JP6414036B2 - Toner for electrostatic latent image development - Google Patents

Description

  The present invention relates to an electrostatic latent image developing toner, and more particularly to a capsule toner.

  The toner particles contained in the capsule toner include a core and a shell layer (capsule layer) that covers the surface of the core. By covering the core with the shell layer, the heat resistant storage stability of the toner can be improved. In the toner described in Patent Document 1, a specific vinyl resin is contained in the shell layer in order to improve the adhesion between the core and the shell layer. This vinyl resin is obtained by polymerizing a styrene monomer and a vinyl polymerizable monomer having both an ester bond and an aryl group.

JP 2012-177787 A

  However, even if the durability of the toner is improved by the technique disclosed in Patent Document 1, the durability of the toner is not necessarily sufficient depending on the use of the toner.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a toner having excellent durability.

  The electrostatic latent image developing toner according to the present invention includes a plurality of toner particles each including a core and a shell layer covering the surface of the core. The core contains a polyester resin. The shell layer includes resin particles. The main chain skeleton of the polymer constituting the resin particles contains one or more kinds of repeating units derived from (meth) acrylic acid ester at a ratio of 50 mol% or more. Among the one or more kinds of repeating units derived from the (meth) acrylic acid ester, the repeating unit of 60 mol% or more is any of methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. Is a repeating unit derived from

  According to the present invention, it is possible to provide a toner having excellent durability.

It is a figure which shows an example of the chromatogram for calculating | requiring the ratio of a specific ester unit about the electrostatic latent image developing toner which concerns on embodiment of this invention.

Embodiments of the present invention will be described in detail. Note that the evaluation results (values indicating shape, physical properties, etc.) regarding the powder (more specifically, the toner core, toner base particles, external additive, toner, etc.) are a considerable number of particles unless otherwise specified. Is the number average of the values measured for. The number average particle diameter of the powder is the number average value of the equivalent circle diameter of primary particles (diameter of a circle having the same area as the projected area of the particles) measured using a microscope unless otherwise specified. It is. Moreover, the measured value of the volume median diameter (D ₅₀ ) of the powder is not specified, and the “Coulter Counter Multisizer 3” manufactured by Beckman Coulter Co., Ltd. is used. ) Measured based on. Moreover, each measured value of an acid value and a hydroxyl value is a value measured according to "JIS (Japanese Industrial Standard) K0070-1992" unless otherwise specified. Moreover, each measured value of a number average molecular weight (Mn) and a mass average molecular weight (Mw) is the value measured using the gel permeation chromatography, if not prescribed | regulated at all.

Hereinafter, a compound and its derivatives may be generically named by adding “system” after the compound name. When the name of a polymer is expressed by adding “system” after the compound name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof. Acrylic and methacrylic are sometimes collectively referred to as “(meth) acrylic”. Further, acryloyl (CH ₂ ═CH—CO—) and methacryloyl (CH ₂ ═C (CH ₃ ) —CO—) may be collectively referred to as “(meth) acryloyl”.

  The toner according to the exemplary embodiment can be suitably used for developing an electrostatic latent image, for example, as a positively chargeable toner. The toner of the present exemplary embodiment is a powder that includes a plurality of toner particles (each having a configuration described later). The toner may be used as a one-component developer. Alternatively, a two-component developer may be prepared by mixing toner and carrier using a mixing device (for example, a ball mill). In order to form a high-quality image, it is preferable to use a ferrite carrier as a carrier. In order to form a high-quality image over a long period of time, it is preferable to use magnetic carrier particles including a carrier core and a resin layer covering the carrier core. In order to produce magnetic carrier particles, the carrier core may be formed from a magnetic material, or the carrier core may be formed from a resin in which magnetic particles are dispersed. Further, magnetic particles may be dispersed in the resin layer covering the carrier core. In order to form a high-quality image, the amount of toner in the two-component developer is preferably 5 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the carrier. The positively chargeable toner is positively charged by friction with the carrier.

  The toner particles contained in the toner according to the exemplary embodiment include a core (hereinafter referred to as a toner core) and a shell layer (capsule layer) formed on the surface of the toner core. The shell layer covers the surface of the toner core. The shell layer may cover the entire surface of the toner core or may partially cover the surface of the toner core. An external additive may be attached to the surface of the toner core and / or the shell layer. A plurality of shell layers may be laminated on the surface of the toner core. If not necessary, the external additive may be omitted. Hereinafter, the toner particles before the external additive adheres are referred to as toner mother particles.

  The toner according to the exemplary embodiment can be used for image formation in, for example, an electrophotographic apparatus (image forming apparatus). Hereinafter, an example of an image forming method using an electrophotographic apparatus will be described.

  First, an electrostatic latent image is formed on a photoconductor (for example, a surface layer portion of a photoconductor drum) based on image data. Next, the formed electrostatic latent image is developed using a developer containing toner. In the developing step, toner (frictionally charged toner) on a developing sleeve (for example, the surface layer portion of the developing roller in the developing device) is attached to the electrostatic latent image on the photosensitive member to form a toner image on the photosensitive member. . In the subsequent transfer step, the toner image on the photosensitive member is transferred to an intermediate transfer member (for example, a transfer belt), and then the toner image on the intermediate transfer member is further transferred to a recording medium (for example, paper). Thereafter, the toner is heated to fix the toner on the recording medium. As a result, an image is formed on the recording medium. For example, a full color image can be formed by superposing four color toner images of black, yellow, magenta, and cyan.

  The toner according to the exemplary embodiment is an electrostatic latent image developing toner having the following configuration (hereinafter referred to as a basic configuration).

(Basic toner configuration)
The electrostatic latent image developing toner includes a plurality of toner particles including a toner core and a shell layer. The toner core contains a polyester resin. The shell layer includes resin particles. The main chain skeleton of the polymer constituting the resin particles contains one or more kinds of repeating units derived from (meth) acrylic acid ester at a ratio of 50 mol% or more. In addition, among one or more kinds of repeating units derived from (meth) acrylic acid esters, 60 mol% or more of repeating units are any of methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. It is a repeating unit derived from crab. Hereinafter, the repeating unit derived from (meth) acrylic acid ester is referred to as a specific skeleton unit. A repeating unit derived from any of methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate is referred to as a specific ester unit.

  The inventor has found that the toner having the above basic structure is excellent in durability. Specifically, when the ratio of the specific skeleton unit is 50 mol% or more and the ratio of the specific ester unit is 60 mol% or more, the surface of the toner core is formed at the boundary between the toner core and the shell layer (particularly, resin particles). The inventor has found that a hydroxyl group present (particularly, a hydroxyl group derived from a polyester resin) and an ester moiety of a resin contained in the shell layer are easily bonded by transesterification. Among the specific skeleton units, it is considered that the specific ester unit in particular tends to form a bond by a transesterification reaction between the toner core and the shell layer. It is considered that the durability of the toner is improved by chemically bonding the toner core and the shell layer. When a plurality of types of specific ester units are included in the main chain skeleton of the polymer constituting the resin particles, the total number of moles of these specific ester units is the sum of the number of moles of all the specific skeleton units. The value obtained by dividing corresponds to the ratio of the specific ester unit. When the ratio is expressed as a percentage (mol%), the calculated value may be multiplied by 100.

  An example (a repeating unit derived from butyl acrylate) is shown in Formula (1). Formula (2) shows an example of the specific ester unit (a repeating unit derived from methyl methacrylate). Formula (3) shows an example of a repeating unit derived from a (meth) acryloyl group-containing quaternary ammonium compound (a repeating unit derived from 2- (methacryloyloxy) ethyltrimethylammonium chloride). Formula (4) shows an example of a repeating unit derived from a monomer other than (meth) acrylic acid ester (a repeating unit derived from styrene). In formula (1)-formula (4), n shows the repeating number (molar number) of a repeating unit each independently.

  For example, in the above basic configuration, when the polymer of the resin particles includes only four repeating units represented by the formulas (1) to (4), three repetitions represented by the formulas (1) to (3) A value obtained by dividing the total number of moles of units by the total number of moles of all repeating units (four repeating units) corresponds to the ratio of the specific skeleton unit. Further, the value obtained by dividing the number of moles of the repeating unit represented by the formula (2) by the total number of moles of the three repeating units represented by the formulas (1) to (3) corresponds to the ratio of the specific ester unit. To do. In addition, what is necessary is just to multiply the calculated value 100 times when expressing a ratio by a percentage (mol%).

  The number of moles of repeating units contained in the resin can be measured by quantitative analysis by the GC / MS method. FIG. 1 illustrates an example in which the polymer of the resin particles substantially includes only three repeating units represented by the formulas (1) to (3) (specifically, toner T-1 according to Example 1 described later). Shows an example (chromatogram L1) of the chromatogram measured by the GC / MS method. In addition, as a reference example, GC / MS is used for a resin particle material (butyl acrylate, methyl methacrylate, and 2- (methacryloyloxy) ethyltrimethylammonium chloride) that is mixed and dried without heating (GC / MS). An example of the chromatogram (chromatogram L0) measured by the method is also shown in FIG. In FIG. 1, the vertical axis represents signal intensity (unit: arbitrary unit), and the horizontal axis represents retention time (unit: minutes). The measurement conditions are the same as in the examples described later.

  In the chromatogram L1 in FIG. 1, a peak is detected at a retention time of 9.25 minutes where a characteristic peak appears in ethylene glycol dimethacrylate. From these measurement results, it is considered that the hydroxyl group present on the surface of the toner core and the ester site of the resin contained in the shell layer are bonded by transesterification at the boundary between the toner core and the shell layer. In the structural formula of ethylene glycol dimethacrylate shown in FIG. 1, it is considered that both end portions are derived from the shell layer and the central portion is derived from the toner core.

  In order to improve the durability of the toner, it is preferable that the toner core is produced by a dry method and the shell layer is formed on the surface of the toner core by a wet method. As the dry method, a pulverization method is particularly preferable. The pulverization method is a method of obtaining a powder (for example, a toner core) through a step of obtaining a kneaded product by melting and kneading a plurality of types of materials (resins and the like) and a step of pulverizing the obtained kneaded product. By causing the toner core produced by the dry method and the resin particles (shell layer material) to react in the liquid, the transesterification reaction between the toner core and the resin particles easily proceeds.

  In order to improve the durability of the toner, an alkylsulfonic acid having an alkyl group having 10 to 18 carbon atoms and a salt thereof, and a carbon number of 10 at a ratio of 0.1 nmol to 50 nmol with respect to 1 g of the toner. It is preferable that at least one compound selected from the group consisting of alkylbenzenesulfonic acid having an alkyl group of 18 or less and a salt thereof (hereinafter referred to as a specific sulfonic acid compound) is contained in the toner. When two or more kinds of specific sulfonic acid compounds are contained in the toner, the total of moles of the specific sulfonic acid compounds is preferably 0.1 nmol or more and 50 nmol or less with respect to 1 g of the toner. When the shell layer is formed, the toner core and the resin particles (shell layer material) are present by adding an appropriate amount of the specific sulfonic acid compound (an amount remaining at a ratio of 0.1 nmol to 50 nmol with respect to 1 g of the manufactured toner). The transesterification reaction easily proceeds. The specific sulfonic acid compound can function as a surfactant. When the shell layer is formed on the surface of the toner core in the liquid, if the amount of the specific sulfonic acid compound in the liquid is too small, the toner cores easily aggregate in the liquid. If the amount of the specific sulfonic acid compound in the liquid is too large, the transesterification reaction between the toner core and the resin particles in the liquid is difficult to proceed. Further, the specific sulfonic acid compound has a strong effect of promoting the transesterification reaction between the toner core and the resin particles (shell layer material). For example, the transesterification reaction may proceed by using a specific sulfonic acid compound instead of the polyethylene glycol 200 under the condition that the transesterification reaction does not proceed even when polyethylene glycol 200 is used.

  The toner according to the present embodiment includes a plurality of toner particles (hereinafter, referred to as toner particles according to the present embodiment) defined by the basic configuration described above. The toner including a plurality of toner particles of the present embodiment is excellent in durability (see Tables 1 and 2 described later). In order to improve the durability of the toner, the toner preferably contains the toner particles of the present embodiment at a ratio of 80% by number or more, and the toner particles of the present embodiment at a ratio of 90% by number or more. It is more preferable that the toner particles of the present exemplary embodiment be included at a ratio of 100% by number.

  In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner, it is preferable that the shell layer covers an area of 50% to 99% of the surface area of the toner core. In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner, the maximum thickness of the shell layer is preferably 1 nm or more and 100 nm or less.

In order to achieve both the heat resistant storage stability and the low-temperature fixability of the toner, the volume median diameter (D ₅₀ ) of the toner is preferably 1 μm or more and less than 10 μm.

  Next, a material for forming the toner core (hereinafter referred to as toner core material) and a material for forming the shell layer (hereinafter referred to as shell material) will be described. Resins suitable for forming toner particles are as follows.

<Preferable thermoplastic resin>
Examples of the thermoplastic resin constituting the toner particles (particularly, the toner core and the shell layer) include, for example, a styrene resin, an acrylic resin (more specifically, an acrylic ester polymer or a methacrylic ester polymer), Olefin resin (more specifically, polyethylene resin or polypropylene resin), vinyl resin (more specifically, vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, or N-vinyl resin), polyester resin, polyamide resin Or, a urethane resin can be preferably used. A copolymer of each of these resins, that is, a copolymer in which an arbitrary repeating unit is introduced into the resin (specifically, a styrene-acrylic acid resin or a styrene-butadiene resin) is also used as a toner. It can be suitably used as a thermoplastic resin constituting the particles.

  The thermoplastic resin can be obtained by addition polymerization, copolymerization, or condensation polymerization of one or more thermoplastic monomers. The thermoplastic monomer is a monomer that becomes a thermoplastic resin by homopolymerization (more specifically, an acrylic acid monomer or a styrene monomer), or a monomer that becomes a thermoplastic resin by condensation polymerization (for example, by condensation polymerization). Alcohol and carboxylic acid to be polyester resin).

  The styrene-acrylic acid resin is a copolymer of one or more styrene monomers and one or more acrylic monomers. In order to synthesize a styrene-acrylic acid resin, for example, a styrene monomer and an acrylic acid monomer as shown below can be suitably used. By using an acrylic acid monomer, a carboxyl group can be introduced into the styrene-acrylic acid resin. Further, by using a monomer having a hydroxyl group (more specifically, p-hydroxystyrene, m-hydroxystyrene, (meth) acrylic acid hydroxyalkyl ester, or the like), the hydroxyl group can be introduced into the styrene-acrylic acid resin. .

  Preferable examples of the styrene monomer include styrene, alkyl styrene (more specifically, α-methyl styrene, p-ethyl styrene, 4-tert-butyl styrene, etc.), p-hydroxy styrene, m-hydroxy styrene. , Vinyl toluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, or p-chlorostyrene.

  Preferable examples of the acrylic acid monomer include (meth) acrylic acid, (meth) acrylic acid alkyl ester, or (meth) acrylic acid hydroxyalkyl ester. Suitable examples of the (meth) acrylic acid alkyl ester include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and (meth) acrylic. Examples include n-butyl acid, iso-butyl (meth) acrylate, or 2-ethylhexyl (meth) acrylate. Suitable examples of the (meth) acrylic acid hydroxyalkyl ester include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, or (meth) acrylic. The acid 4-hydroxybutyl is mentioned.

  The polyester resin is obtained by polycondensing one or more alcohols and one or more carboxylic acids. As the alcohol for synthesizing the polyester resin, for example, dihydric alcohols (more specifically, diols or bisphenols) as shown below or trihydric or higher alcohols can be suitably used. As the carboxylic acid for synthesizing the polyester resin, for example, divalent carboxylic acids or trivalent or higher carboxylic acids as shown below can be suitably used.

  Suitable examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, Examples include 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, di1,2-propanediol, polyethylene glycol, poly1,2-propanediol, or polytetramethylene glycol.

  Preferable examples of the bisphenol include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, or bisphenol A propylene oxide adduct.

  Preferable examples of trihydric or higher alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butane. Triol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, or 1,3,5- Trihydroxymethylbenzene is mentioned.

  As preferable examples of the divalent carboxylic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacic acid, azelaic acid, malonic acid Succinic acid, alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, etc.), or alkenyl succinic acid (more specific Specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, or isododecenyl succinic acid, etc.) may be mentioned.

  Preferred examples of the trivalent or higher carboxylic acid include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) Examples include methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, or empole trimer acid.

  Hereinafter, the toner core (binder resin and internal additive), shell layer, and external additive will be described in order. Depending on the toner application, unnecessary components (for example, an internal additive or an external additive) may be omitted.

[Toner core]
The toner core contains a binder resin. The toner core may contain internal additives (for example, a colorant, a release agent, a charge control agent, and magnetic powder).

(Binder resin)
In the toner core, the binder resin generally occupies most of the components (for example, 85% by mass or more). For this reason, it is considered that the properties of the binder resin greatly affect the properties of the entire toner core. By using a combination of a plurality of types of resins as the binder resin, the properties of the binder resin (more specifically, the hydroxyl value, acid value, Tg, Tm, etc.) can be adjusted. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner core tends to become anionic, and the binder resin has an amino group or an amide group. The toner core tends to become cationic. In order for the binder resin to have a strong anionic property, the hydroxyl value and acid value of the binder resin are each preferably 10 mgKOH / g or more.

  The binder resin is preferably a resin having one or more groups selected from the group consisting of ester groups, hydroxyl groups, ether groups, acid groups, and methyl groups. The binder resin having such a functional group easily reacts with the shell material and is chemically bonded. When such a chemical bond occurs, the bond between the toner core and the shell layer becomes strong. Further, as the binder resin, a resin having a functional group containing active hydrogen in the molecule is also preferable.

  In order to improve toner fixability during high-speed fixing, the glass transition point (Tg) of the binder resin is preferably 20 ° C. or higher and 55 ° C. or lower. In order to improve toner fixability at high-speed fixing, the softening point (Tm) of the binder resin is preferably 100 ° C. or lower. In addition, each measuring method of Tg and Tm is the same method as the Example mentioned later, or its alternative method.

  The toner according to the exemplary embodiment has the basic configuration described above. In the toner according to the exemplary embodiment, the toner core contains one or more polyester resins. The binder resin of the toner core may be only a polyester resin, and the toner core may be a resin other than the polyester resin (more specifically, a resin selected from the above-mentioned preferred thermoplastic resins). You may contain. In order to improve the dispersibility of the colorant in the toner core, the chargeability of the toner, and the fixability of the toner to the recording medium, it is preferable to use a styrene-acrylic resin or a polyester resin as the binder resin. In order to achieve both low-temperature fixability and durability of the toner, 80% by mass or more of the resin contained in the toner core is preferably a polyester resin, and 90% by mass or more of the resin is a polyester resin. More preferably, 100% by mass of the resin is more preferably a polyester resin.

  When a polyester resin is used as the binder resin for the toner core, the number average molecular weight (Mn) of the polyester resin is preferably 1000 or more and 2000 or less in order to improve the strength of the toner core and the toner fixing property. The molecular weight distribution of the polyester resin (the ratio Mw / Mn of the mass average molecular weight (Mw) to the number average molecular weight (Mn)) is preferably 9 or more and 21 or less.

(Coloring agent)
The toner core may contain a colorant. As the colorant, a known pigment or dye can be used according to the color of the toner. In order to form a high-quality image using toner, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

  The toner core may contain a black colorant. An example of a black colorant is carbon black. The black colorant may be a colorant that is toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

  The toner core may contain a color colorant such as a yellow colorant, a magenta colorant, or a cyan colorant.

  As the yellow colorant, for example, one or more compounds selected from the group consisting of condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and arylamide compounds can be used. Examples of the yellow colorant include C.I. I. Pigment Yellow (3, 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 151, 154, 155 168, 174, 175, 176, 180, 181, 191, or 194), naphthol yellow S, Hansa yellow G, or C.I. I. Vat yellow can be preferably used.

  The magenta colorant is, for example, selected from the group consisting of condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. One or more compounds can be used. Examples of the magenta colorant include C.I. I. Pigment Red (2, 3, 5, 6, 7, 19, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 150, 166, 169, 177 184, 185, 202, 206, 220, 221 or 254) can be preferably used.

  As the cyan colorant, for example, one or more compounds selected from the group consisting of a copper phthalocyanine compound, an anthraquinone compound, and a basic dye lake compound can be used. Examples of cyan colorants include C.I. I. Pigment blue (1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, or 66), phthalocyanine blue, C.I. I. Bat Blue, or C.I. I. Acid blue can be preferably used.

(Release agent)
The toner core may contain a release agent. The release agent is used, for example, for the purpose of improving the fixing property or offset resistance of the toner. In order to increase the anionicity of the toner core, it is preferable to produce the toner core using an anionic wax. In order to improve the fixing property or offset resistance of the toner, the amount of the release agent is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

  Examples of the release agent include low molecular weight polyethylene, low molecular weight polypropylene, polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax, or aliphatic hydrocarbon wax such as Fischer-Tropsch wax; oxidized polyethylene wax or a block thereof Oxides of aliphatic hydrocarbon waxes such as copolymers; plant waxes such as candelilla wax, carnauba wax, wood wax, jojoba wax, or rice wax; animal properties such as beeswax, lanolin, or whale wax Waxes; mineral waxes such as ozokerite, ceresin, or petrolatum; waxes based on fatty acid esters such as montanate ester wax or castor wax; fats such as deoxidized carnauba wax The wax portion of the ester or the whole was deoxygenated can be suitably used. One type of release agent may be used alone, or multiple types of release agents may be used in combination.

  In order to improve the compatibility between the binder resin and the release agent, a compatibilizer may be added to the toner core.

(Charge control agent)
The toner core may contain a charge control agent. The charge control agent is used, for example, for the purpose of improving the charge stability or charge rising property of the toner. The charge rising characteristic of the toner is an index as to whether or not the toner can be charged to a predetermined charge level in a short time.

  By adding a negatively chargeable charge control agent to the toner core, the anionicity of the toner core can be enhanced. Further, the cationic property of the toner core can be increased by including a positively chargeable charge control agent in the toner core. However, if sufficient chargeability is ensured in the toner, it is not necessary to include a charge control agent in the toner core.

(Magnetic powder)
The toner core may contain magnetic powder. Examples of magnetic powder materials include ferromagnetic metals (more specifically, iron, cobalt, nickel, etc.) or alloys thereof, ferromagnetic metal oxides (more specifically, ferrite, magnetite, or chromium dioxide). Etc.) or a material subjected to a ferromagnetization treatment (more specifically, a heat treatment etc.) can be suitably used. One type of magnetic powder may be used alone, or a plurality of types of magnetic powder may be used in combination.

  In order to suppress elution of metal ions (for example, iron ions) from the magnetic powder, it is preferable to surface-treat the magnetic powder. When a shell layer is formed on the surface of the toner core under acidic conditions, if the metal ions are eluted on the surface of the toner core, the toner cores are easily fixed to each other. It is considered that fixing of the toner cores can be suppressed by suppressing elution of metal ions from the magnetic powder.

[Shell layer]
In the toner according to the exemplary embodiment, the shell layer includes resin particles that are substantially composed of a polymer that satisfies the requirements of the basic configuration described above. In order to improve the charging stability of the toner (particularly the stability in a high temperature and high humidity environment), the polymer constituting the resin particles is preferably a water-insoluble thermoplastic resin. In order to improve the positive chargeability of the toner, the polymer constituting the resin particles preferably contains a positively chargeable charge control agent. In order to contain the charge control agent in the resin particles, a repeating unit derived from the charge control agent may be incorporated in the resin, or the charged particles may be dispersed in the resin. Preferred examples of the positively chargeable charge control agent contained in the polymer constituting the resin particles include azine compounds (more specifically, pyridine, pyridazine, pyrimidine, pyrazine, oxazine, thiazine, triazine, oxadiazine, and thiadiazine. , Tetrazine, phthalazine, quinazoline, or quinoxaline), nigrosine, or a quaternary ammonium compound.

  In order to obtain a toner having excellent chargeability, heat-resistant storage stability, and low-temperature fixability, the polymer constituting the resin particles contains a repeating unit derived from a (meth) acryloyl group-containing quaternary ammonium compound as a charge control agent. It is particularly preferred. Examples of the (meth) acryloyl group-containing quaternary ammonium compound include (meth) acrylamidoalkyltrimethylammonium salts (more specifically, (3-acrylamidopropyl) trimethylammonium chloride) or (meth) acryloyloxyalkyltrimethyl. An ammonium salt (more specifically, 2- (methacryloyloxy) ethyltrimethylammonium chloride or the like) can be preferably used.

  In order to obtain a toner having excellent chargeability, heat-resistant storage stability, and low-temperature fixability, the shell layer further includes resin particles that do not contain a charge control agent in addition to the resin particles defined in the basic configuration described above. Is preferred. Hereinafter, when the shell layer includes resin particles containing a charge control agent and resin particles not containing a charge control agent, the resin particles containing the charge control agent are referred to as charged particles, and the charge control agent is Resin particles not contained are referred to as uncharged particles.

  In order to improve the low-temperature fixability of the toner, it is preferable that the uncharged particles contain a thermoplastic resin (more specifically, the above-described suitable thermoplastic resin or the like). In order to obtain a toner having excellent low-temperature fixability and charge stability, the resin constituting the uncharged particles preferably contains one or more repeating units derived from an acrylic acid monomer. A copolymer of a styrene monomer (for example, styrene) and one or more acrylic acid monomers (for example, an acrylate ester) is particularly preferable. Styrene-acrylic acid resins are more hydrophobic than polyester resins and tend to be positively charged.

[External additive]
Inorganic particles may be attached to the surface of the toner base particles as an external additive. The external additive is used, for example, to improve the fluidity or handleability of the toner. In order to improve the fluidity or handleability of the toner, the amount of the external additive is preferably 0.5 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner base particles. In order to improve the fluidity or handleability of the toner, the particle diameter of the external additive is preferably 0.01 μm or more and 1.0 μm or less.

  As the external additive (inorganic particles), particles of silica particles or metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) are preferably used. Can be used. One type of external additive may be used alone, or a plurality of types of external additives may be used in combination.

[Toner Production Method]
Hereinafter, an example of a method for producing the toner according to the exemplary embodiment having the above configuration will be described.

(Preparation of toner core)
In order to easily obtain a suitable toner core, the toner core is preferably produced by an aggregation method or a pulverization method, and more preferably produced by a pulverization method.

  Hereinafter, an example of the pulverization method will be described. First, a binder resin and an internal additive (for example, at least one of a colorant, a release agent, a charge control agent, and magnetic powder) are mixed. Subsequently, the obtained mixture is melt-kneaded. Subsequently, the obtained melt-kneaded product is pulverized and classified. As a result, a toner core having a desired particle size can be obtained.

  Hereinafter, an example of the aggregation method will be described. First, these particles are agglomerated in an aqueous medium containing fine particles of a binder resin, a release agent, and a colorant until a desired particle diameter is obtained. Thereby, aggregated particles containing the binder resin, the release agent, and the colorant are formed. Subsequently, the obtained aggregated particles are heated to unite the components contained in the aggregated particles. As a result, a toner core dispersion is obtained. Thereafter, an unnecessary substance (such as a surfactant) is removed from the dispersion liquid of the toner core to obtain the toner core.

(Formation of shell layer)
First, an aqueous medium (for example, ion exchange water) is prepared. In order to suppress dissolution or elution of the toner core components (particularly the binder resin and the release agent) during the formation of the shell layer, it is preferable to form the shell layer in an aqueous medium. The aqueous medium is a medium containing water as a main component (more specifically, pure water or a mixed liquid of water and a polar medium). The aqueous medium may function as a solvent. A solute may be dissolved in the aqueous medium. The aqueous medium may function as a dispersion medium. The dispersoid may be dispersed in the aqueous medium. As a polar medium in the aqueous medium, for example, alcohol (more specifically, methanol or ethanol) can be used.

  Subsequently, the pH of the aqueous medium is adjusted to a predetermined pH (for example, 4) using, for example, hydrochloric acid. Subsequently, the toner core and the shell material are added to an aqueous medium whose pH is adjusted (for example, an acidic aqueous medium). As the shell material, for example, a dispersion of charged particles and a dispersion of uncharged particles are added.

  The charged particles and the non-charged particles each adhere to the surface of the toner core in the liquid. In order to uniformly attach charged particles and uncharged particles to the surface of the toner core, it is preferable to highly disperse the toner core in a liquid containing charged particles and uncharged particles. In order to highly disperse the toner core in the liquid, a surfactant may be included in the liquid, or the liquid is stirred using a powerful stirring device (for example, “Hibis Disper Mix” manufactured by Primics Co., Ltd.). May be. When the toner core has an anionic property, aggregation of the toner core can be suppressed by using an anionic surfactant having the same polarity. As the surfactant, for example, sulfate ester salt, sulfonate salt, phosphate ester salt, or soap can be used.

  Subsequently, while stirring the liquid containing the toner core, charged particles, and uncharged particles, the temperature of the liquid is set at a predetermined speed (for example, a speed selected from 0.1 ° C./min to 3.0 ° C./min). The temperature is raised to a predetermined holding temperature (for example, a temperature selected from 50 ° C. to 85 ° C.). Furthermore, the temperature of the liquid is maintained at the holding temperature for a predetermined time (for example, a time selected from 30 minutes to 4 hours) while stirring the liquid. Thereafter, a dispersion of toner base particles is obtained by adding cold water to quench the liquid. While the temperature of the liquid is kept high, shell materials (charged particles and uncharged particles) adhere to the surface of the toner core. The shell material also reacts with the toner core. In addition, it is considered that a film (shell layer) having a granular feeling is formed by two-dimensionally connecting the resin particles on the surface of the toner core.

(Washing process)
The obtained toner base particles may be washed. As a method for cleaning the toner base particles, for example, the dispersion containing the toner base particles is solid-liquid separated to collect the wet cake-like toner base particles, and the collected wet cake-like toner base particles are washed with water. Is preferred. As a method for cleaning the toner base particles, a method is preferred in which the toner base particles in the dispersion containing the toner base particles are settled, the supernatant liquid is replaced with water, and the toner base particles are redispersed in water after the replacement.

(Drying process)
After the cleaning step, the toner base particles may be dried. For example, the toner base particles can be dried using a dryer (more specifically, a spray dryer, a fluidized bed dryer, a vacuum freeze dryer, a vacuum dryer, or the like). In order to suppress aggregation of the toner base particles during drying, it is preferable to dry the toner base particles using a spray dryer. In the case of using a spray dryer, for example, by spraying a dispersion liquid in which an external additive is dispersed onto the toner base particles, the drying step and the external addition step described later can be performed simultaneously.

(External addition process)
Thereafter, if necessary, the toner base particles and the external additive are mixed using a mixer (for example, FM mixer or UM mixer manufactured by Nippon Coke Kogyo Co., Ltd.), and the external additive is added to the surface of the toner base particles. May be attached. Thus, a toner containing a large number of toner particles is obtained.

  The contents and order of the toner manufacturing method can be arbitrarily changed according to the required configuration or characteristics of the toner. For example, when reacting a material (for example, a shell material) in a liquid, the material may be reacted in the liquid for a predetermined time after the material is added to the liquid, or the material is added to the liquid over a long period of time. Then, the material may be reacted in the liquid while adding the material to the liquid. Further, the shell material may be added to the liquid at once, or may be added to the liquid in a plurality of times. The toner may be sieved after the external addition step. Further, unnecessary steps may be omitted. For example, when a commercially available product can be used as a material as it is, the step of preparing the material can be omitted by using a commercially available product. Moreover, even if it does not adjust pH of a liquid, when reaction for forming a shell layer advances favorably, you may omit a pH adjustment process. If an external additive is unnecessary, the external addition process may be omitted. When the external additive is not attached to the surface of the toner base particles (the step of external addition is omitted), the toner base particles correspond to the toner particles. The toner core material and the shell material are not limited to the above-described compounds (such as various monomers for synthesizing the resin). For example, if necessary, a derivative of the aforementioned compound may be used as the toner core material or shell material, or a prepolymer may be used instead of the monomer. Further, in order to obtain the above-mentioned compound, a salt, ester, hydrate, or anhydride of the compound may be used as a raw material. In order to produce the toner efficiently, it is preferable to form a large number of toner particles simultaneously.

  Examples of the present invention will be described. Table 1 shows toners T-1 to T-13 (each positively chargeable toner for developing an electrostatic latent image) according to Examples or Comparative Examples. In addition, in the item “(meth) acrylic acid ester” in Table 1, “lower alkyl monomer” indicates a monomer used for introducing a specific ester unit into the resin particle, and “skeleton” indicates a specific skeleton unit. The ratio (unit: mol%) is shown, and “lower alkyl” shows the ratio (unit: mol%) of the specific ester unit. “Surfactant (remaining amount)” in Table 1 is the surfactant contained in 1 g of toner (specifically, sodium 1-decanesulfonate or sodium octyldecanesulfonate used in the formation of the shell layer). Amount (unit: nmol) is shown.

  Hereinafter, a manufacturing method, an evaluation method, and an evaluation result of the toners T-1 to T-13 will be described in order. In the evaluation in which an error occurs, a considerable number of measurement values with sufficiently small errors are obtained, and the arithmetic average of the obtained measurement values is used as the evaluation value. The number average particle diameter of the resin particles contained in the suspension is the number average of the equivalent circle diameter of the primary particles (diameter of the circle having the same area as the projected area of the particles) measured using a transmission electron microscope (TEM). Value. Moreover, the measuring methods of Tg (glass transition point) and Tm (softening point) are as follows, respectively.

<Measurement method of Tg>
A differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) was used to determine the endothermic curve of the sample (eg, resin). Subsequently, the Tg (glass transition point) of the sample was read from the obtained endothermic curve. The temperature of the specific heat change point (intersection of the extrapolation line of the base line and the extrapolation line of the falling line) in the obtained endothermic curve corresponds to the Tg (glass transition point) of the sample.

<Tm measurement method>
A sample (for example, resin) is set on a Koka type flow tester (“CFT-500D” manufactured by Shimadzu Corporation), a die pore diameter of 1 mm, a plunger load of 20 kg / cm ² , and a temperature rising rate of 6 ° C./min. Then, a 1 cm ³ sample was melted and discharged, and an S-shaped curve (horizontal axis: temperature, vertical axis: stroke) of the sample was obtained. Subsequently, the Tm (softening point) of the sample was read from the obtained S-shaped curve. In the obtained S-curve, if the maximum stroke value is S ₁ and the low-temperature baseline stroke value is S ₂ , the stroke value in the S-curve is “(S ₁ + S ₂ ) / 2”. Corresponds to the Tm (softening point) of the sample.

[Production Method of Toner T-1]
(Production of toner core)
By reacting an acid having a polyfunctional group (specifically, terephthalic acid) with a bisphenol A ethylene oxide adduct (specifically, an alcohol obtained by adding ethylene oxide with bisphenol A as a skeleton), a polyester resin (condensation of the toner core) is performed. Resin). Regarding the obtained polyester resin, the hydroxyl value was 20 mgKOH / g, the acid value was 10 mgKOH / g, Tm was 100 ° C., and Tg was 48 ° C.

  100 parts by mass of the polyester resin obtained as described above, 5 parts by mass of a colorant (CI Pigment Blue 15: 3, component: copper phthalocyanine pigment), and a release agent (“NISSAN” manufactured by NOF CORPORATION) Electol (registered trademark) WEP-3 ”and 5 parts by mass of an ester wax having a melting point of 73 ° C. were mixed (dry mixing) at a rotational speed of 2400 rpm using an FM mixer (manufactured by Nippon Coke Industries, Ltd.).

Subsequently, the obtained mixture was melt-kneaded using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.). Thereafter, the obtained kneaded material was cooled. Subsequently, the cooled kneaded material was pulverized using a mechanical pulverizer (“Turbo Mill T250” manufactured by Freund Turbo). Subsequently, the obtained pulverized product was classified using a classifier (“Elbow Jet EJ-LABO type” manufactured by Nippon Steel Mining Co., Ltd.). As a result, a toner core having a volume median diameter (D ₅₀ ) of 6 μm was obtained.

(Preparation of first shell material)
A 1 L three-necked flask equipped with a thermometer and a stirring blade was set in a water bath, and 815 mL of ion-exchanged water at 30 ° C. and an anionic surfactant (“Latemul® WX” manufactured by Kao Corporation) were placed in the flask. , Component: sodium polyoxyethylene alkyl ether sulfate, solid content concentration: 26% by mass) and 75 mL. Thereafter, the temperature in the flask was raised to 80 ° C. using a water bath, and then kept at that temperature (80 ° C.). Subsequently, two kinds of liquids (first liquid and second liquid) were dropped into the contents of the flask at 80 ° C. over 5 hours. The first liquid was a mixed liquid of 15 g of styrene and 3 g of butyl acrylate. The second liquid was a solution in which 0.5 g of potassium persulfate was dissolved in 30 mL of ion exchange water. Subsequently, the temperature in the flask was kept at 80 ° C. for another 2 hours to polymerize the flask contents. As a result, a suspension of resin fine particles (uncharged particles) having a solid content concentration of 21% by mass (hereinafter referred to as suspension A) was obtained. The resin fine particles contained in the obtained suspension A had a number average particle diameter of 32 nm and Tg of 71 ° C.

(Preparation of second shell material)
In a 1 L three-necked flask equipped with a thermometer, a condenser tube, a nitrogen inlet tube, and a stirring blade, 90 g of isobutanol, 100 g of methyl methacrylate, 37 g of butyl acrylate, and 2- (methacryloyloxy) ethyl 30 g of trimethylammonium chloride (Alfa Aesar), 6 g of 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) (“VA-086” manufactured by Wako Pure Chemical Industries, Ltd.) Put. Subsequently, the contents of the flask were reacted for 3 hours under conditions of a nitrogen atmosphere and a temperature of 80 ° C. Thereafter, 3 g of 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) (“VA-086” manufactured by Wako Pure Chemical Industries, Ltd.) was added to the flask, and the nitrogen atmosphere and temperature were increased. The flask contents were further reacted for 3 hours under the condition of 80 ° C. to obtain a liquid containing a polymer. Subsequently, the liquid containing the obtained polymer was dried under a reduced pressure atmosphere and a temperature of 150 ° C. Subsequently, the dried polymer was crushed to obtain a positively chargeable resin.

  Subsequently, 200 g of the positively chargeable resin obtained as described above and ethyl acetate (Wako Pure Chemical Industries, Ltd.) were placed in a container of a mixing apparatus (“Hibismix (registered trademark) 2P-1 type” manufactured by PRIMIX Corporation). 184 mL of “Ethyl acetate special grade” manufactured by company was added. Subsequently, the container contents were stirred for 1 hour at a rotation speed of 20 rpm to obtain a highly viscous solution. Thereafter, an aqueous solution of ethyl acetate or the like (specifically, 18 mL of 1N hydrochloric acid and an anionic surfactant (“Emar (registered trademark) 0” manufactured by Kao Corporation, ingredient: sodium lauryl sulfate) 20 g) was added to the resulting highly viscous solution. And 16 g of ethyl acetate (“Ethyl acetate special grade” manufactured by Wako Pure Chemical Industries, Ltd.) in 562 mL of ion-exchanged water) were added. As a result, a suspension (hereinafter referred to as suspension B) of positively chargeable resin fine particles (charged particles) having a solid content concentration of 26% by mass was obtained. The resin fine particles contained in the obtained suspension B had a number average particle diameter of 35 nm and Tg of 90 ° C.

(Shell layer forming process)
A 1 L three-necked flask equipped with a thermometer and a stirring blade was set in a water bath, and 300 mL of ion-exchanged water was placed in the flask. Thereafter, the temperature in the flask was kept at 30 ° C. using a water bath. Subsequently, the pH of the flask contents was adjusted to 4 using hydrochloric acid. Subsequently, 37 g of the first shell material (Suspension A prepared by the above procedure) and 1 g of the second shell material (Suspension B prepared by the above procedure) are added to the flask, and further the toner core (the above procedure). 300 g of toner core prepared in 1) and 1 g of sodium 1-decanosulfonate were added to the flask, and the contents of the flask were sufficiently stirred.

  Subsequently, 500 mL of ion exchange water was further added to the flask. Subsequently, while stirring the contents of the flask, the temperature in the flask was increased to 65 ° C. at a rate of 1 ° C./min. Subsequently, the flask contents were stirred for 1 hour under conditions of a temperature of 65 ° C. and a rotation speed of 100 rpm. Subsequently, sodium hydroxide was added to the flask to adjust the pH of the flask contents to 7. Subsequently, the flask contents were cooled until the temperature reached room temperature (about 25 ° C.) to obtain a dispersion liquid containing toner mother particles.

(Washing process)
The dispersion of toner base particles obtained as described above was filtered (solid-liquid separation) using a Buchner funnel to obtain wet cake-like toner base particles. Thereafter, the obtained wet cake-like toner base particles were redispersed in ion-exchanged water. Further, dispersion and filtration were repeated 5 times to wash the toner base particles.

(Drying process)
Subsequently, the obtained toner base particles were dispersed in an aqueous ethanol solution having a concentration of 50% by mass. As a result, a slurry of toner base particles was obtained. Subsequently, the toner base particles in the slurry were removed under the conditions of a hot air temperature of 45 ° C. and a blower air volume of 2 m ³ / min. Dried. As a result, toner mother particle powder was obtained.

(External addition process)
Subsequently, the obtained toner base particles were externally added. Specifically, 100 parts by mass of toner base particles and 1.0 part by mass of dry silica particles (“AEROSIL (registered trademark) REA90” manufactured by Nippon Aerosil Co., Ltd.) and a 10 L capacity FM mixer (manufactured by Nippon Coke Industries, Ltd.) By using and mixing for 5 minutes, an external additive (silica particles) was adhered to the surface of the toner base particles. Thereafter, the obtained toner was sieved using a sieve of 200 mesh (aperture 75 μm). As a result, Toner T-1 containing a large number of toner particles was obtained.

[Production Method of Toner T-2]
The production method of the toner T-2 was the same as the production method of the toner T-1, except that 10 g of sodium octyldecane sulfonate was used instead of 1 g of sodium 1-decanosulfonate.

[Production Method of Toner T-3]
The production method of the toner T-3 was the same as the production method of the toner T-1, except that 100 g of acrylonitrile was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 37 nm and Tg of 92 ° C.

[Production Method of Toner T-4]
Toner T-4 was produced in the same manner as in the preparation of the second shell material except that 30 g of methyl methacrylate, 32 g of butyl acrylate, and 47 g of styrene were used instead of 100 g of methyl methacrylate and 37 g of butyl acrylate. It was the same as the manufacturing method of T-1. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 86 ° C.

[Production Method of Toner T-5]
Toner T-5 was produced in the same manner as in the preparation of the second shell material except that 27 g of methyl methacrylate, 29 g of butyl acrylate, and 52 g of styrene were used instead of 100 g of methyl methacrylate and 37 g of butyl acrylate. It was the same as the manufacturing method of T-1. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 37 nm and Tg of 88 ° C.

[Production Method of Toner T-6]
Toner T-6 was manufactured in the same manner as in the preparation of the second shell material except that 27 g of methyl methacrylate, 36 g of butyl acrylate, and 47 g of styrene were used instead of 100 g of methyl methacrylate and 37 g of butyl acrylate. It was the same as the manufacturing method of T-1. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 83 ° C.

[Production Method of Toner T-7]
The manufacturing method of the toner T-7 was the same as the manufacturing method of the toner T-1, except that 26 g of methyl acrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 56 ° C.

[Production Method of Toner T-8]
The production method of the toner T-8 was the same as the production method of the toner T-1, except that 32 g of ethyl acrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 48 ° C.

[Production Method of Toner T-9]
The production method of the toner T-9 was the same as the production method of the toner T-1, except that 35 g of normal propyl acrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 61 ° C.

[Production Method of Toner T-10]
The production method of the toner T-10 was the same as the production method of the toner T-1, except that 35 g of isopropyl acrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 62 ° C.

[Production Method of Toner T-11]
The production method of the toner T-11 was the same as the production method of the toner T-1, except that 35 g of ethyl methacrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 78 ° C.

[Production Method of Toner T-12]
The production method of the toner T-12 was the same as the production method of the toner T-1, except that 39 g of normal propyl methacrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 65 ° C.

[Production Method of Toner T-13]
The production method of the toner T-13 was the same as the production method of the toner T-1, except that 26 g of isopropyl methacrylate was used instead of 100 g of methyl methacrylate in the preparation of the second shell material. The resin fine particles contained in the obtained second shell material (suspension) had a number average particle diameter of 35 nm and Tg of 75 ° C.

  For each of the toners T-1 to T-13 obtained as described above, the ratio of the specific skeleton unit and the specific ester unit, and the surfactant (sodium 1-decanesulfonate or sodium octyldecanesulfonate) The amount of was measured. Specifically, quantitative analysis by the GC / MS method was performed using a calibration curve (a calibration curve based on a standard substance) under the following conditions. The measurement results were as shown in Table 1.

<GC / MS method>
As a measuring device, a gas chromatograph mass spectrometer (“GCMS-QP2010 Ultra” manufactured by Shimadzu Corporation) and a multi-shot pyrolyzer (“PY-3030D” manufactured by Frontier Laboratories) were used. As the column, a metal capillary column ("Ultra ALLOY (registered trademark) -5 (MS / HT)" manufactured by Frontier Laboratories, Inc., an inner diameter of 0.25 mm, a film thickness of 0.25 μm, and a length of 30 m) was used.
(Measurement condition)
・ Thermal decomposition temperature: heating furnace “600 ° C”, interface section “400 ° C”
・ Temperature raising condition: Temperature raised from 40 ° C to 320 ° C at a rate of 14 ° C / min (held at 320 ° C for 15 minutes)
Carrier gas: Helium (He) gas Column head pressure: 53.5 kPa
Injection mode: split injection (split ratio 1: 200)
Carrier flow rate: total flow rate “204 mL / min”, column flow rate “1 mL / min”, purge flow rate “3 mL / min”

[Evaluation method]
The evaluation method of each sample (toners T-1 to T-13) is as follows.

(durability)
Using a ball mill, a sample (toner) and a developer carrier (carrier for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd.) were mixed for 30 minutes to prepare a developer for evaluation (two-component developer). Each of the sample (toner) and the developer carrier was added so that the amount of the sample (toner) was 12% by mass with respect to the total mass of the developer for evaluation.

A color multifunction peripheral (“TASKalfa 5550ci” manufactured by Kyocera Document Solutions Inc.) was used as an evaluation machine. The developer for evaluation prepared as described above was put into the developing device of the evaluation machine, and the sample (supplementary toner) was put into the toner container of the evaluation machine. In an environment where the temperature is 20 ° C. and the humidity is 60% RH, the image density between the developing sleeve and the magnet roll of the evaluation machine is adjusted so that the image density of the image formed initially is in the range of 1.0 to 1.2. The voltage was adjusted between 200V and 300V. After that, using the adjusted evaluation machine, a printing durability test was performed to perform continuous printing on 10,000 sheets of paper (A4 size plain paper) at a printing rate of 5% in an environment of a temperature of 20 ° C. and a humidity of 60% RH. It was. After the printing durability test, the charge amount of the toner in the developing unit of the evaluation machine was measured by the following method using a Q / m meter (“MODEL210HS-1” manufactured by Trek).
<Measurement method of charge amount of toner in developer>
0.10 g of developer (carrier and toner) was charged into a Q / m meter measurement cell, and only the toner out of the charged developer was sucked through a sieve (metal mesh) for 10 seconds. Then, based on the formula “total electric amount of sucked toner (unit: μC) / mass of sucked toner (unit: g)”, the charge amount of toner in the developer (unit: μC / g) is calculated. Calculated.

The measured charge amount was evaluated according to the following criteria.
○ (Good): The charge amount was 20 μC / g or more and 27 μC / g or less.
X (not good): The charge amount was less than 20 μC / g or more than 27 μC / g.

[Evaluation results]
Table 2 shows the evaluation results (durability: charge amount ◯ / x) for each of the toners T-1 to T-13.

  Toners T-1, T-2, T-4, and T-7 to T-13 (toners according to Examples 1 to 10) each had the above-described basic configuration. Specifically, in each of the toners according to Examples 1 to 10, the toner core contained a polyester resin. The shell layer contained charged particles. The main chain skeleton of the polymer constituting the charged particles contained one or more specific skeleton units at a ratio of 50 mol% or more. Moreover, 60 mol% or more of repeating units were 1 or more types of specific ester units among the 1 or more types of repeating units derived from (meth) acrylic acid ester. As shown in Table 2, the toners according to Examples 1 to 10 are superior in durability to the toners according to Comparative Examples 1 to 3 (toners T-3, T-5, and T-6). It was.

  The toner for developing an electrostatic latent image according to the present invention can be used for forming an image in, for example, a copying machine, a printer, or a multifunction machine.

Claims (5)

An electrostatic latent image developing toner comprising a plurality of toner particles each including a core containing a polyester resin and a shell layer covering the surface of the core,
The shell layer includes resin particles,
The resin particles include charged particles and uncharged particles,
The main chain skeleton of the polymer constituting the charged particles includes one or more repeating units derived from (meth) acrylic acid ester at a ratio of 50 mol% or more,
Among the one or more kinds of repeating units derived from the (meth) acrylic acid ester, the repeating unit of 60 mol% or more is any of methyl (meth) acrylate, ethyl (meth) acrylate, and propyl (meth) acrylate. repeating units der derived from is,
The polymer constituting the charged particles includes a repeating unit derived from 2- (methacryloyloxy) ethyltrimethylammonium chloride as a charge control agent,
The toner for developing an electrostatic latent image, wherein the uncharged particles include a repeating unit derived from styrene and a repeating unit derived from butyl acrylate . The electrostatic latent image developing toner according to claim 1, wherein the polymer constituting the charged particles is a water-insoluble thermoplastic resin. An alkylsulfonic acid having an alkyl group having 10 to 18 carbon atoms and a salt thereof, an alkylbenzenesulfonic acid having an alkyl group having 10 to 18 carbon atoms, and a ratio of 0.1 nmol to 50 nmol with respect to 1 g of the toner; comprises one or more compounds selected from the group consisting of a salt thereof, an electrostatic latent image developing toner according to claim 1 or 2. The electrostatic latent image developing toner according to claim 3, wherein the compound contained at a ratio of 0.1 nmol to 50 nmol with respect to 1 g of the toner is sodium 1-decanesulfonate or sodium octyldecanesulfonate. And hydroxyl groups present on the surface of the core, wherein the ester moiety of the polymer constituting the charged particles are bound by an ester exchange reaction, an electrostatic latent image according to any one of claims 1-4 Development toner.

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