 to 22 carbon atoms (preferably 6 to 18 carbon atoms). When other monomers are contained, the amount of other monomers is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, still more preferably 10% by mass or less, still more preferably 5% by mass or less in the raw material monomers of the addition polymer E1.

[0098] From the viewpoint of further improving the image density, the weight average molecular weight of the addition polymer E1 is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 20,000 or more, still more preferably 40,000 or more, still more preferably 48,000 or more, and preferably 200,000 or less, more preferably 90,000 or less, still more preferably 60,000 or less, still more preferably 53,000 or less. The measurement of the weight average molecular weight can be carried out by the method described in the examples.

[0099] When the colorant is a white pigment, preferably titanium oxide, the addition polymer E (hereinafter, the addition polymer E when the colorant is a white pigment is also referred to as "addition polymer E2") is preferably an addition polymer of a raw material monomer containing an addition polymerizable monomer having an ionic group and an addition polymerizable monomer having a polyalkylene oxide group from the viewpoint of excellent dispersibility of titanium oxide and obtaining an image with excellent whiteness. Examples of the addition polymerizable monomer having an ionic group in the addition polymer E2 are the same as the monomer b in the above-described addition polymer E1, and preferred embodiments are also the same. Examples of the addition polymerizable monomer having a polyalkylene oxide group in the addition polymer E2 are the same as the monomer c in the above-described addition polymer E1, and preferred embodiments are also the same. The average number of moles of alkylene oxide added to the polyalkylene oxide group of the addition polymerizable monomer having a polyalkylene oxide group in the addition polymer E2 is preferably 1 or more, more preferably 5 or more, still more preferably 10 or more, and preferably 60 or less, more preferably 40 or less, still more preferably 30 or less.

[0100] As the ionic group-containing monomer, from the viewpoint of improving the dispersibility of the white pigment in the dispersion liquid and the dispersibility of the white pigment in the toner, it is preferably a carboxy group-containing monomer, more preferably at least one selected from acrylic acid and methacrylic acid, and still more preferably methacrylic acid. The ionic group-containing monomer may form a salt, and examples of the salt include a sodium salt and a potassium salt.

[0101] The content of the ionic group-containing monomer in the raw material monomer of the addition polymer E2 is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 20% by mass or less, from the viewpoints of excellent dispersibility of the white pigment and improvement of whiteness and low-temperature fixability.

[0102] From the viewpoints of improving whiteness and low-temperature fixability, the content of the polyalkylene oxide group-containing monomer in the raw material monomers of the addition polymer E2 is preferably 50% by mass or more, more preferably 65% by mass or more, still more preferably 80% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or less, still more preferably 85% by mass or less.

[0103] From the viewpoints of improving whiteness and low-temperature fixability, the mass ratio (ionic group-containing monomer / polyalkylene oxide group-containing monomer) of the ionic group-containing monomer to the polyalkylene oxide group-containing monomer in the raw material monomers of the addition polymer E2 is preferably 5 / 95 or more, more preferably 10 / 90 or more, still more preferably 15 / 85 or more, and is preferably 50 / 50 or less, more preferably 35 / 65 or less, still more preferably 20 / 80 or less.

[0104] In the present invention, in addition to the ionic group-containing monomer and the polyalkylene oxide group-containing monomer, the raw material monomers of the addition polymer E2 may further contain the monomer a, monomer d, and addition polymerizable monomers other than monomers a to d (other monomers) described above in the addition polymer E1 as long as the effects of the present invention are not impaired. When the raw material monomers contain monomers other than the ionic group-containing monomer and the polyalkylene oxide group-containing monomer, the content of the monomers other than the ionic group-containing monomer and the polyalkylene oxide group-containing monomer in the raw material monomers is preferably 0.1% by mass or more and is preferably 5% by mass or less.

[0105] The weight average molecular weight of the addition polymer E2 is preferably 3,000 or more, more preferably 20,000 or more, still more preferably 40,000 or more, and still more preferably 48,000 or more from the viewpoints of excellent dispersibility of the white pigment, further improvement in whiteness, and low-temperature fixability. And it is preferably 200,000 or less, more preferably 80,000 or less, and still more preferably 70,000 or less. The measurement of the weight average molecular weight can be carried out by the method described in the examples.

[0106] The addition polymer E can be produced, for example, by copolymerizing raw material monomers by a known polymerization method. As the polymerization method, preferably, it is a solution polymerization method in which the raw material monomers are heated and polymerized together with a polymerization initiator, a polymerization chain transfer agent, etc. in a solvent.

[0107] Examples of the polymerization initiator include peroxides such as dibutyl peroxide, persulfates such as ammonium persulfate and sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The addition amount of the polymerization initiator is preferably 0.5 parts by mass or more and preferably 30 parts by mass or less with respect to 100 parts by mass of the raw material monomers. Examples of the polymerization chain transfer agent (also simply referred to as "chain transfer agent") include mercaptans such as 2-mercaptoethanol and 3-mercaptopropionic acid. The addition amount of the polymerization chain transfer agent is preferably 0.01 parts by mass or more and preferably 10 parts by mass or less with respect to 100 parts by mass of the raw material monomers. After completion of the polymerization reaction, the produced polymer may be isolated and purified by known methods such as reprecipitation from the reaction solution and distillation off of the solvent. Also, the reaction solution after completion of the reaction may be used as it is as a dispersion of the addition polymer.

[0108] In the colorant particles, the mass ratio of the colorant other than the white pigment to the addition polymer E1 (colorant / addition polymer E1) is preferably 50 / 50 or more, more preferably 60 / 40 or more, still more preferably 70 / 30 or more, still more preferably 75 / 25 or more, from the viewpoints of further improving the hiding power and low-temperature fixability, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, still more preferably 85 / 15 or less. Also, in the colorant particles, the mass ratio of the white pigment (preferably titanium oxide) to the addition polymer E2 (white pigment / addition polymer E2) is preferably 50 / 50 or more, more preferably 70 / 30 or more, still more preferably 85 / 15 or more, still more preferably 90 / 10 or more, still more preferably 95 / 5 or more, from the viewpoints of excellent dispersibility of the white pigment, further improving the whiteness, and low-temperature fixability, and is preferably 99.5 / 0.5 or less, more preferably 99.2 / 0.8 or less.

[0109] (Method for producing colorant particles and colorant particle dispersion liquid) The colorant particles can be obtained, for example, by mixing a colorant and an addition polymer E. There is no particular limitation on the method for producing the colorant particle dispersion liquid, and it may be controlled to obtain colorant particles having a desired volume median diameter D 50 using a known kneader, disperser, etc., but preferably, it is obtained by mixing a colorant and a dispersion liquid of an addition polymer E with a bead mill or a homogenizer.

[0110] The method for producing the colorant particles preferably includes Step a: a step of obtaining a dispersion liquid of an addition polymer E, and Step b: a step of subjecting the dispersion liquid obtained in Step a and a colorant to a dispersion treatment to obtain a dispersion liquid of colorant particles (colorant particle dispersion liquid 2). It is a method having these steps. When the colorant is a colorant other than the white pigment, Step a is preferably a step (hereinafter also referred to as Step a1) of mixing an addition polymer E1 and an organic solvent, then mixing a neutralizing agent as necessary, and further mixing an aqueous medium to obtain a dispersion liquid of the addition polymer E1. The inclusion of an organic solvent causes the addition polymer E1 to dissolve in the organic solvent, making it easier for the addition polymer E to adsorb onto the colorant, and thus enabling better dispersion of the colorant. Also, when the colorant is a white pigment, step a is preferably a step of obtaining an aqueous dispersion of the neutralized addition polymer E2 (hereinafter also referred to as step a2). If the reaction solution after the reaction can be used directly as a dispersion of the addition polymer, step a may be omitted. Moreover, step b is preferably a step of dispersing the dispersion obtained in step a and the colorant using a bead mill or a homogenizer.

[0111] When the colorant is a colorant other than a white pigment, in step a1, it is preferable to first mix the addition polymer E1 and the organic solvent to dissolve the addition polymer E1. Examples of the organic solvent used herein include alkyl alcohols having 1 to 3 carbon atoms, dialkyl ketones having a total of 3 to 5 carbon atoms, and cyclic ethers. Among these, dialkyl ketones having a total of 3 to 5 carbon atoms are preferred, and methyl ethyl ketone is more preferred. When the addition polymer E1 is synthesized by a solution polymerization method, the solvent used in the polymerization may be used as it is.

[0112] Examples of the neutralizing agent include basic substances. Examples of the basic substances include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide; nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. When the addition polymer E is the addition polymer E1, the degree of neutralization of the addition polymer E1 is preferably 15 mol% or more, more preferably 20 mol% or more, still more preferably 40 mol% or more, still more preferably 60 mol% or more, still more preferably 70 mol% or more, still more preferably 80 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less. Also, when the addition polymer E is the addition polymer E2, the degree of neutralization of the addition polymer E2 is preferably 10 mol% or more, more preferably 20 mol% or more, still more preferably 30 mol% or more, and preferably 100 mol% or less, more preferably 80 mol% or less, still more preferably 60 mol% or less, still more preferably 50 mol% or less. The degree of neutralization of the addition polymer E can be determined by the following formula. Degree of neutralization (mol%) = [{Mass of neutralizing agent added (g) / Equivalent of neutralizing agent} / {Mass ratio of addition polymerizable monomer having an acidic group constituting the addition polymer E × Mass of addition polymer E (g) / Molecular weight of addition polymerizable monomer having an acidic group}] × 100 In the case where the degree of neutralization exceeds 100 in calculation, the degree of neutralization is taken as 100 mol%. In step a, examples of the apparatus used for mixing include a mixing and stirring apparatus equipped with an anchor blade, a dispersing blade, etc. The temperature during mixing in step a1 is preferably 0°C or higher, more preferably 10°C or higher, and preferably 40°C or lower, more preferably 30°C or lower, still more preferably 25°C or lower. The mixing time in step a1 is preferably 1 minute or more, more preferably 3 minutes or more, still more preferably 5 minutes or more, and preferably 30 hours or less, more preferably 10 hours or less, still more preferably 5 hours or less, still more preferably 3 hours or less, still more preferably 1 hour or less.

[0113] In step b, the mass ratio of the colorant to the addition polymer E [colorant / addition polymer E] is as described above. In step b, after mixing the dispersion obtained in step a and the colorant, a dispersion treatment may be performed. Examples of the apparatus used for mixing in step b include the same apparatuses as those used for mixing in step a. The temperature during mixing in step b is preferably 0°C or higher, more preferably 10°C or higher, and preferably 40°C or lower, more preferably 30°C or lower, still more preferably 25°C or lower. Also, the mixing time in step b is preferably 1 minute or more, more preferably 10 minutes or more, still more preferably 30 minutes or more, and preferably 30 hours or less, more preferably 10 hours or less, still more preferably 5 hours or less, and even more preferably 3 hours or less.

[0114] Examples of the apparatus used for the dispersion treatment in step b include kneaders such as roll mills and kneaders, homogenizers such as Microfluidizer (manufactured by Microfluidic) and Starburst (manufactured by Sugino Machine Limited), paint shakers, and media dispersers such as bead mills. One or more of these apparatuses may be used. Among these, from the viewpoint of reducing the particle size of the pigment, homogenizers and media dispersers are preferred. When using a homogenizer, the treatment pressure is preferably 60 MPa or more, more preferably 100 MPa or more, still more preferably 130 MPa or more, and preferably 270 MPa or less, more preferably 200 MPa or less, still more preferably 180 MPa or less. Also, the number of passes is preferably 5 or more, more preferably 8 or more, still more preferably 12 or more, and preferably 30 or less, more preferably 20 or less. When using a media disperser, the material of the media is preferably ceramics such as zirconia and titania, polymer materials such as polyethylene and polyamide, metals, etc. From the viewpoint of wear and the like, zirconia is preferred. Also, the shape of the media is not particularly limited, but it is preferably bead-shaped (spherical). When using a media disperser, the dispersion time is preferably 0.3 hours or more, more preferably 1 hour or more, from the viewpoint of sufficiently refining the colorant, and preferably 100 hours or less, more preferably 50 hours or less, still more preferably 20 hours or less, from the viewpoint of the production efficiency of the colorant dispersion.

[0115] It is preferable to remove the organic solvent from the obtained colorant particle dispersion, if necessary. Further, it is preferable to filter the colorant particle dispersion with a wire mesh or the like to remove coarse particles and the like. Further, from the viewpoint of improving the productivity and storage stability of the dispersion, the addition polymer E of the colorant particles may be crosslinked. Also, various additives such as an organic solvent, a preservative, and a fungicide may be added to the colorant particle dispersion.

[0116] When the colorant is a colorant other than a white pigment, in the colorant particle dispersion, the colorant is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, and still more preferably 25% by mass or less. Also, in the above case, the solid content concentration of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less.

[0117] When the colorant is a white pigment, in the colorant particle dispersion, the content of the white pigment is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and still more preferably 25% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less. Also, in the above case, the solid content concentration of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, and preferably 70% by mass or less, more preferably 50% by mass or less, still more preferably 35% by mass or less.

[0118] When the colorant is a colorant other than a white pigment, the volume median diameter D of the colorant particles in the colorant particle dispersion 50 is preferably 0.05 μm or more, more preferably 0.07 μm or more, still more preferably 0.08 μm or more, and preferably 0.4 μm or less, more preferably 0.3 μm or less, still more preferably 0.2 μm or less, from the viewpoint of improving the image density. In the above case, from the viewpoint of improving the image density, the CV value of the colorant particles in the colorant particle dispersion is preferably 10% or more, more preferably 15% or more, and preferably 45% or less, more preferably 40% or less, still more preferably 35% or less. The volume median diameter D of the colorant particles 50 and the CV value are measured by the method described in the examples.

[0119] When the colorant is a white pigment, the volume median diameter D of the colorant 50 is preferably 0.10 μm or more, more preferably 0.15 μm or more, still more preferably 0.20 μm or more, and preferably 0.55 μm or less, more preferably 0.45 μm or less, still more preferably 0.35 μm or less, from the viewpoint of obtaining a toner with excellent whiteness. In the above case, the CV value of the volume median diameter D of the colorant 50 is preferably 10% or more, more preferably 20% or more, and preferably 45% or less, more preferably 35% or less, from the viewpoint of improving the whiteness. The volume median diameter D of the colorant 50 and the CV value are measured by the method of the examples.

[0120] When the colorant is a colorant other than a white pigment, the amount of the colorant particles is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, still more preferably 20 parts by mass or less, with respect to 100 parts by mass of the resin particles, from the viewpoint of further improving the image density. When the colorant is a white pigment, the amount of the colorant particles is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, still more preferably 50 parts by mass or more, and preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 70 parts by mass or less, with respect to 100 parts by mass of the resin particles, from the viewpoint of further improving the whiteness.

[0121] <<Release agent particles>> The release agent is preferably incorporated into the agglomerated particles by mixing and agglomerating it as a dispersion of release agent particles with a resin particle dispersion and a colorant particle dispersion. The dispersion of release agent particles can be obtained using a surfactant, but it is preferably obtained by mixing the release agent with resin particles Z described later. By preparing 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 considered that in the dispersion of release agent particles, a structure in which a large number of resin particles Z adhere to the surface of the release agent particles is present.

[0122] The resin constituting the resin particles Z for dispersing the release agent is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition-polymerized resin segment.

[0123] The softening point of the composite resin D is preferably 70°C or higher, more preferably 80°C or higher, still more preferably 85°C or higher, and preferably 140°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower. The acid value of the composite resin D is preferably 5 mgKOH / g or higher, more preferably 10 mgKOH / g or higher, still more preferably 15 mgKOH / g or higher, still more preferably 20 mgKOH / g or higher, and preferably 40 mgKOH / g or lower, more preferably 35 mgKOH / g or lower, still more preferably 30 mgKOH / g or lower, from the viewpoints of obtaining fine resin particles and obtaining a fine release agent particle dispersion.

[0124] The preferred ranges of other resin properties of the composite resin D, preferred examples of the raw material monomers constituting the resin, etc. are the same as the examples shown for the amorphous polyester resin A. The dispersion of the resin particles Z can be obtained, for example, by the phase inversion emulsification method described above. The volume median particle diameter (D 50 ) of the resin particles Z is preferably 0.01 μm or more, more preferably 0.03 μm or more, and preferably 0.3 μm or less, more preferably 0.2 μm or less, from the viewpoint of the dispersion stability of the release agent particles. From the viewpoint of the dispersion stability of the release agent particles, the CV value of the resin particles Z is preferably 10% or more, more preferably 15% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less. The volume median particle diameter (D 50 ) and the CV value of the resin particles Z are measured by the method described in the examples.

[0125] (Method for producing release agent particle dispersion liquid) The release agent particle dispersion liquid can be obtained, for example, by dispersing a release agent, a dispersion liquid of resin particles Z, and, if necessary, an aqueous medium at a temperature equal to or higher than the melting point of the release agent using a dispersing machine such as a homogenizer, a high-pressure dispersing machine, or an ultrasonic dispersing machine. The heating temperature during dispersion is preferably equal to or higher than the melting point of the release agent and 80°C or higher, more preferably 85°C or higher, still more preferably 90°C or higher, and preferably less than a temperature 10°C higher than the softening point of the resin contained in the resin particles Z and 100°C or lower, more preferably 98°C or lower, still more preferably 95°C or lower.

[0126] The amount of the resin particles Z is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass or more, still more preferably 30 parts by mass or more, based on 100 parts by mass of the release agent, and preferably 100 parts by mass or less, more preferably 70 parts by mass or less, still more preferably 50 parts by mass or less.

[0127] The volume median particle diameter (D 50 ) of the release agent particles is preferably 0.05 μm or more, more preferably 0.2 μm or more, still more preferably 0.4 μm or more, from the viewpoint of obtaining uniform aggregated particles by aggregation, and preferably 1 μm or less, more preferably 0.8 μm or less, still more preferably 0.6 μm or less. The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less. The volume median particle diameter (D 50) and the CV value is measured by the method described in the examples.

[0128] ≪Surfactant≫ In Step 1, after preparing a mixed dispersion liquid by mixing a resin particle dispersion liquid and, if necessary, a colorant particle dispersion liquid and a mold release agent particle dispersion liquid, it is preferable to aggregate resin particles X, colorant particles, and mold release agent particles. When preparing the mixed dispersion liquid, from the viewpoint of improving the dispersion stability of resin particles X and optional components such as colorant particles and mold release agent particles that are added as necessary, it may be carried out in the presence of a surfactant. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. When using a surfactant, the amount used is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of resin particles X as the total amount of the surfactant.

[0129] The dispersion of the aforementioned resin particles X and the mixing of optional components are carried out by conventional methods. From the viewpoint of efficiently performing aggregation, it is preferable to add a flocculant to the mixed dispersion liquid obtained by the mixing.

[0130] ≪Flocculant≫ Examples of the flocculant include organic flocculants such as quaternary salt cationic surfactants and polyethyleneimine; inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium nitrate; and inorganic flocculants such as divalent or higher metal complexes. From the viewpoint of improving flocculability and obtaining uniform flocculated particles, inorganic flocculants with a valence of 1 or more and 5 or less are preferred, inorganic metal salts and inorganic ammonium salts with a valence of 1 or more and 2 or less are more preferred, and ammonium sulfate is even more preferred. The flocculant may be added as it is, but it is preferably dissolved in an aqueous medium and added as an aqueous solution. Further, when the flocculant is added as an aqueous solution, the pH of the flocculant aqueous solution may be adjusted.

[0131] Using a flocculant, for example, to a mixed dispersion containing resin particles X at 0°C or higher and 40°C or lower, and optionally colorant particles and release agent particles, preferably 5 parts by mass or more and 50 parts by mass or less of the flocculant is added per 100 parts by mass of resin particles X, and the resin particles X and the colorant particles are flocculated in an aqueous medium to obtain flocculated particles 1. Further, from the viewpoint of promoting flocculation, it is preferable to raise the temperature of the dispersion after adding the flocculant.

[0132] The volume median diameter D of the flocculated particles 1 obtained in Step 1 50 is preferably 3 μm or more, more preferably 4 μm or more, still more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less. It is preferable to continue the flocculation process until the desired volume median diameter is reached.

[0133] 〔Step 2〕 Step 2 is a step of flocculating resin particles Y containing an amorphous polyester-based resin B with respect to the flocculated particles 1 obtained in Step 1 to obtain flocculated particles 2. ≪Resin particles Y≫ The resin particle dispersion used in Step 2 contains resin particles Y, and the resin particles Y contain an amorphous polyester-based resin B. The content of the amorphous polyester resin B is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and 100% by mass or less, and still more preferably 100% by mass, based on the total amount of the resin components of the resin particles Y.

[0134] (Preparation of the resin particle Y dispersion) The resin particles Y are preferably produced by a method in which a resin component containing the amorphous polyester resin B and optional components such as a surfactant, if necessary, are dispersed in an aqueous medium to obtain a resin particle Y dispersion. As a method for obtaining the resin particle Y dispersion, the same methods as those for the resin particle dispersion of the resin particles X are exemplified. Among these, from the viewpoint of improving the low-temperature fixability of the resulting toner, it is preferable to obtain the resin particle Y dispersion by the phase inversion emulsification method. As in the case of the resin particles X, as the phase inversion emulsification method, a method in which an aqueous medium is added to a solution obtained by dissolving a resin and optional components such as a surfactant in an organic solvent to cause phase inversion emulsification is preferable. Preferred embodiments of the aqueous medium and the organic solvent that can be used are the same as those of the aqueous medium and the organic solvent used for the production of the resin particles X. Further, in the phase inversion emulsification method, the preferable ranges of the mass ratio of the amorphous polyester resin B to the organic solvent, the neutralization degree of the amorphous polyester resin B, the amount of the aqueous medium to be added, the mixing temperature, etc. are the same as those for the production of the resin particles X.

[0135] The solid content concentration of the obtained resin particle Y dispersion is preferably 7% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, still more preferably 25% by mass or less, from the viewpoints of improving the productivity of the toner and the dispersion stability of the resin particles Y. The solid content is the total amount of non-volatile components such as the resin and the surfactant.

[0136] The volume median particle diameter (D of the resin particles Y in the resin particle dispersion 50) is preferably 0.04 μm or more, more preferably 0.06 μm or more, still more preferably 0.08 μm or more, and preferably 0.5 μm or less, more preferably 0.3 μm or less, still more preferably 0.2 μm or less, still more preferably 0.15 μm or less, from the viewpoint of obtaining a toner that can provide a high-quality image.

[0137] Also, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles Y is preferably 5% or more, more preferably 10% or more, still more preferably 15% or more, from the viewpoint of improving the productivity of the resin particle Y dispersion liquid, and preferably 50% or less, more preferably 40% or less, still more preferably 30% or less, still more preferably 25% or less, from the viewpoint of obtaining a toner that can provide a high-quality image. The volume median particle size (D 50 ) and the coefficient of variation (CV value) of the resin particles Y are measured by the method described in the examples.

[0138] In step 2, it is preferable to obtain a dispersion liquid of agglomerated particles 2 by adding a dispersion liquid of resin particles Y to the dispersion liquid of the aforementioned agglomerated particles 1, thereby further attaching the resin particles Y to the agglomerated particles 1.

[0139] Before adding the dispersion liquid of resin particles Y to the dispersion liquid of agglomerated particles 1, an aqueous medium may be added to the dispersion liquid of agglomerated particles 1 for dilution. Also, when adding the dispersion liquid of resin particles Y to the dispersion liquid of agglomerated particles 1, the flocculant may be used in this step in order to efficiently attach the resin particles Y to the agglomerated particles 1. The temperature at the time of adding the dispersion liquid of resin particles Y is preferably 40°C or more, more preferably 45°C or more, still more preferably 50°C or more, and preferably 80°C or less, more preferably 70°C or less, still more preferably 65°C or less, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0140] The resin particle Y dispersion may be added continuously over a certain period of time, added all at once, or added in multiple divided portions. However, it is preferable to add it continuously over a certain period of time or add it in multiple divided portions. By adding it as described above, the resin particles Y are more likely to selectively adhere to the aggregated particles 1. Among them, from the viewpoints of promoting selective adhesion and improving the productivity of the toner, it is preferable to add it continuously over a certain period of time. The time for continuous addition is preferably 1 hour or more, more preferably 1.2 hours or more, and preferably 10 hours or less, more preferably 7 hours or less, still more preferably 3 hours or less, from the viewpoints of obtaining uniform aggregated particles 2 and improving the productivity of the toner.

[0141] The addition amount of the resin particles Y is such that the mass ratio of the resin particles Y to the resin particles X (resin particles Y / resin particles X) is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.12 or more, and preferably 0.9 or less, more preferably 0.5 or less, still more preferably 0.3 or less, still more preferably 0.25 or less, still more preferably 0.2 or less, from the viewpoints of achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0142] The volume median diameter (D 50 ) of the obtained aggregated particles 2 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6.5 μm or less, from the viewpoints of obtaining a toner that can provide high-quality images and achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0143] 〔Step 3〕 Step 3 is a step of heating and fusing the aggregated particles 2 obtained in Step 2 to obtain fused particles. In Step 3, each of the particles that were mainly physically attached to each other in the aggregated particles is fused into one body, and toner particles having a core-shell structure are formed. In this process, from the viewpoint of improving the fusion property of the aggregated particles and achieving both low-temperature fixability and heat-resistant storage stability of the toner, it is maintained at a temperature equal to or higher than the glass transition temperature of the amorphous polyester resin B. The holding temperature in the fusing step is, from the viewpoints of improving the fusion property of the aggregated particles and improving the productivity of the toner, preferably a temperature equal to or higher than 2°C, more preferably 3°C, still more preferably 5°C higher than the glass transition temperature of the amorphous polyester resin B, and preferably a temperature equal to or lower than 30°C, more preferably 25°C, still more preferably 20°C higher than the glass transition temperature of the amorphous polyester resin B. At that time, the holding time at a temperature equal to or higher than the glass transition temperature of the amorphous polyester resin B is preferably 1 minute or more, more preferably 10 minutes or more, still more preferably 30 minutes or more, and preferably 240 minutes or less, more preferably 180 minutes or less, still more preferably 120 minutes or less, still more preferably 90 minutes or less, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner. It is preferable to hold at the above temperature until the desired roundness is achieved.

[0144] The volume median diameter (D 50 ) of the fused particles (core-shell particles) obtained in Step 3 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner. In addition, the volume median diameter of the core-shell particles obtained in Step 3 is preferably equal to or less than the volume median diameter of the aggregated particles 2. That is, in this Step 3, it is preferable that aggregation and fusion of the aggregated particles 2 do not occur.

[0145] 〔Post-treatment step〕 In the present invention, a post-treatment step may be performed after Step 3, and it is preferable to obtain toner particles by isolation. Since the core-shell particles obtained in Step 3 are present in an aqueous medium, it is first preferable to perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used. It is preferable to perform washing after solid-liquid separation. At this time, since it is preferable to remove the added surfactant or the like, when the surfactant has a cloud point, it is preferable to wash with an aqueous medium below the cloud point of the surfactant. It is preferable to perform washing a plurality of times.

[0146] Next, it is preferable to perform drying. The temperature during drying is preferably such that the temperature of the core-shell particles themselves is lower than the glass transition temperature of the amorphous polyester resin A, and more preferably 10°C or lower. As the drying method, a vacuum low-temperature drying method, a vibration-type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like is preferably used.

[0147] [Toner particles] The toner particles obtained by performing drying or the like can be used as they are as a toner for electrostatic charge image development, but it is preferable to use those obtained by treating the surface of the toner particles as a toner for electrostatic charge image development as described below. The volume median diameter (D 50 ) of the toner particles is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less, from the viewpoint of improving the productivity of the toner and achieving both low-temperature fixability and heat-resistant storage stability of the toner. The CV value of the toner particles is preferably 12% or more, more preferably 14% or more, still more preferably 16% or more, from the viewpoint of improving the productivity of the toner, and preferably 32% or less, more preferably 30% or less, still more preferably 29% or less, from the viewpoint of obtaining a high-quality image. The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, still more preferably 0.965 or more, and preferably 0.990 or less, more preferably 0.985 or less, still more preferably 0.980 or less, from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability of the toner.

[0148] 〔External additive〕 The toner particles can be used as toner as they are, but it is preferable to use those obtained by adding a fluidizing agent or the like as an external additive to the surface of the toner particles. Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferable. The external additive may be used alone or in combination of two or more. Also, the same kind of external additives having different particle sizes may be used in combination. When performing surface treatment of the toner particles using an external additive, the addition amount of the external additive is preferably 1 part by mass or more, more preferably 2 parts by mass or more, still more preferably 3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, still more preferably 4 parts by mass or less, based on 100 parts by mass of the toner particles.

[0149] 〔Toner for electrostatic charge image development〕 The toner for electrostatic charge image development obtained as described above can be used as a one-component developer or as a two-component developer by mixing with a carrier.

Examples

[0150] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods. In the notation such as “alkylene oxide (X)”, the numerical value X in parentheses means the average number of moles of addition of the alkylene oxide.

[0151] [Measurement Method] [Acid Value of Resin, and Acid Value and Hydroxyl Value of Hydrocarbon Wax] The acid value of the resin, and the acid value and hydroxyl value of the hydrocarbon wax were measured according to the neutralization titration method described in JIS K 0070:1992. However, chloroform was used as the measurement solvent.

[0152] [Softening Point, Crystallinity Index, Melting Point and Glass Transition Temperature of Resin] (1) Softening Point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6 °C / min, a load of 1.96 MPa was applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. With respect to the temperature, the plunger descent amount of the flow tester was plotted, and the temperature at which half of the sample flowed out was taken as the softening point.

[0153] (2) Crystallinity Index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled to 0 °C at a cooling rate of 10 °C / min. Then the sample was left stationary for 1 minute as it was, and thereafter, the temperature was raised to 180 °C at a heating rate of 10 °C / min and the heat quantity was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (1), and the crystallinity index was determined by (softening point (°C)) / (maximum endothermic peak temperature (1) (°C)).

[0154] (3) Melting Point and Glass Transition Temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, the temperature was raised to 200 °C, and then cooled from that temperature to 0 °C at a cooling rate of 10 °C / min. Then the sample was heated at a heating rate of 10 °C / min and the heat quantity was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (2). In the case of a crystalline resin, the 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 defined as the glass transition temperature. When no peak is observed but a step is observed, the temperature at the intersection of the tangent line indicating the maximum slope of the curve at the step portion and the extension of the baseline on the low-temperature side of the step is defined as the glass transition temperature.

[0155] 〔Melting Point of Film (Film Label)〕 A sample was prepared by peeling the film portion from the release paper, weighing 0.015 g of it into an aluminum pan, heating it to 200 °C, and then cooling it to 0 °C at a cooling rate of 10 °C / min from that temperature. Subsequently, the sample was heated at a heating rate of 10 °C / min, and the heat quantity was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the melting point of the film, which was the maximum peak temperature of the endotherm.

[0156] 〔Melting Point of Untreated Biaxially Oriented Polypropylene Film〕 The melting point of the polypropylene film was measured in the same manner as above, except that the untreated biaxially oriented polypropylene film was used as the sample.

[0157] 〔Weight-Average Molecular Weight of the Addition Polymer E1〕 Using a solution prepared by dissolving phosphoric acid and lithium bromide in N,N-dimethylformamide at concentrations of 60 mmol / L and 50 mmol / L, respectively, as the eluent, gel permeation chromatography [GPC apparatus "HLC-8320GPC" (manufactured by Tosoh Corporation), columns "TSKgel SuperAWM-H", "TSKgel SuperAW3000", "TSKgel guardcolum Super AW-H" (manufactured by Tosoh Corporation), flow rate: 0.5 mL / min], and a monodisperse polystyrene kit 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), manufactured by Tosoh Corporation] as the standard substance, the measurement was carried out.

[0158] 〔Weight-Average Molecular Weight of the Addition Polymer E2〕 Using a solution of 0.2 M phosphate buffer / acetonitrile = 9 / 1 (volume ratio) as the eluent, gel permeation chromatography [GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation, column (PW + G4000PW + G2500PW) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, temperature: 40 °C] was used to measure using polyethylene glycol with a pre-determined weight average molecular weight that is monodisperse as the standard substance.

[0159] 〔Melting point of the release agent〕 Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated up to 200 °C, and then cooled from 200 °C to 0 °C at a cooling rate of 10 °C / min. Next, the sample was heated up at a heating rate of 10 °C / min, the heat quantity was measured, and the maximum peak temperature of the endotherm was taken as the melting point.

[0160] 〔Volume median diameter D of resin particles, colorant particles, and release agent particles 50 and CV value〕 (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: The sample dispersion was placed in the measurement cell, distilled water was added, and from the particle size distribution obtained at a concentration where the absorbance was in the appropriate range, the volume median diameter D 50 and the volume average diameter D V were determined. Also, the CV value (particle size distribution) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average diameter D V ) × 100

[0161] 〔Solid content concentration of resin particle dispersion, colorant particle dispersion, and release agent particle dispersion〕 Using an infrared moisture meter "FD-230" (manufactured by Kett Science Laboratory Co., Ltd.), 5 g of the measurement sample was measured for moisture (mass%) at a drying temperature of 150 °C and a measurement mode of 96 (monitoring time 2.5 minutes, fluctuation range of moisture content 0.05%). The solid content concentration was calculated according to the following formula. Solid content concentration (mass%) = 100 - moisture (mass%)

[0162] 〔Volume median diameter D of aggregated particles 50 〕 The volume median diameter D of aggregated particles 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" (manufactured by Beckman Coulter, Inc.) · Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) · Measurement conditions: By adding the sample dispersion to 100 mL of the electrolyte, the concentration was adjusted to a concentration at which the particle sizes of 30,000 particles could be measured in 20 seconds, and then 30,000 particles were measured. The volume median diameter D 50 was determined from the particle size distribution.

[0163] 〔Circularity of fused particles〕 The circularity of fused particles was measured under the following conditions. · Measuring device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) · Preparation of dispersion: The dispersion of fused particles was diluted with deionized water so that the solid content concentration was 0.001 mass% or more and 0.05 mass% or less. · Measurement mode: HPF measurement mode

[0164] 〔Volume median diameter D 50 and CV value of toner particles〕 The volume median diameter D 50 of toner particles was measured as follows. The measuring device, aperture diameter, analysis software, and electrolyte used were the same as those used in the measurement of the volume median diameter D 50 of the above-mentioned aggregated particles. · Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6) was dissolved in the electrolyte to obtain a dispersion with a concentration of 5 mass%. ·Dispersion conditions: 10 mg of the measurement sample of toner particles after drying was added to 5 mL of the dispersion liquid, and it was dispersed for 1 minute with an ultrasonic disperser. Then, 25 mL of the electrolytic solution was added, and it was further dispersed for 1 minute with an ultrasonic disperser to prepare a sample dispersion liquid. ·Measurement conditions: By adding the sample dispersion liquid to 100 mL of the electrolytic solution, after adjusting the concentration to a level where the particle sizes of 30,000 particles can be measured in 20 seconds, 30,000 particles were measured, and the volume median particle size D 50 and the volume average particle size D V were obtained. Also, the CV value (%) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size D V ) × 100

[0165] 〔Surface tension of PP film and PE film (label film)〕 According to the content described in J. Phys. Chem. C 2012, 116, 14568 - 14574, the surface tension of the printing surface of the PP film and the PE film was calculated. The film (surface substrate) of the label film was peeled off from the release paper and smoothly pasted onto a glass plate. At 25 °C, 2 μL each of ion-exchanged water and diiodomethane (manufactured by FUJIFILM Wako Pure Chemical Corporation) was dropped onto the surface of the film, and the contact angle after 30 seconds was measured using a fully automatic contact angle meter DM - 701 (manufactured by Kyowa Interface Science Co., Ltd.). The average value measured 5 times with each solvent was taken as θw (average value of the contact angle measured with ion-exchanged water) and θd (average value of the contact angle measured with diiodomethane), respectively. From Young-Owens' formula, the obtained θw was substituted into the following formula (1), and θd was substituted into the following formula (2). From formula (1) and formula (2), the non-polar component term (γ a ) and the polar component term (γ b ) of the surface tension of each label were calculated. Then, from the obtained γ a , γ b , the surface tension (γ) was calculated according to the following formula (3). Formula (1): (γ a × γ a w ) 1 / 2 +(γb ×γ b w ) 1 / 2 =0.5×γ w ×(1 + cosθw) Here, the surface tension γ of water w , γ a w , γ b w is as described in Owens, D. K. and Wendt, R. C., J. Appl. Polym. Sci. 1969, 13, 1741 - 1747, γ a w = 21.8 mN / m, γ b w = 51.0 mN / m, γ w = 72.8 mN / m was used. Equation (2): (γ a ×γ a d ) 1 / 2 +(γ b ×γ b d ) 1 / 2 = 0.5×γ d ×(1 + cosθd) Here, the surface tension γ of iodoform d , γ a d , γ b d is as described in Owens, D. K. and Wendt, R. C., J. Appl. Polym. Sci. 1969, 13, 1741 - 1747, γ a d = 49.5 mN / m, γ b d = 1.3 mN / m, γ d = 50.8 mN / m was used. Equation (3): γ = γ a +γ b

[0166] 〔Surface tension of untreated biaxially oriented polypropylene film〕 The surface tension was calculated in the same manner as above, except that the polypropylene film was smoothly attached onto a glass plate.

[0167] [Evaluation] [Scratch resistance (resistance to claw scratching) evaluation] Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Okidata Co., Ltd.), on various film labels (film labels and untreated biaxially stretched polypropylene films) shown in Table 7 cut to A4 size, the toner adhesion amount on the film was 0.43 - 0.45 mg / cm 2 A solid image with this condition was output leaving a 5 mm margin from the upper end of the A4-sized film without fixing at a length of 50 mm. Next, using an external fixing device with variable temperature and rotation speed, the temperature of the external fixing device was set to 105°C, and the toner was fixed at a speed of 3 seconds per sheet in the A4 vertical direction to obtain a label print (equivalent to 20 sheets per minute in the A4 vertical direction). The scratch resistance of the obtained label prints was evaluated as follows. 5: No image defects even after 20 reciprocations with a claw 4: No image defects even after 15 reciprocations with a claw, but image defects such as peeling occur after 20 reciprocations 3: No image defects even after 10 reciprocations with a claw, but image defects such as peeling occur after 15 reciprocations 2: No image defects even after 5 reciprocations with a claw, but image defects such as peeling occur after 10 reciprocations 1: Image defects occur at the stage of 5 reciprocations with a claw

[0168] [Image density of the print] Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Okidata Co., Ltd.), on various film labels (film labels) shown in Table 7 cut to A4 size, the toner adhesion amount on the film was 0.43 - 0.45 mg / cm 2 A solid image with this condition was output leaving a 5 mm margin from the upper end of the A4-sized film without fixing at a length of 50 mm. Next, using an external fixing device with variable temperature and rotation speed, the temperature of the external fixing device was set to 105°C, and the toner was fixed at a speed of 3 seconds per sheet in the A4 vertical direction to obtain a label print (equivalent to 20 sheets per minute in the A4 vertical direction). The label of the printed matter was peeled off and pasted onto high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Data Corporation). Under the condition that the high-quality paper with this label pasted on it was placed on 30 sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Data Corporation), the reflection image density of the solid image part of the printed matter 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), and the values measured at 10 arbitrary points on the image were averaged to obtain the image density. The larger the numerical value, the better the image density. 〔Image density of untreated biaxially stretched polypropylene film printed matter〕 In the same manner as above, toner was printed on biaxially stretched polypropylene, and then under the condition that the obtained printed matter was placed on 30 sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Data Corporation), the reflection image density of the solid image part of the printed matter 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), and the values measured at 10 arbitrary points on the image were averaged to obtain the image density.

[0169] 〔Whiteness of printed matter (Examples 14 to 16, Comparative Example 6)〕 Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Data Corporation), a solid image with a toner adhesion amount of 0.36 to 0.40 mg / cm on various film labels (film labels) in the form of labels shown in Table 7 cut to A4 size was output leaving a 5-mm margin from the upper end of the A4-size film and without fixing at a length of 50 mm. Next, an external fixing device with variable temperature and rotation speed was used, the temperature of the external fixing device was set to 105°C, and the toner was fixed at a speed of 3 seconds per sheet in the A4 vertical direction to obtain a label printed matter (equivalent to 20 sheets per minute in the A4 vertical direction). 2 ​Peel off the label of the printed matter and stick it on the colored coated paper "Manufactured by Hokuriku Kishu Paper Co., Ltd., extra thick, black". Measure the reflection image density of the solid image part 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), and average the values measured at three arbitrary points on the image to obtain the image density. The smaller the numerical value, the higher the whiteness.

[0170] [Manufacture of Resin] [Manufacture of Amorphous Polyester Resin] Production Example A1 (Production of Resin A-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen. 3253 g of a propylene oxide (2.2) adduct of bisphenol A, 1003 g of terephthalic acid, 25 g of tin(II) bis(2-ethylhexanoate), 2.5 g of 3,4,5-trihydroxybenzoic acid, and 394 g of a hydrocarbon wax "Paracol 6490" (manufactured by Nippon Seiro Co., Ltd., acid value 18 mgKOH / g, hydroxyl value 97 mgKOH / g) were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235°C and held at 235°C for 8 hours. Then, the pressure inside the flask was reduced and held at 8 kPa for 1 hour. Thereafter, after cooling to 160°C and returning to atmospheric pressure, while maintaining at 160°C, a mixture of 2139 g of styrene, 535 g of stearyl methacrylate, 107 g of acrylic acid, and 321 g of dibutyl peroxide was added dropwise over 3 hours. Then, after holding at 160°C for 30 minutes, the temperature was raised to 200°C, and the pressure inside the flask was further reduced and held at 8 kPa for 1 hour. Thereafter, after returning to atmospheric pressure, it was cooled to 190°C, 129 g of fumaric acid, 94 g of sebacic acid, 214 g of trimellitic anhydride, and 2.5 g of 4-tert-butylcatechol were added, and the temperature was raised to 210°C at 10°C / hr. Then, the reaction was carried out at 4 kPa until the desired softening point was reached to obtain Resin A-1, which is an amorphous polyester resin. The physical properties are shown in Table 1.

[0171] Production Example A2 (Production of Resin A-2) A resin A-2, which is an amorphous polyester resin, was obtained in the same manner as in Production Example A1 except that the raw material composition was changed as shown in Table 1. The physical properties are shown in Table 1.

[0172] Production Example A3 (Production of Resin A-3) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen, and 3558 g of a propylene oxide (2.2) adduct of bisphenol A, 1416 g of an ethylene oxide (2.2) adduct of bisphenol A, 1229 g of terephthalic acid, 1518 g of dodecenyl succinic anhydride, and 40 g of tin(II) bis(2-ethylhexanoate) were placed therein. While stirring under a nitrogen atmosphere, the temperature was raised to 230 °C and held at 230 °C for 6 hours. Then, the pressure inside the flask was reduced and held at 8.3 kPa for 1 hour. Thereafter, after cooling to 215 °C and returning to atmospheric pressure, 279 g of trimellitic anhydride was added and held at 215 °C for 1 hour. Then, the pressure inside the flask was reduced and held at 8.3 kPa for 3 hours to obtain a resin A-3, which is an amorphous polyester resin. The physical properties are shown in Table 1.

[0173] Production Example B1 (Production of Resin B-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen, and 5001 g of an ethylene oxide (2.2) adduct of bisphenol A, 1788 g of terephthalic acid, 30 g of tin(II) bis(2-ethylhexanoate), and 3.0 g of 3,4,5-trihydroxybenzoic acid were placed therein. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held at 235 °C for 8 hours. Then, the pressure inside the flask was reduced and held at -8 kPa(G) for 1 hour. Thereafter, after returning to atmospheric pressure, it was cooled to 180 °C, and 179 g of fumaric acid, 206 g of dodecenyl succinic anhydride, 325 g of trimellitic anhydride, and 3.8 g of 4-tert-butylcatechol were added. The temperature was raised to 220 °C at 10 °C / hr, and then the pressure inside the flask was reduced, and the reaction was carried out at -10 kPa(G) until the desired softening point was reached to obtain a resin B-1, which is an amorphous polyester resin. The physical properties are shown in Table 1.

[0174] Production Example D1 (Production of Resin D-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen. 4313 g of a propylene oxide (2.2) adduct of bisphenol A, 818 g of terephthalic acid, 727 g of succinic acid, 30 g of tin(II) bis(2-ethylhexanoate), and 3.0 g of 3,4,5-trihydroxybenzoic acid were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held at 235 °C for 5 hours. Then, the pressure inside the flask was reduced and held at 8 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 160 °C and held at 160 °C. While maintaining this state, 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. Then, after holding at 160 °C for 30 minutes, the temperature was raised to 200 °C, and further, the pressure inside the flask was reduced, and the reaction was carried out at 8 kPa until the desired softening point was reached, to obtain Resin D-1, which is an amorphous polyester resin. The physical properties are shown in Table 1.

[0175]

Table 1

[0176] 〔Production of crystalline resin〕 Production Example C1 (Production of Resin C-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen. 3416 g of 1,10-decanediol and 4084 g of sebacic acid were added. While stirring, the temperature was raised to 135 °C and held at 135 °C for 3 hours. Then, it was heated from 135 °C to 200 °C over 10 hours. After that, 23 g of tin(II) bis(2-ethylhexanoate) was added, and after holding at 200 °C for 1 hour, the pressure inside the flask was reduced and held under a reduced pressure of 8.3 kPa for 1 hour to obtain Resin C-1, which is a crystalline polyester resin. The physical properties are shown in Table 2.

[0177] Production Examples C2 to C5 (Production of Resins C-2 to C-5) Resin C-2 to Resin C-5, which are crystalline polyester resins, were obtained in the same manner as in Production Example C1, except that the raw material composition was changed as shown in Table 2. The physical properties are shown in Table 2.

[0178]

Table 2

[0179] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) Into a 3 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 210 g of Resin A-1, 90 g of Resin C-1, 300 g of methyl ethyl ketone, and 49 g of deionized water were placed, and the resin was dissolved at 73°C over 2 hours. To the resulting solution, a 5 mass% aqueous sodium hydroxide solution was added so that the neutralization degree became 50 mol% with respect to the acid value of the resin, 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 with stirring at 280 r / min (peripheral speed 88 m / min) to effect phase inversion emulsification. Subsequently, while maintaining 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 (peripheral speed 63 m / min), the aqueous dispersion was cooled to 30°C, and then deionized water was added so that the solid content concentration became 20 mass% to obtain Resin Particle Dispersion X-1. The volume median diameter D of the obtained resin particles 50 and the CV value are shown in Table 3.

[0180] Production Examples X2 to X7, X51 to X52 (Production of Resin Particle Dispersions X-2 to X-7, X-51 to X-52) Resin Particle Dispersions X-2 to X-7, X-51 to X-52 were obtained in the same manner as in Production Example X1, except that the resin used was changed as shown in Table 3.

[0181] Production Example Y1 (Production of Aqueous Dispersion Y-1 of Resin Particles) In a 3 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 300 g of amorphous resin B-1, 300 g of methyl ethyl ketone, and a mixed solvent of 41 g of deionized water were placed, and the resin was dissolved at 73 °C over 2 hours. To the resulting solution, a 5 mass% aqueous sodium hydroxide solution was added to a neutralization degree of 60 mol% with respect to the acid value of amorphous resin B-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73 °C and stirring at 200 r / min (peripheral speed 63 m / min), 600 g of deionized water was added over 60 minutes to effect phase inversion emulsification. Subsequently, while maintaining 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 (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30 °C, and then deionized water was added to adjust the solid content concentration to 20 mass%, thereby obtaining an aqueous dispersion Y-1 of resin particles. The physical properties are shown in Table 3.

[0182]

Table 3

[0183] Production Example P1 (Production of resin particle dispersion P-1) In a 3 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 200 g of resin D-1 and 200 g of methyl ethyl ketone were placed, and the resin was dissolved at 73 °C over 2 hours. To the resulting solution, a 5 mass% aqueous sodium hydroxide solution was added to a neutralization degree of 60 mol% with respect to the acid value of resin D-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73 °C and stirring at 280 r / min (peripheral speed 88 m / min), 700 g of deionized water was added over 50 minutes to effect phase inversion emulsification. Subsequently, while maintaining 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 (peripheral speed 88 m / min), the aqueous dispersion was cooled to 30 °C, and then deionized water was added to adjust the solid content concentration to 20 mass%, thereby obtaining a resin particle dispersion P-1. The volume median diameter D of the obtained resin particles 50 was 0.09 μm, and the CV value was 23%.

[0184] [Production of Release Agent Particle Dispersion Liquid] Production Example W1 (Production of Release Agent Particle Dispersion Liquid W-1) In a beaker with an internal volume of 1 L, 120 g of deionized water, 86 g of resin particle dispersion liquid P-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added, and the temperature was maintained at 90 to 95°C to melt and stir to obtain a molten mixture. While maintaining the temperature of the obtained molten mixture at 90 to 95°C, it was dispersed using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Co., Ltd.) for 20 minutes and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content concentration to 20% by mass to obtain release agent particle dispersion liquid W-1. The volume median diameter D of the release agent particles in the dispersion liquid 50 was 0.47 μm and the CV value was 27%.

[0185] [Production of Addition Polymer E] Production Example E1 (Synthesis of Addition Polymer E-1) The raw material monomers of the types and amounts shown in Table 4 were mixed to prepare a monomer mixture solution with a total monomer amount of 100 g. The inside of a four-necked flask equipped with a nitrogen inlet tube, a dropping funnel, a stirrer, and a thermocouple was purged with nitrogen, 18 g of methyl ethyl ketone, 0.03 g of 2-mercaptoethanol, and 10% by mass of the monomer mixture solution were put in, and the temperature was raised to 75°C while stirring. While maintaining at 75°C, the remaining 90% by mass of the monomer mixture solution, 0.27 g of 2-mercaptoethanol, 42 g of methyl ethyl ketone, and a mixture of 3 g of 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Wako Pure Chemical Industries, Ltd.) were added dropwise from the dropping funnel over 3 hours. After completion of the dropwise addition, it was maintained at 75°C for 2 hours, then a solution prepared by dissolving 3 g of V-65 in 5 g of methyl ethyl ketone was added, and it was further maintained at 75°C for 2 hours and at 80°C for 2 hours. Thereafter, methyl ethyl ketone was distilled off under reduced pressure to obtain addition polymer E-1. The weight average molecular weight of the obtained addition polymer is shown in Table 4.

[0186] Production Example E2 233 g of water was charged into a 2 L glass reaction vessel equipped with a dropping funnel, and the temperature was raised to 80 °C under a nitrogen atmosphere. Next, under a nitrogen gas atmosphere, as dropping solution 1, a monomer solution of 166 g of methoxypolyethylene glycol methacrylate (average number of moles of ethylene oxide (EO) added, n = 23, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester M-230G") and 34 g of methacrylic acid, as dropping solution 2, 27 g of a 7% aqueous solution of 2-mercaptoethanol, and as dropping solution 3, 32 g of a 6% aqueous solution of ammonium persulfate were each gradually dropped into the reaction vessel over 90 minutes simultaneously. Next, 11 g of a 6% aqueous solution of ammonium persulfate was gradually dropped into the reaction vessel over 30 minutes. After completion of the dropping, it was aged at 80 °C for 1 hour. Then, it was cooled to 40 °C, 13 g of a 48% aqueous solution of sodium hydroxide was added for neutralization (degree of neutralization 40 mol%), and water was added to obtain an aqueous solution of the addition polymer E-2 with a solid content concentration of 40%. The weight average molecular weight of the obtained addition polymer is shown in Table 4.

[0187]

Table 4

[0188] [Production of Coloring Agent Particle Dispersion Liquid] Production Example Z1 (Production of Coloring Agent Particle Dispersion Liquid Z-1) Into a 5 L container equipped with a stirrer with a dispersing blade, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, 75 g of an addition polymer E-1 and 630 g of methyl ethyl ketone were placed, and the resin was dissolved at 20°C. To the resulting solution, 101 g of a 5 mass% aqueous sodium hydroxide solution (the neutralization degree of the addition polymer E-1 becomes 91 mol%) was added, and further 955 g of deionized water was added, followed by stirring at 20°C for 10 minutes with a dispersing blade. Next, 300 g of Pigment Yellow 155 (manufactured by Clariant Chemicals Ltd., "Toner Yellow 3GP-CT", molecular weight 717) was added, and stirring was carried out at 6400 r / min at 20°C for 2 hours with a dispersing blade. Thereafter, it was passed through a 200-mesh filter and treated for 15 passes at a pressure of 150 MPa using a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics). While stirring the resulting dispersion, methyl ethyl ketone and a part of water were removed at 70°C under reduced pressure. After cooling, it was passed through a 200-mesh filter, and deionized water was added so that the solid content concentration became 20 mass% to obtain a colorant particle dispersion Z-1. The volume median diameter D of the obtained colorant particles 50 and the CV value are shown in Table 5.

[0189] Production Example Z2 (Production of Colorant Particle Dispersion Z-2) Into a 250 mL polyethylene bottle, 0.765 g (active ingredient 0.306 g) of an aqueous solution of the addition polymer E-2 (solid content concentration 40%) obtained in Production Example E2, 15 g of titanium oxide (CR-80 manufactured by Ishihara Sangyo Co., Ltd., rutile type, Al, Si-treated, average primary particle diameter 250 nm), and 15.3 g of water were added, and 369 g of zirconia beads (diameter 2 mm) were added, followed by dispersion at 25°C for 8 hours using a tabletop pot mill stand (manufactured by AS ONE Corporation). The zirconia beads were removed using a mesh, and the solid content concentration was adjusted with water to obtain a colorant dispersion Z-2 (solid content concentration 30 mass%). The volume median diameter D of the obtained colorant particles 50 and the CV value are shown in Table 5.

[0190]

Table 5

[0191] [Manufacture of Toner] Preparation of Toner 1 Into a 3 L four-necked flask equipped with a dehydrating tube, a stirring device, and a thermocouple, 500 g of resin particle dispersion liquid X-1, 56 g of mold release agent particle dispersion liquid W-1, 95 g of colorant particle dispersion liquid Z-1, and 10 g of a 15 mass% aqueous sodium dodecylbenzenesulfonate solution "Neoperex G-15" (manufactured by Kao Corporation, an anionic surfactant) were mixed at a temperature of 25°C. Next, while stirring the mixture, an aqueous solution prepared by dissolving 40 g of ammonium sulfate in 568 g of deionized water was added dropwise with a 4.8 mass% aqueous potassium hydroxide solution adjusted to pH 8.6 over 10 minutes at 25°C, and then the temperature was raised to 59°C over 2 hours. The mixture was held at 59°C until the volume median diameter D 50 became 5.5 μm to obtain a dispersion liquid of aggregated particles (1). While maintaining the temperature of the dispersion liquid of the aggregated particles (1) at 59°C, 66 g of resin particle dispersion liquid Y-1 was added dropwise at a rate of 0.7 mL / min to obtain a dispersion liquid of aggregated particles (2). To the obtained dispersion liquid of aggregated particles (2), an aqueous solution obtained by mixing 36 g of sodium polyoxyethylene lauryl ether sulfate "Emal E-27C" (manufactured by Kao Corporation, an anionic surfactant, effective concentration 27 mass%), 313 g of deionized water, and 40 g of 0.1 mol / L sulfuric acid aqueous solution was added. Then, the temperature was raised to 80°C over 1 hour, held at 80°C for 30 minutes, 20 g of 0.1 mol / L sulfuric acid aqueous solution was added, and it was further held at 80°C for 15 minutes. Then, 20 g of 0.1 mol / L sulfuric acid aqueous solution was added again, and the mixture was held at 80°C until the circularity became 0.970 to obtain a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained fused particle dispersion was cooled to 30°C, and the dispersion was suction filtered to separate the solid content. Then, it was washed with deionized water at 25°C and suction filtered at 25°C for 2 hours. Thereafter, using a vacuum isothermal dryer "DRV622DA" (manufactured by ADVANTEC), vacuum drying was performed at 33°C for 24 hours to obtain toner particles. The particle size of the obtained toner particles was 5.6 μm, and the circularity was 0.970. 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size; 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cab-O-Sil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size; 0.012 μm) were put into a Henschel mixer and stirred, and then passed through a 150-mesh sieve to obtain Toner 1. Table 7 shows the content of the crystalline polyester resin in the binder resin of the toner.

[0192] Preparation of Toners 2 to 7 and 51 to 52 Toners 2 to 7 and 51 to 52 were prepared in the same manner as in Example 1, except that the type of the resin particle dispersion used was changed as shown in Table 6.

[0193] Preparation of Toner 8 Into a 5-L four-necked flask equipped with a dehydrating tube, a stirring device, and a thermocouple, 400 g of resin particle dispersion X-1, 72 g of mold release agent particle dispersion W-1, 177 g of colorant dispersion Z-2, 8 g of a 10% by mass aqueous solution of polyoxyethylene (50) lauryl ether "Emulgen 150" (manufactured by Kao Corporation, nonionic surfactant), and 5 g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant) were mixed at a temperature of 25°C. Next, while stirring the mixture, an aqueous solution prepared by dissolving 34 g of ammonium sulfate in 550 g of deionized water and adding 41 g of a 4.8% by mass aqueous solution of potassium hydroxide was added dropwise at 25°C over 10 minutes, and then the temperature was raised to 53°C over 2 hours, and the mixture was maintained at 53°C until the volume median diameter D 50 of the aggregated particles became 5.5 μm to obtain a dispersion of the aggregated particles (1). The dispersion of the aggregated particles (1) was cooled to 50°C, and while maintaining at 50°C, 52 g of the resin particle dispersion Y-1 was added over 100 minutes to obtain a dispersion of aggregated particles (2) in which resin particles were aggregated to the aggregated particles. To the obtained dispersion of the aggregated particles (2), 226 g of sodium polyoxyethylene lauryl ether sulfate “Emal E-27C” (manufactured by Kao Corporation, an anionic surfactant, effective concentration 27% by mass) and 1,584 g of deionized water were added. Thereafter, the temperature was raised to 75°C over 1 hour and held at 75°C until the circularity became 0.970 to obtain a dispersion of fused particles in which the aggregated particles were fused. The obtained dispersion of the fused particles was cooled to 30°C, the dispersion was suction filtered to separate the solid content, washed with deionized water at 25°C, and then vacuum dried at 30°C for 48 hours to obtain toner particles. The obtained toner particles had a particle size of 5.6 μm and a circularity of 0.970. 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica “RY50” (manufactured by Nippon Aerosil Co., Ltd., number average particle size; 0.04 μm), and 1.0 part by mass of hydrophobic silica “Cab-O-Sil (registered trademark) TS720” (manufactured by Cabot Japan Co., Ltd., number average particle size; 0.012 μm) were put into a Henschel mixer and stirred, and passed through a 150-mesh sieve to obtain toner 8. Table 7 shows the content of the crystalline polyester resin in the binder resin of the toner.

[0194]

Table 6

[0195] Examples 1 to 13, Comparative Examples 1 to 5 Using the obtained toner, printing was performed on the labels shown in Table 7 and an untreated biaxially stretched polypropylene film, and the scratch resistance and the image density of the printed matter were evaluated as described above. The results are shown in Table 7 below.

[0196] Examples 14 to 16, Comparative Example 6 Using the obtained toner, printing was performed on the labels shown in Table 7, and the scratch resistance and the whiteness of the printed matter were evaluated as described above. The results are shown in Table 7 below.

[0197]

Table 7-1

[0198]

Table 7-2

[0199] As described above, from the results of the examples and comparative examples, according to the present invention, there is provided an image forming method that is excellent in abrasion resistance and can obtain an image excellent in image density or whiteness with respect to a PP film and a PE film. On the other hand, in Comparative Examples 1 to 3 where the surface tension of the printing surface of the PP film and the PE film does not satisfy the range of the present invention, the abrasion resistance is poor, and sufficient image density cannot be obtained. In Comparative Example 6, the abrasion resistance is poor, and sufficient whiteness cannot be obtained. On the other hand, in Comparative Example 4 where the content of the crystalline polyester resin is less than 5% by mass in the binder resin, the abrasion resistance is poor, and sufficient image density cannot be obtained. In Comparative Example 5 where the SP value of the crystalline polyester resin exceeds 10.1, sufficient image density cannot be obtained.

Claims

1. A method for forming an image on a polypropylene film or a polyethylene film using a toner containing a crystalline polyester resin C in a binder resin, wherein the SP value of the crystalline polyester resin C is 9.0 or more and 10.1 or less, the content of the crystalline polyester resin C in the binder resin is 10% by mass or more and 60% by mass or less, the surface tension of the printing surface of the polypropylene film or the polyethylene film is 40 mN / m or more and 49 mN / m or less, and the fixing temperature is equal to or lower than a temperature 5°C higher than the melting point of the polypropylene film or the polyethylene film, An image forming method.

2. The image forming method according to claim 1, wherein the SP value of the crystalline polyester resin C is 9.7 or less.

3. The image forming method according to claim 1 or 2, wherein the toner further contains an amorphous polyester resin A.

4. The image forming method according to claim 3, wherein the amorphous polyester resin A is at least one selected from a polyester resin which is a polycondensate of an alcohol component and a carboxylic acid component, and an amorphous composite resin containing a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component and an addition polymer resin segment which is an addition polymer of a raw material monomer containing a styrene-based compound.

5. The image forming method according to claim 3 or 4, wherein the amorphous polyester resin A is an amorphous composite resin containing a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component and an addition polymer resin segment which is an addition polymer of a raw material monomer containing a styrene-based compound.

6. The image forming method according to claim 5, wherein the amorphous polyester resin A further contains a structural unit derived from a hydrocarbon wax having at least one of a carboxy group and a hydroxy group in addition to the polyester resin segment and the addition polymer resin segment. Claim 7 The image forming method according to any one of claims 1 to 6, wherein the toner has a core-shell structure. Claim 8 The image forming method according to claim 7, wherein the core portion contains the crystalline polyester resin C. Claim 9 The image forming method according to claim 7 or 8, wherein the core portion contains the amorphous polyester resin A. Claim 10 The image forming method according to any one of claims 7 to 9, wherein the shell portion contains the amorphous polyester resin B.

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