Toner

Abstract

The present invention relates to a toner. The toner includes toner particles, the toner particles comprising a core particle containing a resin component and a shell on the surface of the core particle, wherein the resin component contains more than 50.0% by mass of a polyester resin containing a monomer unit containing a heterocyclic group, and the shell contains at least one resin selected from the group consisting of a specific (meth)acrylic resin and a melamine resin.

Description

Technical Field

[0001] The present disclosure relates to a toner used for forming a toner image by developing an electrostatic latent image formed by a method such as an electrophotographic method, an electrostatic recording method, or a toner jet system recording method. Background Art

[0002] In recent years, due to the further development of devices such as copiers, printers, and fax receiving devices, users have increasingly stringent requirements for the electrophotographic technology used in these devices. In recent years, there has been a strong demand for the ability to perform good quality printing over a long period of time while using a compact design.

[0003] From the viewpoint of compact design, efforts have been made to achieve miniaturization, for example, by simplifying or slimming a fixing member, that is, a heat roller or film that plays a role in fixing a toner image to a transfer material. This method requires fixing to be performed without heating the fixing member as much as possible, and therefore a low-melting-point release agent or binder resin having a low melting point or glass transition point is generally used to produce a toner having excellent low-temperature fixability. Therefore, when such a toner is stored at a high temperature, the problem of toners fusing to each other easily occurs.

[0004] In view of the above problems, for example, Japanese Patent Application Laid-Open No. 2015-045844 discloses a core-shell toner using a thermosetting resin and a thermoplastic resin in its shell layer. Summary of the invention

[0005] However, from the viewpoint of being able to print with good quality for a long time, when repeated printing is continued using the aforementioned toner, the shell of the core-shell toner may eventually peel off from the core. Therefore, the charging property is disturbed, and further, the peeled shell and the exposed core may cause contamination of, for example, a developing member and a charging member or be fused to, for example, a developing member and a charging member, and then may eventually cause image defects. That is, it has been found that the core-shell toner such as mentioned above is problematic with respect to its durability.

[0006] There remains a need to improve the properties of toners in order to provide an image forming apparatus capable of long-term good quality printing while having a compact design as required by the market.

[0007] The present disclosure provides a toner that exhibits improved core / shell adhesion and suppresses peeling of the shell even in long-term use, and has excellent long-term developing performance.

[0008] A toner, comprising toner particles, wherein the toner particles contain:

[0009] A core particle containing a resin component and

[0010] A shell on the surface of the core particle, wherein

[0011] The resin component contains more than 50.0% by mass of a polyester resin containing a monomer unit represented by the following formula (1), and

[0012] The shell comprises at least one resin selected from the group consisting of the following (A) and (B):

[0013] (A) a (meth)acrylic resin comprising at least one monomer unit selected from the group consisting of the following formulae (2) and (3);

[0014] (B) Melamine-based resin

[0015] In formula (1), R 1 represents a heterocyclic group containing at least one heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur,

[0016] In formula (2), R 2 represents a hydrogen atom or a methyl group,

[0017] In formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 It represents an alkylene group having 1 to 3 carbon atoms.

[0018]

[0019] The present invention provides a toner which shows improved core / shell adhesion and suppresses peeling of the shell even in long-term use, and has excellent long-term developing performance.

[0020] Further features of the present invention will become apparent from the following description of exemplary embodiments. DETAILED DESCRIPTION

[0021] In the present disclosure, unless otherwise specified, the descriptions "from XX to YY" and "XX to YY" indicating a numerical range refer to a numerical range including its lower limit and upper limit as endpoints. In the case of describing a numerical range in stages, the upper and lower limits of each numerical range can be arbitrarily combined.

[0022] In this disclosure, "(meth)acrylate" refers to acrylate and / or methacrylate. "Monomer unit" refers to the reacted form of a monomeric species in a polymer.

[0023] The present inventors have found that by using core particles whose main component is a polyester resin having the aforementioned components and by using a shell having the aforementioned components, core particle / shell adhesion is improved and shell peeling is suppressed even in long-term use.

[0024] Specifically, for a toner having toner particles having a core particle containing a binder resin and having a shell on the surface of the core particle, the resin component of the core particle must contain more than 50.0% by mass of a polyester resin having a monomer unit represented by formula (1). The monomer unit given by formula (1) is a monomer unit of a condensed heterocyclic diol.

[0025] Furthermore, the shell has at least one resin selected from the group consisting of the following (A) and (B).

[0026] (A) (meth)acrylic resin having at least one monomer unit selected from the group consisting of formula (2) and formula (3)

[0027] (B) Melamine-based resin

[0028]

[0029] In formula (1), R 1 represents a heterocyclic group containing at least one heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur, wherein R 2 represents a hydrogen atom or a methyl group, in formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 It represents an alkylene group having 1 to 3 (more preferably 2 or 3) carbon numbers.

[0030] The present inventors believe that the detailed mechanism is as follows. When a polyester resin having a monomer unit derived from a heterocyclic diol represented by formula (1) is used for the resin component of the core particle, polarization is generated by the heteroatoms in the heterocyclic structure, so the polyester resin has high polarity. It is also believed that since formula (1) is a rigid ring structure, it promotes the exposure of highly polar heteroatoms at the interface of the core particle / shell.

[0031] When the aforementioned (meth)acrylic resin or melamine resin is used for the shell, these resins form hydrogen bonds with heteroatoms in the resin component of the core particles, and the adhesion between the core particles and the shell is improved due to intermolecular interaction.

[0032] Therefore, shell peeling can be suppressed even in long-term use. Due to such suppression of shell peeling, a toner exhibiting excellent durability is obtained, and also enables long-term suppression of development defects such as fogging and streaking.

[0033] The resin component of the core particle contains more than 50.0% by mass of a polyester resin having a monomer unit represented by formula (1) in the resin component of the core particle.

[0034] When the content is within this range, core particle / shell adhesion is improved and shell peeling is suppressed even in long-term use. More preferably, it is 55.0% by mass or more, and even more preferably, it is 60.0% by mass or more.

[0035] The upper limit is not particularly limited, but is preferably 100.0% by mass or less, more preferably 98.0% by mass or less, and still more preferably 95.0% by mass or less.

[0036] The content of the polyester resin of the monomer unit derived from the heterocyclic diol represented by formula (1) is preferably 5.0% to 35.0% by mass. When this range is observed, while the glass transition temperature of the resin is adjusted to an appropriate temperature, the intermolecular interaction required for the core particle / shell adhesion is obtained to a satisfactory degree. More preferably, it is 20.0% to 35.0% by mass.

[0037] The heterocyclic diol that can form the monomer unit represented by formula (1) can be exemplified by spirodiol and isosorbide and its derivatives. Among them, isosorbide and its alkylene oxide adduct are preferred. When isosorbide or its alkylene oxide adduct is used, the charge rise performance is excellent and the suppression of initial fogging is promoted.

[0038] R 1 An oxygen-containing heterocyclic group is preferred. In addition, the monomer unit represented by formula (1) is more preferably represented by at least one selected from the group consisting of the following formulae (1-2) and (1-3), and is still more preferably represented by the following formula (1-2).

[0039]

[0040] In formula (1-2), each R 5 Each of m and n is independently a linear or branched alkylene group having 2 to 8 carbon atoms (more preferably 2 or 3). m and n are each independently an integer of 0 or 1 to 5, and m+n satisfies 0 to 10. m and n are more preferably 0. In formula (1-3), each R 6 independently represents a hydrogen atom or a methyl group.

[0041] In addition to the monomer unit represented by formula (1), the polyester resin preferably contains at least one selected from the group consisting of a structure in which an aliphatic diol is condensed with a carboxylic acid component (preferably a dicarboxylic acid or a tricarboxylic acid) and a structure in which an alicyclic diol is condensed with a carboxylic acid component (preferably a dicarboxylic acid or a tricarboxylic acid), and the polyester resin more preferably contains a structure in which an aliphatic diol is condensed with a carboxylic acid component.

[0042] The aliphatic diol is exemplified by at least one selected from the group consisting of, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropylenetriol, and 2-methyl-1,2,4-butanetriol.

[0043] The alicyclic diol is exemplified by at least one selected from the group consisting of, for example, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 4-(2-hydroxyethyl)cyclohexanol, 4-(hydroxymethyl)cyclohexanol, 4,4′-dicyclohexanol, 2-cyclohexene-1,4-diol, 4-cyclohexene-1,2-dimethanol, 5-norbornene-2,3-dimethanol, and 5-norbornene-2,3-diol.

[0044] Examples of acid monomers are aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid, and their anhydrides; alkyl dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, and their anhydrides; succinic acid and its anhydride substituted by an alkyl or alkenyl group having a carbon number of 6 to 18; and unsaturated dicarboxylic acids such as fumaric acid, maleic acid, and citraconic acid, and their anhydrides.

[0045] Among them, polycarboxylic acids such as terephthalic acid, succinic acid, adipic acid, fumaric acid, trimellitic acid, pyromellitic acid, benzophenonetetracarboxylic acid and their anhydrides are preferably used as the acid monomer component. The weight average molecular weight Mw of the polyester resin is preferably 20,000 to 100,000.

[0046] The toner particles have a shell on the surface of the core particles. The shell does not need to cover the entire core particles, and the core particles may be partially exposed on the surface of the toner particles.

[0047] A melamine-based resin and / or a (meth)acrylic resin having at least one monomer unit selected from the group consisting of formula (2) and formula (3) must be used for the shell to improve the adhesion between the shell and the resin component of the core particle through the above-mentioned interaction.

[0048] The shell is more preferably a (meth)acrylic resin having at least one monomer unit selected from the group consisting of formula (2) and formula (3).

[0049] The melamine resin is preferably at least one selected from the group consisting of methylolmelamine resin, hexamethylolmelamine resin, and methoxymethylolmelamine resin. The melamine resin is more preferably hexamethylolmelamine resin.

[0050] Acrylic acid and methacrylic acid are (meth)acrylic monomers forming the monomer units of formula (2). Preferred examples of (meth)acrylic monomers forming the monomer units of formula (3) are 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and 2-hydroxypropyl methacrylate.

[0051] The (meth)acrylic resin has a monomer unit provided by the reaction of (meth)acrylic acid and / or (meth)acrylic acid ester. The (meth)acrylic resin is not limited to (meth)acrylic acid and (meth)acrylic acid ester, and a monomer having an ethylenically unsaturated bond may be used.

[0052] Free radical copolymerizable monomers other than the above-indicated monomers may also be used in combination therewith for the shell resin.

[0053] Examples are as follows: styrene and styrene derivatives, for example, α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, p-butylstyrene, p-tert-butylstyrene, p-hexylstyrene, p-octylstyrene, p-nonylstyrene, p-decylstyrene, p-dodecylstyrene, p-methoxystyrene, and p-phenylstyrene; acrylate monomers, for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylate isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, and benzyl acrylate; and methacrylate monomers such as methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, and n-nonyl methacrylate.

[0054] Di(meth)acrylates such as ethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate may also be used.

[0055] Among them, styrene is preferred. That is, the (meth)acrylic resin is preferably a styrene-(meth)acrylic resin having a monomer unit provided by a reaction of styrene as a constituent component.

[0056] The total content of at least one monomer unit selected from the group consisting of formula (2) and formula (3) in the (meth) acrylic resin is preferably 5.0% to 35.0% by mass. When the total content is within the specified range, the charging characteristics are excellent and the intermolecular interaction required for the core particle / shell adhesion is obtained to a satisfactory degree. More preferably, it is 10.0% to 25.0% by mass.

[0057] The shell content is preferably 0.5 parts by mass or more and 3.0 parts by mass or less relative to 100.0 parts by mass of the resin component in the core particles. When the shell content is within the specified range, there is no damage to the fixing performance induced by the shell and the storage stability is excellent. More preferably, it is 0.7 parts by mass or more and 2.5 parts by mass or less, and still more preferably, it is 0.7 parts by mass or more and 1.5 parts by mass or less.

[0058] Resin component of core particles

[0059] Other resins may also be used as the resin component of the core particles as long as the resin component of the core particles contains more than 50.0% by mass of a polyester resin having a monomer unit represented by the above formula (1).

[0060] For example, the following resins can be used.

[0061] The resins may be exemplified by the following: homopolymers of styrene and substituted forms thereof, such as polystyrene, polyparachlorostyrene, and polyvinyltoluene; styrene copolymers, such as styrene-parachlorostyrene copolymers, styrene-vinyltoluene copolymers, styrene-vinylnaphthalene copolymers, styrene-acrylate copolymers, styrene-methacrylate copolymers, styrene-methylα-chloromethacrylate copolymers, styrene-acrylonitrile copolymers, styrene-vinyl methyl ether copolymers, styrene-vinyl ethyl ether copolymers, styrene-vinyl methyl ketone copolymers, and styrene-acrylonitrile-indene copolymers; and polyvinyl chloride, phenolic resins, natural resin-modified phenolic resins, natural resin-modified maleic acid resins, acrylic resins, methacrylic resins, polyvinyl acetate, silicone resins, non-crystalline polyesters, crystalline polyesters, polyurethane resins, polyamide resins, furan resins, epoxy resins, xylene resins, polyvinyl butyral, terpene resins, coumarone-indene resins, and petroleum resins.

[0062] The resin component of the core particles preferably contains a styrene-acrylic resin such as a styrene-acrylate copolymer or a styrene-methacrylate copolymer.

[0063] The aforementioned styrene derivatives, acrylate monomers, and methacrylate monomers can be used for the styrene-acrylic resin. The aforementioned diacrylate can also be used.

[0064] The content of the styrene-acrylic resin in the resin component of the core particles is preferably 2.0% by mass or more and less than 50.0% by mass, and more preferably 5.0% by mass or more and 45.0% by mass or less.

[0065] Colorants

[0066] The toner particles preferably contain a colorant. Examples of the colorant include the following.

[0067] Black colorants can be exemplified by carbon black and colorants provided by toning to black using yellow colorants, magenta colorants, and cyan colorants. Pigments can be used as toners by themselves; however, the use of a dye / pigment combination brings about improved clarity and is therefore more preferred from the viewpoint of the quality of a full-color image.

[0068] Magenta pigments include the following: CI Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48:2, 48:3, 48:4, 49, 50, 51, 52, 53, 54, 55, 57:1 , 58, 60, 63, 64, 68, 81:1, 83, 87, 88, 89, 90, 112, 114, 122, 123, 146, 147, 150, 163, 184, 202, 206, 207, 209, 238, 269, and 282; CI Pigment Violet 19; and CI Vat Red 1, 2, 10, 13, 15, 23, 29, and 35.

[0069] Magenta dyes can be exemplified by the following: oil-soluble dyes such as CI Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 49, 81, 82, 83, 84, 100, 109, and 121; CI Disperse Red 9; CI Solvent Violet 8, 13, 14, 21, and 27; and CI Disperse Violet 1, and basic dyes exemplified by CI Basic Red 1, 2, 9, 12, 13, 14, 15, 17, 18, 22, 23, 24, 27, 29, 32, 34, 35, 36, 37, 38, 39, and 40 and CI Basic Violet 1, 3, 7, 10, 14, 15, 21, 25, 26, 27, and 28.

[0070] Cyan pigments can be exemplified by the following: CI Pigment Blue 2, 3, 15:2, 15:3, 15:4, 16, and 17; CI Vat Blue 6; CI Acid Blue 45; and copper phthalocyanine pigments in which 1 to 5 phthalimidomethyl groups are substituted on the phthalocyanine skeleton.

[0071] CI Solvent Blue 70 can be exemplified as the cyan dye.

[0072] The yellow pigment can be exemplified by the following: CI Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16, 17, 23, 62, 65, 73, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155, 168, 174, 175, 176, 180, 181, and 185, and CI Vat Yellow 1, 3, and 20.

[0073] CI Solvent Yellow 162 can be exemplified as the yellow dye.

[0074] The amount of the colorant used is preferably 0.1 parts by mass or more and 30 parts by mass or less relative to 100.0 parts by mass of the binder resin.

[0075] wax

[0076] The toner particles preferably contain wax. The wax is not particularly limited, but it can be exemplified by the following: hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, alkylene copolymers, microcrystalline waxes, paraffin waxes, and Fischer-Tropsch waxes; oxides of hydrocarbon waxes such as oxidized polyethylene waxes and block copolymers thereof; waxes in which the main component is a fatty acid ester, such as palm wax; and waxes provided by partial or complete deacidification of a fatty acid ester, such as deacidified palm wax.

[0077] Other examples are as follows: saturated straight-chain fatty acids such as palmitic acid, stearic acid, and montanic acid; unsaturated fatty acids such as brazileic acid, eleostearic acid, and stearidonic acid; saturated alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauba alcohol, wax alcohol, and myricol; polyols such as sorbitol; esters between fatty acids such as palmitic acid, stearic acid, behenic acid, or montanic acid and alcohols such as stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauba alcohol, wax alcohol, or myricol; fatty acid amides such as linoleamide, oleamide, and lauramide; saturated fatty acid bisamides such as methylene bisstearamide, ethylene bisdecylamide, ethylene bislaurylamide, and ethylene biscaprylamide. amides, and hexamethylene bisstearamide; unsaturated fatty acid amides, such as ethylene bisoleamide, hexamethylene bisoleamide, N,N′-dioleoyl adipamide and N,N′-dioleoyl sebacamide; aromatic bisamides, such as meta-xylene bisstearamide and N,N′-distearyl isophthalamide; fatty acid metal salts (usually, called metal soaps), such as calcium stearate, calcium laurate, zinc stearate, and magnesium stearate; waxes obtained by grafting aliphatic hydrocarbon waxes with vinyl monomers such as styrene or acrylic acid; partial esters between fatty acids and polyols, such as monoglyceride of behenic acid; and hydroxyl-containing methyl ester compounds obtained by hydrogenation of vegetable oils.

[0078] Among these waxes, from the viewpoint of improving low-temperature fixability and resistance to wraparound during fixation, for example, paraffin wax, ester wax such as Fischer-Tropsch wax, and hydrocarbon wax are preferred.

[0079] The content of the wax is preferably 0.5 parts by mass or more and 25.0 parts by mass or less relative to 100.0 parts by mass of the binder resin.

[0080] From the viewpoint of the coexistence of the storage stability of the toner and its high-temperature offset resistance, the peak temperature of the maximum endothermic peak of the wax present in the temperature range of 30°C to 200°C in the endothermic curve during heating as measured by a differential scanning calorimeter (DSC) is preferably 50°C to 110°C.

[0081] Charge control agent

[0082] A charge control agent may also be optionally introduced into the toner. A known charge control agent may be used as the charge control agent. The charge control agent may be added internally or externally to the toner particles. The added amount of the charge control agent is preferably 0.2 parts by mass or more and 10.0 parts by mass or less relative to 100.0 parts by mass of the binder resin.

[0083] The toner may be used in the form of a one-component developer. From the viewpoint of obtaining a stable image over a long period of time, the toner may be mixed with a magnetic carrier and used as a two-component developer.

[0084] Carrier

[0085] For example, the following well-known magnetic carriers can be used as the magnetic carrier here: magnetic bodies, such as surface-oxidized iron powder; unoxidized iron powder; metal particles such as iron, lithium, calcium, magnesium, nickel, copper, zinc, cobalt, manganese, and rare earths, and their alloy particles, oxide particles, and ferrite, and magnetic body-dispersed resin carriers (referred to as resin carriers) containing a magnetic body and a binder resin for maintaining the magnetic body in a dispersed state.

[0086] When the colorant is mixed with a magnetic carrier and used as a two-component developer, excellent results are generally obtained when the carrier mixing ratio, which is expressed as the colorant concentration in the two-component developer in this case, is preferably greater than 2 mass % and less than 15 mass %, more preferably greater than 4 mass % and less than 13 mass %.

[0087] The method for producing the toner particles may be a known method such as an emulsion polymerization method, a pulverization method, and a dissolution suspension method, but is not particularly limited.

[0088] The following describes a manufacturing method using a pulverization method. In the pulverization method, a resin component is mixed with any optional components such as a colorant, a wax, and a charge control agent, and then the resulting mixture is melt-kneaded. The melt-kneaded material obtained is pulverized and classified to obtain core particles having a desired particle size.

[0089] The shell covering the core particles is preferably formed by adding a shell-forming material to an aqueous solution. The shell-forming material is preferably added in the form of a dispersion of resin particles.

[0090] After adding the core particles to the aqueous medium, the core particles are dispersed in the aqueous medium. The method for performing the dispersion can be exemplified by a method in which the core particles are mechanically dispersed in the aqueous medium using a device capable of vigorously stirring the dispersion liquid, and a method in which the core particles are dispersed in an aqueous medium containing a dispersant. The method of using a toner with a dispersant is advantageous in that a uniform dispersion of the core particles is produced in the aqueous medium, and thus the shell formation is promoted without exposing the surface of the core particles.

[0091] As an apparatus capable of vigorously stirring the dispersion liquid, for example, an apparatus such as HIVIS MIX (PRIMIX Corporation) is preferred.

[0092] The shell can be formed by adding a shell forming material and attaching the shell forming material to the core particles and raising the temperature. The temperature during the shell layer formation is preferably 65° C. or higher and 95° C. or lower, more preferably 70° C. or higher and 90° C. or lower. By performing the shell layer formation at a temperature within this range, unification between and among the formed toner particles is suppressed while the shell layer formation is well performed.

[0093] After the shell formation is performed as described above, a toner particle dispersion can be obtained by cooling the dispersion containing the shell-coated core particles to room temperature. Then, the toner particles are washed and dried as necessary to obtain toner particles.

[0094] The weight average molecular particle diameter of the toner particles is preferably 4.0 μm to 8.0 μm.

[0095] The toner particles can be used directly as a toner. If necessary, an external additive can be attached to the surface of the toner particles, which can then be used as a toner. In a preferred method, the toner particles are mixed with the external additive using a mixer such as FM mixer (Nippon Coke & Engineering Co., Ltd.) by adjusting the conditions to avoid the external additive from being buried in the surface of the toner particles.

[0096] The methods used to determine various properties are described below.

[0097] Identification of resins present in the core and shell

[0098] The composition and ratio of the constituent compounds of the resins present in the core and shell are identified using pyrolysis gas chromatography-mass spectrometry (hereinafter also referred to as "pyrolysis GC / MS") and NMR. When the resins present in the core and shell are available separately, they can also be measured separately.

[0099] Pyrolysis GS / MS is used to analyze the types of constituent compounds of the resin. The types of constituent compounds are identified by analyzing the mass spectrum of components in the resin pyrolyzate produced by pyrolyzing the resin at 550° C. to 700° C. Specific measurement conditions are provided below.

[0100] Pyrolysis GC / MS conditions

[0101] Pyrolysis equipment: JPS-700 (Japan Analytical Industry Co., Ltd.)

[0102] Pyrolysis temperature: 590℃

[0103] GC / MS instrument: Focus GC / ISQ (Thermo Fisher)

[0104] Column: HP-5MS, length 60m, inner diameter 0.25mm, membrane thickness 0.25μm

[0105] Inlet temperature: 200℃

[0106] Flow pressure: 100kPa

[0107] Split: 50mL / min

[0108] MS ionization: EI

[0109] Ion source temperature: 200°C Mass range 45 to 650

[0110] Then use solid 1 H-NMR was used to measure and calculate the occurrence ratio of the identified constituent compounds of the resin. 1 The structure was confirmed by H-NMR (400 MHz, CDCl3, room temperature (25°C)).

[0111] Measurement device: JNM-EX400 FT-NMR instrument (JEOL Ltd.)

[0112] Measurement frequency: 400MHz

[0113] Pulse condition: 5.0μs

[0114] Frequency range: 10,500Hz

[0115] Total times: 1024

[0116] The molar ratio of each monomer component was determined from the integrated value in the obtained spectrum, and the composition ratio (mass %) was calculated based on this.

[0117] Method for measuring weight average particle size (D4) of toner particles

[0118] The weight average particle size (D4) of the toner particles is determined by measuring in an effective measurement channel number of 25,000 channels, using a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, Beckman Coulter, Inc.) equipped with a 100 μm orifice tube and operating based on the pore resistance method, and using the accompanying dedicated software, namely "Beckman Coulter Multisizer 3 3.51 version" (Beckman Coulter, Inc.) to set measurement conditions and analyze measurement data, and to analyze measurement data.

[0119] The aqueous electrolyte solution used for the measurement is prepared by dissolving special grade sodium chloride in deionized water to provide a concentration of about 1 mass %, and, for example, "ISOTON II" (Beckman Coulter, Inc.) can be used.

[0120] The dedicated software was set as follows before measurement and analysis. On the "Change Standard Measurement Method (SOM)" screen of the dedicated software, the total count in the control mode was set to 50,000 particles; the number of measurements was set to 1; and the Kd value was set to the value obtained using "Standard Particles 10.0 μm" (Beckman Coulter, Inc.). The threshold and noise level were automatically set by pressing the Threshold / Noise Level Determination button. In addition, the current was set to 1600 μA; the gain was set to 2; the electrolyte solution was set to ISOTON II; and an input check was used for post-measurement mouth tube flushing.

[0121] On the "Pulse to Particle Size Conversion Settings" interface of the dedicated software, the element interval was set to the logarithmic particle size; the particle size element was set to 256 particle size elements; and the particle size range was set to be greater than 2 μm and less than 60 μm.

[0122] The specific measurement method is as follows.

[0123] (1) About 200 mL of the above electrolyte aqueous solution was introduced into a 250-mL round-bottom glass beaker for use with Multisizer 3, placed in a sample holder and stirred counterclockwise at 24 revolutions per second with a stirring rod. Dirt and bubbles in the nozzle were preliminarily removed by the "swept nozzle flushing" function of the dedicated software.

[0124] (2) About 30 mL of an aqueous electrolyte solution was introduced into a 100-mL flat-bottom glass beaker, and about 0.3 mL of the following dilution liquid as a dispersant was added thereto.

[0125] · Dilution: A dilution prepared by diluting “Contaminon N” (a 10% by mass aqueous solution of a neutral detergent for cleaning precision measuring instruments having a pH of 7, the neutral detergent comprising a nonionic surfactant, an anionic surfactant and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd.) with deionized water three times (by mass).

[0126] (3) A specified amount of deionized water was introduced into a water tank of an ultrasonic disperser described below having a power output of 120 W and equipped with two oscillators (oscillation frequency = 50 kHz) set with a phase shift of 180°, and about 2 mL of Contaminon N was added to the water tank.

[0127] Ultrasonic Dispersion System Tetora 150 (Nikkaki Bios Co., Ltd.)

[0128] (4) The beaker described in (2) is set in the beaker fixing hole of the ultrasonic disperser and the ultrasonic disperser is started. The height position of the beaker is adjusted so as to maximize the resonance state of the surface of the aqueous electrolyte solution in the beaker.

[0129] (5) While irradiating the electrolyte aqueous solution in the beaker set according to (4) with ultrasonic waves, about 10 mg of the toner is added to the electrolyte aqueous solution in small portions and dispersed. The ultrasonic dispersion treatment is continued for another 60 seconds. During the ultrasonic dispersion, the water temperature in the water tank is appropriately controlled to be 15° C. or more and 40° C. or less.

[0130] (6) Using a pipette, the aqueous electrolyte solution containing the dispersed toner prepared in (5) is added dropwise to the round-bottom beaker set in the sample holder as described in (1), while adjusting to provide a measurement concentration of about 5%. Then, measurement is performed until the number of particles measured reaches 50,000.

[0131] (7) The measurement data is analyzed by the dedicated software attached to the device to calculate the weight average particle size (D4). When the dedicated software is set to graph / volume %, the "average diameter" on the analysis / volume statistics (arithmetic mean) interface is the weight average particle size (D4).

[0132] Example

[0133] The present invention is described in more detail below using examples. The present invention is not limited by the following examples. Unless otherwise specified, the parts in the examples and comparative examples are based on mass in all cases.

[0134] Production of core particle polyester resin 1

[0135] 100.0 parts of terephthalic acid, 23.1 parts of trimellitic anhydride, 11.7 parts of adipic acid, 70.4 parts of isosorbide, and 42.8 parts of 1,3-propylene glycol were added to a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introduction tube, a water separation tube, and a pressure reducing device, and heated to 130° C. while stirring.

[0136] 0.5 parts of isopropoxytitanium (IV) was added as an esterification catalyst, after which the temperature was raised to 160° C. and polycondensation was performed for 5 hours. The temperature was then raised to 180° C. and a reaction was performed under reduced pressure until the desired molecular weight was reached to produce polyester resin 1. The weight average molecular weight Mw of polyester resin 1 was 50,000.

[0137] Production of core particle polyester resins 2 to 8

[0138] Polyester resins 2 to 8 were prepared using the same manufacturing method as that of polyester resin 1, except that the starting materials were changed as shown in Table 1.

[0139] [Table 1]

[0140]

[0141] The "amount of formula (1)" in the table means the content of the monomer unit represented by formula (1) in the polyester resin.

[0142] Production of core particle styrene-acrylic resin

[0143] 80.0 parts of styrene, 20.0 parts of n-butyl acrylate, and 0.3 parts of hexanediol diacrylate were added to a reaction container equipped with a stirrer, a thermometer, and a nitrogen inlet tube, and heated to a temperature of 80° C. while stirring.

[0144] Then, 2.0 parts of Perbutyl O (10-hour half-life, temperature 72.1° C. (NOF Corporation)) was added as a polymerization initiator and polymerization was performed for 5 hours to obtain a styrene-acrylic resin for core particles.

[0145] Production of Shell Resin 1

[0146] 62.8 parts of styrene, 20.9 parts of 2-hydroxyethyl methacrylate, 15.5 parts of n-butyl acrylate, and 0.8 parts of ethylene glycol dimethacrylate were added and dispersed to an aqueous solution of 3.0 parts of a surfactant Neogen RK (Dai-ichi Kogyo Seiyaku Co., Ltd.) dissolved in 50 parts of deionized water.

[0147] While gently stirring for 10 minutes, an aqueous solution of 0.3 parts of potassium persulfate dissolved in 10 parts of deionized water was also added. After nitrogen substitution had been performed, emulsion polymerization was performed at 70° C. for 6 hours. After the polymerization was completed, the reaction solution was cooled to room temperature and deionized water was added to produce an aqueous dispersion of shell resin 1 having a solid concentration of 50.0% by mass (shell resin 1 dispersion).

[0148] Production Examples of Shell Resins 2 to 6

[0149] Shell resins 2 to 6 were obtained by the same procedure as in the production example of shell resin 1 except that the monomer composition was changed as shown in Table 2.

[0150] [Table 2]

[0151]

[0152] In the table, "the amount of formula (2) and (3)" refers to the total content of at least one monomer unit selected from the group consisting of formula (2) and formula (3). The following abbreviations are also used.

[0153] 2-HEMA: 2-Hydroxyethyl Methacrylate

[0154] MMA-EG: Ethylene glycol dimethacrylate

[0155] Production of Toner 1

[0156] Preparation of core particle 1

[0157]

[0158]

[0159] These materials were preliminarily mixed using a Mitsui Henschel mixer (Mitsui Miike Chemical Engineering Machinery Co., Ltd.), and then melt-kneaded using a twin-screw extruder (trade name: PCM-30, Ikegai Ironworks Corporation) at a temperature set so that the temperature of the molten material at the discharge port was 140°C.

[0160] The obtained kneaded material was cooled and coarsely pulverized using a hammer mill and then pulverized using a pulverizer (trade name: TurboMill T250, Turbo Kogyo Co., Ltd.) The finely pulverized powder was classified using a multi-classifier based on the Coanda effect to produce core particles 1 having a weight average particle size (D4) of 6.8 μm.

[0161] Production of toner particles 1

[0162] An aqueous medium was prepared by adding 1.8 parts of tricalcium phosphate to 250.0 parts of deionized water heated to a temperature of 40° C. and stirring at a stirring rate of 15,000 rpm using a TK Homomixer (Tokushu Kika Kogyo Co., Ltd.).

[0163] A core particle 1 slurry was prepared by adding 100.0 parts of the core particle 1 to an aqueous medium. Then, 2.0 parts of a shell resin 1 dispersion having a solid concentration of 50.0% by mass was added so that 1.0 part of the shell resin 1 was added per 100.0 parts of the core particle 1, and a shell layer was formed on the surface of the core particle by heating to 75° C. and maintaining for 2 hours.

[0164] After cooling to room temperature, the calcium phosphate dispersant was dissolved by adding hydrochloric acid, filtered, washed with water, dried, and then toner particles 1 having a core-shell structure and having a weight average particle diameter (D4) of 6.8 μm were obtained.

[0165] Production of Toner 1

[0166] 100.0 parts of Toner Particles 1 were mixed with 1.5 parts of dry silica particles ("AEROSIL (registered trademark) REA90", positively charged hydrophobized silica particles, Nippon Aerosil Co., Ltd.) for 3 minutes using an FM mixer (Nippon Coke & Engineering Co., Ltd.) to attach the silica particles to Toner Particles 1. This was then sieved with 300 mesh (aperture = 48 μm) to produce Toner 1.

[0167] Production of Toners 2 to 9, 11 to 14, and 17 to 19

[0168] Toners 2 to 9, 11 to 14, and 17 to 19 were obtained by the same manufacturing method as for Toner 1 except for the changes as shown in Table 3.

[0169] Production of Toner 10

[0170] Production of Toner Particles 10

[0171] The aqueous medium in the beaker was adjusted to pH 4 by adding dilute hydrochloric acid to 250.0 parts of deionized water heated to a temperature of 30°C.

[0172] Then, 1.25 parts of a hexamethylolmelamine prepolymer ("Milben 607", solid concentration = 80.0% by mass, Showa Denko Kabushiki Kaisha) was added and dissolved in the aqueous medium by stirring.

[0173] Then, 100.0 parts of the core particles 1 were added to the aqueous medium and stirred while being heated to 70° C. at a rate of 1° C. / min and maintained for 2 hours to form a shell layer on the surface of the core particles. After cooling to room temperature, the mixture was filtered, washed with water, and dried to produce toner particles 10 having a core-shell structure and having a weight average particle size (D4) of 6.8 μm.

[0174] Production of Toner 10

[0175] 100.0 parts of Toner Particles 10 were mixed with 1.5 parts of dry silica particles ("AEROSIL (registered trademark) REA90", positively charged hydrophobized silica particles, Nippon Aerosil Co., Ltd.) for 3 minutes using an FM mixer (Nippon Coke & Engineering Co., Ltd.) to attach the silica particles to Toner Particles 10. This was then sieved with 300 mesh (aperture = 48 μm) to produce Toner 10.

[0176] Production of Toner 15

[0177] Preparation of polyester resin particle dispersion

[0178] ·Polyester resin 1 200.0 parts

[0179] ·500.0 parts of deionized water

[0180] These materials were introduced into a stainless steel container; heated to 95°C and melted in a hot water bath; and, while being thoroughly stirred at 7,800 rpm using a homogenizer (Ultra-Turrax T50, IKA), the pH was made higher than 7.0 by adding 0.1 mol / L of sodium bicarbonate. Then, while emulsifying and dispersing, a mixed solution of 3.0 parts of sodium dodecylbenzenesulfonate and 297.0 parts of deionized water was gradually added dropwise to obtain a polyester resin particle dispersion.

[0181] When the particle size distribution of the polyester resin particle dispersion was measured using a particle size distribution analyzer (LA-920, Horiba, Ltd.), the weight average particle size of the contained polyester resin particles was 0.25 μm, and coarse particles exceeding 1 μm were not observed.

[0182] Preparation of styrene-acrylic resin particle dispersion

[0183] · 200.0 parts of styrene-acrylic resin for core resin

[0184] ·500.0 parts of deionized water

[0185] These materials were introduced into a stainless steel container; heated to 95°C and melted in a hot water bath; and, while being thoroughly stirred at 7,800 rpm using a homogenizer (Ultra-Turrax T50, IKA), the pH was made higher than 7.0 by adding 0.1 mol / L of sodium bicarbonate. Then, while emulsifying and dispersing, a mixed solution of 3.0 parts of sodium dodecylbenzenesulfonate and 297.0 parts of deionized water was gradually added dropwise to obtain a styrene-acrylic resin particle dispersion.

[0186] When the particle size distribution of the styrene-acrylic resin particle dispersion was measured using a particle size distribution analyzer (LA-920, Horiba, Ltd.), the number average particle size of the contained styrene-acrylic resin particles was 0.25 μm and coarse particles exceeding 1 μm were not observed.

[0187] Preparation of wax particle dispersion

[0188] ·500.0 parts of deionized water

[0189] Fischer-Tropsch wax (C105, Sasol Limited, melting point: 105°C) 250.0 parts

[0190] These materials were introduced into a stainless steel container; heated to 95°C and melted in a hot water bath; and, while being thoroughly stirred at 7,800 rpm using a homogenizer (Ultra-Turrax T50, IKA), the pH was made higher than 7.0 by adding 0.1 mol / L of sodium bicarbonate. Then, while emulsifying and dispersing, a wax particle dispersion was obtained by gradually dropping a mixed solution of 5.0 parts of sodium dodecylbenzenesulfonate and 245.0 parts of deionized water.

[0191] When the particle size distribution of the wax particle dispersion was measured using a particle size distribution analyzer (LA-920, Horiba, Ltd.), the number average particle size of the contained wax particles was 0.35 μm and coarse particles exceeding 1 μm were not observed.

[0192] Preparation of colorant particle dispersion

[0193] ·CI Pigment Blue 15:3 100.0 parts

[0194] 5.0 parts of sodium dodecylbenzene sulfonate

[0195] ·400.0 parts of deionized water

[0196] The foregoing were mixed and then dispersed using a sand mill. When the particle size distribution of the colorant particles contained in the colorant particle dispersion was measured using a particle size distribution analyzer (LA-920, Horiba, Ltd.), the number average particle size of the contained colorant particles was 0.2 μm and coarse particles exceeding 1 μm were not observed.

[0197] Preparation of core particles 15

[0198]

[0199] The polyester resin particle dispersion, styrene-acrylic resin particle dispersion, wax particle dispersion, and sodium dodecylbenzene sulfonate were introduced into a reactor (a 1-liter flask equipped with an anchor wing with a baffle) and mixed uniformly. The colorant particle dispersion was mixed uniformly separately in a 500-mL beaker and gradually added to the reactor while stirring to provide a mixed dispersion. While stirring the obtained mixed dispersion, an aluminum sulfate aqueous solution having a solid content of 0.5 parts was added dropwise to form aggregated particles.

[0200] After the dropwise addition was completed, the inside of the system was replaced with nitrogen and maintained at 50°C for 1 hour and at 55°C for another 1 hour.

[0201] Then, the mixture was heated and maintained at 90°C for 30 minutes, cooled to 63°C, and maintained for 3 hours to form fused particles. After a predetermined time, the mixture was cooled to 40°C at a temperature drop rate of 0.5°C / min to obtain a core particle 15 dispersion.

[0202] Production of Toner Particles 15

[0203] 2.0 parts of the shell resin 1 dispersion were added to 100.0 parts of the solid portion of the core particle 15 dispersion, and the temperature was raised to 75° C. and maintained for 2 hours to form a shell layer on the surface of the core particles. After cooling to room temperature, the mixture was filtered, washed with water, and dried to produce toner particles 15 having a core-shell structure and having a weight average particle size (D4) of 6.5 μm.

[0204] Production of Toner 15

[0205] 100.0 parts of Toner Particles 15 were mixed with 1.5 parts of dry silica particles ("AEROSIL (registered trademark) REA90", positively charged hydrophobized silica particles, Nippon Aerosil Co., Ltd.) for 3 minutes using an FM mixer (Nippon Coke & Engineering Co., Ltd.) to attach the silica particles to Toner Particles 15. This was then sieved with 300 mesh (aperture = 48 μm) to produce Toner 15.

[0206] Production of Toner 16

[0207] Preparation of core particles 16

[0208]

[0209] These materials were dispersed using an attritor (Mitsui Mining & Smelting Co., Ltd.) for 3 hours to obtain a colorant dispersion.

[0210] On the other hand, an aqueous medium was prepared by adding 1.8 parts of tricalcium phosphate to 300.0 parts of deionized water heated to a temperature of 60° C. and stirring at a stirring rate of 10,000 rpm using a TK homomixer (Tokushu Kika Kogyo Co., Ltd.). The colorant dispersion was introduced into the aqueous medium and stirred at a temperature of 65° C. for 15 minutes using a TK homomixer to granulate the colorant particles.

[0211] The TK homomixer was changed to a conventional propeller stirrer. The stirring rate of the stirrer was maintained at 150 rpm; the internal temperature was raised to a temperature of 95° C.; and the solvent was removed from the dispersion by maintaining for 3 hours to prepare a core particle 16 dispersion.

[0212] Production of Toner Particles 16

[0213] 2.0 parts of the shell resin 1 dispersion were added to 100.0 parts of the solid portion of the core particle 16 dispersion, and the temperature was raised to 75° C. and maintained for 2 hours to form a shell layer on the surface of the core particles. After cooling to room temperature, the calcium phosphate dispersant was dissolved by adding hydrochloric acid, filtered, washed with water, and dried to produce toner particles 16 having a core-shell structure and having a weight average particle size (D4) of 6.9 μm.

[0214] Production of Toner 16

[0215] 100.0 parts of Toner Particles 16 were mixed with 1.5 parts of dry silica particles ("AEROSIL (registered trademark) REA90", positively charged hydrophobized silica particles, Nippon Aerosil Co., Ltd.) for 3 minutes using an FM mixer (Nippon Coke & Engineering Co., Ltd.) to attach the silica particles to Toner Particles 16. This was then sieved with 300 mesh (aperture = 48 μm) to produce Toner 16.

[0216] [Table 3]

[0217]

[0218] Image evaluation

[0219] Image evaluations were performed using a commercially available color laser printer "FS-C5250DN" from Kyocera Document Solutions Inc. that had been partially modified. Modifications included the ability to operate with a process cartridge installed for only a single color. Other modifications enabled the fixing unit to be set to a freely selectable temperature. A two-component developer prepared by the following method was introduced into the developing section of the test machine and the following image evaluations were performed.

[0220] Preparation of two-component developer

[0221] A two-component developer is prepared by mixing 10 parts of the toner to be evaluated with 100 parts of a developer carrier (carrier for FS-C5250DN) using a ball mill for 30 minutes.

[0222] The specific image evaluation is as follows.

[0223] Fogging

[0224] The operation was carried out in a low temperature and low humidity environment (15°C, 10% RH) or a high temperature and high humidity environment (temperature 32°C / humidity 85% RH), and the reflectivity (%) of the non-image area was measured using a "Reflectometer Model TC-6DS" (Tokyo Denshoku Co., Ltd.) at the beginning and after completion of a 30,000-sheet printout test of a horizontal line image with 1% image coverage.

[0225] Evaluation was performed using a numerical value (%) provided by subtracting the reflectance obtained from the reflectance (%) of unused printed paper (reference paper) measured similarly. A smaller numerical value indicates greater suppression of image fogging. Flat paper (HP Brochure Paper 200 g, Glossy, Hewlett-Packard, 200 g / m 2 ) were evaluated in glossy paper mode.

[0226] Evaluation Criteria

[0227] A: less than 0.5%

[0228] B: 0.5% or more and less than 1.5%

[0229] C: 1.5% or more and less than 3.0%

[0230] D: 3.0% or more

[0231] Streaks (development performance)

[0232] The operation was carried out in a high temperature and high humidity environment (temperature 32°C / humidity 85% RH), and a 30,000-sheet printout test was performed using a horizontal line image with an image coverage of 1%. After the test was completed, the printout was printed on letter-sized XEROX 4200 paper (75 g / m 2 , Xerox Corporation) to print halftones (toner loading: 0.3 mg / cm 2 The presence / absence of vertical streaks in the paper output direction in the halftone image was scored and the developing performance was evaluated as follows.

[0233] Evaluation Criteria

[0234] A: No

[0235] B: One or more but no more than three vertical streaks occur in the halftone image in the paper output direction

[0236] C: Four or more but six or less vertical streaks occur in the halftone image in the paper output direction

[0237] D: 7 or more vertical streaks appear in the halftone image in the paper output direction, or vertical streaks with a width of 0.5 mm or more appear

[0238] Fixing performance

[0239] Solid images printed on transfer materials at different fixing temperatures (toner loading: 0.9 mg / cm 2 ) and evaluated using the criteria given below. The fixing temperature is a value measured on the fixing roller surface using a non-contact thermometer. Letter-sized flat paper (XEROX 4200, 75 g / m 2 , Xerox Corporation) was used as a transfer material.

[0240] Evaluation Criteria

[0241] A: No staining at 140°C

[0242] B: Defacement occurs at 140°C

[0243] C: fouling at 150°C

[0244] D: Defacement occurs at 160°C

[0245] Caking (storage stability)

[0246] 5 g of each specific toner was placed in a 50-mL plastic cup; it was left to stand at temperature = 60° C. / humidity = 10% RH for 3 days; and then the presence / absence of cohesion clusters was checked and evaluated using the following criteria.

[0247] Evaluation Criteria

[0248] A: No agglomerates are produced

[0249] B: Slightly aggregated lumps are formed, which can be broken by pressing lightly with fingers.

[0250] C: Agglomerates are formed and do not break even when pressed lightly with fingers

[0251] D: Completely condensed

[0252] Examples 1 to 16

[0253] Using each of Toners 1 to 16 as a toner, the above-mentioned evaluation was respectively performed in Examples 1 to 16. The results of the evaluation are given in Table 4.

[0254] Comparative Examples 1 to 3

[0255] Using each of Toners 17 to 19 as a toner, the above-mentioned evaluation was respectively performed in Comparative Examples 1 to 3. The results of the evaluation are given in Table 4.

[0256] [Table 4]

[0257]

[0258] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. A toner, characterized in that: Includes toner particles, the toner particles comprising: A core particle containing a resin component and a shell on the surface of the core particle, wherein The toner particles are particles obtained by forming a shell on the surface of the core particles in an aqueous medium in which the core particles are dispersed. The resin component contains more than 50.0% by mass of a polyester resin containing a monomer unit represented by the following formula (1), and The shell includes a (meth)acrylic resin containing at least one monomer unit selected from the group consisting of the following formulae (2) and (3), In formula (1), R 1 represents a heterocyclic group containing at least one heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur, In formula (2), R 2 represents a hydrogen atom or a methyl group, In formula (3), R 3 represents a hydrogen atom or a methyl group, R 4 It represents an alkylene group having 1 to 3 carbon atoms. 2 . The toner according to claim 1 , wherein the content of the monomer unit represented by the formula (1) in the polyester resin is 5.0 to 35.0% by mass.

3. The toner according to claim 1 or 2, wherein the monomer unit represented by formula (1) is represented by at least one selected from the group consisting of the following formulae (1-2) and (1-3): In formula (1-2), each R 5 independently represents a linear or branched alkylene group having a carbon number of 2 to 8, m and n are each independently 0 or an integer of 1 to 5, and m+n satisfies 0 to 10, and In formula (1-3), each R 6 independently represents a hydrogen atom or a methyl group. 4 . The toner according to claim 3 , wherein the monomer unit represented by formula (1) is represented by formula (1-2). 5 . The toner according to claim 1 , wherein the polyester resin comprises at least one selected from the group consisting of a structure in which an aliphatic diol is polycondensed with a carboxylic acid component and a structure in which an alicyclic diol is polycondensed with a carboxylic acid component.

6. The toner according to claim 1 or 2, wherein In the (meth)acrylic resin, the total content of at least one monomer unit selected from the group consisting of formula (2) and formula (3) is 5.0 to 35.0% by mass. 7 . The toner according to claim 1 , wherein the content of the shell is 0.5 parts by mass or more and 3.0 parts by mass or less relative to 100.0 parts by mass of the resin component of the core particle. 8 . The toner according to claim 1 , wherein the resin component of the core particle comprises a styrene-acrylic resin.

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