Method for producing toner for developing electrostatic images

Abstract

To provide a toner for electrostatic charge image development which is excellent in low temperature fixability and charge amount distribution, and a method for producing the same.SOLUTION: There are provided [1] a toner for electrostatic charge image development containing toner particles, wherein the toner particles contain a crystalline polyester resin and a silicone-modified polyester resin; and [2] a method for producing a toner for electrostatic charge image development including a step of aggregating and fusing resin particles in an aqueous medium.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a toner for developing electrostatic images. [Background technology]

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of toners for developing electrostatic images that can meet the demands for higher image quality and higher speeds. In particular, toners containing core-shell toner particles have been proposed in order to improve the trade-off between low-temperature fixability and heat-resistant storage stability.

[0003] Patent Document 1 describes a toner for developing electrostatic images that has both excellent low-temperature fixability and heat-resistant storage stability and is also excellent in chargeability, the toner having a core-shell structure, in which a binder resin containing composite resin (A) and crystalline polyester (B) and wax are contained in the core portion, and a binder resin containing polyester resin (C) is contained in the shell portion, and the composite resin (A) contains a segment (a1) made of a polyester resin obtained by polycondensation of an alcohol component containing 80 mol % or more of a propylene oxide adduct of bisphenol A and a polycarboxylic acid component, and a structural unit derived from a styrene-based compound. and a vinyl resin segment (a2) having a carbon number of 8 to 16, wherein the crystalline polyester (B) is a crystalline polyester obtained by polycondensation of an alcohol component containing 80 mol % or more of an α,ω-aliphatic diol having 8 to 16 carbon atoms and a polycarboxylic acid component containing 80 mol % or more of an aliphatic saturated dicarboxylic acid having 8 to 16 carbon atoms, and the polyester resin (C) is a polyester resin obtained by polycondensation of an alcohol component containing 80 mol % or more of an ethylene oxide adduct of bisphenol A and a polycarboxylic acid component. Furthermore, Patent Document 2 discloses an electrophotographic toner composition that contains a binder resin, a colorant, a silicone oil, and a silicone-modified resin for the purpose of improving offset resistance and blocking resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-114934 [Patent Document 2] Japanese Patent Application Publication No. 8-87127 Summary of the Invention [Problem to be solved by the invention]

[0005] Core-shell toners such as those described in Patent Documents 1 and 2 have a shell structure that can prevent components inside the toner from leaking out before fixing. However, as electrophotographic systems are required to have higher image quality and faster speeds, there is room for improvement in order to achieve both faster fixing at low temperatures and better charging performance. The present invention relates to a toner for developing electrostatic images, which has excellent low-temperature fixability and charge distribution, and a method for producing the same. [Means for solving the problem]

[0006] One embodiment of the present invention relates to the following [1] or [2]. [1] A toner for developing electrostatic images, comprising toner particles, the toner particles contain a crystalline polyester resin and a silicone-modified polyester resin; Toner for developing electrostatic images. [2] The method for producing the toner for developing electrostatic images according to [1], comprising a step of aggregating and fusing resin particles in an aqueous medium. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a toner for developing electrostatic images, which has excellent low-temperature fixability and charge amount distribution, and a method for producing the same. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Electrostatic image developing toner and method for producing electrostatic image developing toner] The toner for developing electrostatic images of the present invention (hereinafter also simply referred to as "toner") is a toner for developing electrostatic images containing toner particles, and the toner particles contain a crystalline polyester resin (hereinafter also referred to as crystalline polyester resin C or resin C) and a silicone-modified polyester resin (hereinafter also referred to as silicone-modified polyester resin A or resin A). The method for producing a toner for developing electrostatic images of the present invention includes a step of aggregating and fusing resin particles in an aqueous medium, and the resin particles contain a crystalline polyester resin and a silicone-modified polyester resin within the same or different particles. The toner for developing electrostatic images of the present invention is preferably obtained by the method for producing the toner for developing electrostatic images of the present invention. According to the present invention, there can be provided a toner for developing electrostatic images, which has excellent low-temperature fixability and charge distribution, and a method for producing the same. "Excellent charge distribution" means that the charge distribution is narrow.

[0009] The detailed mechanism by which the above effects are obtained is unknown, but is thought to be as follows. Crystalline polyester resins are effective in improving the low-temperature fixability of toners, but to effectively realize this effect, it is important to finely disperse the crystalline polyester. Also, from the viewpoint of charging characteristics, it is undesirable for hydrophobic components to be exposed on the surface of toner particles. On the other hand, it is believed that the silicone-modified polyester resin forms nano-domains derived from silicone chains in the toner particles. Because the crystalline polyester resin is hydrophobic, it is finely dispersed together with the silicone nano-domains, and since the crystalline polyester remains inside the toner even if the toner particles do not have a core-shell structure, it is believed that the amount of crystalline polyester and silicone chains present on the toner surface is small. In particular, when toner particles are produced by a production method that includes an aggregation step and a fusion step of resin particles in an aqueous medium, as in the preferred production method of the toner of the present invention, it is believed that the hydrophobic component is present inside the resin particles in water, and that the silicone chains and the silicone nano-domains associated therewith, and the crystalline polyester resin are also present inside the resin particles, and as described above, the obtained toner particles have finely dispersed crystalline polyester resin, while the amount of crystalline polyester resin and silicone chains present on the toner surface is low. As a result, it is believed that a toner for developing electrostatic images having good low-temperature fixing properties and excellent charge distribution can be obtained.

[0010] The definitions of various terms used in this specification are shown below. Whether a resin is crystalline or amorphous is determined by its crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the endothermic maximum peak temperature (softening point (°C) / endothermic maximum peak temperature (°C)) measured by the method described in the Examples below. A crystalline resin is one with a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or, if an endothermic peak is observed, one with a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be adjusted appropriately by adjusting the types and ratios of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. In the specification, the carboxylic acid component of the polyester resin includes not only the compound itself, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). Volume median particle size (D 50 )" is the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle size. The coefficient of variation of particle size distribution (hereinafter also simply referred to as "CV value") is a value expressed by the following formula: The volume average particle size in the formula is the particle size obtained by multiplying the particle size of all measured particles by the volume of that particle, and then dividing the sum by the total volume of the measured particles. CV value (%) = [Standard deviation of particle size distribution (μm) / Volume average particle size (μm)] x 100 The term "carboxylic acid compound" includes not only the carboxylic acid itself, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (the alkyl group has 1 to 3 carbon atoms). "Bisphenol A" is 2,2-bis(4-hydroxyphenyl)propane. The term "binder resin" refers to resin components contained in the toner, including resin A, as well as resin B and resin C, which will be described later.

[0011] [Toner for developing electrostatic images] The electrostatic image developing toner of the present invention contains toner particles, and preferably contains an external additive in addition to the toner particles. That is, the toner particles are toner base particles obtained by excluding the external additive from the electrostatic image developing toner. The toner for developing electrostatic images of the present invention is a dry toner. <Toner particles> The toner particles contain a crystalline polyester resin (resin C) and a silicone-modified polyester resin (resin A). The toner particles may have a core-shell structure, and when the toner particles have a core-shell structure, it is preferable that the core portion contains resin C and resin A, and it is more preferable that only the core portion contains resin C and resin A. When the toner particles have a core-shell structure, the binder resin of the shell portion is not particularly limited, but preferably contains an amorphous polyester resin (hereinafter also referred to as amorphous polyester resin B or resin B). The toner particles may contain other additives such as a release agent, a colorant, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, an antiaging agent, a cleaning property improver, etc. The toner particles preferably contain at least a release agent and a colorant. Furthermore, when the toner particles have a core-shell structure, it is preferable that the core portion contains at least a release agent and a colorant.

[0012] (Silicone-modified polyester resin (Resin A)) In the toner of the present invention, the toner particles contain a silicone-modified polyester resin (resin A). Resin A is a silicone-modified polyester resin from the viewpoint of obtaining a toner excellent in low-temperature fixability and charge distribution. Resin A is preferably a reaction product of an alcohol component containing a divalent or higher alcohol, a carboxylic acid component containing a divalent or higher carboxylic acid compound, and a modified silicone having a hydroxy group, a carboxy group, or an epoxy group at one or both ends.

[0013] <Alcohol content> The alcohol component includes dihydric or higher alcohols. The content of dihydric or higher alcohol in the alcohol component is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and 100% by mass or less. Examples of dihydric or higher alcohols include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols and linear or branched aliphatic diols are preferred, and alkylene oxide adducts of aromatic diols are more preferred.

[0014] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I): [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 are each independently an ethylene group or a propylene group, x and y are each a positive number that indicates the average number of moles of alkylene oxide added, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, and more preferably 4 or less.

[0015] Examples of alkylene oxide adducts of bisphenol A include propylene oxide adducts of bisphenol A and ethylene oxide adducts of bisphenol A. One or more of these may be used. Among these, a combination of a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A is preferred. The molar ratio of the propylene oxide adduct of bisphenol A to the ethylene oxide adduct of bisphenol A (propylene oxide adduct of bisphenol A / ethylene oxide adduct of bisphenol A) is preferably 10 / 90 or more, more preferably 30 / 70 or more, even more preferably 50 / 50 or more, even more preferably 70 / 30 or more, and is preferably 95 / 5 or less, more preferably 90 / 10 or less. When an alkylene oxide adduct of bisphenol A is contained, the amount thereof is preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol% in the alcohol component.

[0016] As the linear or branched aliphatic diol, an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is preferred. The aliphatic diol having a hydroxyl group bonded to a secondary carbon atom preferably has 3 or more and 4 or less carbon atoms. Examples of aliphatic diols having a hydroxyl group bonded to a secondary carbon atom include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, and 2,3-butanediol. When an aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is used as the alcohol component, the amount thereof in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0017] Other linear or branched aliphatic diols include, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol.

[0018] Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and adducts of hydrogenated bisphenol A with alkylene oxides having 2 to 4 carbon atoms (average number of added moles: 2 to 12). Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0019] <Carboxylic acid component> The carboxylic acid component includes a divalent or higher carboxylic acid compound. The content of the divalent or higher carboxylic acid compound in the carboxylic acid component is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, and is 100% by mass or less. Examples of divalent or higher carboxylic acid compounds include aromatic dicarboxylic acid compounds, linear or branched aliphatic dicarboxylic acid compounds, alicyclic dicarboxylic acid compounds, and trivalent or higher polycarboxylic acid compounds. Among these, aromatic dicarboxylic acid compounds are preferred.

[0020] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, and is 100 mol% or less, preferably 85 mol% or less, even more preferably 70 mol% or less.

[0021] The number of carbon atoms in the linear or branched aliphatic dicarboxylic acid compound is preferably 2 or more, more preferably 4 or more, even more preferably 8 or more, and even more preferably 10 or more, and is preferably 22 or less, more preferably 16 or less. Examples of linear or branched aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms, or anhydrides or alkyl esters having from 1 to 3 carbon atoms. Examples of succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms, or anhydrides thereof, are preferred. When a linear or branched aliphatic dicarboxylic acid compound is contained, the amount thereof is preferably 3 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and preferably 50 mol% or less, more preferably 40 mol% or less, even more preferably 30 mol% or less, of the carboxylic acid component.

[0022] The trivalent or higher polyvalent carboxylic acid compound is preferably a trivalent carboxylic acid, such as trimellitic acid or its anhydride, of which trimellitic acid or its anhydride is preferred. When a trivalent or higher polycarboxylic acid compound is contained, the amount of the trivalent or higher polycarboxylic acid compound in the carboxylic acid component is preferably 1 mol% or more, more preferably 5 mol% or more, even more preferably 10 mol% or more, and is preferably 35 mol% or less, more preferably 30 mol% or less. These carboxylic acid compounds may be used alone or in combination of two or more.

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

[0024] <Modified silicone> The modified silicone used in Resin A reacts with at least one of an alcohol component and a carboxylic acid component, and from the viewpoint of obtaining an electrophotographic toner excellent in low-temperature fixing property and charge amount distribution, it is preferably a modified silicone having a hydroxy group, a carboxy group, or an epoxy group on a side chain, one end, or both ends, and more preferably a modified silicone having a hydroxy group, a carboxy group, or an epoxy group on one end or both ends.

[0025] More specifically, the modified silicone is preferably a compound represented by the formula (1): [ka] [In the formula, each R is independently a hydrocarbon group having from 1 to 6 carbon atoms, each R' is independently an alkylene group having from 1 to 10 carbon atoms, each R'' is independently a hydrocarbon group having from 1 to 10 carbon atoms, each X is independently a hydroxy group, a hydroxyalkyloxy group, a carboxy group, a carboxyalkyloxy group, an epoxy group, a glycidyl group, a glycidyloxy group, or an alicyclic epoxy group, s is an integer of from 1 to 3, t is an integer of from 0 to 3, and n is an integer of from 5 to 300.]

[0026] The hydrocarbon group of R has 6 or less carbon atoms, preferably 5 or less, more preferably 4 or less, even more preferably 3 or less, even more preferably 2 or less, and even more preferably 1 carbon atom. Examples of hydrocarbon groups for R include methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, pentyl, and phenyl groups. Among these, methyl is preferred. The alkylene group of R' has 10 or less carbon atoms, preferably 8 or less, more preferably 5 or less, even more preferably 4 or less, still more preferably 3 or less carbon atoms, and preferably 1 or more, more preferably 2 or more carbon atoms. Examples of the alkylene group represented by R' include methanediyl, ethane-1,2-diyl, ethane-1,1-diyl, n-propane-1,3-diyl, n-propane-1,2-diyl, 2-methylethane-1,2-diyl, 1,4-n-butyl, 1,2-tert-butyl, and 1,5-pentyl. Among these, ethane-1,2-diyl, n-propane-1,3-diyl, and n-propane-1,2-diyl are preferred, with n-propane-1,2-diyl being more preferred. The hydrocarbon group of R'' has 10 or less carbon atoms, preferably 8 or less, more preferably 6 or less, even more preferably 4 or less, even more preferably 3 or less, even more preferably 2 or less, and even more preferably 1 carbon atom. Examples of the hydrocarbon group for R'' include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, and a benzyl group.

[0027] X is a hydroxy group, a hydroxyalkyloxy group, a carboxy group, a carboxyalkyloxy group, an epoxy group, a glycidyl group, a glycidyloxy group, or an alicyclic epoxy group. The hydroxyalkyloxy group and the hydroxyalkyloxy group may have multiple hydroxy groups. The carboxyalkyloxy group may have multiple carboxy groups. s is 3 or less, preferably 2 or less, and more preferably 1. t is 3 or less, preferably 2 or less, and more preferably 0 or 1. n is 300 or less, preferably 200 or less, more preferably 100 or less, and even more preferably 50 or less, and is 5 or more, preferably 8 or more, and more preferably 10 or more.

[0028] The weight average molecular weight (Mw) of the modified silicone is preferably 600 or more, more preferably 800 or more, even more preferably 1,000 or more, and preferably 20,000 or less, more preferably 10,000 or less, even more preferably 7,000 or less, even more preferably 6,000 or less, even more preferably 5,000 or less, even more preferably 4,000 or less. The number average molecular weight (Mn) of the modified silicone is preferably 500 or more, more preferably 700 or more, even more preferably 800 or more, and preferably 10,000 or less, more preferably 5,000 or less, even more preferably 4,000 or less, even more preferably 3,000 or less.

[0029] The kinematic viscosity of the modified silicone is preferably 10 mm at 25°C. 2 / s or more, preferably 15 mm 2 / s or more, more preferably 20 mm 2 / s or more, and preferably 500 mm 2 / s or less, preferably 400 mm 2 / s or less, more preferably 300 mm 2 / s or less. The kinematic viscosity of the modified silicone is measured at 25°C using a fully automatic micro kinematic viscometer (manufactured by Viscotec Co., Ltd.).

[0030] The functional group equivalent weight of the modified silicone is preferably 300 g / mol or more, more preferably 500 g / mol or more, even more preferably 700 g / mol or more, and is preferably 5,000 g / mol or less, more preferably 4,000 g / mol or less, even more preferably 3,000 g / mol or less. The functional group equivalent weight means the mass of the modified silicone per mole of the functional group.

[0031] As the modified silicone used in Resin A, from the viewpoint of obtaining a toner excellent in low-temperature fixing property and charge amount distribution, a modified silicone (a) having a hydroxy group at one or both ends (hereinafter also simply referred to as "modified silicone (a)") is preferred. That is, the modified silicone (a) is preferably a compound represented by the formula (1a): [ka] [wherein R, R', R'', s, t and n are defined as in the above formula (1). X 1 are each independently a hydroxy group or a hydroxyalkyloxy group.

[0032] The hydroxyalkyloxy group may have a plurality of hydroxy groups. The number of carbon atoms in the hydroxyalkyl group is preferably 10 or less, more preferably 8 or less, and even more preferably 6 or less. R'X 1 Examples of the group represented by the formula include the following substituents 2a-1 to 2a-3. Among these, the substituent 2a-1 or the substituent 2a-2 is preferred, and the substituent 2a-1 is more preferred. * is a bonding site with Si.

[0033] [ka]

[0034] The modified silicone (a) preferably has a hydroxy group at one end from the viewpoint of further improving low-temperature fixability and charge distribution. That is, the modified silicone (a) preferably has a hydroxy group at one end from the viewpoint of further improving low-temperature fixability and charge distribution. 1 That is, in the above formula (1a), s is 1 and t is 0. Examples of modified silicones (a) include silicones modified with carbinol at both ends (commercially available products include "X-22-160AS," "KF-6000," "KF-6001," "KF-6002," and "KF-6003" (all manufactured by Shin-Etsu Chemical Co., Ltd.)), and silicones modified with carbinol at one end (commercially available products include "X-22-170BX," "X-22-170DX," "X-22-176DX," and "X-22-176GX-A" (all manufactured by Shin-Etsu Chemical Co., Ltd.)).

[0035] As the modified silicone used in the resin A, from the viewpoint of obtaining a toner excellent in low-temperature fixability and charge amount distribution, modified silicone (b) having an epoxy group at one or both ends is also preferred. In other words, the modified silicone (b) is Preferably, the compound of formula (1b): [ka] [wherein R, R', R'', s, t and n are defined as in the above formula (1). X 2 are each independently an epoxy group, a glycidyl group, a glycidyloxy group, or an alicyclic epoxy group.

[0036] R'X 2 Examples of the group represented by the formula include the following substituents 2b-1 to 2b-3. Among these, the substituent 2b-1 is preferred.

[0037] [ka]

[0038] Examples of modified silicones (b) include silicones modified at both ends with epoxy groups (commercially available products include "KF-105," "X-22-163A," "X-22-163B," "X-22-163C," "X-22-169AS," and "X-22-169B" (all manufactured by Shin-Etsu Chemical Co., Ltd.)), and silicones modified at one end with epoxy groups (commercially available products include "X-22-173BX" and "X-22-173DX" (all manufactured by Shin-Etsu Chemical Co., Ltd.)).

[0039] As the modified silicone used in the resin A, from the viewpoint of obtaining a toner excellent in low-temperature fixability and charge amount distribution, modified silicone (c) having a carboxy group at one or both ends is also preferred.

[0040] That is, the modified silicone (c) is preferably a compound represented by the formula (1c): [ka] [wherein R, R', R'', s, t and n are defined as in the above formula (1). X 3 are each independently a carboxy group or a carboxyalkyloxy group. R'X 3 Examples of the group represented by the formula include the following substituent 2c-1.

[0041] [ka]

[0042] Examples of modified silicones (c) include silicones modified with carboxyl groups at both ends (commercially available products include "X-22-162C" and "BY16-750" manufactured by Shin-Etsu Chemical Co., Ltd.), and silicones modified with carboxyl groups at one end (commercially available product includes "X-22-3710" manufactured by Shin-Etsu Chemical Co., Ltd.).

[0043] The amount of modified silicone in the raw materials for resin A is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, even more preferably 4% by mass or more, relative to the total amount of the alcohol component, carboxylic acid component, and modified silicone, because this further improves low-temperature fixability and charge distribution, and is preferably 9% by mass or less, more preferably 7% by mass or less, even more preferably 6% by mass or less.

[0044] In the raw materials for Resin A, the total amount of the alcohol component and the carboxylic acid component relative to the total amount of the alcohol component, the carboxylic acid component, and the modified silicone is preferably 91% by mass or more, more preferably 93% by mass or more, even more preferably 94% by mass or more, and is preferably 99.9% by mass or less, more preferably 99% by mass or less, even more preferably 98% by mass or less.

[0045] The above amounts are calculated based on the alcohol component, carboxylic acid component, and modified silicone, and do not take into account the amount of water removed by condensation. When the modified silicone has a hydroxy group or a carboxy group, it can also be understood as an alcohol component or a carboxylic acid component, but when a compound having a hydroxy group or a carboxy group contains a silicone skeleton, it is considered to be a modified silicone. For example, when calculating the total amount of the alcohol component and the carboxylic acid component, the modified silicone having a hydroxy group or a carboxy group is not included in this total amount.

[0046] <Physical properties of Resin A> The number average molecular weight of Resin A is preferably 800 or more, and from the viewpoint of obtaining an excellent charge amount distribution, more preferably 1,500 or more, and even more preferably 3,000 or more, and is preferably 30,000 or less, more preferably 20,000 or less, and from the viewpoint of obtaining excellent low-temperature fixability, it is more preferably 10,000 or less, more preferably 7,000 or less, and even more preferably 5,000 or less.

[0047] The acid value of Resin A is preferably 0.1 mgKOH / g or more, more preferably 1 mgKOH / g or more, even more preferably 5 mgKOH / g or more, even more preferably 10 mgKOH / g or more, and is preferably 50 mgKOH / g or less, more preferably 40 mgKOH / g or less, even more preferably 30 mgKOH / g or less.

[0048] From the viewpoint of further improving low-temperature fixability and charge distribution, the softening point of Resin A is preferably 70°C or higher, more preferably 90°C or higher, even more preferably 110°C or higher, and is preferably 150°C or lower, more preferably 140°C or lower, even more preferably 130°C or lower.

[0049] The glass transition temperature of Resin A is preferably 40°C or higher, more preferably 45°C or higher, and even more preferably 50°C or higher, from the viewpoint of further improving low-temperature fixability and charge amount distribution, and is preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 60°C or lower, from the viewpoint of further improving low-temperature fixability.

[0050] The number average molecular weight, acid value, softening point, and glass transition temperature of Resin A can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values can be determined by the methods described in the examples. When two or more resins A are used in combination, it is preferable that the number average molecular weight, acid value, hydroxyl value, softening point, and glass transition temperature obtained as a mixture thereof each fall within the above-mentioned ranges.

[0051] <Manufacturing method of resin A> Resin A can be obtained, for example, by reacting an alcohol component, a carboxylic acid component, and a modified silicone. If necessary, the reaction may be carried out using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropylate bistriethanolamine in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the alcohol component and the carboxylic acid component combined, or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the alcohol component and the carboxylic acid component combined. The reaction temperature is preferably 120°C or higher, more preferably 160°C or higher, even more preferably 180°C or higher, and is preferably 250°C or lower, more preferably 240°C or lower. The reaction may be carried out in an inert gas atmosphere.

[0052] From the viewpoint of further improving the low-temperature fixability and charge amount distribution of the toner, the content of resin A in the binder resin of the toner particles is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, and is 90% by mass or less, more preferably 85% by mass or less.

[0053] (Crystalline polyester resin (resin C)) The toner of the present invention contains a crystalline polyester resin (resin C) in the toner particles. When the toner particles have a core-shell structure, it is preferable that the core portion contains the crystalline polyester resin (resin C), and it is preferable that only the core portion contains the resin C.

[0054] Resin C is, for example, a crystalline polyester resin that is a polycondensation product of an alcohol component and a carboxylic acid component. Resin C is a polycondensate of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol preferably has 2 or more carbon atoms, more preferably 4 or more carbon atoms, and even more preferably 6 or more carbon atoms, and preferably has 16 or less carbon atoms, more preferably 14 or less carbon atoms, and even more preferably 12 or less carbon atoms. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, 1,6-hexanediol, 1,8-octanediol, and 1,10-decanediol are more preferred, and 1,6-hexanediol and 1,10-decanediol are even more preferred.

[0055] The amount of α,ω-aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0056] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols, such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0057] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 8 or more carbon atoms, and even more preferably 10 or more carbon atoms, and preferably has 14 or less carbon atoms, more preferably 12 or less carbon atoms. Examples of aliphatic dicarboxylic acids include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid and tetradecanedioic acid are preferred. These carboxylic acid components may be used alone or in combination of two or more.

[0058] The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0059] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and polycarboxylic acids having three or more carboxylic acids. These carboxylic acid components may be used alone or in combination.

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

[0061] Resin C is produced, for example, by a method of polycondensing an alcohol component and a carboxylic acid component. During polycondensation, the above-mentioned esterification catalyst may be used in the above-mentioned amount, and the above-mentioned esterification co-catalyst may be used in the above-mentioned amount, if necessary. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, the above-mentioned radical polymerization inhibitor may be used in the above-mentioned amount, if necessary. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, and more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0062] <Physical properties of Resin C> From the viewpoint of the storage stability of the toner, the softening point of Resin C is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 120°C or lower, even more preferably 100°C or lower, and even more preferably 95°C or lower. From the viewpoint of the storage stability of the toner, the melting point of Resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 100°C or lower, more preferably 90°C or lower, even more preferably 85°C or lower, and even more preferably 80°C or lower.

[0063] The acid value of Resin C is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less, even more preferably 20 mgKOH / g or less.

[0064] The softening point, melting point, and acid value of resin C can be appropriately adjusted by the type and amount of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the Examples below. When two or more crystalline polyester resins C are used in combination, it is preferable that the softening point, melting point, and acid value of the mixture thereof each fall within the above-mentioned ranges.

[0065] The mass ratio of resin C to resin A in the toner particles [resin C / resin A] is preferably 3 / 97 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, even more preferably 15 / 85 or more, and is preferably 50 / 50 or less, more preferably 40 / 60 or less, even more preferably 35 / 65 or less.

[0066] (Amorphous polyester resin (Resin B)) When the toner particles have a core-shell structure, the shell portion preferably contains an amorphous polyester resin (resin B). The amorphous polyester resin (resin B) is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of amorphous polyester resins include polyester resins and modified polyester resins. Examples of modified polyester resins include urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition-polymerized resin segments. Among these, preferred are polyester resins that are polycondensates of alcohol components and carboxylic acid components, or amorphous composite resins that contain polyester resin segments that are polycondensates of alcohol components and carboxylic acid components and addition-polymerized resin segments that are addition-polymerized raw material monomers containing styrene-based compounds, and more preferred are polyester resins that are polycondensates of alcohol components and carboxylic acid components.

[0067] Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of obtaining a toner with excellent low-temperature fixing properties. Examples of alkylene oxide adducts of aromatic diols include those exemplified for resin A.

[0068] Examples of alkylene oxide adducts of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination. Among these, the ethylene oxide adduct of bisphenol A is preferred. The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0069] Examples of the linear or branched aliphatic diol, alicyclic diol, and trihydric or higher polyhydric alcohol are the same as those exemplified for the resin A above, and the preferred ranges are also the same. These alcohol components may be used alone or in combination of two or more.

[0070] Examples of the carboxylic acid component include dicarboxylic acids and trivalent or higher polycarboxylic acids. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. Examples of aromatic dicarboxylic acids include those exemplified above for Resin A. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, even more preferably 60 mol% or more, and is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less.

[0071] Examples of linear or branched aliphatic dicarboxylic acids include those exemplified above for Resin A. Among these, fumaric acid, sebacic acid, and succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms are preferred, and fumaric acid and succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms are more preferred. The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 10 mol% or more, and is preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 40 mol% or less, even more preferably 25 mol% or less.

[0072] Examples of trivalent or higher polycarboxylic acids include those exemplified above for resin A. Trimellitic acid or its anhydride is preferred. When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0073] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0074] Resin B may be produced, for example, in step A by polycondensing an alcohol component and a carboxylic acid component. In step A, if necessary, polycondensation may be carried out using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxybis(triethanolaminate) in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, and more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0075] <Physical properties of Resin B> The softening point of Resin B is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 110°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 135°C or lower, and even more preferably 125°C or lower. The glass transition temperature of Resin B is preferably 30°C or higher, more preferably 45°C or higher, and even more preferably 55°C or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower.

[0076] The acid value of Resin B is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less. The softening point, glass transition temperature, and acid value of Resin B can be appropriately adjusted by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values can be determined by the methods described in the examples. When two or more resins B are used in combination, the softening point, glass transition temperature and acid value of the resulting mixture are preferably within the above-mentioned ranges.

[0077] The content of resin B relative to the total amount of binder resin in the shell portion is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and is 100% by mass or less, even more preferably 100% by mass.

[0078] The amount of the shell part is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, even more preferably 8 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, when the mass of the core part is 100 parts by mass.

[0079] (coloring agent) In this embodiment, the toner particles preferably contain a colorant, and when the toner particles have a core-shell structure, it is more preferable that the core portion contains the colorant. As the coloring component of the colorant, any of the dyes and pigments used as colorants for toners can be used, with pigments being preferred among these. Examples of coloring components of the colorant include carbon black, phthalocyanine blue (e.g., pigment blue 15:3), permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow (e.g., pigment yellow 155). The toner may be either black toner or a color toner other than black. The content of the coloring component in the toner particles is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

[0080] The colorant is preferably a coloring component whose dispersion is stabilized by a surfactant or a polymer, and more preferably a colorant whose dispersion is stabilized by a polymer. That is, the colorant preferably contains a pigment and a polymer, and the polymer functions as a dispersant and preferably coats at least a portion of the pigment, and more preferably coats the entire pigment. Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. From the viewpoint of improving the dispersion stability of the colorant, anionic surfactants are preferred. Examples of the anionic surfactant include dodecylbenzenesulfonate, dodecyl sulfate, lauryl ether sulfate, and alkenyl succinate. Among these, dodecylbenzenesulfonate is preferred. The polymer may be any polymer that can be used as a polymer dispersant for pigments, such as vinyl polymers, polyesters, and polyurethanes. Commercially available dispersions of polymer particles may also be used. Among these, the polymer contained in the colorant is preferably an addition polymer (hereinafter also referred to as "addition polymer E") of raw material monomers including an addition polymerizable monomer having an anionic group and an addition polymerizable monomer having a polyalkylene oxide group.

[0081] ≪Addition polymer E≫ Addition polymer E is an addition polymer of raw material monomers including an addition polymerizable monomer having an anionic group (hereinafter also referred to as "monomer a") and an addition polymerizable monomer having a polyalkylene oxide group (hereinafter also referred to as "monomer b"). In addition to monomer a and monomer b, the raw material monomers of addition polymer E preferably contain an addition polymerizable monomer having an aromatic group (hereinafter also referred to as "monomer c"), and more preferably further contain a macromonomer (hereinafter also referred to as "monomer d").

[0082] The anionic group in the monomer a means a group that undergoes ion dissociation in water to exhibit anionic properties. Examples of the anionic group include a carboxy group, a sulfo group, a phosphate group, or salts thereof. As the anionic group, an acidic group or a salt thereof is preferred, a carboxy group, a sulfo group or a salt thereof is more preferred, and a carboxy group or a salt thereof is even more preferred. Examples of addition polymerizable monomers having a carboxy group include (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and 2-methacryloyloxymethylsuccinic acid. Among these, (meth)acrylic acid is preferred as the addition polymerizable monomer having an anionic group, and methacrylic acid is more preferred. The amount of monomer a in the raw material monomers of addition polymer E is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less.

[0083] The average number of moles of alkylene oxide added in the polyalkylene oxide group of monomer b is preferably 1 or more, more preferably 2 or more, even more preferably 3 or more, and preferably 30 or less, more preferably 20 or less, even more preferably 10 or less. Monomer b is preferably non-ionic. Examples of monomer b 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. The amount of monomer b in the raw material monomers of addition polymer E is preferably 3% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less.

[0084] The addition-polymerizable monomer c having an aromatic group is preferably nonionic. Examples of the addition-polymerizable monomer c having an aromatic group include a styrene-based compound c-1 and an aromatic group-containing (meth)acrylate c-2. Examples of the styrene-based compound c-1 include substituted or unsubstituted styrene. Examples of the substituent substituted on styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, or a salt thereof. The molecular weight of the styrene-based compound c-1 is preferably 1,000 or less, more preferably 800 or less, even more preferably 500 or less, even more preferably 300 or less, and preferably 80 or more, more preferably 90 or more, even more preferably 100 or more. Examples of the styrene-based compound c-1 include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene is preferred. From the viewpoint of further improving image quality, the amount of the styrene-based compound c-1 in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 10% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and is preferably 90% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less.

[0085] Examples of the aromatic group-containing (meth)acrylate c-2 include benzyl (meth)acrylate and phenoxyethyl (meth)acrylate. The molecular weight of the aromatic group-containing (meth)acrylate c-2 is preferably 1,000 or less, more preferably 800 or less, even more preferably 500 or less, even more preferably 300 or less, and preferably 160 or more. When an aromatic group-containing (meth)acrylate c-2 is used, from the viewpoint of further improving image quality, the content of the aromatic group-containing (meth)acrylate c-2 in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less.

[0086] From the viewpoint of further improving image density, the amount of the addition polymerizable monomer c having an aromatic group in the raw material monomers of the addition polymer E is preferably 1% by mass or more, more preferably 10% by mass or more, even more preferably 30% by mass or more, even more preferably 35% by mass or more, and is preferably 90% by mass or less, more preferably 70% by mass or less, even more preferably 50% by mass or less.

[0087] Examples of the monomer d include a styrene compound polymer having an addition polymerizable functional group at one end (hereinafter also referred to as a "styrene macromonomer"). Examples of the addition polymerizable functional group include a vinyl group, an allyl group, and a (meth)acryloyl group. Among these, a (meth)acryloyl group is preferred. In the monomer d, the styrene-based compound is preferably styrene. The number average molecular weight of the 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 dodecyldimethylamine as a solvent and polystyrene as a standard substance. Commercially available styrene macromonomers include, for example, "AS-6," "AS-6S," "AN-6," "AN-6S," "HS-6," and "HS-6S" (all manufactured by Toagosei Co., Ltd.). When monomer d is contained, the amount of monomer d in the raw material monomers of addition polymer E is preferably 3% by mass or more, more preferably 6% by mass or more, even more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less.

[0088] Furthermore, the raw material monomers of the addition polymer E may contain addition polymerizable monomers (other monomers) other than the monomers a to d. 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 the other monomers in the raw material monomers of the addition polymer E is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less.

[0089] From the viewpoint of further improving image density, the weight-average molecular weight of addition polymer E is preferably 3,000 or more, more preferably 5,000 or more, even more preferably 20,000 or more, even more preferably 40,000 or more, even more preferably 48,000 or more, and is preferably 200,000 or less, more preferably 90,000 or less, even more preferably 60,000 or less, even more preferably 53,000 or less. The weight-average molecular weight can be measured by the method described in the examples.

[0090] The addition polymer E can be produced, for example, by copolymerizing raw material monomers by a known polymerization method, preferably a solution polymerization method in which raw material monomers are polymerized by heating in a solvent together with a polymerization initiator, a polymerization chain transfer agent, etc. Examples of the polymerization initiator 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 polymerization initiator added is preferably 0.5 parts by mass or more and preferably 30 parts by mass or less based on 100 parts by mass of the raw material monomer. 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 amount of the polymerization chain transfer agent added is preferably 0.01 parts by mass or more and preferably 10 parts by mass or less, based on 100 parts by mass of the raw material monomer. After the polymerization reaction is completed, the produced polymer may be isolated and purified by a known method such as reprecipitation from the reaction solution or distillation of the solvent.

[0091] In the colorant, the mass ratio of the coloring component (preferably a pigment) to the addition polymer E (coloring component / addition polymer E) is preferably 50 / 50 or more, more preferably 60 / 40 or more, even more preferably 70 / 30 or more, even more preferably 75 / 25 or more, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, even more preferably 85 / 15 or less, from the viewpoint of obtaining a toner with excellent image quality.

[0092] <Release agent> In this embodiment, the toner particles preferably contain a release agent, and when the toner particles have a core-shell structure, the core preferably contains a release agent. Examples of release agents include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more. The melting point of the release agent is preferably 60°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher, and is preferably 150°C or lower, more preferably 130°C or lower, and even more preferably 100°C or lower. When two or more types of release agents are used in combination, it is preferable that the melting points of the waxes used are within the above-mentioned ranges.

[0093] The content of the release agent in the toner particles is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 2% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less.

[0094] [Method for producing toner for developing electrostatic images] The method for producing the toner for developing electrostatic images of the present invention is not particularly limited, and it may be produced by a chemical method such as an emulsion polymerization method or a suspension method, or it may be produced by a kneading and pulverization method. From the viewpoint of obtaining a toner having excellent low-temperature fixing properties and charge distribution, it is preferable to produce it by a chemical method such as an emulsion polymerization method or a suspension method, and it is more preferable to produce it by a method including a process of aggregating and fusing resin particles in an aqueous medium. The resin particles contain a crystalline polyester resin and a silicone-modified polyester resin in the same or different particles. More specifically, the toner of the present invention is preferably obtained by a method having the following steps 1 and 2: Step 1: A step of aggregating resin particles X containing a silicone-modified polyester resin (resin A) and a crystalline polyester resin (resin C) in the same or different particles in an aqueous medium to obtain aggregated particles 1; Step 2: A step of heating and fusing the aggregated particles 1 obtained in step 1 to obtain fused particles. When the toner particles have a core-shell structure, they are preferably obtained by a method including the following steps 1' to 3'. Step 1': a step of aggregating resin particles X containing a silicone-modified polyester resin (resin A) and a crystalline polyester resin (resin C) in the same or different particles in an aqueous medium to obtain aggregated particles 1 (core particles); Step 2': a step of aggregating resin particles Y containing an amorphous polyester-based resin B to the aggregated particles 1 obtained in Step 1 to obtain aggregated particles 2 (core-shell particles); Step 3': A step of heating and fusing the aggregated particles 2 obtained in step 2 to obtain fused particles.

[0095] In steps 1 and 1', resin particles X are aggregated in an aqueous medium to obtain aggregated particles 1. Here, the resin particles X contain a silicone-modified polyester resin (resin A) and a crystalline polyester resin (resin C). In addition to the resin particles X, it is preferable to aggregate colorant and release agent particles, and it is more preferable to mix a resin particle dispersion containing the resin particles X, a colorant dispersion containing a colorant, and a release agent particle dispersion containing release agent particles to aggregate these particles. Each step will be described below.

[0096] [Step 1 and Step 1'] Step 1 and step 1′ are steps for obtaining aggregated particles 1 by aggregating resin particles X, which contain resin A and resin C in the same or different particles, in an aqueous medium. In steps 1 and 1′, aggregated particles 1 are preferably obtained by aggregating a colorant together with resin particles X. Furthermore, in steps 1 and 1′, it is preferable to aggregate release agent particles containing a release agent together with resin particles X and the colorant. The resin particles X, colorant, and release agent particles used in Step 1 and Step 1', as well as their manufacturing methods, will be described in detail below.

[0097] <Resin particle X> The resin particle dispersion used in step 1 and step 1′ contains resin particles X. In order to obtain excellent low-temperature fixability and charge amount distribution, the resin particles X preferably contain resin A and resin C in the same or different resin particles, and from the viewpoint of further improving the low-temperature fixability and charge amount distribution of the resulting toner, preferably, resin A and resin C are contained in the same resin particles.

[0098] (Preparation of Resin Particle Dispersion) A resin particle dispersion containing resin particles X, preferably a resin particle dispersion containing resin A and resin C in the same or different resin particles, can be prepared using a known method, but is preferably dispersed by a phase inversion emulsification method, such as 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.

[0099] The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin, but from the viewpoint of facilitating phase inversion, examples include alcohol-based solvents such as ethanol, isopropanol, isobutanol, etc.; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, etc.; ether-based solvents such as dibutyl ether, tetrahydrofuran, dioxane, etc.; and acetate-based solvents such as ethyl acetate, isopropyl acetate, etc. Among these, from the viewpoint of ease of removal from the mixed solution after addition of the aqueous medium, ketone-based solvents and acetate-based 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 substance include alkali metal hydroxides 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 used relative 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, even more preferably 40 mol% or more, from the viewpoint of obtaining fine resin particles and improving dispersion stability, and is preferably 90 mol% or less, more preferably 70 mol% or less. The equivalent amount (mol %) of the neutralizing agent used can be calculated by the following formula: When the equivalent amount of the neutralizing agent used is 100 mol % or less, it is synonymous with the degree of neutralization. Equivalent amount of neutralizing agent used (mol%) = [{mass of neutralizing agent added (g) / equivalent amount of neutralizing agent} / [{weighted average acid value of resin constituting resin particle X (mg KOH / g) × mass of resin constituting resin particle X (g)} / (56 × 1000)]] × 100

[0100] While stirring the organic solvent solution or the molten resin, the aqueous medium is gradually added to cause phase inversion. From the viewpoint of improving the dispersion stability of the resin particles X, the temperature of the organic solvent solution when the aqueous medium is added is preferably equal to or higher than the glass transition temperature of the resin constituting the resin particles X, more preferably equal to or higher than 50°C, even more preferably equal to or higher than 60°C, and is preferably equal to or lower than 85°C, more preferably equal to or lower than 80°C. The contents of resin A and resin C are as described above.

[0101] After the phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation, etc. In this case, the amount of the remaining organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0102] The volume median particle size (D 50 ) is preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.12 μm or more, and is preferably 0.8 μm or less, more preferably 0.4 μm or less, even more preferably 0.3 μm or less, from the viewpoint of obtaining a toner that can produce high-quality images. From the viewpoint of obtaining a toner that can produce 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 is preferably 40% or less, more preferably 35% or less. The volume median particle size of resin particle X (D 50 ) and the CV value can be determined by the method described in the Examples below.

[0103] When resin particles Xa containing resin A and resin particles Xc containing resin C are used in combination, resin particles Xa and Xc can be obtained by the same method as described above. The amount of resin particles Xa and resin particles Xc added is preferably the amount corresponding to the content of resin A and resin C described above.

[0104] (aqueous medium) In the present invention, the aqueous medium is a medium containing water as a main component, and the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. The water is preferably deionized water, ion-exchanged water, or distilled water. Examples of components other than water that can constitute the aqueous medium together with water include water-soluble organic solvents such as alkyl alcohols having 1 to 5 carbon atoms, dialkyl ketones having 3 to 5 carbon atoms such as acetone and methyl ethyl ketone, and cyclic ethers such as tetrahydrofuran. Among these, alkyl alcohols having 1 to 5 carbon atoms are preferred, and methanol or ethanol is more preferred.

[0105] <Coloring agent> The colorant is preferably mixed with the resin particles as a dispersion of the colorant, and then aggregated to be contained in the aggregated particles. The colorant dispersion is preferably obtained by dispersing a colorant component (preferably a pigment) 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, the dispersion is preferably carried out in the presence of a polymer or a surfactant, and more preferably in the presence of a polymer so that at least a portion of the colorant component is coated with the polymer. As the polymer, addition polymer E is preferred, as described above. When a surfactant is used to disperse the coloring component, 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, and even more preferably 10 parts by mass or more, relative to 100 parts by mass of the coloring component, from the viewpoint of improving the dispersion stability of the coloring component, and is preferably 40 parts by mass or less, and more preferably 30 parts by mass or less.

[0106] The colorant is preferably obtained by mixing a coloring component with the addition polymer E. There is no particular limitation on the method for producing the colorant dispersion liquid. 50 It is sufficient if the coloring agent can be controlled to obtain the coloring agent described above, but it is preferably obtained by mixing a coloring component (preferably a pigment) and a dispersion of the addition polymer E using a bead mill or a homogenizer.

[0107] The method for producing the colorant preferably comprises the steps of: Step a: mixing the addition polymer E with an organic solvent, optionally adding a neutralizing agent, and then adding an aqueous medium to obtain a dispersion of the addition polymer E; and Step b: A step of dispersing the dispersion obtained in step a and a coloring component to obtain a dispersion of a colorant (colorant dispersion). It is a method having the following. By including an organic solvent, the addition polymer E dissolves in the organic solvent, which makes it easier for the addition polymer E to be adsorbed onto the coloring component, thereby further increasing the dispersibility of the coloring component. Furthermore, the step b is preferably a step of dispersing the dispersion liquid obtained in the step a and the coloring component using a bead mill or a homogenizer.

[0108] In step a, it is preferable to first mix the addition polymer E with an organic solvent to dissolve the addition polymer E. Examples of the organic solvent used here 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 E is synthesized by solution polymerization, the solvent used in the polymerization may be used as is.

[0109] Examples of the neutralizing agent include basic substances, such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The degree of neutralization of the addition polymer E is preferably 15 mol% or more, more preferably 20 mol% or more, even more preferably 40 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, and is preferably 100 mol% or less, more preferably 95 mol% or less. The degree of neutralization of the addition polymer E can be determined by the following formula. Degree of neutralization (mol%) = [{weight (g) of neutralizing agent added / equivalent weight of neutralizing agent} / {weight ratio of addition polymerizable monomer having an acidic group constituting addition polymer E × weight (g) of addition polymer E / molecular weight of addition polymerizable monomer having an acidic group}] × 100 In step a, the device used for mixing may be, for example, a mixer / stirrer equipped with an anchor blade, a disperser blade, or the like. The temperature during mixing is preferably 0°C or higher, more preferably 10°C or higher, and preferably 40°C or lower, more preferably 30°C or lower, and even more preferably 25°C or lower. The mixing time is preferably 1 minute or more, more preferably 3 minutes or more, even more preferably 5 minutes or more, and is preferably 30 hours or less, more preferably 10 hours or less, even more preferably 5 hours or less, even more preferably 3 hours or less.

[0110] In step b, the mass ratio of the coloring component to the addition polymer E [coloring component / addition polymer E] is as described above. In step b, it is preferable to mix the dispersion obtained in step a with a coloring component and then perform a dispersion treatment. Examples of the device used for mixing in step b include the same device as the device 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, and even more preferably 25°C or lower. The mixing time in step b is preferably 1 minute or longer, more preferably 10 minutes or longer, even more preferably 30 minutes or longer, and is preferably 30 hours or shorter, more preferably 10 hours or shorter, even more preferably 5 hours or shorter, even more preferably 3 hours or shorter.

[0111] Examples of devices used in the dispersion treatment in step b include kneaders such as roll mills and kneaders, homogenizers such as Microfluidizer (manufactured by Microfluidic Corp.) and Starburst (manufactured by Sugino Machine Co., Ltd.), and media-type dispersers such as paint shakers and bead mills. One or more of these devices may be used. Among these, bead mills and homogenizers are preferred from the viewpoint of reducing the particle size of the pigment. When a homogenizer is used, the processing pressure is preferably 60 MPa or more, more preferably 100 MPa or more, even more preferably 130 MPa or more, and preferably 270 MPa or less, more preferably 200 MPa or less, even more preferably 180 MPa or less. The number of passes is preferably 5 or more, more preferably 8 or more, and even more preferably 12 or more, and is preferably 30 or less, and more preferably 20 or less.

[0112] It is preferable to remove the organic solvent from the obtained colorant dispersion. The colorant dispersion is preferably filtered through a wire mesh or the like to remove coarse particles, etc. From the viewpoint of improving the productivity and storage stability of the dispersion, the addition polymer E of the colorant particles may be crosslinked. In addition, various additives such as organic solvents, preservatives, and antifungal agents may be added to the colorant particle dispersion liquid.

[0113] In the colorant dispersion, the coloring component 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, even more preferably 30% by mass or less, and even more preferably 25% by mass or less. The solids concentration of the colorant dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less.

[0114] Volume median particle size D of the colorant in the colorant dispersion 50 From the viewpoint of improving image density, the thickness is preferably 0.05 μm or more, more preferably 0.07 μm or more, even more preferably 0.08 μm or more, and is preferably 0.4 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less. From the viewpoint of improving 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 is preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. Volume median particle size D of colorant particles 50 The CV value is measured by the method described in the Examples.

[0115] From the viewpoint of further improving image density, the amount of colorant is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 8 parts by mass or more, and is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, relative to 100 parts by mass of resin particles X.

[0116] <Release agent particles> The release agent is preferably contained in the aggregated particles 1 by mixing the release agent particle dispersion with the resin particle dispersion and the colorant dispersion and aggregating them. A dispersion of release agent particles can be obtained using a surfactant, but is preferably obtained by mixing the release agent with resin particles P, which will be described later. By preparing release agent particles using the release agent and resin particles P, the release agent particles are stabilized by the resin particles P, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is believed that the dispersion of release agent particles has a structure in which a large number of resin particles P adhere to the surfaces of the release agent particles. The release agent particles are preferably contained in the aggregated particles by mixing the resin particle dispersion and the colorant dispersion as a dispersion of the release agent particles and aggregating them. A dispersion of release agent particles can be obtained using a surfactant, but is preferably obtained by mixing the release agent with resin particles P. By preparing release agent particles using the release agent and resin particles P, the release agent particles are stabilized by the resin particles P, making it possible to disperse the release agent in an aqueous medium without using a surfactant. It is believed that the dispersion of release agent particles has a structure in which a large number of resin particles P adhere to the surfaces of the release agent particles. The resin constituting the resin particles P in which the release agent is dispersed is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition polymerization resin segment. For details about the release agent particle dispersion and the composite resin D, see JP 2021-026129 A.

[0117] Aggregated particles 1 may also contain additives such as charge control agents, magnetic powders, flowability improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, and cleaning property improvers.

[0118] <Mixing conditions> In step 1, it is preferable to mix resin particles X and colorant particles in an aqueous medium and aggregate the resin particles X and colorant to obtain aggregated particles. The mixing of resin particles X and colorant is preferably carried out by mixing a resin particle dispersion containing resin particles X with a colorant dispersion containing the colorant. Furthermore, it is preferable that the resin particle dispersion is an aqueous dispersion of resin particles, and the colorant dispersion is an aqueous dispersion of a colorant. In step 1, it is preferable to aggregate the release agent particles together with the resin particles X and the colorant.

[0119] (surfactant) In step 1, it is preferable to prepare a mixed dispersion by mixing a resin particle dispersion with, if necessary, a colorant dispersion and a release agent particle dispersion, and then aggregate the resin particles X, colorant, and release agent particles. The mixed dispersion may be prepared in the presence of a surfactant in order to improve the dispersion stability of the resin particles X and optional components, such as a colorant and release agent particles, which are added as needed. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; and nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. When a surfactant is used, the amount of surfactant used is, as the total amount of surfactants, preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, per 100 parts by mass of resin particles X.

[0120] The dispersion of the resin particles X and the optional components are mixed by a conventional method. From the viewpoint of efficiently carrying out aggregation, it is preferable to add an aggregating agent to the mixed dispersion obtained by the mixing.

[0121] (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 flocculation properties and obtaining uniform flocculated particles, inorganic flocculants having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts are more preferred, and ammonium sulfate is even more preferred. The flocculant may be added as is, but is preferably dissolved in an aqueous medium and added as an aqueous solution. When the flocculant is added as an aqueous solution, the pH of the aqueous flocculant solution may be adjusted.

[0122] For example, a flocculant is added to a mixed dispersion containing resin particles X, and, if necessary, colorant particles and release agent particles, at a temperature of 0° C. or higher and 40° C. or lower, in an amount of preferably 5 parts by mass or higher and 50 parts by mass or lower relative to 100 parts by mass of resin particles X, to aggregate the resin particles X and colorant particles in an aqueous medium to obtain aggregated particles 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion after adding the flocculant.

[0123] Volume median particle size D of aggregated particles 1 obtained in step 1 or step 1' 50 is preferably 3 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6.5 μm or less. It is preferred to continue the agglomeration process until the desired volume median particle size is achieved.

[0124] [Step 2'] Step 2′ is a step of aggregating resin particles Y containing amorphous polyester resin B with aggregated particles 1 obtained in step 1′ to obtain aggregated particles 2. In step 2′, it is preferable to add a dispersion of resin particles Y to the dispersion of aggregated particles 1 described above, thereby causing resin particles Y to further adhere to aggregated particles 1, thereby obtaining a dispersion of aggregated particles 2.

[0125] <Resin particle Y> The resin particle dispersion used in step 2' contains resin particles Y. The resin particles Y contain a polyester resin (resin B) in order to obtain excellent low-temperature fixability and charge amount distribution. (Preparation of Resin Particle Dispersion) The resin particles Y are preferably produced by dispersing a resin component containing the resin B and, if necessary, optional components such as a surfactant in an aqueous medium to obtain a resin particle Y dispersion. The method for obtaining the resin particle Y dispersion can be exemplified by the same methods as those for the resin particle dispersion of resin particle X. Among these, it is preferable to obtain the resin particle Y dispersion by a phase inversion emulsification method, from the viewpoint of improving the low-temperature fixability of the resulting toner. As in the case of resin particles X, the phase inversion emulsification method is also preferably 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, and then phase inversion emulsification is carried out. Preferred embodiments of the aqueous medium and organic solvent that can be used are the same as those of the aqueous medium and organic solvent used in the production of resin particles X. In addition, in the phase inversion emulsification method, preferred ranges for the mass ratio of resin B to organic solvent, the degree of neutralization of resin B, the amount of aqueous medium to be added, the mixing temperature, and the like are the same as those in the production of resin particles X.

[0126] The solid content concentration of the resulting dispersion of resin particles Y is preferably 7% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of improving toner productivity and dispersion stability of resin particles Y, and is preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less. The solid content is the total amount of nonvolatile components such as resin and surfactant.

[0127] The volume median particle diameter (D 50 ) is preferably 0.04 μm or more, more preferably 0.06 μm or more, even more preferably 0.08 μm or more, and is preferably 0.5 μm or less, more preferably 0.3 μm or less, even more preferably 0.2 μm or less, from the viewpoint of obtaining a toner that can produce high-quality images. Furthermore, 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, and even more preferably 15% or more, from the viewpoint of improving the productivity of the resin particle Y dispersion, and is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less, from the viewpoint of obtaining a toner that can produce high-quality images. The volume median particle size of resin particle Y (D 50 ) and coefficient of variation (CV value) are measured by the method described in the Examples.

[0128] Before adding the dispersion of resin particles Y to the dispersion of aggregated particles 1, the dispersion of aggregated particles 1 may be diluted by adding an aqueous medium. When the dispersion of resin particles Y is added to the dispersion of aggregated particles 1, the aggregating agent may be used in this step to efficiently attach the resin particles Y to the aggregated particles 1. The temperature when the resin particle Y dispersion is added is preferably 40°C or higher, more preferably 45°C or higher, even more preferably 50°C or higher, from the viewpoint of further improving the low-temperature fixability and charge amount distribution of the toner, and is preferably 80°C or lower, more preferably 70°C or lower, even more preferably 65°C or lower.

[0129] The resin particle Y dispersion may be added continuously over a certain period of time, all at once, or in multiple divided portions. Continuous addition over a certain period of time or multiple divided portions is preferred. Addition in this manner facilitates selective adhesion of the resin particles Y to the aggregated particles 1. From the viewpoints of promoting selective adhesion and improving toner productivity, continuous addition over a certain period of time is particularly preferred. The time for continuous addition depends on the scale of production, but from the viewpoints of obtaining uniform aggregated particles 2 and improving toner productivity, it 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, and even more preferably 3 hours or less.

[0130] From the viewpoint of further improving the low-temperature fixability and charge distribution of the toner, the amount of resin particles Y added is an amount such that the mass ratio of resin particles Y to resin particles X (resin particles Y / resin particles X) is preferably 0.05 or more, more preferably 0.08 or more, even more preferably 0.10 or more, and is preferably 0.9 or less, more preferably 0.5 or less, even more preferably 0.3 or less, even more preferably 0.2 or less.

[0131] The volume median particle size (D 50 ) is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6.5 μm or less, from the viewpoint of obtaining a toner that can produce high-quality images and further improving the low-temperature fixability and charge amount distribution of the toner.

[0132] [Step 2, Step 3'] Step 2 is a step of increasing the temperature of agglomerated particles 1 obtained in step 1 to fuse them together, thereby obtaining fused particles, and step 3' is a step of increasing the temperature of agglomerated particles 2 obtained in step 2 to fuse them together, thereby obtaining fused particles. Step 2 and step 3' differ in that the agglomerated particles to be fused are agglomerated particles 1 and agglomerated particles 2, but other preferable requirements are similar. In steps 2 and 3', the particles in the aggregated particles, which were primarily physically attached to each other, are fused together to form toner particles. In this step, the temperature is maintained at or above the glass transition temperatures of resin A and resin B from the viewpoint of improving the fusion property of the aggregated particles and improving the low-temperature fixability and charge amount distribution of the toner. From the viewpoint of improving the fusion properties of the aggregated particles and improving the productivity of the toner, the holding temperature in the fusion step is preferably at least 2°C higher than the glass transition temperatures of Resin A and Resin B, more preferably at least 3°C higher, and even more preferably at least 5°C higher, and is preferably not higher than 30°C higher than the glass transition temperatures of Resin A and Resin B. In this case, the time for maintaining the temperature at or above the glass transition temperature of Resin A and Resin B is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, from the viewpoint of further improving the low-temperature fixability and charge amount distribution of the toner, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, even more preferably 90 minutes or less. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0133] The volume median particle size (D 50 ) is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less, from the viewpoint of further improving the low-temperature fixability and charge amount distribution of the toner. The volume median particle size of the fused particles obtained in step 2 or 3' is preferably equal to or smaller than the volume median particle size of the aggregated particles. That is, in step 2 or 3', it is preferable that aggregation or fusion between aggregated particles 1 or between aggregated particles 2 does not occur.

[0134] [Post-processing process] In the present invention, a post-treatment step may be carried out after step 2 or step 3', and it is preferable to obtain toner particles by isolation. The fused particles obtained in step 2 or step 3' are present in an aqueous medium, so it is preferable to first carry out solid-liquid separation, which is preferably carried out by suction filtration or the like. It is preferable to wash the solid-liquid separation product. At this time, it is preferable to remove the added surfactant and the like. Therefore, if the surfactant has a cloud point, washing with an aqueous medium at a temperature below the cloud point of the surfactant is preferable. It is preferable to wash the solid-liquid separation product multiple times.

[0135] Next, it is preferable to carry out drying. The temperature during drying is preferably set so that the temperature of the toner particles themselves is lower than the glass transition temperature of Resin A or Resin B, and more preferably 10°C or more lower. As the drying method, it is preferable to use a vacuum low-temperature drying method, a vibration-type fluidized bed drying method, a spray drying method, a freeze drying method, a flash jet method, or the like.

[0136] [Toner particles] The toner particles obtained by drying or the like can be used as they are as a toner for developing electrostatic images, but it is preferable to use toner particles whose surfaces are treated with an external additive as described later as a toner for developing electrostatic images. The volume median particle size of the toner particles (D 50 ) is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less, from the viewpoint of improving the productivity of the toner and further improving the low-temperature fixability and charge amount distribution of the toner. The CV value of the toner particles is preferably 12% or more, more preferably 14% or more, and even more preferably 16% or more from the viewpoint of improving toner productivity, and is preferably 32% or less, more preferably 30% or less, and even more preferably 29% or less from the viewpoint of obtaining high-quality images. From the viewpoint of further improving the low-temperature fixability and charge distribution of the toner, the circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, even more preferably 0.965 or more, and is preferably 0.990 or less, more preferably 0.985 or less, even more preferably 0.980 or less.

[0137] <External additives> The toner particles can be used as they are as a toner for developing electrostatic images, but it is preferable to use the toner particles after adding a fluidizing agent or the like as an external additive to the surface of the toner particles. Examples of external additives 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, and among these, hydrophobic silica is preferred. The external additives may be used alone or in combination of two or more. Also, external additives of the same type but different particle diameters may be used in combination. When the surface treatment of the toner particles is performed using an external additive, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, even 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, even more preferably 4 parts by mass or less, relative to 100 parts by mass of the toner particles.

[0138] <Toner for developing electrostatic images> The toner for developing electrostatic images obtained as described above can be used as a one-component developer, or mixed with a carrier to form a two-component developer. [Example]

[0139] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods. In the notation "alkylene oxide (X)" and the like, the number X in parentheses means the average number of moles of alkylene oxide added.

[0140] [Measurement method] [Kinematic Viscosity of Modified Silicone] The kinematic viscosity of the modified silicone was determined using the catalog value for each product. [Functional group equivalent of modified silicone] The functional group equivalent weight of the modified silicone was determined from the catalog value of each product. [Acid value of resin] The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070:1992, except that the measurement solvent was chloroform.

[0141] [Softening point, crystallinity index, melting point and glass transition temperature of resin] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while a load of 1.96 MPa was applied by the plunger, and the sample was extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point. (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, and then heated to 180°C at a rate of 10°C / min, and the calorific value was measured. The temperature of the peak with the largest peak area among the observed endothermic peaks was defined as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C)) / (endothermic maximum peak temperature (1) (°C)). (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and cooled from that temperature to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the calorific value was measured. Of the endothermic peaks observed, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (2). For crystalline resins, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak is observed, the temperature of the peak is taken as the glass transition temperature. When a step is observed instead of a peak, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step is taken as the glass transition temperature.

[0142] [Number average molecular weight and weight average molecular weight of resins A, B, and modified silicone] The molecular weight distribution was measured by gel permeation chromatography (GPC) according to the following method, and the number average molecular weight and weight average molecular weight were determined. (1) Preparation of sample solution The sample was dissolved in tetrahydrofuran at 25° C. to a concentration of 0.5 g / 100 mL. Next, this solution was filtered using a fluororesin filter "DISMIC-25JP" (manufactured by Advantec Toyo Co., Ltd.) with a pore size of 0.2 μm to remove insoluble components, and a sample solution was obtained. (2) Molecular weight measurement Using the following measuring equipment and analytical column, tetrahydrofuran was used as the eluent at a flow rate of 1 mL per minute, and the column was stabilized in a thermostatic bath at 40°C. 100 μL of sample solution was injected into the column for measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curve used here included several types of monodisperse polystyrene "A-500" (5.0 × 10 2 ), "A-1000" (1.01 x 10 3 ), "A-2500" (2.63 x 10 3 ), "A-5000" (5.97 x 10 3 ), "F-1" (1.02 x 10 4 ), "F-2" (1.81 x 10 4 ), "F-4" (3.97 x 10 4 ), "F-10" (9.64 x 10 4 ), "F-20" (1.90 x 10 5 ), "F-40" (4.27 x 10 5 ), "F-80" (7.06 x 10 5 ), "F-128" (1.09 x 10 6 ) (all manufactured by Tosoh Corporation) were used as standard samples. Measuring device: "HLC-8220GPC" (Tosoh Corporation) Analytical column: "GMHXL" + "G3000HXL" (both manufactured by Tosoh Corporation)

[0143] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the calorific value was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0144] [Volume median particle diameter D of resin particles, colorant particles, and release agent particles 50 and CV value) (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and measure the volume median particle size D at a concentration where the absorbance is in the appropriate range. 50 and volume average particle size D v The CV value was calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution) / volume average particle size D v ) x 100

[0145] [Solid Content Concentration of Resin Particle Dispersion, Colorant Particle Dispersion, and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture content (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, moisture content fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0146] [Volume median particle size of agglomerated particles D 50 〕 Volume median particle size of agglomerated particles D 50 was measured as follows: Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured again, and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0147] [Circularity of fused particles] The circularity of the fused particles was measured under the following conditions. Measurement equipment: Flow particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: The dispersion of fused particles was diluted with deionized water to a solids concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0148] [Volume median particle size D of toner particles 50 and CV value) Volume median particle size D of toner particles 50 was measured as follows: The measurement device, aperture diameter, analysis software, and electrolyte were determined based on the volume median particle diameter D 50 The same material as that used in the measurement was used. Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6) was dissolved in the electrolyte solution to obtain a dispersion with a concentration of 5 mass %. Dispersion conditions: 10 mg of a measurement sample of dried toner particles was added to 5 mL of the dispersion liquid, and the mixture was dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of the electrolyte solution was added, and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 and volume average particle size D V asked for. The CV value (%) was calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution) / volume average particle size D V ) x 100

[0149] [Evaluation method] [Low-Temperature Fixability of Toner] Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by OKI Data Corporation) on high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), the amount of toner adhered to the paper was 0.80±0.01 mg / cm 2 The solid image was printed without fixing, leaving a 5mm margin from the top edge of an A4 sheet of paper, and a length of 50mm. Next, the same printer was prepared with a modified temperature-variable fixing unit, and the temperature of the fixing unit was set to 80°C. The toner was fixed at a speed of 1.2 seconds per sheet of A4 paper in portrait orientation, resulting in a printed product. In the same manner, the temperature of the fixing device was increased by 5° C. each time, and the toner was fixed to obtain a printed matter. A 50 mm length of Scotch (registered trademark) Mending Tape 810 (manufactured by Sumitomo 3M Limited, width 18 mm) was lightly applied from the top margin of the printed image to the solid image, and then a 500 g weight (contact area 1963 mm) was applied. 2 ) was placed on the print and pressed back and forth at a speed of 10 mm / s. The applied tape was then peeled off from the bottom edge at a peeling angle of 180° and a speed of 10 mm / s to obtain a print after tape removal. Thirty sheets of high-quality paper "Excellent White Paper, A4 size" (manufactured by OKI Data Corporation) were placed under the print before and after tape removal. The reflection image density of the fixed image portion of each print before and after tape removal was measured using a "SpectroEye" colorimeter (manufactured by GretagMacbeth, lighting conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The fixation rate was calculated from each reflection image density according to the following formula: Fixation rate (%) = (reflected image density after tape peeling / reflected image density before tape application) x 100 The lowest temperature at which the fixing rate was 90% or more was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing ability.

[0150] [Charge amount distribution of toner] Toner 0.6g and ferrite carrier (ferrite core, silicone coated, saturation magnetization: 71Am 2 19.4 g of the powder (19.4 g / kg) was placed in a 50 mL polypropylene bottle "PP Sample Bottle Wide Mouth" (manufactured by Sanplatec Co., Ltd.) and stirred for 20 minutes in a ball mill. After that, 5 g was sampled and measured using a charge amount measuring device "q-test" (manufactured by Epping) under the following measurement conditions. Toner Flow (mL / min): 160 Electrode Voltage (V): 4000 Deposition Time(s):2 The median q / d was taken as the toner charge Q / d (fC / 10 μm), where the specific density was 1.2 g / cm 3 and Median Diameter is the volume median particle diameter of the toner D 50 In the obtained graph of charge distribution, the range of Q / d from -0.4 to 0.4 (fC / 10 μm) is an unmeasurable region, so this range was connected by a straight line to create a graph of charge distribution. The charge distribution was evaluated based on the half-width of the maximum peak of this charge distribution (the width of the cut when the distribution is cut at half the value of the maximum peak height in the distribution). The smaller the value, the narrower the charge distribution.

[0151] [Resin manufacturing] [Production of (Silicone-Modified) Amorphous Polyester Resin A] Production Example A1 (Production of Resin A-1) The inside of a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 4,548 g of a propylene oxide (2.2) adduct of bisphenol A, 745 g of an ethylene oxide (2.2) adduct of bisphenol A, 1,649 g of terephthalic acid, 374 g of silicone "X-22-170BX" (manufactured by Shin-Etsu Chemical Co., Ltd.), and 40 g of tin (II) di(2-ethylhexanoate) were added. The mixture was heated to 235°C with stirring under a nitrogen atmosphere and maintained at 235°C for 12 hours, after which the pressure inside the flask was reduced and maintained at 8 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190°C, and 440g of trimellitic anhydride and 618g of sebacic acid were added and reacted for 1 hour. The temperature was then increased to 210°C at a rate of 10°C / hr, and the pressure in the flask was reduced. The reaction was continued at 8kPa until the desired softening point was reached, yielding Resin A-1. The physical properties are shown in Table 1.

[0152] Production Examples A2 and A3 (Production of Resins A-2 and A-3) Resin A-2 and Resin A-3 were obtained in the same manner as in Production Example A1, except that the raw material compositions were changed as shown in Table 1. The physical properties are shown in Table 2. The silicones used in Production Examples A1 to A3 have the following composition. X-22-170BX: Modified silicone oil "X-22-170BX" (a silicone with a carbinol group at one end [the aforementioned silicone (1a) (only one end is substituted with 2a-1)], kinematic viscosity (25°C) 40mm 2 / s, number average molecular weight Mn 1,900, weight average molecular weight Mw 3,500, functional group equivalent 2,800 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd. KF96-100cs: Silicone oil "KF96-100cs" (silicone oil, kinematic viscosity (25°C) 100mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0153] [Table 1]

[0154] [Production of amorphous polyester resin B] Manufacturing Example B1 (Manufacturing of Resin B-1) A four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen. 5,001 g of ethylene oxide (2.2) adduct of bisphenol A, 1,788 g of terephthalic acid, 30 g of tin(II) di(2-ethylhexanoate), and 3.0 g of 3,4,5-trihydroxybenzoic acid were added. The mixture was heated to 235°C under a nitrogen atmosphere with stirring. After maintaining the temperature at 235°C for 8 hours, the pressure inside the flask was reduced and the mixture was maintained under a reduced pressure of 8 kPa for 1 hour. The mixture was then cooled to 180°C, and 179 g of fumaric acid, 206 g of dodecenylsuccinic anhydride, 325 g of trimellitic anhydride, and 3.8 g of 4-tert-butylcatechol were added. The mixture was heated to 220°C at a rate of 10°C / hr. The pressure inside the flask was then reduced and the reaction was continued under a reduced pressure of 10 kPa until the desired softening point was reached, yielding amorphous polyester resin B-1. The physical properties are shown in Table 2.

[0155] [Production of amorphous polyester resin D] Manufacturing Example D1 (Manufacturing of Resin D-1) A 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 4,313 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) di(2-ethylhexanoate), and 3.0 g of 3,4,5-trihydroxybenzoic acid (gallic acid) were added. The mixture was heated to 235°C under a nitrogen atmosphere with stirring and maintained at 235°C for 5 hours. The pressure in the flask was then reduced and maintained at 8 kPa for 1 hour. The pressure was then returned to atmospheric pressure, cooled to 160°C, and a mixture of 2,756 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 while maintaining the temperature at 160°C. After that, the temperature was maintained at 160°C for 30 minutes, and then the temperature was raised to 200°C. The pressure inside the flask was further reduced and the reaction was continued at 8 kPa until the desired softening point was reached, yielding Resin D-1. The physical properties are shown in Table 2.

[0156] [Table 2]

[0157] [Production of Crystalline Polyester Resin C] Manufacturing Example C1 (Manufacturing of Resin C-1) A 10 L four-neck flask equipped with a nitrogen inlet, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 3,416 g of 1,10-decanediol and 4,084 g of sebacic acid were added and heated to 135°C with stirring. The mixture was then held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. 23 g of tin(II) di(2-ethylhexanoate) was then added. The mixture was then held at 200°C for another hour. The pressure inside the flask was then reduced and the mixture was held under a reduced pressure of 8 kPa for 1 hour, yielding Resin C-1, a crystalline polyester resin. The physical properties are shown in Table 3.

[0158] Production Example C2 (Production of Crystalline Polyester Resin C-2) Resin C-2, a crystalline polyester resin, was obtained in the same manner as in Production Example C1, except that the raw material composition was changed as shown in Table 3. The physical properties are shown in Table 3.

[0159] [Table 3]

[0160] [Production of resin particle dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 210 g of Resin A-1, 90 g of Resin C-1, 300 g of methyl ethyl ketone, and 59 g of deionized water were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resins were dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min), resulting in phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while stirring at 280 r / min (circumferential speed 63 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion X-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values are shown in Table 4.

[0161] Production examples X2, X3, X51, X52 (manufacture of resin particle dispersions X-2, X-3, X-51, X-52) Resin particle dispersions X-2, X-3, X-51, and X-52 were obtained in the same manner as in Production Example X1, except that the type of resin used was changed as shown in Table 4. The volume median particle diameter D of the obtained resin particles was 50 and CV values are shown in Table 4.

[0162] [Table 4]

[0163] Production Example Y1 (Production of Resin Particle Dispersion Y-1) A 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube was charged with 300 g of amorphous resin B-1 and a mixed solvent of 180 g of methyl ethyl ketone and 25 g of deionized water. The mixture was then dissolved at 73°C for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution to achieve a neutralization degree of 60 mol% relative 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, 600 g of deionized water was added over 60 minutes while stirring at 200 r / min (circumferential speed 63 m / min), resulting in phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30°C while stirring at 280 r / min (circumferential speed 88 m / min), and deionized water was added to obtain an aqueous dispersion Y-1 of amorphous resin particles (Y) by adding deionized water so that the solids concentration became 20% by mass. The volume median particle diameter D of the obtained resin particles was 50 The particle size was 0.11 μm and the CV value was 23%.

[0164] Production Example P1 (Production of Resin Particle Dispersion P-1) 200 g of Resin D-1 and 200 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added to adjust the solids concentration to 20% by mass, thereby obtaining resin particle dispersion P-1. The volume median particle diameter D of the resulting resin particles was 50 The particle size was 0.09 μm and the CV value was 23%.

[0165] [Production of release agent particle dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) 120 g of deionized water, 86 g of resin particle dispersion P-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added to a 1 L beaker, and the mixture was melted by maintaining the temperature at 90-95°C and stirred to obtain a molten mixture. The obtained molten mixture was further dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content to 20% by mass, thereby obtaining release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles in the dispersion was 50 The particle size was 0.47 μm and the CV value was 27%.

[0166] [Production of Addition Polymer E] Production Example E1 (Synthesis of Addition Polymer E-1) The types and amounts of raw material monomers shown in Table 5 were mixed to prepare a monomer mixture having a total monomer amount of 100 g. The inside of a four-neck flask equipped with a nitrogen inlet tube, dropping funnel, stirrer, and thermocouple was replaced with nitrogen. 18 g of methyl ethyl ketone, 0.03 g of 2-mercaptoethanol, and 10% by weight of the monomer mixture were added and heated to 75°C with stirring. While maintaining the temperature at 75°C, a mixture of the remaining 90% by weight of the monomer mixture, 0.27 g of 2-mercaptoethanol, 42 g of methyl ethyl ketone, and 3 g of 2,2'-azobis(2,4-dimethylvaleronitrile) "V-65" (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise via the dropping funnel over 3 hours. After the addition was completed, the temperature was maintained at 75°C for 2 hours. A solution of 3 g of V-65 in 5 g of methyl ethyl ketone was added, and the mixture was further maintained at 75°C for 2 hours and then at 80°C for 2 hours. The methyl ethyl ketone was then distilled off under reduced pressure to obtain addition polymer E-1. The weight-average molecular weight of the resulting addition polymer is shown in Table 5.

[0167] [Table 5]

[0168] [Production of colorant dispersion] Production Example Z1 (Production of Colorant Dispersion Z-1) A 5L vessel equipped with a stirrer equipped with a disperser blade, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube was charged with 75g of addition polymer E-1 and 630g of methyl ethyl ketone, and the resin was dissolved at 20°C. To the resulting solution, 101g of a 5% by weight aqueous sodium hydroxide solution (resulting in a neutralization degree of addition polymer E-1 of 91mol%) was added, followed by 955g of deionized water. The mixture was stirred with a disperser blade for 10 minutes at 20°C. Next, 300g of Pigment Yellow 155 (Clariant Chemicals, "Toner Yellow 3GP-CT", molecular weight 717) was added, and the mixture was stirred with a disperser blade at 6400 r / min for 2 hours at 20°C. The mixture was then passed through a 200-mesh filter and subjected to 15 passes at 150MPa using a homogenizer "Microfluidizer M-110EH" (Microfluidics). The resulting dispersion was stirred at 70°C under reduced pressure to remove methyl ethyl ketone and a portion of the water. After cooling, the mixture was passed through a 200-mesh filter, and deionized water was added to give a solids concentration of 20% by mass, to obtain colorant dispersion Z-1. The volume median particle diameter D of the resulting colorant was 50 The particle size was 0.10 μm and the CV value was 28%.

[0169] [Toner manufacturing] Example 1 (Production of Toner 1) Preparation of Toner 1 In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 500 g of resin particle dispersion X-1, 49 g of release agent particle dispersion W-1, 63 g of colorant particle dispersion Z-1, and 3.3 g of a 15 mass % aqueous solution of sodium dodecylbenzenesulfonate "Neopelex G-15" (Kao Corporation, an anionic surfactant) were mixed at 25° C. Next, while stirring the mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8 mass % aqueous solution of potassium hydroxide to adjust the pH to 8.2 was added dropwise over 10 minutes at 25° C., and the temperature was then raised to 62° C. over 2 hours to measure the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 62° C. until the particle size reached 6.2 μm, thereby obtaining a dispersion of aggregated particles (1). To the resulting dispersion of aggregated particles (1), an aqueous solution containing 18 g of polyoxyethylene lauryl ether sodium sulfate "EMAL E-27C" (Kao Corporation, anionic surfactant, effective concentration 27% by mass), 250 g of deionized water, and 30 g of 0.1 mol / L aqueous sulfuric acid solution was added. The mixture was then heated to 80°C over 1 hour and maintained at 80°C for 30 minutes. After that, 10 g of 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 80°C for 15 minutes. Another 15 g of 0.1 mol / L aqueous sulfuric acid solution was then added, and the mixture was maintained at 80°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which aggregated particles (1) were fused. The resulting fused particle dispersion was cooled to 30°C, filtered under suction to separate the solids, washed with deionized water at 25°C, and filtered under suction for 2 hours at 25°C. The solids were then vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC Corporation). Toner particles were obtained. 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by weight of hydrophobic silica "Cabosil® TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size: 0.012 μm) were mixed in a Henschel mixer and passed through a 150-mesh sieve to obtain Toner 1. The resulting toner had a particle size of 6.0 μm and a circularity of 0.970.

[0170] Examples 2 and 3 and Comparative Examples 1 and 2 (Production of Toners 2, 3, 51, and 52) Toners 2, 3, 51, and 52 were prepared in the same manner as in Example 1, except that the type of resin particle dispersion used was changed as shown in Table 6. The physical properties of the obtained toner particles and the evaluation results of the toners are shown in Table 6.

[0171] Example 4 (Production of Toner 4) In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 500 g of resin particle dispersion X-1, 49 g of release agent particle dispersion W-1, 63 g of colorant particle dispersion Z-1, and 3.3 g of a 15 mass % aqueous solution of sodium dodecylbenzenesulfonate "Neopelex G-15" (Kao Corporation, an anionic surfactant) were mixed at 25° C. Next, while stirring the mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8 mass % aqueous solution of potassium hydroxide to adjust the pH to 8.2 was added dropwise over 10 minutes at 25° C., and the temperature was then raised to 61° C. over 2 hours to measure the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 61° C. until the particle size reached 6.0 μm, thereby obtaining a dispersion of aggregated particles (1). While maintaining the temperature of the dispersion of aggregated particles (1) at 61° C., 60 g of resin particle dispersion Y-1 was added dropwise at a rate of 0.6 mL / min to obtain a dispersion of core-shell particles (1). To the resulting dispersion of core-shell particles (1), an aqueous solution containing 20 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (Kao Corporation, an anionic surfactant, effective concentration 27% by mass), 280 g of deionized water, and 40 g of 0.1 mol / L aqueous sulfuric acid solution was added. The mixture was then heated to 80°C over 1 hour and maintained at 80°C for 30 minutes. Then, 15 g of 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 80°C for 15 minutes. Another 15 g of 0.1 mol / L aqueous sulfuric acid solution was then added, and the mixture was maintained at 80°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which core-shell particles were fused together. The resulting fused particle dispersion was cooled to 30°C, and the solids were separated by suction filtration. The solids were then washed with deionized water at 25°C and suction filtered at 25°C for 2 hours. The solids were then vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC Corporation). Toner particles were obtained. 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by weight of hydrophobic silica "Cabosil® TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size: 0.012 μm) were mixed in a Henschel mixer and passed through a 150-mesh sieve to obtain Toner 4. The evaluation results of the resulting toner are shown in Table 6.

[0172] [Table 6]

[0173] From the results of the Examples and Comparative Examples, it is clear that the present invention provides a toner having excellent low-temperature fixability and charge amount distribution.

Claims

1. A method for producing a toner for developing an electrostatic image, the method comprising the steps of aggregating and fusing resin particles in an aqueous medium, the toner for developing an electrostatic image contains toner particles, the toner particles contain a crystalline polyester resin and a silicone-modified polyester resin, The silicone-modified polyester resin is a reaction product of an alcohol component containing a divalent or higher alcohol, a carboxylic acid component containing a divalent or higher carboxylic acid compound, and a modified silicone having a hydroxy group, a carboxy group, or an epoxy group at only one end, the resin particles contain the crystalline polyester resin and the silicone-modified polyester resin in the same or different particles, In the fusion step, the temperature is maintained at a temperature that is 2°C higher than the glass transition temperature of the silicone-modified polyester resin or higher. A method for producing a toner for developing electrostatic images.

2. The modified silicone is represented by the formula (1): 【Chemical 1】 2. The method for producing a toner for developing electrostatic images according to claim 1, comprising a modified silicone represented by the following formula: (wherein R each independently represents a hydrocarbon group having from 1 to 6 carbon atoms; R' each independently represents an alkylene group having from 1 to 10 carbon atoms; R'' each independently represents a hydrocarbon group having from 1 to 10 carbon atoms; X each independently represents a hydroxy group, a hydroxyalkyloxy group, a carboxy group, a carboxyalkyloxy group, an epoxy group, a glycidyl group, a glycidyloxy group, or an alicyclic epoxy group; s is an integer of from 1 to 3; t is 0; and n is an integer of from 5 to 300).

3. 3. The method for producing a toner for developing electrostatic images according to claim 1, wherein the modified silicone has a hydroxy group at only one end.

4. 4. The method for producing a toner for developing electrostatic images according to claim 1, wherein a content of the modified silicone is 1% by mass or more and 7% by mass or less with respect to a total amount of the alcohol component, the carboxylic acid component, and the modified silicone.

5. 5. The method for producing a toner for developing electrostatic images according to claim 1, wherein the mass ratio of the crystalline polyester resin to the silicone-modified polyester resin (crystalline polyester resin / silicone-modified polyester resin) is 3 / 97 or more and 50 / 50 or less.

6. 6. The method for producing a toner for developing electrostatic images according to claim 1, wherein the toner particles further contain a colorant, and the colorant contains a pigment and an addition polymer of raw material monomers including an addition polymerizable monomer having an anionic group and an addition polymerizable monomer having a polyalkylene oxide group.

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