toner

Abstract

To provide a toner that has good low temperature fixability and heat-resistant storage properties, can achieve prevention of image streaks caused by chipping and poor cleaning of a developing member, and can prevent fogging.SOLUTION: A toner has a toner particle having a core particle having a binder resin, and a shell having a thermosetting resin on the surface of the core particle. The binder resin contains at least one of (i) a vinyl resin and a polyester resin, and (ii) a hybrid resin in which a vinyl resin and a polyester resin are coupled to each other. The polyester resin has a cyclic structure on a main chain. The content of the polyester resin in a tetrahydrofuran soluble element of the toner is 51 mass% or more. The vinyl resin has a specific monomer unit. The thermosetting resin is at least one resin selected from a melamine resin, a urea resin, and a vinyl resin containing an oxazoline group. The average circularity of the toner is within a specific range.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a toner used in an electrophotographic image forming apparatus. [Background technology]

[0002] In recent years, there has been a demand for higher speeds and higher image quality in electrophotographic image forming apparatuses such as copiers and printers. Furthermore, due to global efforts to reduce environmental impact, there has been an increasing demand for energy-saving and longer-life products. To meet these demands, further improvements in various performance characteristics are being sought for toners. In particular, from the viewpoint of higher speeds and energy savings, further improvements in low-temperature fixability are being sought.

[0003] One way to achieve low-temperature fixability of a toner is to lower the softening temperature of the binder resin of the toner. However, if the softening temperature of the binder resin is low, the heat-resistant storage stability of the toner decreases, and there is a problem that toner particles fuse together, that is, so-called blocking occurs, particularly in a high-temperature environment.

[0004] In response to these issues, Patent Document 1 describes a pulverized toner in which the toner particles are of a core-shell type having a toner core and a shell layer covering the surface of the toner core, and the shell layer contains a thermosetting resin, in order to improve the low-temperature fixability and heat-resistant storage stability of the toner. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-040024 Summary of the Invention [Problem to be solved by the invention]

[0006] The toner described in the above document has improved heat-resistant storage stability due to the presence of a thermosetting resin layer on the toner surface. However, under harsh conditions such as long-term use in a printer that places a heavy load on the toner for high-speed image output, the protrusions on the toner surface rub against the developing member, making the developing member more susceptible to wear. Therefore, it was found that image defects (image streaks) occur due to wear of the developing member after long-term use. Furthermore, pulverized toners such as the above-mentioned toners tend to have unevenness, which is advantageous for cleaning properties, but tends to reduce fluidity, making fogging more likely to occur. The present disclosure provides a toner that solves the above-mentioned problems, i.e., a toner that has good low-temperature fixability and high-temperature storage stability, and that can simultaneously suppress image streaks caused by abrasion of a developing member or poor cleaning, and further suppress fogging. [Means for solving the problem]

[0007] The present disclosure provides a toner having toner particles each having a core particle having a binder resin and a shell having a thermosetting resin on the surface of the core particle, The binder resin contains at least one of the following (i) and (ii): (i) Vinyl resins and polyester resins (ii) Hybrid resins made by combining vinyl resins and polyester resins The polyester resin has a cyclic structure in the main chain. It is an amorphous polyester resin that , The fraction of the toner with a molecular weight of 2000 or more separated by preparative GPC from the tetrahydrofuran soluble fraction was In the main chain Has a cyclic structure Amorphous The content of polyester resin is 51% by mass or more, The vinyl resin has a monomer unit represented by the following formula (1): the thermosetting resin is at least one resin selected from the group consisting of a melamine resin, a urea resin, and a vinyl resin containing an oxazoline group, The toner has an average circularity of 0.920 or more and 0.965 or less. (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms.

[0008] [ka] [Effects of the Invention]

[0009] The present disclosure makes it possible to provide a toner that has good low-temperature fixability and heat-resistant storage stability, and at the same time, can suppress image streaks caused by abrasion of the developing member or poor cleaning, and can also suppress fogging. DETAILED DESCRIPTION OF THE INVENTION

[0010] Unless otherwise specified, the expressions "XX to YY" or "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined in any way.

[0011] The term "monomer unit" refers to the reacted form of a monomer substance in a polymer, and one unit is defined as one section of carbon-carbon bond in the main chain formed by polymerizing a vinyl monomer in a polymer. A vinyl monomer can be represented by the following formula (Z): [ka] [In formula (Z), Z1 represents a hydrogen atom or an alkyl group (preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group), and Z2 represents an arbitrary substituent.]

[0012] As described in the above document, a core-shell toner containing a thermosetting resin in the shell layer is effective in improving the heat-resistant storage stability of a toner. However, simply using such a core-shell toner is insufficient to simultaneously achieve the heat-resistant storage stability of the toner, the suppression of image streaks caused by abrasion of the developing member, good cleanability, and the suppression of fogging. In particular, under the harsh conditions of long-term use in a printer that places a heavy burden on the toner for high-speed image output, the protrusions on the toner surface rub against the developing member, resulting in noticeable image streaks caused by abrasion of the developing member.

[0013] The present inventors have conducted extensive research into a toner structure that not only has good heat-resistant storage stability but also suppresses abrasion of the developing member even when used in a printer that places a heavy burden on the toner, maintains cleaning properties, and can suppress fogging due to reduced fluidity. To obtain good cleaning properties, it is effective to make the toner particle surface uneven to improve scraping performance with a cleaning blade. On the other hand, to prevent the protrusions on the toner particle surface from scraping the developing member, it is necessary to control the amount of deformation of the toner in a direction that relaxes the shape of the protrusions in response to the stress applied to the toner when the toner particles are rubbed against the developing member under room temperature conditions. Furthermore, to prevent the toner deformed by rubbing from being crushed under the stress, it is necessary to control the viscoelasticity of the toner under room temperature conditions to a high level.

[0014] Therefore, the inventors have focused on vinyl resins and polyester resins containing a monomer unit represented by formula (1) as the binder resin for core particles. 2 The long-chain alkyl group of formula (1) has a large carbon number, which gives the alkyl group terminal a high degree of freedom. Therefore, by incorporating the monomer unit of formula (1) into the binder resin, it is thought that the mobility of the binder resin can be locally increased even in a temperature range below the glass transition point of the entire binder resin, such as in a room temperature environment. As a result, when the toner particles are rubbed against the developing member and a large stress is applied to the toner particles, the amount of deformation of the toner in the direction of alleviating the stress applied to the convex portions of the toner particles can be increased, and it is thought that abrasion of the developing member can be suppressed.

[0015] Furthermore, the physical properties of polyester resins can be easily controlled by the monomer composition, and by introducing a moiety having a cyclic structure into the main chain, the rigidity of the binder resin can be increased, thereby increasing the elastic modulus of the toner. It is believed that increasing the elastic modulus of the toner can suppress toner crushing due to toner deformation. In addition, when the toner is melted, the molecular mobility is high, and the entire toner is instantly plasticized, resulting in good low-temperature fixability.

[0016] Furthermore, by controlling the average circularity of the toner, it is possible to achieve good cleaning properties while maintaining fluidity, and therefore it is thought that the occurrence of fogging can be suppressed. The present inventors have found that the above problems can be solved by the following toner.

[0017] That is, the present disclosure provides a toner having toner particles each having a core particle having a binder resin and a shell having a thermosetting resin on the surface of the core particle, The binder resin contains at least one of the following (i) and (ii): (i) Vinyl resins and polyester resins (ii) Hybrid resins made by combining vinyl resins and polyester resins The polyester resin has a cyclic structure in the main chain, the content of the polyester resin having a cyclic structure in a fraction having a molecular weight of 2000 or more obtained by preparative GPC from the tetrahydrofuran soluble matter of the toner is 51% by mass or more, The vinyl resin has a monomer unit represented by the following formula (1): the thermosetting resin is at least one resin selected from the group consisting of a melamine resin, a urea resin, and a vinyl resin containing an oxazoline group, The toner has an average circularity of 0.920 or more and 0.965 or less. (In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents a linear alkyl group having 10 to 14 carbon atoms. [ka]

[0018] <Binder resin> The binder resin contained in the toner particles is (i) vinyl and polyester resins, and (ii) Hybrid resins made by combining vinyl resins and polyester resins It contains at least one of the above. It may contain both (i) and (ii). For example, the binder resin may contain a vinyl resin and a polyester resin, and at least a part or all of the vinyl resin may be bonded to at least a part or all of the polyester resin to form a hybrid resin. For example, the binder resin may contain a vinyl resin, a polyester resin, and a hybrid resin, or may contain a vinyl resin and a hybrid resin, or may contain a polyester resin and a hybrid resin. The bond may be, for example, a covalent bond.

[0019] <Vinyl resin> Vinyl resin refers to a polymer of a monomer having a vinyl group (hereinafter referred to as a vinyl monomer). Examples of vinyl resins include styrene-acrylic resin, styrene resin, and acrylic resin.

[0020] The vinyl resin has a monomer unit represented by the following formula (1). [ka]

[0021] In formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2represents a linear alkyl group having a carbon number of 10 to 14. The monomer unit of formula (1) (hereinafter also referred to as a "long-chain acrylate unit") has a high degree of freedom at the alkyl group terminal.

[0022] Therefore, as described above, a resin having a long-chain acrylate unit can locally increase the mobility of the resin even in a temperature range lower than the glass transition point of the entire resin. As a result, the deformation rate of the toner is improved, which makes it possible to suppress abrasion of the developing member. 2 Preferably, has 11 to 13 carbon atoms, and more preferably has 12 carbon atoms.

[0023] The content of the monomer unit represented by formula (1) in the vinyl resin is preferably 1.0% by mass or more and 15.0% by mass or less, and more preferably 3.0% by mass or more and 12.0% by mass or less. By making the content 1.0% by mass or more, the long-chain acrylate unit can be uniformly dispersed throughout the binder resin. On the other hand, since the monomer unit of formula (1) has a long-chain alkyl ester, it tends to lower the glass transition temperature of the vinyl resin. Therefore, from the viewpoint of heat-resistant storage stability, the content of the monomer unit of formula (1) in the vinyl resin is preferably 15.0 mass% or less.

[0024] Examples of acrylic polymerizable monomers (vinyl monomers) for synthesizing styrene-acrylic resins include methacrylic acid ester derivatives such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate; and acrylic acid ester derivatives such as methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, and phenyl acrylate, with n-butyl acrylate being particularly preferred. These may be used alone or in combination of two or more.

[0025] Examples of styrene polymerizable monomers (vinyl monomers) for synthesizing styrene-acrylic resins include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, and pn-dodecylstyrene, and other styrene or styrene-styrene derivatives. In particular, it is preferable to use styrene, which is a hydrophobic monomer. These can be used alone or in combination of two or more.

[0026] The content of monomer units of styrene polymerizable monomers in the vinyl resin is preferably 50.0 to 98.0 mass%, more preferably 70.0 to 90.0 mass%, and the content of monomer units of acrylic polymerizable monomers in the vinyl resin is preferably 1.0 to 30.0 mass%, more preferably 2.0 to 20.0 mass%.

[0027] <Polyester resin> The polyester resin has a cyclic structure in the main chain. The polyester resin having a cyclic structure is preferably an amorphous polyester resin.

[0028] Monomers that can be used to produce amorphous polyester resins include conventionally known divalent or trivalent or higher carboxylic acids and divalent or trivalent or higher alcohols. Specific examples of these monomers include the following. The polyester resin is a condensation polymer of an alcohol component and a carboxylic acid component, and it is preferred that at least one of the alcohol component and the carboxylic acid component contains a monomer having a cyclic structure.

[0029] Examples of alcohols having a cyclic structure include alicyclic diols (such as 1,4-cyclohexanedimethanol); bisphenols (such as bisphenol A); alkylene oxide (such as ethylene oxide and propylene oxide) adducts of alicyclic diols, alkylene oxide (such as ethylene oxide and propylene oxide) adducts of bisphenols (such as bisphenol A), and isosorbide.

[0030] Examples of alcohols having a straight-chain structure include alkylene diols (1,2-ethanediol, 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, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,20-icosanediol); alkylene ether glycols (trimethylene glycol, tetramethylene glycol); and the like. The alkyl moiety of the alkylene diol and alkylene ether glycol may be linear or branched. Branched alkylene diols are also preferably used.

[0031] Examples of the carboxylic acid having a cyclic structure include dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and dodecenylsuccinic acid, as well as anhydrides of these.

[0032] Examples of carboxylic acids having a straight-chain structure include dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, and 1,18-octadecanedicarboxylic acid, as well as anhydrides and lower alkyl esters thereof. Examples include aliphatic unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid, as well as lower alkyl esters and anhydrides thereof. Other examples include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, anhydrides thereof, and lower alkyl esters thereof. These may be used alone or in combination of two or more.

[0033] Aliphatic diols having a double bond can also be used, such as 2-butene-1,4-diol, 3-hexene-1,6-diol, and 4-octene-1,8-diol. Examples of the trihydric or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. These may be used alone or in combination of two or more.

[0034] The polyester resin may be bonded to a vinyl resin to form a hybrid resin. Preferably, the polyester resin and the vinyl resin are bonded to form a hybrid resin. The formation of the hybrid resin improves the dispersibility of the vinyl resin in the binder resin, thereby effectively suppressing scraping of the component.

[0035] A method for producing a hybrid resin in which a vinyl resin and a polyester resin are bonded can be exemplified by a polymerization method using a compound that can react with both of the monomers that produce both resins (hereinafter referred to as a "bireactive compound"). The bireactive compounds include fumaric acid, acrylic acid, methacrylic acid, citraconic acid, maleic acid, and difumaric acid in the monomers of condensation polymerization resins and addition polymerization resins. Among these, fumaric acid, acrylic acid, and methacrylic acid are preferably used.

[0036] The content of the polyester resin having a cyclic structure in the fraction having a molecular weight of 2000 or more separated by preparative GPC from the tetrahydrofuran soluble matter of the toner must be 51% by mass or more. When the polyester resin content is 51% by mass or more, the portion having a cyclic structure contained in the molecular chain of the polyester resin increases the rigidity of the binder resin, thereby increasing the elastic modulus of the toner. It is believed that increasing the elastic modulus of the toner can suppress toner crushing due to deformation of the toner. The content of the polyester resin having a cyclic structure in a fraction having a molecular weight of 2000 or more separated by preparative GPC from the tetrahydrofuran (THF) soluble matter of the toner is preferably 60% by mass or more and 80% by mass or less, and more preferably 65% ​​by mass or more and 75% by mass or less.

[0037] The vinyl resin content in a fraction having a molecular weight of 2000 or more, separated from the tetrahydrofuran-soluble fraction of the toner by preparative GPC, is preferably 1% by mass to 49% by mass, more preferably 3% by mass to 25% by mass, and even more preferably 5% by mass to 12% by mass. Within the above ranges, the toner has good heat-resistant storage stability and can suppress image streaks caused by member abrasion.

[0038] The mass ratio of the polyester resin having a cyclic structure to the vinyl resin in the fraction with a molecular weight of 2000 or more separated by preparative GPC from the THF-soluble portion of the toner is preferably in the range of polyester resin:vinyl resin = 60:40 to 99:1. Within this range, it is easier to achieve both suppression of abrasion of the developing member and suppression of toner crushing. A more preferred ratio is polyester resin:vinyl resin = 85:15 to 95:5.

[0039] The content of monomer units of monomers having a cyclic structure in the polyester resin is preferably 50% by mass to 100% by mass, more preferably 80% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass. The polyester resin is preferably a condensation polymer of an alcohol having a cyclic structure and a carboxylic acid having a cyclic structure.

[0040] <Thermosetting resin> A thermosetting resin is a crosslinked resin that forms a network structure by thermal crosslinking and hardens. The toner contains a thermosetting resin in the shell on the surface of the core particle. The thermosetting resin is at least one resin selected from the group consisting of a melamine resin, a urea resin, and a vinyl resin containing an oxazoline group. In this disclosure, the vinyl resin containing an oxazoline group is treated as a thermosetting resin in accordance with the above definition.

[0041] The shell may contain a plurality of thermosetting resins other than the above-mentioned thermosetting resins, such as sulfonamide-based resins, glyoxal-based resins, guanamine-based resins, aniline-based resins, polyimide resins, and xylene-based resins.

[0042] The shell may contain multiple thermoplastic resins in addition to the thermosetting resins. Examples of thermoplastic resins include styrene-based resins, acrylic acid-based resins, olefin-based resins, vinyl chloride resins, polyvinyl alcohol, vinyl ether resins, N-vinyl resins, polyester resins, polyamide resins, and urethane resins. Copolymers of these resins, i.e., copolymers in which any repeating unit is introduced into the resins, may also be used.

[0043] Shell consists of melamine resin, urea resin, and vinyl resin containing oxazoline group. The content of at least one selected from the group consisting of is preferably 50% by mass to 100% by mass, more preferably 80% by mass to 100% by mass, and even more preferably 90% by mass to 100% by mass.

[0044] The melamine resin is preferably a methylol melamine resin, a hexamethylol melamine resin, or a methoxymethylol melamine resin. The urea resin is preferably an alkylated urea resin or a methylolated urea resin.

[0045] The vinyl resin containing an oxazoline group is a vinyl resin containing a monomer unit containing an oxazoline group. The monomer forming the monomer unit containing an oxazoline group is, for example, a monomer represented by the following formula (5). 2-vinyl-2-oxazoline is more preferred. The vinyl resin containing an oxazoline group is preferably a vinyl resin containing a monomer unit containing an oxazoline group, and more preferably has a monomer unit in which 2-vinyl-2-oxazoline is vinyl-polymerized.

[0046] The vinyl resin containing an oxazoline group preferably has a monomer unit represented by the following formula (5B) which is derived from a monomer represented by the following formula (5). [ka]

[0047] In formula (5) or (5B), R 4 represents a hydrogen atom or an alkyl group. 4 Examples of the alkyl group represented by R are preferably alkyl groups having 1 to 6 carbon atoms, and more preferably methyl, ethyl, or isopropyl. 4 is more preferably a hydrogen atom. A suitable example of the vinyl compound represented by formula (5) is 2-vinyl-2-oxazoline.

[0048] A more preferred example of the vinyl resin containing an oxazoline group is a copolymer of a vinyl compound represented by formula (5) and a vinyl compound other than the vinyl compound represented by formula (5). Examples of vinyl compounds other than the vinyl compound represented by formula (5) include ethylene, propylene, butadiene, vinyl chloride, (meth)acrylic acid, (meth)acrylic acid esters, acrylonitrile, and styrene. The (meth)acrylic acid ester is preferably a (meth)acrylic acid alkyl ester, and the number of carbon atoms in the alkyl group is preferably 1 to 4. The (meth)acrylic acid alkyl ester is preferably methyl (meth)acrylate or ethyl (meth)acrylate, and more preferably methyl methacrylate.

[0049] The vinyl resin is preferably a copolymer of a vinyl compound represented by formula (5) and an alkyl (meth)acrylate, more preferably a copolymer of a vinyl compound represented by formula (5) and methyl methacrylate. The content of the structure represented by formula (5B) in the vinyl resin is preferably 5% by mass to 98% by mass, and more preferably 20% by mass to 95% by mass.

[0050] To form a shell using a vinyl resin containing an oxazoline group, for example, an aqueous solution of a polymer containing an oxazoline group ("Epocross (registered trademark) WS series" manufactured by Nippon Shokubai Co., Ltd.) can be used. "Epocross WS-300" and "Epocross WS-700" each contain a copolymer of 2-vinyl-2-oxazoline and an alkyl methacrylate ester.

[0051] <Average circularity of toner> The average circularity of the toner must be between 0.920 and 0.965. When the average circularity of the toner is 0.920 or more, sufficient toner fluidity is obtained, and the charging property is improved, which makes it possible to suppress image defects (fog) caused by the toner being developed in non-image areas. On the other hand, when the average circularity of the toner is 0.965 or less, the uneven shape of the toner particle surface can improve scraping performance with a cleaning blade, thereby suppressing image defects (image streaks) caused by poor cleaning. The average circularity of the toner is preferably 0.940 or more and 0.962 or less, more preferably 0.945 or more and 0.955 or less. The average circularity of the toner can be controlled by the toner manufacturing method. The method for measuring the average circularity of the toner will be described later.

[0052] <Ester compounds formulas (2) to (4)> The toner particles preferably contain at least one ester compound selected from the group consisting of an ester compound represented by the following formula (2), an ester compound represented by the following formula (3), and an ester compound represented by the following formula (4). [ka]

[0053] In formula (2), formula (3) and formula (4), R 31 , R 41 is an alkylene having 2 to 8 carbon atoms represents a hydroxyl group, and R 32 , R 33 , R 42 , R 43 , R 51 and R 52 each independently represents a linear alkyl group having 14 to 24 carbon atoms (preferably 16 to 24, more preferably 17 to 22). The ester compounds of formulas (2) to (4) have a high structural similarity to the monomer unit of formula (1) of the vinyl resin, and have high affinity, so that compatibility can be easily improved when melted, and good low-temperature fixability can be achieved.

[0054] Examples of the compound represented by formula (2) include ethylene glycol dipalmitate, ethylene glycol distearate, ethylene glycol dieicosanate, ethylene glycol dibehenate, ethylene glycol ditetracosanate, butanediol distearate, butanediol dibehenate, hexanediol distearate, hexanediol dibehenate, octanediol distearate, and octanediol dibehenate.

[0055] Examples of the compound represented by formula (3) include distearyl succinate, dibehenyl succinate, distearyl adipate, dibehenyl adipate, distearyl suberate, dibehenyl suberate, distearyl sebacate, and dibehenyl sebacate.

[0056] Examples of the compound represented by formula (4) include palmityl palmitate, stearyl palmitate, behenyl palmitate, palmityl stearate, stearyl stearate, behenyl stearate, palmityl behenate, stearyl behenate, and behenyl behenate.

[0057] Among the above ester compounds, from the perspective of having a preferred melting point and molecular weight as described below and enhancing the compatibility during melting with the monomer unit of formula (1), as the ester compound, at least one selected from the group consisting of ethylene glycol distearate, ethylene glycol dibehenate, dibehenyl sebacate, stearyl behenate, behenyl behenate, and behenyl stearate is preferred.

[0058] The melting point of the ester compound is preferably 60°C or higher and 90°C or lower, more preferably 65°C or higher and 85°C or lower. The molecular weight of the ester compound is preferably 500 or higher and 900 or lower, more preferably 550 or higher and 850 or lower.

[0059] The content of the ester compound is preferably 1.0 part by mass or more and 40.0 parts by mass or less, more preferably 3.0 parts by mass or more and 30.0 parts by mass or less, still more preferably 5.0 parts by mass or more and 25.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

[0060] <SP value> Let the SP value of the monomer unit represented by formula (1) be SPm (J / cm 3 ) 1 / 2 and the SP value of the ester compound be SPw (J / cm 3 ). At this time, it is preferable that SPm is 18.00 or higher and 19.00 or lower, and SPm and SPw satisfy the following formula (a). |SPm - SPw| ≤ 1.50 ···(a)

[0061] Since SPm being 18.00 or higher and 19.00 or lower makes the polarity of the monomer unit appropriate, the affinity with the vinyl resin can be kept high. As a result, the deformation range of the toner in the temperature region below the glass transition point of the entire vinyl resin can be increased, so that the wear of the developing member can be more effectively suppressed. SPm is preferably 18.50 to 18.90. Also, SPw is preferably 17.00 to 18.50, more preferably 17.40 to 18.20.

[0062] ​​ Furthermore, by satisfying |SPm-SPw|≦1.50, the affinity between the monomer unit of formula (1) and the ester compound is high, as described above, and therefore compatibility is easily improved when melted, resulting in better low-temperature fixability. |SPm-SPw| is preferably 1.30 or less, and more preferably 1.20 or less. There is no particular lower limit, but it is preferably 0.00 or more, 0.30 or more, or 0.50 or more.

[0063] The SP value of the ester compound, SPw, is calculated according to Fedors. The SP value of the monomer unit, SPm, is calculated as follows, according to the calculation method proposed by Fedors. Here, the monomer unit constituting the vinyl resin (when the polymer constituting the resin is produced by the polymerization reaction of a vinyl monomer) means the molecular structure in which the double bond of the vinyl monomer is cleaved by polymerization.

[0064] For example, the SP value (SPm) of a monomer unit (J / cm 3 ) 1 / 2 When calculating the evaporation energy (Δei) (J / mol) and molar volume (Δvi) (cm) for the atom or atomic group in the molecular structure of the monomer unit, refer to the table in "Polym. Eng. Sci., 14(2), 147-154 (1974)". 3 / mol) and calculate using the following formula. SPm=(ΣΔei / ΣΔvi) 1 / 2 The unit of SP value is (J / cm 3 ) 1 / 2 However, 1 (cal / cm 3 ) 1 / 2 =2.046×10 -3 (J / cm 3 ) 1 / 2 by (cal / cm 3 ) 1 / 2 can be converted into units of

[0065] The loss modulus G" (Pa) of the toner at 30°C in dynamic viscoelasticity measurement is 1.0 x 10 7 Over 7.0 x 10 7 Preferably, it is 1.0 x 10 or less. 7 Over 6.0 x 10 7 By controlling the amount of the toner in the above range, the heat-resistant storage stability of the toner is good, and image streaks caused by scraping of the members can be suppressed.

[0066] <Crystalline polyester resin> The toner particles preferably further contain a crystalline polyester resin. Any known crystalline polyester resin can be used as long as it exhibits crystallinity. "Exhibiting crystallinity" means that the endothermic curve obtained by DSC has a clear endothermic peak at the melting point, i.e., during heating. "Clear endothermic peak" means a peak with a half-width of 15°C or less in the endothermic curve when heated at a heating rate of 10°C / min.

[0067] Specifically, crystalline polyester resin refers to a resin that exhibits crystallinity among polyester resins obtained by a polymerization reaction between a divalent or higher carboxylic acid (polycarboxylic acid) monomer and a divalent or higher alcohol (polyhydric alcohol) monomer.

[0068] The crystalline polyester resin can be formed using a known esterification catalyst in the same manner as in the case of the amorphous polyester resin described above, and a polycarboxylic acid monomer and a polyhydric alcohol monomer that can be used in the synthesis of the crystalline polyester resin described below.

[0069] Examples of polycarboxylic acid monomers that can be used in the synthesis of crystalline polyester resins include saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecylsuccinic acid, 1,10-decanedicarboxylic acid (dodecanedioic acid), and 1,12-dodecanedicarboxylic acid (tetradecanedioic acid); alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid; trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid; and carboxylic acid derivatives thereof. Examples of the carboxylic acid include anhydrides of the carboxylic acid compound and alkyl esters having 1 to 3 carbon atoms. These may be used alone or in combination of two or more.

[0070] Examples of polyhydric alcohol monomers that can be used in the synthesis of crystalline polyester resins include aliphatic diols such as diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, and 1,4-butenediol; and trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These may be used alone or in combination of two or more.

[0071] Among the above polyhydric alcohol monomers, it is preferable to use ethylene glycol as the polyhydric alcohol monomer from the viewpoint of increasing compatibility with the unit of formula (1) when melted. Furthermore, among the above polycarboxylic acid monomers, it is preferable to use adipic acid, sebacic acid, azelaic acid, n-dodecylsuccinic acid, or 1,10-decanedicarboxylic acid (dodecanedioic acid) from the viewpoint of increasing the crystallinity of the crystalline polyester resin and improving its heat-resistant storage stability.

[0072] Furthermore, from the viewpoint of obtaining excellent low-temperature fixability, the content of the crystalline polyester resin in the toner is preferably 1.0% by mass or more and 30.0% by mass or less, and more preferably 5.0% by mass or more and 20.0% by mass or less. If the content is 1% by mass or more, sufficient low-temperature fixability can be obtained.

[0073] In addition, the molecular chains of crystalline polyester are oriented with a certain regularity. Therefore, due to the orientation, it has the property of being brittle and easily cracked. If the content is 30% by mass or less, it is possible to suppress component contamination caused by toner cracking, and therefore image defects (image streaks) can be suppressed. The content of the crystalline polyester resin is preferably 1.0 to 30.0 parts by mass, more preferably 5.0 to 25.0 parts by mass, and even more preferably 10.0 to 20.0 parts by mass, relative to 100 parts by mass of the binder resin.

[0074] The crystalline polyester resin preferably has a monomer unit represented by the following formula (A) and a monomer unit represented by the following formula (B): In formula (B), n represents an integer of 4 to 14 (preferably 6 to 12, more preferably 8 to 12). [ka]

[0075] <Release agent> The toner particles may contain a known wax as a release agent in addition to the above specific ester compound. Examples of release agents include petroleum waxes and derivatives thereof, such as paraffin wax, microcrystalline wax, and petrolatum, montan wax and derivatives thereof, hydrocarbon waxes and derivatives thereof produced by the Fischer-Tropsch process, polyolefin waxes and derivatives thereof, such as polyethylene, and natural waxes and derivatives thereof, such as carnauba wax and candelilla wax. The derivatives also include oxides, block copolymers with vinyl monomers, and graft-modified products. These may be used alone or in combination. The content of the release agent other than the ester compound is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass, relative to 100 parts by mass of the binder resin.

[0076] <Coloring agent> The toner particles may contain a colorant, which may be any of conventionally known pigments and dyes of black, yellow, magenta, cyan, and other colors, magnetic materials, and the like, without any particular limitation. Examples of black colorants include black pigments such as carbon black. Examples of yellow colorants include yellow pigments and yellow dyes such as monoazo compounds, disazo compounds, condensed azo compounds, isoindolinone compounds, benzimidazolone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds. Specific examples include CI Pigment Yellow 74, 93, 95, 109, 111, 128, 155, 174, 180, and 185, and CI Solvent Yellow 162.

[0077] Examples of magenta colorants include magenta pigments and magenta dyes such as monoazo compounds, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specific examples include CI Pigment Red 2, 3, 5, 6, 7, 23, 48:2, 48:3, 48:4, 57:1, 81:1, 122, 144, 146, 150, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, 269, and CI Pigment Violet 19.

[0078] Examples of cyan colorants include cyan pigments and cyan dyes such as copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, and basic dye lake compounds. Specific examples include CI Pigment Blue 1, 7, 15, 15:1, 15:2, 15:3, 15:4, 60, 62, and 66. The content of the colorant is preferably 1.0 part by mass or more and 20.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin or polymerizable monomer.

[0079] The toner may also contain a magnetic material to form a magnetic toner, in which case the magnetic material may also serve as a colorant. Examples of magnetic materials include iron oxides such as magnetite, hematite, and ferrite; metals such as iron, cobalt, and nickel, and alloys and mixtures of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium. When a magnetic material is used as the colorant, the content of the magnetic material is preferably 30.0 parts by mass or more and 100.0 parts by mass or less with respect to 100.0 parts by mass of the binder resin.

[0080] <Charge control agent> The toner may contain a charge control agent. As the charge control agent, any known charge control agent can be used without any particular limitation. Specifically, examples of the positive charge control agent include quaternary ammonium salts, polymeric compounds having quaternary ammonium salts in the side chains, guanidine compounds, pyridine compounds, nigrosine compounds, and imidazole compounds. Further, examples of negative charge control agents include metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, and dicarboxylic acids, and polymers or copolymers having metal compounds of the above aromatic carboxylic acids; polymers or copolymers having a sulfonic acid group, a sulfonate salt group, or a sulfonate ester group; metal salts or metal complexes of azo dyes or azo pigments; boron compounds, silicon compounds, and calixarenes. The charge control agent is preferably a quaternary ammonium salt or a polymer compound having a quaternary ammonium salt on a side chain. The content of the charge control agent in the toner is preferably 0.01% by mass or more and 5.00% by mass or less.

[0081] <External additives> The toner may contain an external additive. Any conventionally known external additive can be used as the external additive without any particular limitation. Specific examples include inorganic particles such as silica particles or metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.), organic particles made of vinyl resins, silicone resins, melamine resins, etc., and organic-inorganic composite particles.

[0082] The external additive may be surface-treated. Examples of the surface treatment agent include silicone varnish, various modified silicone varnishes, unmodified silicone oil, various modified silicone oils, silane compounds, silane coupling agents, other organosilicon compounds, and organotitanium compounds, and these may be used alone or in combination. The content of the external additive in the toner is preferably 0.1 parts by mass or more and 5.0 parts by mass or less with respect to 100 parts by mass of the toner particles.

[0083] The toner preferably contains crosslinked resin particles as an external additive. That is, the toner preferably contains toner particles and crosslinked resin particles. Among particles used as external additives, crosslinked resin particles have a relatively hard surface. Therefore, the crosslinked resin particles function as spacers that prevent the external additive from being embedded in the toner particles. As a result, image defects (fog) due to a decrease in the toner's chargeability can be further suppressed even after long-term use.

[0084] Examples of styrene-based monomers for synthesizing crosslinked resin microparticles include styrene, alkylstyrene, hydroxystyrene, and halogenated styrene. Examples of alkylstyrenes include α-methylstyrene, m-methylstyrene, p-methylstyrene, p-ethylstyrene, and 4-t-butylstyrene. Examples of hydroxystyrenes include p-hydroxystyrene and m-hydroxystyrene. Examples of halogenated styrenes include α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene. In order to easily synthesize the specific crosslinked polymer, styrene is preferred as the styrene-based monomer.

[0085] Examples of acrylic acid-based monomers for synthesizing crosslinked resin particles include (meth)acrylic acid, (meth)acrylamide, (meth)acrylonitrile, (meth)acrylic acid alkyl esters, and (meth)acrylic acid hydroxyalkyl esters. Examples of (meth)acrylic acid alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of (meth)acrylic acid hydroxyalkyl esters include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. In order to easily synthesize the crosslinked resin particles, the acrylic acid monomer is preferably an alkyl (meth)acrylate, more preferably methyl methacrylate.

[0086] Examples of crosslinking agents having two or more unsaturated bonds for synthesizing crosslinked resin particles include N,N'-methylenebisacrylamide, divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, tripropylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, 1,4-butanediol dimethacrylate, and 1,6-hexanediol dimethacrylate. In order to continuously form images of higher quality, divinylbenzene is preferred as the crosslinking agent having two or more unsaturated bonds.

[0087] The crosslinked resin particles are preferably styrene-acrylic resin particles crosslinked by a crosslinking agent. Furthermore, in order to continuously form high-quality images, the crosslinked resin particles preferably contain a polymer of styrene, an alkyl (meth)acrylate ester, and divinylbenzene as the constituent resin. For the same reason, the crosslinked resin particles more preferably contain only a polymer of styrene, an alkyl (meth)acrylate ester, and divinylbenzene as the constituent resin, and even more preferably contain only a polymer of styrene, methyl methacrylate, and divinylbenzene as the constituent resin.

[0088] The crosslinked resin particles preferably contain 5 to 40 mass % of styrene-based monomer units, and more preferably 10 to 30 mass %. The crosslinked resin particles preferably contain 20 to 90 mass % of (meth)acrylic acid alkyl ester-based monomer units, and more preferably 50 to 70 mass %. The crosslinked resin particles preferably contain 5 to 40 mass % of divinylbenzene-based monomer units, and more preferably 10 to 30 mass %. The crosslinked resin fine particles preferably have a number average primary particle diameter of 80 nm or more and 250 nm or less, and more preferably 100 nm or more and 150 nm or less.

[0089] <Toner manufacturing method> Known methods such as suspension polymerization, dissolution suspension, emulsion aggregation, and pulverization can be used as a method for producing toner, but are not limited to these. The toner comprises core particles containing a binder resin and a shell on the surface of the core particles. A production method in which core particles are prepared by the above-mentioned production method and then a shell is formed from the outside is preferred. Among these, a production method in which core particles are produced by a pulverization method or emulsion aggregation method and then a shell is formed from the outside in an aqueous system is more preferred. Note that the shell does not necessarily need to cover the entire core particle, and some parts of the core particle may be exposed.

[0090] <Method of manufacturing core particles> An example of the pulverization method will be described below. First, a binder resin and, if necessary, an internal additive (e.g., For example, at least one of a colorant, a release agent, a charge control agent, and a magnetic powder is mixed. The resulting mixture is then melt-kneaded. The resulting melt-kneaded mixture is then pulverized, and the pulverized product is classified. As a result, core particles having a desired particle size are obtained.

[0091] <Shell formation method> The core particles and the shell material (for example, an aqueous solution of a vinyl resin containing an oxazoline group) are added to an aqueous medium (for example, ion-exchanged water). The shell material (e.g., a vinyl resin containing an oxazoline group dissolved in an aqueous medium) adheres to the surface of the core particles in the liquid. To uniformly adhere the shell material to the surface of the core particles, it is preferable to highly disperse the core particles in the liquid containing the shell material. To highly disperse the core particles in the liquid, a surfactant may be added to the liquid, or the liquid may be stirred using a powerful stirring device (e.g., "Hivis Dispermix" manufactured by Primix Corporation).

[0092] Subsequently, a basic substance (for example, an aqueous ammonia solution) is further added to the aqueous medium. By controlling the amount of the basic substance added, the amount of unopened oxazoline groups contained in the toner can be adjusted. Subsequently, the temperature of the liquid containing the shell material and the like is increased at a predetermined rate (e.g., a rate selected from a range of 0.1°C / min to 3°C / min) to a predetermined holding temperature (e.g., a temperature selected from a range of 45°C to 85°C (preferably 50°C to 60°C)) while stirring. During this temperature increase, a ring-opening agent and / or a shell material (e.g., an aqueous solution of a vinyl resin containing an oxazoline group) may be added. Alternatively, after the temperature increase is complete (after the holding temperature is reached), a ring-opening agent and / or a shell material (e.g., an aqueous solution of a vinyl resin containing an oxazoline group) may be added.

[0093] After the temperature increase is complete, the liquid is maintained at the above-mentioned holding temperature for a predetermined time (for example, a time selected from 30 minutes to 4 hours) while stirring the liquid. While the liquid temperature is maintained at a high temperature (or while the temperature is increasing), a shell layer is formed. It is believed that a reaction (shell fixation) occurs between the core particles and the shell material. For example, it is believed that the oxazoline group of the shell material reacts with a functional group present on the surface of the binder resin that constitutes the toner core, causing ring opening, and a crosslinked structure derived from the ring-opened oxazoline group is formed inside the shell layer. A shell is formed on the surface of the core particles in the liquid, resulting in a dispersion of toner particles.

[0094] After the shell is formed, the dispersion of toner particles is neutralized using, for example, sodium hydroxide. The dispersion of toner particles is then cooled to, for example, room temperature (approximately 25°C). The dispersion of toner particles is then filtered using, for example, a Buchner funnel. This separates the toner particles from the liquid (solid-liquid separation), yielding wet cake-like toner particles.

[0095] The content and order of the shell manufacturing method can be changed as desired depending on the required toner configuration or properties. For example, the shell material may be added to the liquid all at once, or may be added to the liquid in multiple batches. When reacting a material (e.g., a shell material) in a liquid, the material may be added to the liquid and then reacted in the liquid for a predetermined period of time, or the material may be added to the liquid over a long period of time and reacted in the liquid while being added to the liquid. The content of the shell is preferably 1.0 to 10.0 parts by mass, and more preferably 3.0 to 7.0 parts by mass, relative to 100 parts by mass of the core particles.

[0096] The methods for measuring the various physical properties are described below. <Proportion of polyester resin and vinyl resin in the fraction with a molecular weight of 2000 or more separated by preparative GPC from the THF-soluble fraction of toner> The toner is dissolved in tetrahydrofuran (THF), and the solvent is removed from the resulting soluble fraction under reduced pressure to obtain the tetrahydrofuran (THF)-soluble component of the toner. The resulting tetrahydrofuran (THF)-soluble component of the toner is dissolved in chloroform to prepare a sample solution with a concentration of 25 mg / mL. 3.5 mL of the resulting sample solution is poured into the following apparatus, and under the conditions shown below, low-molecular-weight components derived from the release agent with a molecular weight of less than 2000 and high-molecular-weight components derived from the binder resin with a molecular weight of 2000 or more are separated. Preparative GPC device: Preparative HPLC (product name: LC-980 model, manufactured by Nippon Analytical Industry Co., Ltd.) Preparative columns: JAIGEL 3H, JAIGEL 5H (manufactured by Japan Analytical Industry Co., Ltd.) Eluent: chloroform Flow rate: 3.5mL / min

[0097] After the separation, the solvent is distilled off from each fraction under reduced pressure, and the fraction is further dried under reduced pressure in an atmosphere at 90°C for 24 hours. Thereafter, the high molecular weight component derived from the binder resin having a molecular weight of 2000 or more is taken as the component derived from the binder resin in the THF soluble matter (binder resin-derived component 1). Next, the proportion of vinyl resin in the binder resin-derived components in the THF-soluble matter is determined as follows. Weigh out 100 mg of binder resin-derived component 1 and dissolve it in 3 mL of chloroform. The chloroform-soluble fraction obtained above is introduced into a preparative HPLC (apparatus: LC-9130 NEXT manufactured by Japan Analytical Industry Co., Ltd.) with preparative columns: JAIGEL 3H and JAIGEL 5H (manufactured by Japan Analytical Industry Co., Ltd.) at a flow rate of 3.5 mL / min, using chloroform as the eluent. Using the above-mentioned device, binder resin-derived component 1 is separated into a high-polarity component and a low-polarity component, and the high-polarity component is separated as a polyester resin component and the low-polarity component is separated as a vinyl resin component. After separation, the solvent is distilled off from each fraction under reduced pressure, and the fraction is further dried for 24 hours under reduced pressure in an atmosphere at 90° C. The masses of the polyester resin component and the vinyl resin component are then precisely weighed, divided by the mass (100 mg) of the binder resin-derived component 1, and then multiplied by 100 to determine the proportions of polyester resin and vinyl resin in the fraction with a molecular weight of 2000 or more separated from the THF-soluble fraction by preparative GPC.

[0098] Furthermore, the content of polyester resin having a cyclic structure in the main chain in a fraction having a molecular weight of 2000 or more separated from the THF soluble fraction by preparative GPC is calculated by separating the polyester resin component as follows. 500 mL of acetone is added to 100 mg of polyester resin component, heated to 70°C until completely dissolved, and then gradually cooled to 25°C to recrystallize the crystalline polyester resin. The crystalline polyester resin is then suction filtered to separate it from the filtrate. The separated filtrate is then slowly added to 500 mL of methanol to reprecipitate the polyester resin having a cyclic structure in its main chain, and the polyester resin having a cyclic structure in its main chain is then collected using a suction filter. The obtained polyester resin having a cyclic structure in its main chain and crystalline polyester resin are dried under reduced pressure for 24 hours at 40° C. The masses of the polyester resin having a cyclic structure in its main chain and the crystalline polyester resin are each precisely weighed, divided by the mass of the polyester resin component (100 mg), and then multiplied by 100 to determine the proportions of the polyester resin having a cyclic structure in its main chain and the crystalline polyester resin. The ratio of polyester resin to vinyl resin in the hybrid resin is calculated using NMR as described below.

[0099] <Vinyl resin composition analysis> The vinyl resin component separated in the section on the proportion of the vinyl resin in the THF-soluble matter of the toner is used to measure the composition ratio and weight ratio by nuclear magnetic resonance spectroscopy (NMR). 1 mL of deuterated chloroform was added to 20 mg of a vinyl resin sample, and the dissolved resin was The NMR spectrum of the proton is measured. The molar ratio and mass ratio of each monomer are calculated from the obtained NMR spectrum, and the content ratio of each monomer unit can be determined. For example, in the case of a styrene-acrylic copolymer, the composition ratio and mass ratio can be calculated based on the peak at around 6.5 ppm derived from the styrene monomer and the peak at around 3.5-4.0 ppm derived from the acrylic monomer. The following equipment and measurement conditions can be used for nuclear magnetic resonance spectroscopy (NMR). NMR device: JEOL RESONANCE ECX500 Observed nucleus: proton Measurement mode: Single pulse

[0100] <Molecular weight measurement of ester compounds by mass spectrometry> Separation of ester compounds from toner The molecular weight of the ester compound in the toner can be determined by measuring the toner, but it is more preferable to measure it after carrying out a separation operation. The toner is dispersed in ethanol, a poor solvent for the toner, and the temperature is raised to a temperature above the melting point of the ester compound. Pressure may be applied at this time if necessary. By this operation, the ester compound exceeds its melting point and is melted and extracted into the ethanol. If pressure is applied in addition to heating, the ester compound can be separated from the toner by performing solid-liquid separation while still under pressure.

[0101] The extract is then dried and solidified to obtain the ester compound. The ester compound can be identified and its molecular weight measured by pyrolysis GCMS using the following equipment and measurement conditions. Mass spectrometer: ISQ manufactured by ThermoFisher Scientific GC equipment: ThermoFisher Scientific FocusGC Ion source temperature: 250℃ Ionization method: EI Mass range: 50-1000m / z Column: HP-5MS [30 m] Pyrolysis equipment: Japan Analytical Industry Co., Ltd. JPS-700

[0102] A small amount of the ester compound separated by extraction and 1 μL of tetramethylammonium hydroxide (TMAH) are added to a pyrofoil at 590°C. The resulting sample is subjected to pyrolysis GCMS measurement under the above conditions, and peaks are obtained for the alcohol and carboxylic acid components derived from the ester compound. The alcohol and carboxylic acid components are detected as methylated products due to the action of the methylating agent TMAH. The molecular weight of the ester compound can be determined by analyzing the peaks obtained and identifying the structure of the ester compound. When the ester compound is identified and its molecular weight is measured by the direct introduction method, the following apparatus and measurement conditions can be used. Mass spectrometer: ISQ manufactured by ThermoFisher Scientific Ion source temperature: 250°C Electron energy: 70 eV Mass range: 50-1000 m / z (CI) Reagent Gas: Methane (Cl) Ionization method: ThermoFisher Scientific Direct Exposure Probe (DEP), 0mA (10sec) - 10mA / sec - 1000mA (10sec) The ester compounds separated by the extraction operation are directly placed on the filament of the DEP unit and measured. The mass spectrum of the main component peak in the chromatogram obtained, which is located around 0.5 to 1 minute, is The molecular ions of the ester compounds are confirmed, and the ester compounds are identified and their molecular weights are determined.

[0103] <Method for measuring the content of ester compounds in toner> The content of the ester compound in the toner can be measured using a thermal analyzer (trade name: DSC Q2000, manufactured by TA Instruments Japan, Inc.). 5.0 mg of toner was placed in a sample container in an aluminum pan (KIT No. 0219-0041), the sample container was placed on a holder unit, and set in an electric furnace. Under a nitrogen atmosphere, the sample was heated from 30°C to 200°C at a temperature increase rate of 10°C / min, and a differential scanning calorimeter (DSC) was used to measure the DSC curve, and the endothermic heat of the ester compound in the toner was calculated. The endothermic heat of the ester compound in the toner was also calculated in the same manner using a 5.0 mg sample of the ester compound alone. The endothermic heat of the ester compound obtained in each measurement was then used to calculate the wax content using the following formula: Content of ester compound in toner (mass%) = (endothermic heat amount of ester compound in toner sample (J / g)) / (endothermic heat amount of ester compound alone (J / g)) × 100

[0104] <Volume Average Particle Size Dv and Particle Size Distribution Dv / Dn of Toner> The volume average particle diameter Dv, number average particle diameter Dn, and particle size distribution Dv / Dn of the toner are measured using a particle size analyzer (manufactured by Beckman Coulter, Inc., trade name: Multisizer). Measurements using this Multisizer are performed under the following conditions: aperture diameter: 100 μm, dispersion medium: Isoton II (trade name), concentration: 10%, number of particles measured: 100,000. Specifically, 0.2 g of toner is placed in a beaker, and an alkylbenzene sulfonic acid aqueous solution (manufactured by Fujifilm Corporation, product name: Drywell) is added as a dispersant. 2 mL of dispersion medium is then added to moisten the toner, after which 10 mL of dispersion medium is added, and the toner is dispersed in an ultrasonic disperser for 1 minute before measurement using the particle size measuring instrument described above.

[0105] <Method for measuring the melting point of ester compounds> 6 mg to 8 mg of the ester compound is weighed into a sample holder, and a differential scanning calorimeter (Seiko Instruments Inc., product name: RDC-220) is used to measure the temperature from 0°C to 150°C at a rate of 10°C / min to obtain a DSC curve. The peak temperature of the endothermic peak in the DSC curve is taken as the melting point.

[0106] <Method for measuring the glass transition temperature of toner> The glass transition temperature of the toner is measured in accordance with ASTM D3418-97. Specifically, 10 mg of the dried toner was weighed out and placed in an aluminum pan. An empty aluminum pan was used as a reference. The glass transition temperature of the weighed toner was measured using a differential scanning calorimeter (manufactured by SII NanoTechnology, Inc., product name: DSC6220) in accordance with ASTM D 3418-97 at a temperature range of 0°C to 150°C and a heating rate of 10°C / min.

[0107] <Method for measuring weight average molecular weight (Mw) and peak molecular weight (Mp) of resins, etc.> The weight average molecular weight (Mw) and peak molecular weight (Mp) of a resin are measured using gel permeation chromatography (GPC) as follows. (1) Preparation of measurement samples The sample and tetrahydrofuran (THF) are mixed at a concentration of 5.0 mg / mL, left at room temperature for 5 to 6 hours, and then shaken thoroughly to thoroughly mix the THF and sample until the sample no longer combines. The mixture is then left at room temperature for at least 12 hours. The time from the start of mixing the sample and THF to the end of the standing period is set at at least 72 hours, and the tetrahydrofuran (THF)-soluble portion of the sample is obtained. Thereafter, the solution is filtered through a solvent-resistant membrane filter (pore size 0.45 μm to 0.50 μm, Myshoridisc H-25-2 [manufactured by Tosoh Corporation]) to obtain a sample solution.

[0108] (2) Measurement of the sample Using the obtained sample solution, measurements are carried out under the following conditions. Apparatus: High-speed GPC apparatus LC-GPC 150C (Waters) Column: Shodex GPC KF-801, 802, 803, 804, 805, 806, 807 (Showa Denko Co., Ltd.) in 7-unit series Mobile phase: THF Flow rate: 1.0mL / min Column temperature: 40℃ Sample injection volume: 100 μL Detector: RI (refractive index) detector

[0109] When measuring the molecular weight of a sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithm of the calibration curve prepared using several monodisperse polystyrene standard samples and the count number. The standard polystyrene samples used to create the calibration curve were those manufactured by Pressure Chemical Co. or Tosoh Corporation, with a molecular weight of 6.0 × 10 2 , 2.1×10 3 , 4.0×10 3 , 1.75×10 4 , 5.1×10 4 , 1.1×10 5 , 3.9 × 10 5 , 8.6×10 5 , 2.0×10 6 , 4.48×10 6 Use the following.

[0110] <Method for measuring average circularity of toner> The average circularity of the toner is measured using a flow particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) under the measurement and analysis conditions used during the calibration process. The specific measurement method is as follows. First, 20 mL of ion-exchanged water from which impurities such as solids have been removed is placed in a glass container, and 0.2 mL of a solution prepared by diluting "Contaminon N" (a 10% aqueous solution of a pH 7 neutral detergent for cleaning precision measuring instruments, consisting of a nonionic surfactant, anionic surfactant, and organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) three times by mass with ion-exchanged water is added as a dispersant. 0.02 g of the sample to be measured was then added, and the mixture was dispersed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. The dispersion was then cooled appropriately so that the temperature was between 10°C and 40°C. A tabletop ultrasonic cleaner disperser "VS-150" (manufactured by Vervoclear) with an oscillation frequency of 50 kHz and an electrical output of 150 W was used as the ultrasonic disperser. A predetermined amount of ion-exchanged water was placed in the water tank, and 2 mL of the Contaminon N was added to the water tank.

[0111] For the measurement, the flow particle image analyzer described above equipped with the "LUCPLFLN" objective lens (magnification 20x, numerical aperture 0.40) was used, and the particle sheath "PSE-900A" (manufactured by Sysmex Corporation) was used as the sheath liquid. The dispersion prepared according to the above procedure was introduced into the flow particle image analyzer, and 2,000 toner particles were counted in HPF measurement mode and total count mode. The average circularity of the toner was calculated from the results.

[0112] <Observation of the presence or absence of a shell on toner particles> The presence or absence of a shell in a toner particle can be observed by observing the cross-sectional shape of the toner particle. A specific method for observing the cross-sectional shape of a toner particle is as follows. First, toner particles are thoroughly dispersed in a photocurable epoxy resin, and then the epoxy resin is cured by irradiating it with ultraviolet light. The resulting cured product is cut using a microtome equipped with a diamond blade to prepare a thin flake sample with a thickness of 100 nm. If necessary, the sample is stained with ruthenium tetroxide, and a transmission electron microscope (TEM) (product name: Tecnai TF20XT electron microscope, manufactured by FEI) is used to observe the cross section of the toner at an accelerating voltage of 120 kV to obtain a TEM image. In the above observation method, when the core and shell parts are made of different components, the difference in the staining state Contrast due to elemental mapping can be observed. The observation magnification is 20,000 times.

[0113] Whether the resin contained in the shell is at least one resin selected from the group consisting of melamine resin, urea resin, and vinyl resin containing an oxazoline group can be confirmed using TOF-SIMS (TRIFT-IV, manufactured by ULVAC-PHI, Inc.). The analysis conditions are as follows. Sample preparation: Toner is deposited on an indium sheet. Sample preparation: None Primary ion: Au + Accelerating voltage: 30 kV Charge neutralization mode: On Measurement mode: Positive Raster size: 100 μm Accumulation time: 180 seconds By performing this measurement, it is possible to detect the vinyl resin monomer units present on the toner surface. Because the shell on the toner surface contains vinyl resin, this measurement can detect the melamine resin, urea resin, and oxazoline group contained in the vinyl resin. The contents of melamine resin, urea resin, and oxazoline group contained in the vinyl resin are calculated from the intensity of the secondary ion mass spectrum (vertical axis: intensity, horizontal axis: mass number = m / z) obtained under the above conditions using a calibration curve created based on samples of known concentration.

[0114] <Measurement of dynamic viscoelasticity of toner> The measuring device was a rotating plate type rheometer "ARES" (TA INSTRUMEN A toner tablet press (manufactured by TS Co., Ltd.) is used as the measurement sample. The toner is pressure-molded into a disk shape with a diameter of 7.9 mm and a thickness of 2.0±0.3 mm using a tablet press at 25°C. The sample is attached to a parallel plate, and the temperature is raised from room temperature (25°C) to the viscoelasticity measurement starting temperature (50°C), and measurement is started under the following conditions. (1) Set the sample so that the initial normal force is 0. (2) Use parallel plates with a diameter of 7.9 mm. (3) The frequency is 1.0 Hz. (4) The initial applied strain (Strain) is set to 0.1%. (5) Measurements are performed between 25°C and 160°C at a temperature ramp rate of 2.0°C / min and a sampling frequency of 1 time / °C.

[0115] The measurement is performed under the following automatic adjustment mode setting conditions: Measurement is performed in automatic strain adjustment mode (Auto Strain). (6) Set the maximum applied strain to 20.0%. (7) Set the maximum torque (Max Allowed Torque) to 200.0 g·cm and the minimum torque (Min Allowed Torque) to 0.2 g·cm. (8) Set the strain adjustment to 20.0% of the current strain. The measurement is performed in the auto tension adjustment mode. (9) Set Auto Tension Direction to Compression. (10) Set the initial static force to 10.0 g and the auto tension sensitivity to 40.0 g. (11) The operating condition of the auto tension is a sample modulus of 1.0 × 10 3 (Pa) or more. From the loss modulus G" value at 30°C in this measurement, the loss modulus G" (Pa) of the toner at 30°C in the dynamic viscoelasticity measurement is calculated. [Example]

[0116] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, parts are by mass unless otherwise specified.

[0117] <Production example of polyester resin 1> The following materials were added to an autoclave equipped with a pressure reducing device, a water separating device, a nitrogen gas introducing device, a temperature measuring device and a stirring device. Terephthalic acid 32.3 parts (50.0 mol%) Bisphenol A-propylene oxide 2-mol adduct 67.7 parts (50.0 mol%) Potassium titanium oxalate (catalyst) 0.02 parts Subsequently, the reaction was carried out under a nitrogen atmosphere at normal pressure at 220° C. until the desired molecular weight was reached. After the temperature was lowered, the mixture was pulverized to obtain Polyester Resin 1.

[0118] <Production Example of Crystalline Polyester Resin 1> A reactor equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was charged with 45 mol% diethylene glycol and 55 mol% 1,12-dodecanedioic acid. 1 part tin dioctylate was added as a catalyst per 100 parts of monomers. The mixture was heated to 140°C under a nitrogen atmosphere and reacted for 6 hours while distilling off water at atmospheric pressure. The temperature was then increased to 200°C at a rate of 10°C / hour. After reaching 200°C, the mixture was reacted for 2 hours. The pressure in the reactor was then reduced to 5 kPa or less, and the mixture was reacted at 200°C while monitoring the molecular weight. Crystalline polyester resin 1 was obtained. The weight-average molecular weight (Mw) of crystalline polyester resin 1 was 35,000.

[0119] <Production example of crystalline polyester 2> Crystalline polyester resin 2 was obtained in the same manner as in the production example of crystalline polyester 1, except that the alcohol monomer was changed to 1,9-nonanediol. The weight average molecular weight (Mw) of crystalline polyester resin 2 was 36,000.

[0120] <Production example of vinyl resin 1> The following materials were placed in a reaction vessel equipped with a reflux condenser, a stirrer, a thermometer, and a nitrogen inlet tube under a nitrogen atmosphere. Solvent: Toluene 100.0 parts Monomer composition 100.0 parts (The monomer composition is a mixture of styrene, n-butyl acrylate, and lauryl acrylate in the ratios shown below.) (styrene 82.0 parts) (n-butyl acrylate 12.0 parts) (Lauryl acrylate 6.0 parts) Polymerization initiator: 0.5 parts t-butyl peroxypivalate (NOF Corporation: Perbutyl PV) The reaction vessel was heated to 70°C while stirring at 200 rpm, and a polymerization reaction was carried out for 12 hours, yielding a solution in which a polymer of the monomer composition was dissolved in toluene. The solution was then cooled to 25°C, and then poured into 1,000.0 parts of methanol while stirring, to precipitate the methanol-insoluble matter. The resulting methanol-insoluble matter was filtered, washed with methanol, and vacuum-dried at 40°C for 24 hours to yield vinyl resin 1. The weight-average molecular weight (Mw) of vinyl resin 1 was 21,000.

[0121] <Production Examples of Vinyl Resins 2 to 9> The same procedure was used as in the manufacturing example of vinyl resin 1, except that the types and quantities of materials listed in Table 1 were changed. Vinyl resins 2 to 9 were obtained. [Table 1]

[0122] <Production example of hybrid vinyl resin 1> A surfactant solution prepared by dissolving 2 parts of anionic surfactant (sodium dodecylbenzenesulfonate: DBS) in 740 parts of ion-exchanged water was added to a separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen inlet, and the temperature of the inner temperature chamber was raised to 80°C while stirring at a stirring speed of 230 rpm under a nitrogen stream.

[0123] Styrene 82.0 parts n-Butyl acrylate 12.0 parts Lauryl acrylate 6.0 parts Fumaric acid 1.0 parts On the other hand, the above materials were mixed and dissolved by humidification at 80°C to prepare a monomer solution. The two heated solutions were mixed and dispersed using a mechanical disperser with a circulation path to prepare emulsified particles with a uniform dispersed particle size. Next, a solution of 3.3 parts of a polymerization initiator (potassium persulfate: KPS) dissolved in 350 parts of ion-exchanged water was added, and the mixture was heated and stirred at 80°C for 3 hours to obtain a vinyl resin particle dispersion. Further, ion-exchanged water was added to this dispersion to adjust the solids content (vinyl resin particles) to 20% by mass, thereby obtaining vinyl resin particle dispersion 1.

[0124] Terephthalic acid 32.3 parts Bisphenol A-propylene oxide 2 mole adduct 67.7 parts (50.0 mole%) The above materials were stirred at 80°C for 1 hour to dissolve the solution, which was then added to the resulting vinyl resin particle dispersion 1 and allowed to react for 12 hours under reflux to obtain hybrid vinyl resin particle dispersion 1. The dispersion was then cooled to 25°C, and then poured into 1,000 parts of methanol with stirring to precipitate the methanol-insoluble matter. The resulting methanol-insoluble matter was filtered, washed with methanol, and vacuum-dried at 40°C for 24 hours to obtain hybrid vinyl resin 1. The weight-average molecular weight (Mw) of hybrid vinyl resin 1 was 35,000.

[0125] <Production Example of Ester Compound 1> Into a reaction vessel equipped with a thermometer, a nitrogen inlet tube, a stirrer, a Dean-Stark trap, and a Dimroth condenser, 100 parts of behenyl alcohol as an alcohol monomer and 80 parts of stearic acid as a carboxylic acid monomer were added, and an esterification reaction was carried out at 200°C for 15 hours. To the resulting ester compound, 20 parts of toluene and 25 parts of isopropanol were added, and 190 parts of a 10% aqueous potassium hydroxide solution, in an amount equivalent to 1.5 times the acid value of the ester compound, was added, followed by stirring at 70°C for 4 hours. The water tank was then removed. 20 parts of ion-exchanged water was then added, followed by stirring at 70°C for 1 hour, after which the water tank was removed and washed. The above washing process was repeated until the pH of the removed water tank became neutral. Then, the solvent is removed under reduced pressure at 200°C and 1 kPa to obtain the final product, behentrimonium. The ester compound of behenyl alcohol and stearic acid, behenyl stearate (ester compound 1), was obtained. The physical properties of the obtained ester compound 1 are shown in Table 2.

[0126] <Production Examples of Ester Compounds 2 to 5> Ester compounds 2 to 5 were obtained in the same manner as in the production method of ester compound 1, except that the monomers were changed so as to obtain the compounds shown in Table 2. The physical properties of the obtained ester compounds 2 to 5 are shown in Table 2. [Table 2]

[0127] <Production Example of Crosslinked Resin Particles 1> A glass container equipped with a stirrer, a condenser, a thermometer, and a nitrogen inlet tube was placed in a water bath at 80°C. Subsequently, 200 parts of ion-exchanged water and 3 parts of a surfactant (sodium lauryl sulfate) were placed in the container. Subsequently, while stirring the contents of the container, 1 part of ammonium persulfate and 100 parts of the monomer mixture were each added dropwise at a constant rate over 1 hour under conditions of a nitrogen atmosphere and a temperature of 80°C. The monomer mixture was a mixture of methyl methacrylate, styrene, and divinylbenzene. Furthermore, in the monomer mixture, the mass ratio of methyl methacrylate, styrene, and divinylbenzene (methyl methacrylate:styrene:divinylbenzene) was 3:1:1. The contents of the vessel were then reacted for 1 hour under a nitrogen atmosphere at 80°C while being stirred. As a result, an emulsion was obtained. The resulting emulsion was then cooled and dried at 80°C for 18 hours to obtain crosslinked resin microparticles 1. The number average primary particle diameter of the resulting crosslinked resin microparticles 1 was 120 nm.

[0128] <Production Example of Toner Particle 1> (Production of core particles) Vinyl resin 1: 10.0 parts Polyester resin 1: 90.0 parts Ester compound 1: 20.0 parts Crystalline polyester resin 1: 15.0 parts Fischer Trops Wax (HNP51, manufactured by Nippon Seiro Co., Ltd.): 5.0 parts Colorant: Carbon black (Mitsubishi Chemical, product name: #25B): 7.0 parts The above materials were premixed in a Henschel mixer (manufactured by Nippon Coke Co.), then melt-kneaded in a twin-screw extruder (manufactured by Ikegai Co., Ltd.: PCM-30). The resulting kneaded material was cooled, coarsely pulverized in a hammer mill, and then pulverized in a mechanical pulverizer (manufactured by Freund Turbo Co., Ltd.: T-250). The resulting finely pulverized powder was classified using a multi-division classifier utilizing the Coanda effect to obtain core particles with a weight-average particle size (D4) of 6.6 μm.

[0129] (Shell formation) A 1 L three-necked flask equipped with a thermometer and a stirring blade was placed in a water bath, and 300 g of ion-exchanged water was placed in the flask. The temperature inside the flask was then adjusted to 30°C using the water bath. Subsequently, an aqueous solution of an oxazoline group-containing resin ( "Epocross WS-300" manufactured by Nippon Shokubai Co., Ltd. (solid content concentration: 10% by mass) was added to the flask. The amounts in Table 3 indicate the ratio (unit: parts by mass) of the oxazoline group-containing resin (solid content) to 100 parts by mass of the core particles to be added later.

[0130] Next, 300 g of the core particles prepared in the above procedure was added to the flask, and the mixture was stirred at a rotation speed of 200 min -1 The contents of the flask were stirred for 1 hour at RT, and then 300 g of ion-exchanged water was added to the flask. Next, 6 mL of a 1% by mass aqueous ammonia solution was added to the flask. -1 While stirring the contents of the flask, the temperature inside the flask was raised to 55°C at a rate of 0.5°C / min. -1 The contents of the flask were stirred at 55°C and maintained at that temperature for 2 hours. Subsequently, an aqueous ammonia solution with a concentration of 1% by mass was added to the flask to adjust the pH of the contents of the flask to 7. Subsequently, the obtained slurry was cooled to room temperature (about 25°C).

[0131] (Cleaning process) The dispersion of toner particles obtained as described above was filtered (solid-liquid separation) using a Buchner funnel. As a result, wet cake-like toner particles were obtained. The obtained wet cake-like toner particles were then dispersed again in ion-exchanged water. The dispersion and filtration were repeated a total of five times to wash the toner particles.

[0132] (drying process) The washed toner particles (powder) were then dispersed in a 50% by mass aqueous ethanol solution to obtain a toner particle slurry. The toner particles were then subjected to a continuous surface modification process using a continuous surface modification device (Freund Corporation's "Coatmizer (registered trademark)") with a hot air temperature of 45°C and a blower air volume of 2 m. 3 The toner particles in the slurry were dried under the condition of 0.15 sieve / min, and dried toner particles 1 were obtained.

[0133] <Production Examples of Toner Particles 2 to 31> Toner particles 2 to 31 were produced in the same manner as in the production example of toner particle 1, except that the vinyl resin, polyester resin, ester compound, crystalline polyester resin, shell agent, and crosslinked resin fine particles were changed as shown in Table 3.

[0134] The shell agent used, Milben Resin SM-607 (product name: Showa Denko K.K.), is an aqueous solution of a hexamethylolmelamine prepolymer. Nikalac MX-280 (product name: Sanwa Chemical Co., Ltd.) is an alkylated urea resin. [Table 3]

[0135] <Toner 1 manufacturing example> For 100 parts of toner particles, silica fine particles (hexamethyldimethacrylate) were used as an external additive. Hydrophobic treatment with silazane, number average particle size of primary particles: 10 nm, BET specific surface area: 170 m 2 3.0 parts of the cellulose acetate solution (1.0 parts per 1000 mg / g) and 2.0 parts of crosslinked resin fine particles 1 were added, and the mixture was mixed in a Henschel mixer (manufactured by Nippon Coke Company) for 3,000 min -1 The mixture was mixed for 15 minutes at 100°C to obtain Toner 1. Table 4 shows the physical properties of Toner 1.

[0136] <Production examples of toners 2 to 31> Toner particles 2 to 31 were produced in the same manner as in the production example of toner 1, except that the crosslinked resin particles were changed as shown in Table 3. Table 4 shows the physical properties.

[0137] [Table 4] In the table, "polyester resin content" is the content of polyester resin having a cyclic structure in the fraction having a molecular weight of 2000 or more separated by preparative GPC from the tetrahydrofuran soluble matter of the toner. "Vinyl resin content" is the content of vinyl resin in the fraction having a molecular weight of 2000 or more separated by preparative GPC from the tetrahydrofuran soluble matter of the toner.

[0138] <Toner performance evaluation> The following evaluations were carried out using Toners 1 to 31. The evaluation results are shown in Table 5. The evaluation methods and evaluation criteria of the present invention will be explained below. The image forming apparatus used was a modified version of the commercially available laser printer LBP-712Ci (manufactured by Canon). The modification included changing the process speed to 250 mm / sec. The process cartridge used was a commercially available toner cartridge 040H (cyan) (manufactured by Canon). The product toner was removed from the inside of the cartridge, which was then cleaned with an air blower, and 165 g of the above toner was then refilled. In addition, the yellow, magenta, and black cartridges were inserted into each station with the product toner removed and the remaining toner detection mechanism disabled, and the evaluation was carried out. Changed.

[0139] <Evaluation of low-temperature fixability> The fixing unit was removed from a modified laser printer LBP-712Ci (Canon). Next, various potential settings were changed to enable development with positively charged toner, and the image receiving paper (Canon Office Planner 64 g / m 2 ) and an unfixed toner image (0.9 mg / cm) of 2.0 cm length x 15.0 cm width was created on the 2 ) was formed at a position 1.0 cm from the top edge in the paper feed direction. Next, the removed fixing unit was modified so that the fixing temperature and process speed could be adjusted, and a fixing test of an unfixed image was carried out using this. First, the unfixed image was fixed under a normal temperature and humidity environment (23°C, 60% RH) with a process speed of 250 mm / s, a fixing linear pressure of 27.4 kgf, and an initial temperature of 120°C. Dropouts were evaluated by printing a solid image and enlarging it 10 times with a loupe to check for defects in the black areas. The evaluation criteria were as follows. The evaluation results are shown in Table 5. (Evaluation criteria for low-temperature fixability) A: No missing spots: 0 B: If you look closely, you can see some missing spots: 1 to 3 C: Missing spots are visible but not noticeable: 4 to 6 spots D: Significant missing spots: 7 or more

[0140] <Heat resistance storage test in harsh environments> Approximately 100 g of each of the obtained toners 1 to 30 was placed in a 1000 ml resin cup and left in a low-temperature, low-humidity environment (15°C, 10% RH) for 24 hours, then transferred to a high-temperature, high-humidity environment (55°C, 95% RH) over 24 hours. After being left in the high-temperature, high-humidity environment for 24 hours, the environment was again transferred to a low-temperature, low-humidity environment (15°C, 10% RH) over 24 hours. This procedure was repeated three times, and the toner was then removed. To evaluate image quality after exposure to the above harsh conditions, the cartridge was left in a low-temperature, low-humidity environment (15.0°C, 10% RH) for one day, and then fogging was evaluated in the same environment. In a low-temperature, low-humidity environment, toner is more likely to be charged, resulting in a broader charge distribution and making fogging more likely to occur, resulting in a more severe evaluation.

[0141] Specifically, to test for fogging, a solid white image was printed and its reflectance was measured using a Tokyo Denshoku Reflectometer Model TC-6DS. The reflectance of the transfer paper (standard paper) before the solid white image was formed was also measured in the same way. A green filter was used. Fog was calculated from the reflectance before and after printing the solid white image using the following formula: Fog (reflectance) (%) = reflectance (%) of standard paper - reflectance (%) of white image sample The evaluation criteria for fogging are as follows: The evaluation results are shown in Table 5. (Evaluation criteria for preservation) A: Reflectance less than 1.0% B: Reflectance 1.0% or more and less than 1.5% C: Reflectance 1.5% or more and less than 2.5% D:Reflectance 2.5% or more

[0142] (Durability evaluation) Using the cartridges after the storage stability test in the above-mentioned harsh environment, an image output test of 5,000 sheets per day was carried out for 4 days in a high temperature and high humidity environment (32.5°C, 85%RH) in a mode where a horizontal line pattern with a print rate of 4% was printed on 2 sheets per job, and the machine was stopped between jobs before the next job started, for a total of 20,000 sheets. During this time, a solid image and a halftone image were output every 500 sheets, and vertical deterioration due to abrasion of the developing material was checked. The occurrence of streaks, so-called development streaks, was visually confirmed. The evaluation results are shown in Table 5. (Evaluation criteria for development streaks) A: No development streaks even after 20,000 sheets B: Development streaks occurred between 18,001 and 20,000 sheets C: Development streaks occurred between 16,001 and 18,000 sheets D: Development streaks occurred on 16,000 or fewer sheets

[0143] In addition, in the image output test, a fogging test was conducted after 10,000 sheets had been output. Specifically, a solid white image was output as a fogging test, and its reflectance was measured using a Tokyo Denshoku Reflectometer Model TC-6DS. Meanwhile, the reflectance of the transfer paper (standard paper) before the solid white image formation was also measured in the same manner. A green filter was used. Fog was calculated from the reflectance before and after the solid white image was output using the following formula: Fog (reflectance) (%) = reflectance (%) of standard paper - reflectance (%) of white image sample The evaluation criteria for fogging are as follows: The evaluation results are shown in Table 5. (Evaluation criteria for durability (fogging)) A: Reflectance less than 1.0% B: Reflectance 1.0% or more and less than 1.5% C: Reflectance 1.5% or more and less than 2.5% D:Reflectance 2.5% or more

[0144] [Table 5]

Claims

1. Core particles having a binder resin, and A shell having a thermosetting resin on the surface of the core particle 1. A toner having toner particles having The binder resin contains at least one of the following (i) and (ii): (i) Vinyl resins and polyester resins (ii) Hybrid resins in which vinyl resins and polyester resins are combined the polyester resin is an amorphous polyester resin having a cyclic structure in its main chain, the content of the amorphous polyester resin having a cyclic structure in its main chain in a fraction having a molecular weight of 2000 or more obtained by preparative GPC from the tetrahydrofuran soluble matter of the toner is 51% by mass or more; The vinyl resin has a monomer unit represented by the following formula (1): (In formula (1), R １ represents a hydrogen atom or a methyl group, and R ２ represents a linear alkyl group having 10 to 14 carbon atoms. the thermosetting resin is at least one resin selected from the group consisting of a melamine resin, a urea resin, and a vinyl resin containing an oxazoline group, The average circularity of the toner is 0.920 or more and 0.965 or less. A toner characterized by:

2. 2. The toner according to claim 1, wherein a content of the vinyl resin in a fraction having a molecular weight of 2000 or more separated by preparative GPC from a tetrahydrofuran soluble fraction of the toner is 1% by mass or more and 49% by mass or less.

3. 3. The toner according to claim 1, wherein the content of the monomer unit represented by formula (1) in the vinyl resin is 1.0% by mass or more and 15.0% by mass or less.

4. The toner according to any one of claims 1 to 3, wherein the toner particles contain at least one ester compound selected from the group consisting of an ester compound represented by the following formula (2), an ester compound represented by the following formula (3), and an ester compound represented by the following formula (4): (In formula (2), formula (3) and formula (4), R ３１ , R ４１ represents an alkylene group having 2 to 8 carbon atoms, and R ３２ , R ３３ , R ４２ , R ４３ , R ５１ and R ５２ each independently represents a linear alkyl group having 14 to 24 carbon atoms.

5. The SP value of the monomer unit represented by the formula (1) is SPm (J / cm ３ ) １／２ The SP value of the ester compound is SPw (J / cm ３ ) １／２ When The SPm is 18.00 or more and 19.00 or less, 5. The toner according to claim 4, wherein the SPm and the SPw satisfy the following formula (a): |SPm-SPw|≦1.50...(a)

6. 6. The toner according to claim 1, wherein the toner comprises the toner particles and crosslinked resin fine particles.

7. 7. The toner according to claim 6, wherein the crosslinked resin particles are particles of a styrene-acrylic resin crosslinked with a crosslinking agent.

8. The toner particles further contain a crystalline polyester resin, The crystalline polyester resin contains a monomer unit represented by the following formula (A) and a monomer unit represented by the following formula ( 8. The toner according to claim 1, which comprises a monomer unit represented by the formula (B). (In formula (B), n represents an integer of 4 to 14.)

9. In the monomer unit represented by the formula (1), R 2 is a linear alkyl group having 12 carbon atoms, the content of the monomer unit represented by formula (1) in the vinyl resin is 3.0% by mass or more and 15.0% by mass or less, 9. The toner according to claim 1, wherein the loss modulus G'' (Pa) of the toner at 30° C. is 1.0×10 7 or more and 4.5×10 7 or less in dynamic viscoelasticity measurement.

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