JP2016177264A - Toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic latent image development having a sufficient electrostatic charging property even under a normal temperature and normal humidity environment as well as a high temperature and high humidity environment.SOLUTION: A toner for electrostatic latent image development contains a plurality of toner particles having a core and a shell layer 12. The shell layer 12 is formed on a surface of the core. The shell layer 12 substantially comprises resin. Also, the shell layer 12 has, on its surface, a plurality of dot-like regions R1, and a planar region R2 having stronger hydrophobicity than the dot-like region R1. The dot-like regions R1 each have a stronger electrostatic charging property than the planar region R2.SELECTED DRAWING: Figure 2

Description

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

  For example, Patent Document 1 describes a capsule toner. The toner particles contained in the capsule toner have a core and a shell layer (capsule layer) formed on the surface of the core.

JP 59-187351 A

  In the capsule toner described in Patent Document 1, the shell layer includes a copolymer of aminostyrene and styrene. Aminostyrene has a cationic functional group (more specifically, an amino group). By increasing the density of the cationic functional group in the shell layer, it is considered that the positive chargeability of the toner in a normal temperature and normal humidity environment can be enhanced. However, when the density of the cationic functional group in the shell layer is increased, the hydrophilicity of the surface of the toner particles is increased, and water molecules are easily adsorbed on the surface of the toner particles. Further, when water molecules are adsorbed on the surface of the toner particles, the positive charge amount of the toner particles tends to be attenuated. For this reason, if the density of the cationic functional group in the shell layer is too high, the positive chargeability of the toner in a high temperature and high humidity environment may be insufficient. When an image is formed using a toner having insufficient positive chargeability, the formed image is likely to be fogged.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner for developing an electrostatic latent image having sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment.

  The electrostatic latent image developing toner according to the present invention includes a plurality of toner particles having a core and a shell layer. The shell layer is formed on the surface of the core. The shell layer is substantially composed of a resin. The shell layer has a plurality of point-like regions and a planar region having a hydrophobic property stronger than that of the point-like region on the surface thereof. Further, each of the plurality of dot-like regions has a charging property stronger than that of the planar region.

  According to the present invention, it is possible to provide a toner for developing an electrostatic latent image having sufficient chargeability under a normal temperature and normal humidity environment or a high temperature and high humidity environment.

FIG. 3 is a diagram illustrating an example of a cross-sectional structure of toner particles (particularly, toner mother particles) included in the electrostatic latent image developing toner according to the embodiment of the present invention. FIG. 2 is an enlarged view showing a part of the surface of toner base particles shown in FIG. 1. (A) and (b) are diagrams showing toner mother particles having resin particles protruding from the surface of the resin film, and (c) is a toner mother particle having no resin particles protruding from the surface of the resin film. FIG. It is a figure for demonstrating the manufacturing method of the toner for electrostatic latent image developing which concerns on embodiment of this invention.

  Embodiments of the present invention will be described in detail. Note that the evaluation results (values indicating the shape or physical properties) of the powder (more specifically, the toner core, toner base particles, external additive, toner, etc.) are averaged from the powder unless otherwise specified. This is the number average of the values measured for each of the average particles by selecting a significant number of such particles.

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. . 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.

  The strength of the charging property corresponds to the ease of frictional charging unless otherwise specified. For example, the toner can be triboelectrically charged by mixing and stirring with a standard carrier (anionic: N-01, cationic: P-01) provided by the Imaging Society of Japan. The surface potential of the toner particles is measured with, for example, KFM (Kelvin probe force microscope) before and after the frictional charging, and the portion having a larger potential change before and after the frictional charging has a higher charging property.

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, acrylonitrile and methacrylonitrile may be collectively referred to as “(meth) acrylonitrile”. In addition, functional groups that can be ionized to form salts and salts thereof are sometimes collectively referred to as “hydrophilic functional groups”. Examples of the hydrophilic functional group include an acid group (more specifically, a carboxyl group or a sulfo group), a hydroxyl group, or a salt thereof (more specifically, —COONa, —SO ₃ Na, or —ONa). Etc.). The subscript “n” of the repeating unit in each chemical formula independently indicates the number of repetitions (number of moles) of the repeating unit. Unless otherwise specified, n (number of repetitions) is arbitrary.

  The toner according to the exemplary embodiment can be suitably used for developing an electrostatic latent image. 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 having a carrier core and a resin layer covering the carrier core. In order to impart magnetism to the carrier particles, the carrier core may be formed of a magnetic material (for example, ferrite), or the carrier core may be formed of 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, and 8 parts by mass or more and 12 parts by mass with respect to 100 parts by mass of the carrier. The following is more preferable. The positively chargeable toner contained in the two-component developer is positively charged by friction with the carrier. The negatively chargeable toner contained in the two-component developer is negatively charged by friction with the carrier.

  The toner particles contained in the toner according to the present embodiment have a core (hereinafter referred to as a toner core) and a shell layer (capsule layer) formed on the surface of the toner core. An external additive may be attached to the surface of the shell layer (or the surface region of the toner core not covered with 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. A material for forming the toner core is referred to as a toner core material. A material for forming the shell layer is referred to as a shell material.

  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 the photoconductor based on the image data. Next, the formed electrostatic latent image is developed using a developer containing toner. In the developing process, toner (for example, toner charged by friction with a carrier or blade) on a developing sleeve (for example, a surface layer portion of a developing roller in the developing device) disposed in the vicinity of the photosensitive member is converted into an electrostatic latent image. A toner image is formed on the photoreceptor by adhering. 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 toner includes a plurality of toner particles having a toner core and a shell layer. The shell layer is substantially composed of a resin. Moreover, the shell layer has a plurality of point-like regions and a planar region having a stronger hydrophobic property than the point-like regions on the surface thereof. Each of the plurality of dotted regions has a charging property stronger than that of the planar region.

  Hereinafter, an example of the configuration of toner particles (specifically, toner mother particles) included in the toner according to the present embodiment will be described with reference to FIGS. 1, 2, and 3 (a) to 3 (c). To do. FIG. 1 is a diagram illustrating an example of a cross-sectional structure of toner particles (particularly, toner mother particles) included in the toner according to the present embodiment. FIG. 2 is an enlarged view showing the surface of the toner base particles shown in FIG. FIGS. 3A to 3C correspond to enlarged views of the boundary between the toner core 11 and the shell layer 12 in FIG.

  A toner base particle 10 shown in FIG. 1 has a toner core 11 and a shell layer 12 formed on the surface of the toner core 11. The shell layer 12 is substantially composed of a resin. The shell layer 12 covers the surface of the toner core 11. The shell layer 12 may cover the entire surface of the toner core 11 or may partially cover the surface of the toner core 11.

  Further, as shown in FIG. 2, the shell layer 12 has a plurality of dotted regions R1 and a planar region R2 on the surface thereof. Each of the plurality of dotted regions R1 has a charging property stronger than that of the planar region R2. The planar region R2 has stronger hydrophobicity than the point-like region R1. The number of planar regions R2 may be one or plural. In the example of FIG. 2, the dotted regions R <b> 1 are scattered on the surface of the shell layer 12. Moreover, the dotted | punctate area | region R1 and planar area | region R2 are formed in sea island shape (the sea: planar area | region R2, island: dotted | punctate area | region R1). The dotted region R1 is surrounded by the planar region R2.

  In order for the toner to have the above-described basic configuration, it is preferable that the shell layer 12 has a resin film, and a portion of the resin film exposed on the surface of the shell layer 12 corresponds to the planar region R2. Is more preferably formed. Specifically, when the resin film is substantially made of a hydrophobic resin, the planar region R2 has hydrophobicity. In each of FIGS. 3A to 3C, a hatched region corresponds to a resin film.

  In order for the toner to have the above-described basic configuration, the shell layer 12 preferably has a plurality of resin particles, and a portion of the resin particles exposed on the surface of the shell layer 12 corresponds to the dotted region R1. More preferably, resin particles are formed. Specifically, each of the resin particles is formed of a resin containing a charge control agent (for example, a thermoplastic resin containing a repeating unit derived from the charge control agent), thereby imparting chargeability to the dotted region R1. it can. The resin particles have the property of being easily triboelectrically charged than the resin film.

  As shown in FIGS. 3A and 3B, the resin particles may protrude from the surface of the resin film. In the example of FIGS. 3A and 3B, the portion of the resin particle that protrudes from the surface of the resin film corresponds to the dotted region R1. In order to make the resin particles protrude from the surface of the resin film, it is preferable to make the thickness of the resin film relatively small with respect to the particle diameter of the resin particles. As shown in FIG. 3A, the resin particles may be in contact with the toner core 11. Further, as shown in FIG. 3B, the resin particles may not be in contact with the toner core 11. In the example of FIGS. 3A and 3B, the resin film functions as an adhesive (specifically, a reactive adhesive), and the toner core 11 and the resin particles are bonded by curing.

  As shown in FIG. 3C, the resin particles may be dispersed in the resin film. In the example of FIG. 3C, the part exposed from the resin film among the resin particles located on the surface of the resin film corresponds to the dotted region R1.

  In any of the examples of FIGS. 3A to 3C, the plurality of resin particles are in contact with the resin film. The resin film may be a film having a grainy feeling as shown in FIG. 3 (a), or may be a film having no grainy feeling as shown in FIG. 3 (b) or FIG. 3 (c). . When resin particles are used as a material for forming a resin film, it is considered that if the material (resin particles) is completely melted and cured in a film-like form, a film having no graininess is formed as the resin film. It is done. On the other hand, if the material (resin particles) is not completely melted and cured in a film-like form, a film having a form in which the resin particles are two-dimensionally connected (a film having a granular feeling) is formed as the resin film. it is conceivable that. The shape of the resin particles contained in the shell layer may be spherical or elliptical (or flat). Not all the resin films in the shell layer are formed integrally. The resin film in the shell layer may be a single film or an aggregate of a plurality of films (islands) that are separated from each other.

  The toner having the above-described basic configuration is considered to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment. In addition, it is considered that the toner having the above-described basic configuration can form a high-quality image (for example, an image having a low fog density) in a normal temperature and normal humidity environment or a high temperature and high humidity environment. Specifically, in the toner having the above-described basic configuration, a plurality of point-like regions with relatively strong chargeability are present on the surface of the shell layer, so that sufficient chargeability can be imparted to the toner. In addition, in the toner having the above-described basic configuration, the surface of the shell layer has a planar region having hydrophobicity stronger than that of the dotted region, so that water molecules on the surface of the toner particle in a high temperature and high humidity environment are present. Can be suppressed. It is considered that the attenuation of the charge amount of the toner particles in a high-temperature and high-humidity environment is suppressed by making it difficult for water molecules to adsorb on the surface of the toner particles. By forming an image using toner having sufficient chargeability, a high-quality image (for example, an image having a low fog density) can be formed.

  In order for the toner to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment, it is preferable that the dotted region is surrounded by the planar region. The presence of a strongly hydrophobic planar region around a weakly hydrophobic (relatively strong) point-like region makes it possible to effectively suppress the adsorption of water molecules.

  In order for the toner to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment, it is preferable that the dotted regions are scattered on the surface of the shell layer. Since the dotted regions are scattered without being concentrated in one place, it is possible to improve the charging property of the surface of the toner particles as a whole.

  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 containing a plurality of toner particles of this embodiment is considered to be excellent in charging stability (see Table 1 and Table 2 described later). In order to improve the charging stability of the toner, the toner preferably contains the toner particles of this embodiment at a ratio of 80% by number or more, and the toner particles of this embodiment at a ratio of 90% by number or more. It is more preferable that the toner particles of the present embodiment be included at a ratio of 100% by number.

Total area in order to have a toner sufficient chargeability even under high temperature and high humidity even under normal temperature and normal humidity environment, the surface of the shell layer, to the total area S _A of all of the planar region, all the point-like regions The ratio of S _B (= S _B / S _A ) is preferably 0.01 or more and 0.20 or less, and more preferably 0.05 or more and 0.15 or less.

When the volume median diameter (D ₅₀ ) of the toner is 3 μm or more and 10 μm or less, in order for the toner to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment, more than half of the dotted regions ( More preferably, 80% by number or more) has a circle-equivalent diameter of 20 nm or more and 150 nm or less (a diameter of a circle having the same area as the dotted region).

  In order for the toner to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment, the toner having the basic configuration described above further includes the following configuration (hereinafter referred to as a preferable shell configuration). More preferably.

(Suitable shell configuration)
The shell layer has a resin film and a plurality of resin particles. The resin film is substantially composed of the first resin. Each of the plurality of resin particles is substantially composed of the second resin. The first resin has stronger hydrophobicity than the second resin. The second resin has a stronger charging property than the first resin. A portion of the resin film exposed on the surface of the shell layer corresponds to a planar region. A portion of the resin particles exposed from the resin film corresponds to a dotted area.

With regard to a toner having a suitable shell configuration, in order for the toner to have sufficient chargeability in both a normal temperature and normal humidity environment and a high temperature and high humidity environment, the total mass M _A of all the resins constituting the resin film is all The ratio of the total mass M _B of the resin constituting the resin particles (= 100 × M _B / M _A ) is preferably 1% by mass to 20% by mass, and preferably 5% by mass to 15% by mass. Is more preferable.

In order to easily form resin particles having sufficient positive chargeability, the resin (second resin) constituting the resin particles contains at least one vinyl compound not containing nitrogen and at least one nitrogen containing A monomer polymer containing a vinyl compound is preferable. The vinyl compound is a compound having a vinyl group (CH ₂ ═CH—) or a group in which hydrogen in the vinyl group is substituted (more specifically, ethylene, propylene, vinyl chloride, acrylic acid, methyl acrylate, methacryl Acid, methyl methacrylate, acrylonitrile, or styrene). The vinyl compound can be polymerized by addition polymerization with a carbon double bond “C═C” contained in the vinyl group or the like to become a polymer (resin).

  In the positively chargeable toner, in order for the resin particles in the shell layer to have sufficient positive chargeability, the resin constituting the resin particles (second resin) is, for example, a nitrogen-containing vinyl compound (more specifically, It is preferable to include a repeating unit derived from a quaternary ammonium compound or the like, and it is particularly preferable to include a repeating unit represented by the following formula (1) or a salt thereof.

In formula (1), R ¹¹ and R ¹² each independently represent a hydrogen atom, a halogen atom, or an alkyl group that may have a substituent. R ²¹ , R ²² , and R ²³ each independently represent a hydrogen atom, an alkyl group that may have a substituent, or an alkoxy group that may have a substituent. R ² represents an alkylene group which may have a substituent. R ¹¹ and R ¹² are each independently preferably a hydrogen atom or a methyl group, particularly preferably a combination in which R ¹¹ represents a hydrogen atom and R ¹² represents a hydrogen atom or a methyl group. R ²¹ , R ²² , and R ²³ are each independently preferably an alkyl group having 1 to 8 carbon atoms, and includes a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, and an n-butyl group. The group or iso-butyl group is particularly preferred. R ² is preferably an alkylene group having 1 to 6 carbon atoms, particularly preferably a methylene group or an ethylene group. In the repeating unit derived from 2- (methacryloyloxy) ethyltrimethylammonium chloride, R ¹¹ is a hydrogen atom, R ¹² is a methyl group, R ² is an ethylene group, and each of R ^{21 to} R ²³ is a methyl group. And a quaternary ammonium cation (N ⁺ ) is ionically bonded to chlorine (Cl) to form a salt.

In order for the resin particles in the shell layer to have sufficient negative chargeability in the negatively chargeable toner, the resin constituting the resin particles (second resin) is a sulfo group (—SO ₃ H) and / or a salt thereof. It is preferable that the repeating unit which has these is included, and it is especially preferable that the repeating unit represented by following formula (2) is included.

In formula (2), at least one of R ^{31 to} R ³⁷ represents a sulfo group or a salt thereof, and the others may independently have a hydrogen atom, a halogen atom, a hydroxyl group, or a substituent. It represents a good alkyl group, an alkoxy group that may have a substituent, an alkoxyalkyl group that may have a substituent, or an aryl group that may have a substituent. In the repeating unit derived from sodium p-styrene sulfonate, R ³³ represents a sodium salt of a sulfo group (—SO ₃ Na), and the others (R ³¹ , R ³² , and R ^{34 to} R ³⁷ ) are respectively Represents a hydrogen atom.

In order for the resin particles in the shell layer to have sufficiently strong chargeability and appropriate strength, the resin (second resin) constituting the resin particles is a repeating unit derived from the nitrogen-containing vinyl compound or the sulfone. In addition to a repeating unit having a group (—SO ₃ H) or a salt thereof, (meth) acrylic acid ester (more specifically, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid) It is preferable to include a repeating unit derived from propyl or butyl (meth) acrylate.

  The resin (second resin) constituting the resin particles in the shell layer may include a repeating unit having at least one of an acid group, a hydroxyl group, and a salt thereof. Resins containing such repeating units tend to have relatively strong hydrophilicity. When the toner has the above-mentioned “preferable shell configuration”, the charge attenuation of the toner can be sufficiently suppressed even if the resin particles in the shell layer have a relatively strong hydrophilicity. This is because the resin film (planar region) has a stronger hydrophobicity than the resin particles (dotted region).

  The resin (first resin) constituting the resin film in the shell layer preferably includes, for example, a repeating unit derived from a styrene monomer, and particularly preferably includes a repeating unit represented by the following formula (3). .

In formula (3), R ^{41 to} R ⁴⁵ each independently represent a hydrogen atom, a halogen atom, a hydroxyl group, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, or a substituent. Represents an alkoxyalkyl group which may have a substituent or an aryl group which may have a substituent. R ⁴⁶ and R ⁴⁷ each independently represent a hydrogen atom, a halogen atom, or an alkyl group which may have a substituent. R ^{41 to} R ⁴⁵ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a carbon number (specifically, alkoxy and alkyl The total number of carbon atoms) is preferably an alkoxyalkyl group having 2 to 6 carbon atoms. R ⁴⁶ and R ⁴⁷ are each independently preferably a hydrogen atom or a methyl group, particularly preferably a combination in which R ⁴⁷ represents a hydrogen atom and R ⁴⁶ represents a hydrogen atom or a methyl group. In the repeating unit derived from styrene, each of R ^{41 to} R ⁴⁷ represents a hydrogen atom.

  In order for the resin film in the shell layer to have sufficiently strong hydrophobicity and moderate strength, the resin (first resin) constituting the resin film is made of one or more styrene monomers (more preferably, the formula ( 3) one or more repeating units) and one or more acrylic monomers (more specifically, (meth) acrylonitrile, (meth) acrylic acid alkyl esters, or (meth) acrylic acid hydroxyalkyls). It is preferably a copolymer with an ester or the like.

  In order for the resin film in the shell layer to have sufficiently strong hydrophobicity and appropriate strength, the repeating unit having the highest molar fraction among the repeating units contained in the resin (first resin) constituting the resin film Is preferably a repeating unit derived from a styrene monomer (more preferably, a repeating unit represented by the formula (3)).

  In order to sufficiently suppress the moisture in the air from adsorbing on the surface of the resin film, the repeating unit having a hydrophilic functional group among all the repeating units contained in the resin (first resin) constituting the resin film. The unit ratio is preferably 10% by mass or less, and particularly preferably 0% by mass.

  In order to achieve both the heat-resistant storage stability and the low-temperature fixability of the toner, the thickness of the resin film is preferably 1 nm or more and 30 nm or less. The thickness of the resin film can be measured by analyzing a TEM image of the cross section of the toner particles using commercially available image analysis software (for example, “WinROOF” manufactured by Mitani Corporation). If the thickness of the resin film is not uniform in one toner particle, four equally spaced locations (specifically, two straight lines that are perpendicular to each other at the approximate center of the cross section of the toner particle are drawn, and the two The thickness of the resin film is measured at each of the four points where the straight line intersects the resin film, and the arithmetic average of the four measured values obtained is taken as the evaluation value (the thickness of the resin film) of the toner particles.

  With respect to the toner having a suitable shell configuration, it is more preferable that the shell layer further contains a thermosetting resin in order to achieve both the charging stability and the heat-resistant storage stability of the toner. When the shell layer further includes a thermosetting resin (for example, a hydrophilic thermosetting resin) in addition to the resin film and the resin particles, the strength of the shell layer can be improved. In order to achieve both the charging stability and the heat-resistant storage stability of the toner, it is preferable that 0.01% by mass or more and 50% by mass or less of the resin contained in the shell layer is a thermosetting resin. More preferably, the resin in an amount of 0.01% by mass or more and 10% by mass or less is a thermosetting resin.

  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, and 70% to 95%. It is more preferable to cover the area.

  Next, the toner core (binder resin and internal additive), shell layer, and external additive will be described in order. Depending on the use of the toner, unnecessary components may be omitted.

<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 urethane resin is preferred. Further, 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 suitably used. Can be used.

  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 having a carboxyl group, 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. . The acid value of the styrene-acrylic acid resin obtained can be adjusted by adjusting the amount of the acrylic acid monomer used. Moreover, the hydroxyl value of the styrene-acrylic acid-type resin obtained can be adjusted by adjusting the usage-amount of the monomer which has a hydroxyl group.

  Suitable examples of the styrenic monomer include styrene, α-methylstyrene, p-hydroxystyrene, m-hydroxystyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, Or p-ethylstyrene is mentioned.

  Preferable examples of the acrylic acid monomer include (meth) acrylic acid, (meth) acrylonitrile, (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. Moreover, when synthesizing the polyester resin, the acid value and the hydroxyl value of the polyester resin can be adjusted by changing the amount of alcohol used and the amount of carboxylic acid used. When the molecular weight of the polyester resin is increased, the acid value and hydroxyl value of the polyester resin tend to decrease.

  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, dipropylene glycol, polyethylene glycol, polypropylene glycol, 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.

  Note that the divalent or trivalent or higher carboxylic acid may be transformed into an ester-forming derivative (more specifically, an acid halide, an acid anhydride, or a lower alkyl ester). Here, “lower alkyl” means an alkyl group having 1 to 6 carbon atoms.

<Preferable thermosetting resin>
Examples of the thermosetting resin constituting the toner particles (particularly, the shell layer) include melamine resin, urea resin, sulfonamide resin, glyoxal resin, guanamine resin, aniline resin, polyimide resin (more specifically, Specifically, a maleimide polymer or a bismaleimide polymer) or a xylene-based resin can be preferably used.

The thermosetting resin can be obtained by crosslinking (polymerizing) one or more thermosetting monomers. Moreover, a thermosetting resin can also be synthesize | combined with a thermoplastic monomer by using a crosslinking agent. The thermosetting monomer is a monomer having crosslinkability. For example, when monomers of the same kind are three-dimensionally connected via “—CH ₂ —” to become a thermosetting resin, the monomer corresponds to a “thermosetting monomer”.

  Preferable examples of the thermosetting monomer include methylol melamine, melamine, methylolated urea (more specifically, dimethylol dihydroxyethylene urea), urea, benzoguanamine, acetoguanamine, or spiroguanamine.

[Toner core]
The toner core includes a binder resin. The toner core may also 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. 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 (measurement method: JIS (Japanese Industrial Standard) K0070-1992) and acid value (measurement method: JIS (Japanese Industrial Standard) K0070-1992)) of the binder resin are required. Is preferably 10 mgKOH / g or more, and more preferably 20 mgKOH / g or more.

  As the binder resin, a resin having one or more groups selected from the group consisting of an ester group, a hydroxyl group, an ether group, an acid group, and a methyl group is preferable, and a resin having a hydroxyl group and / or a carboxyl group is more preferable. . 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. The method for measuring the glass transition point (Tg) is the same method as in Examples described later or an alternative method thereof.

  In order to improve toner fixability during high-speed fixing, the softening point (Tm) of the binder resin is preferably 100 ° C. or less, and more preferably 95 ° C. or less. In addition, when the Tm of the binder resin is 100 ° C. or less (more preferably 95 ° C. or less), the toner core is formed during the curing reaction of the shell layer when the shell layer is formed on the surface of the toner core in the aqueous medium. Since the toner core is partially softened, the toner core is easily rounded due to surface tension. In addition, the measuring method of a softening point (Tm) is the same method as the Example mentioned later, or its alternative method. By combining a plurality of types of resins having different Tm, the Tm of the binder resin can be adjusted.

  The binder resin for the toner core is preferably a thermoplastic resin (more specifically, the above-described various resins). 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 particularly preferable to use a styrene-acrylic acid resin or a polyester resin as the binder resin.

  When a styrene-acrylic acid resin is used as the binder resin for the toner core, the number average molecular weight (Mn) of the styrene-acrylic acid resin is 2000 or more and 3000 or less in order to improve the strength of the toner core and the toner fixing property. It is preferable that The molecular weight distribution (the ratio Mw / Mn of the mass average molecular weight (Mw) to the number average molecular weight (Mn)) of the styrene-acrylic acid resin is preferably 10 or more and 20 or less. Gel permeation chromatography can be used to measure Mn and Mw of the styrene-acrylic acid 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. Gel permeation chromatography can be used for the measurement of Mn and Mw of the polyester resin.

(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. It is more preferable that the amount is not more than part by mass.

  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. More preferably, it is 20 parts by mass or less.

  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 increased. Further, the cationic property of the toner core can be enhanced by including a positively chargeable charge control agent in the toner core. However, when 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 “preferred shell configuration” described above, the shell layer includes a resin film and a plurality of resin particles. In addition to the resin film and the resin particles, the shell layer may further include a thermosetting resin (more specifically, the above-described “preferable thermosetting resin” or the like). In order to achieve both charging stability and heat-resistant storage stability of the toner, the shell layer contains one or more thermosetting resins selected from the group consisting of melamine resins, urea resins, and glyoxal resins. It is preferable.

(Resin film)
In the “preferable shell configuration” described above, the resin (first resin) that substantially constitutes the resin film is preferably a thermoplastic resin (more specifically, the “preferred thermoplastic resin” described above). Particularly preferred are copolymers of one or more styrene monomers and one or more acrylic monomers. Styrene-acrylic acid resins are more hydrophobic than polyester resins and tend to be positively charged. Preferred examples of the resin (first resin) constituting the resin film include a copolymer of styrene and butyl (meth) acrylate; styrene, butyl (meth) acrylate, and a hydroxyalkyl ester of (meth) acrylate. A copolymer of styrene, butyl (meth) acrylate, and acrylonitrile.

(Resin particles)
In the above-mentioned “preferable shell configuration”, the resin (second resin) that substantially constitutes the resin particles is a heat in which a repeating unit derived from a charge control agent (hereinafter referred to as a chargeable unit) is introduced. A plastic resin (more specifically, the above-mentioned “suitable thermoplastic resin” or the like) is preferable. The charge control agent for introducing the chargeable unit into the resin is preferably a radical polymerizable monomer.

  As a suitable example of the thermoplastic resin into which the charging unit is introduced, an acrylic resin (more specifically, a copolymer of methyl methacrylate and butyl acrylate) or a styrene-acrylic resin is used. (More specifically, a copolymer of styrene, methyl methacrylate, and butyl acrylate).

  Suitable examples of the charge control agent for introducing the chargeable unit into the resin are shown below. In addition, you may use the derivative | guide_body of each compound shown below as needed.

  As the positively chargeable charge control agent, for example, a compound having a primary amino group, a secondary amino group, a tertiary amino group, or a quaternary ammonium group can be suitably used.

  As the negatively chargeable charge control agent, for example, a sulfonic acid compound, a phosphoric acid compound, or a carboxylic acid compound can be suitably used.

  Examples of the charge control agent for introducing the charging unit into the resin include styrene sulfonic acid, sodium styrene sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, 2-acid phosphooxypropyl methacrylate, 2-methacrylic acid 2- Acid phosphooxyethyl, 3-chloro-2-acid phosphooxypropyl methacrylate, acrylic acid, methacrylic acid, fumaric acid, crotonic acid, tetrahydrophthalic anhydride, itaconic acid, aminostyrene, aminoethyl methacrylate, amino acrylate Particularly preferred are propyl, diethylaminopropyl acrylate, γ-N- (N ′, N′-diethylaminoethyl) aminopropyl methacrylate, or trimethylammonium propyl methacrylate.

[External additive]
An external additive may be attached to the surface of the toner base particles. For example, when the toner base particles and the external additive are stirred together, the external additive adheres (physically bonds) to the surface of the toner base particles with a physical force. 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 are preferable, and particles of silica particles or metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) are particularly preferable. preferable. However, resin particles may be used as an external additive. 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. The toner core and shell material are placed in the liquid. Subsequently, a shell layer substantially composed of a resin is formed on the surface of the toner core by reacting the shell material attached to the surface of the toner core in the liquid.

  In order to form a homogeneous shell layer, it is preferable to dissolve or disperse the shell material in the liquid by, for example, stirring the liquid containing the shell material. In order to suppress dissolution or elution of the toner core components (particularly, the binder resin and the release agent) when forming 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.

  Hereinafter, the toner manufacturing method according to the exemplary embodiment will be further described based on a more specific example.

(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, the fine particles of the binder resin, the release agent, and the colorant are aggregated in an aqueous medium to obtain aggregated particles containing the binder resin, the release agent, and the colorant. 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 dispersant) is removed from the dispersion liquid of the toner core to obtain the toner core.

(Formation of shell layer)
As the liquid into which the toner core and the shell material are put, for example, ion exchange water is prepared. Subsequently, the pH of the liquid is adjusted to a predetermined pH using, for example, hydrochloric acid. In order to promote the formation of the shell layer, the pH is preferably adjusted to 3 or more and 5 or less (weakly acidic).

  Subsequently, the toner core, the suspension of the first resin particles (the material of the resin film constituting the shell layer), and the suspension of the second resin particles (the shell layer) are added to a liquid whose pH is adjusted (for example, an acidic aqueous medium). The material of the resin particles constituting The second resin particles have a stronger charging property than the first resin particles. Further, the hydrophobicity of the first resin particles is stronger than the hydrophobicity of the second resin particles. In order to form the dotted region in the basic configuration described above, it is preferable to control the addition amount of the second resin particles to an appropriate amount. If the amount of the second resin particles that easily adsorb water molecules is too large, the toner charge retention in a high-temperature and high-humidity environment becomes weak, and the toner chargeability tends to be insufficient. A point-like region having strong chargeability may not be formed on the surface of the shell layer. In order for the toner to have the above-described basic configuration, the glass transition point (Tg) of the second resin particles is preferably higher by 5 ° C. than the glass transition point (Tg) of the first resin particles. In addition, the measuring method of a glass transition point (Tg) is the same method as the Example mentioned later, or its alternative method. Moreover, you may add the material (for example, thermosetting monomer) for synthesize | combining a thermosetting resin in a liquid as needed.

  The shell material and the like may be added to a liquid at room temperature. However, the molecular weight of the shell layer can be controlled by controlling the temperature of the liquid. The appropriate addition amount of the shell material can be calculated based on the specific surface area of the toner core. In addition to the shell material and the like, a polymerization accelerator may be added to the liquid.

  As shown in FIG. 4, the second resin particles 12a and the first resin particles 12b adhere to the surface of the toner core 11 in the liquid. In order to uniformly adhere the shell material to the surface of the toner core, it is preferable to highly disperse the toner core in a liquid containing the shell material. In order to highly disperse the toner core in the liquid, a dispersant 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.). Also good.

  Subsequently, while stirring the liquid containing the shell material and the like, the temperature of the liquid is set at a predetermined holding temperature (for example, 50 ° C. at a speed selected from 0.1 ° C./min to 3 ° C./min). To a temperature selected from 85 ° C. to 85 ° C. Furthermore, the temperature of the liquid is maintained at the above holding temperature for a predetermined time (for example, a time selected from 30 minutes to 4 hours) while stirring the liquid. It is considered that the reaction (immobilization of the shell layer) proceeds between the toner core and the shell material while the temperature of the liquid is kept high. The shell material is combined with the toner core to form a shell layer. It is considered that the second resin particles are fixed on the surface of the toner core in the form of particles. The first resin particles are considered to melt in the liquid and cure in a film form. By curing the resin film constituting the shell layer, the toner core and the shell layer (resin film and resin particles) are integrated. The shell layer formed on the surface of the toner core includes a resin film (sea region) and resin particles (island region) distributed in an island shape with respect to the resin film (sea region). By forming a shell layer on the surface of the toner core in the liquid, a dispersion of toner base particles can be obtained.

  As described above, the first resin particles are adhered to the surface of the toner core in the liquid, and the liquid is heated, whereby the first resin particles can be dissolved to form a film. However, the first resin particles may be formed into a film by being heated in the drying step or receiving a physical impact force in the external addition step.

  In order to suppress elution of the toner core component or deformation of the toner core, the holding temperature is preferably less than the glass transition point (Tg) of the toner core. However, the toner core may be intentionally deformed by setting the holding temperature to be equal to or higher than the glass transition point (Tg) of the toner core. When the holding temperature is increased, the deformation of the toner core is promoted, and the shape of the toner base particles tends to approach a true sphere. It is desirable to adjust the holding temperature so that the toner base particles have a desired shape. Further, when the shell material is reacted at a high temperature, the shell layer tends to become hard. Based on the holding temperature, the molecular weight of the shell layer can also be controlled.

  After the shell layer is formed as described above, the dispersion of the toner base particles is neutralized using, for example, sodium hydroxide. Subsequently, the toner mother particle dispersion is cooled to, for example, room temperature (about 25 ° C.). Subsequently, the dispersion of the toner base particles is filtered using, for example, a Buchner funnel. Thereby, the toner base particles are separated from the liquid (solid-liquid separation), and wet cake-like toner base particles are obtained. Subsequently, the obtained wet cake-like toner base particles are washed. Subsequently, the washed toner base particles are dried. Thereafter, if necessary, the toner base particles and the external additive are mixed using a mixer (for example, FM mixer manufactured by Nippon Coke Kogyo Co., Ltd.), and the external additive is adhered to the surface of the toner base particles. May be. When a spray dryer is used in the drying step, the drying step and the external addition step can be performed at the same time by spraying a dispersion of an external additive (for example, silica particles) onto the toner base particles. Thus, a toner having a large number of toner particles is produced.

  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, the timing of adjusting the pH of the liquid (for example, an aqueous medium) may be before or after the aforementioned shell material or the like (shell material and toner core) is added to the liquid. The shell material or the like may be added simultaneously at the same time, or may be added separately. Moreover, you may make it perform the process of heating a liquid to the said holding temperature before the process of adding shell material etc. to a liquid. In addition, when reacting a material (for example, a shell material) in the 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 method for forming the shell layer is arbitrary. For example, the shell layer may be formed using any of an in-situ polymerization method, a submerged cured coating method, and a coacervation method. Further, the toner may be sieved after the external addition step. Further, unnecessary steps 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 aforementioned compounds (monomers for synthesizing the resin, etc.). 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. Various materials may be used in a solid state or in a liquid state. For example, a powder of a solid state material may be used, a solution of the material (a liquid state material dissolved in a solvent) may be used, or a dispersion of the material (a liquid in which the solid state material is dispersed) ) May be used. In order to produce the toner efficiently, it is preferable to form a large number of toner particles simultaneously. The toner particles produced at the same time are considered to have substantially the same configuration.

  Examples of the present invention will be described. Table 1 shows toners A to I (each toner for developing an electrostatic latent image) according to Examples or Comparative Examples.

  Hereinafter, a manufacturing method, an evaluation method, and an evaluation result of toners A to I (each toner for developing an electrostatic latent image) according to Examples or Comparative Examples 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. Moreover, the transmission electron microscope (TEM) was used for the measurement of a number average particle diameter. Moreover, the measuring methods of Tg (glass transition point) and Tm (softening point) are as follows unless otherwise specified.

<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 A]
(Production of toner core)
750 g of low viscosity polyester resin (Tg = 38 ° C., Tm = 65 ° C.), 100 g of medium viscosity polyester resin (Tg = 53 ° C., Tm = 84 ° C.), high viscosity polyester resin (Tg = 71 ° C., Tm = 120 ° C.) ) 150 g, 55 g carnauba wax (“Carnauba Wax No. 1” manufactured by Kato Yoko Co., Ltd.) and 40 g colorant (“KET BLUE 111” manufactured by DIC Corporation, phthalocyanine blue) are mixed with FM mixer (Nippon Coke Industrial Co., Ltd.) Was used at a rotational speed of 2400 rpm.

Subsequently, the obtained mixture was mixed with a material supply speed of 5 kg / hour, a shaft rotation speed of 160 rpm, and a set temperature range (cylinder temperature) of 100 ° C. or higher using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.). It was melt-kneaded under conditions of 130 ° C. or lower. Subsequently, the obtained melt-kneaded product was cooled, and the cooled melt-kneaded product was coarsely pulverized using a pulverizer (“Rotoplex (registered trademark) 16/8 type” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized using a jet mill (“Ultrasonic Jet Mill Type I” manufactured by Nippon Pneumatic Industry Co., Ltd.). Subsequently, the obtained finely 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 875 mL of ion-exchanged water and an anionic surfactant (“Latemul (registered trademark) WX” manufactured by Kao Corporation, components: 75 mL of polyoxyethylene alkyl ether sodium sulfate, solid content concentration: 26% by mass). 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 18 g of styrene and 2 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 (hydrophobic resin) (hereinafter referred to as suspension A-1) was obtained. Regarding the resin fine particles contained in the obtained suspension A-1, the number average particle diameter was 32 nm and Tg was 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 mL of isobutanol, 100 g of methyl methacrylate, 35 g of butyl acrylate, and 2- (methacryloyloxy) ethyl 30 g of trimethylammonium chloride (Alfa Aesar), 6 mL 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. Then, 3 mL of 2,2′-azobis (2-methyl-N- (2-hydroxyethyl) propionamide) (“VA-086” manufactured by Wako Pure Chemical Industries, Ltd.) was added into 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 (“Acetic acid” manufactured by Wako Pure Chemical Industries, Ltd.) were placed in a container of a mixing apparatus (“Hibismix 2P-1” manufactured by PRIMIX Corporation). 184 mL of ethyl special grade)) 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 0” manufactured by Kao Corporation, component: sodium lauryl sulfate) 20 g and ethyl acetate ( Wako Pure Chemical Industries, Ltd. “Ethyl acetate special grade”) 16 g and an aqueous solution in 562 mL of ion-exchanged water) were added. As a result, a suspension of positively chargeable resin fine particles (charge control agent-containing resin) (hereinafter referred to as suspension B-1) was obtained. Regarding the resin fine particles contained in the obtained suspension B-1, the number average particle diameter was 35 nm, and Tg was 80 ° 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 100 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, dilute hydrochloric acid was added to the flask to adjust the pH of the flask contents to 4. Subsequently, in the flask, 0.35 g of an aqueous solution of hexamethylolmelamine initial polymer (“Milben (registered trademark) Resin SM-607” manufactured by Showa Denko KK, solid content concentration: 80% by mass) and suspension A-1 220 g (solid content concentration: 2 mass%) and 1.2 g of suspension B-1 (solid content concentration: 20 mass%) were added.

  Subsequently, 300 g of the toner core prepared by the above-described procedure was added to the flask, and the flask contents were stirred for 1 hour at a rotation speed of 200 rpm. Thereafter, 300 mL of ion exchange water was added into the flask. Subsequently, while stirring the flask contents at a rotation speed of 100 rpm, the temperature in the flask was increased to 70 ° C. at a rate of 1 ° C./min. Subsequently, the flask contents were stirred for 2 hours under the conditions of a temperature of 70 ° 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 using a continuous surface reformer (“Coat Mizer (registered trademark)” manufactured by Freund Sangyo Co., Ltd.). Dried. As a result, toner mother particle powder was obtained. As a result of observing the dried toner base particles using a scanning electron microscope (SEM), a granular feeling was observed in the shell layer, but the particles constituting the shell layer were not separated.

(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 fine particles (“AEROSIL (registered trademark) REA90” manufactured by Nippon Aerosil Co., Ltd.) and a 10 L capacity FM mixer (manufactured by Nippon Coke Industries, Ltd.) Was added for 5 minutes to adhere the external additive (silica particles) 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 A containing a large number of toner particles was obtained.

[Production Method of Toner B]
The manufacturing method of the toner B was the same as the manufacturing method of the toner A except that the amount of the suspension B-1 used was changed from 1.2 g to 0.4 g in the shell layer forming step.

[Method for producing toner C]
The production method of the toner C was the same as the production method of the toner A except that the amount of the suspension B-1 used was changed from 1.2 g to 2.0 g in the shell layer forming step.

[Production Method of Toner D]
The manufacturing method of the toner D is the same as that of the toner A except that 1.2 g of suspension B-2 (solid content concentration: 20% by mass) was used instead of 1.2 g of suspension B-1 in the shell layer forming step. It was the same as the manufacturing method. The suspension B-2 was prepared in the form of an aqueous solution such as ethyl acetate using 18 g of 1N hydrochloric acid, an anionic surfactant (“Emar 0” manufactured by Kao Corporation, component: sodium lauryl sulfate) and ethyl acetate (Wako Pure Chemical Industries, Ltd.). 6 g of 1N hydrochloric acid and an anionic surfactant (“Emar 0”, ingredient: sodium lauryl sulfate) 20 g instead of an aqueous solution obtained by dissolving 16 g of “ethyl acetate special grade” manufactured by Co., Ltd. in 562 g of ion-exchanged water The suspension B-1 was prepared in the same manner as the suspension B-1, except that an aqueous solution prepared by dissolving 16 g of ethyl acetate (“ethyl acetate special grade” manufactured by Wako Pure Chemical Industries, Ltd.) in 574 g of ion-exchanged water was used. Regarding the resin fine particles contained in the obtained suspension B-2, the number average particle diameter was 46 nm, and Tg was 81 ° C.

[Production Method of Toner E]
The production method of the toner E was the same as the production method of the toner A, except that the aqueous solution of the hexamethylol melamine initial polymer (milben resin SM-607) was not used in the shell layer forming step.

[Production Method of Toner F]
In the method for producing toner F, 220 g of suspension A-2 (solid content concentration: 2% by mass) was used instead of 220 g of suspension A-1 in the shell layer forming step, and suspension B-1 was not used. Except for this, it was the same as the manufacturing method of the toner A. The suspension A-2 was prepared by using 18 g of styrene, 2 g of butyl acrylate, and 2- (methacryloyloxy) ethyltrimethylammonium as a first liquid instead of a mixed liquid of 18 g of styrene and 2 g of butyl acrylate. This was the same as the method for preparing the suspension A-1, except that a mixed solution with 0.2 g of chloride (manufactured by Alfa Aesar) was used. The resin fine particles contained in the obtained suspension A-2 had a number average particle size of 30 nm and Tg of 68 ° C.

[Method for producing toner G]
The manufacturing method of the toner G was the same as the manufacturing method of the toner A except that the suspension B-1 was not used.

[Method for producing toner H]
The manufacturing method of the toner H was the same as the manufacturing method of the toner A except that the amount of the suspension B-1 used was changed from 1.2 g to 4.0 g in the shell layer forming step.

[Production Method of Toner I]
The production method of the toner I was the same as the production method of the toner E except that the following points were changed.

  In the shell layer forming step, 1.2 g of suspension B-3 was used instead of 1.2 g of suspension B-1. The suspension B-3 was prepared by replacing 60 g of styrene, 60 g of methyl methacrylate, 15 g of butyl acrylate, and p- Suspension B-1 except that 0.2 ml of sodium styrenesulfonate (“Spinomer NaSS (registered trademark)” manufactured by Tosoh Organic Chemical Co., Ltd.) was used instead of the positively chargeable resin. This was the same as the preparation method. The resin fine particles contained in the obtained suspension B-3 had a number average particle diameter of 37 nm and Tg of 75 ° C.

  In the external addition step, instead of 1.0 part by mass of dry silica fine particles (AEROSIL REA90), silica particles (fumed silica particles surface-treated with polydimethylsiloxane: “CAB-O-SIL (registered trademark)” manufactured by Cabot Corporation TS-720 ") 1.0 part by weight was used.

[Evaluation method]
The evaluation method of each sample (toners A to I) is as follows.

(Charge decay characteristics)
The charge decay constant α of the sample (toner) is measured in accordance with JIS (Japanese Industrial Standards) C 61340-2-1-2006 using an electrostatic diffusivity measuring device (“NS-D100” manufactured by Nano Seeds Co., Ltd.). It was measured. Hereinafter, a method for measuring the charge decay constant of the toner will be described in detail.

  A sample was placed in the measurement cell. The measurement cell was a metal cell in which a recess having an inner diameter of 10 mm and a depth of 1 mm was formed. The sample was pushed in from above using a slide glass, and the concave portion of the cell was filled with the sample. The sample overflowed from the cell was removed by reciprocating the slide glass on the surface of the cell. The filling amount of the sample was 0.04 g or more and 0.06 g or less.

Subsequently, the measurement cell filled with the sample was allowed to stand for 12 hours in an environment of a temperature of 32 ° C. and a humidity of 80% RH. Subsequently, the grounded measurement cell was placed in an electrostatic diffusivity measuring apparatus, and ions were supplied to the sample by corona discharge to charge the sample. The charging time was 0.5 seconds. And after 0.7 second passed after completion | finish of corona discharge, the surface potential of the sample was measured continuously. Based on the measured surface potential and the formula “V = V ₀ exp (−α√t)”, the charge decay constant (charge decay rate) α was calculated. In the formula, V represents the surface potential [V], V ₀ represents the initial surface potential [V], and t represents the decay time [second].

  If the charge decay constant is 0.020 or less, it is evaluated as ◎ (very good), and if the charge decay constant is more than 0.020 and less than 0.025, it is evaluated as ○ (good), and the charge decay constant is 0.00. If it exceeded 025, it was evaluated as x (bad).

(Charge amount)
A developer carrier (a carrier for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd.) and a sample (toner) were mixed for 30 minutes using a ball mill to prepare a developer for evaluation (two-component developer). The ratio of the sample (toner) in the developer for evaluation was 12% by mass. However, in the evaluation of toner I, a carrier for negatively chargeable toner (a carrier for “Anesis 6016” manufactured by Kyocera Document Solutions Inc.) was used as a carrier for developer.

  Subsequently, the developer for evaluation which was allowed to stand for 24 hours in a normal temperature and normal humidity environment (N / N environment: temperature 23 ° C., humidity 50% RH), and a high temperature and high humidity environment (H / H environment: temperature 32.5 ° C.). And the developer for evaluation that was allowed to stand for 24 hours under a humidity of 80% RH), the charge amount of the toner in the developer was measured. The charge amount of the toner in the developer was measured using a Q / m meter (“MODEL 210HS-1” manufactured by Trek) under the following conditions.

<Measurement method of charge amount of toner in developer>
A developer was put into a measurement cell of a Q / m meter, and only the toner out of the put developer was sucked through a sieve 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.

  If the charge amount of the developer for evaluation placed in an N / N environment is +30 μC / g or more or −30 μC / g or less, it is evaluated as “good”, and is more than −30 μC / g and less than 30 μC / g If so, it was evaluated as “× (not good)”.

  If the charge amount of the developer for evaluation placed in an H / H environment is +10 μC / g or more or −10 μC / g or less, it is evaluated as “good”, and more than −10 μC / g and less than 10 μC / g If so, it was evaluated as “× (not good)”.

(FD: fog density)
An evaluation developer (two-component developer) was prepared in the same manner as in the evaluation of the charge amount. Using a developer for evaluation (hereinafter referred to as a developer after standing for H / H) that was allowed to stand for 12 hours in a high-temperature and high-humidity environment (H / H environment: temperature 32.5 ° C., humidity 80% RH). The fog density of the formed image was measured.

  As an evaluation machine, a color multifunction machine (“TASKalfa 5550ci” manufactured by Kyocera Document Solutions Inc.) was used. After standing still for H / H, the developer was charged into the developing device of the evaluation machine, and a sample (replenishment toner) was charged into the toner container of the evaluation machine. Further, the voltage between the developing sleeve of the evaluation machine and the magnet roll so that the initial image density (measurement apparatus: “SpectroEye (registered trademark)” manufactured by X-Rite) is 1.0 or more and 1.2 or less. Was adjusted in the range of 200V to 300V. However, in the evaluation of Toner I, an analog copying machine (“Anessis 6016” manufactured by Kyocera Document Solutions Inc.) was used as an evaluation machine. In the evaluation of Toner I, the surface potential of the photoconductor of the evaluation machine was adjusted to +700 V, and the voltage between the developing sleeve and the magnet roll was adjusted to +150 V, respectively.

Subsequently, a sample image including a solid portion and a blank portion is printed on a recording medium (evaluation paper) using the evaluation machine, and printed using a reflection densitometer (“SpectroEye” manufactured by X-Rite). The reflection density was measured for each of the blank portion of the sample image on the recording medium and unprinted base paper (unprinted paper). Then, the fog density (FD) was calculated based on the following equation.
FD = (reflection density of blank area) − (reflection density of unprinted paper)

  When the fog density (FD) was 0.005 or less, it was evaluated as ◯ (good), and when the fog density (FD) was higher than 0.005, it was evaluated as x (not good).

[Evaluation results]
Table 2 shows the evaluation results of the toners A to I. For each of the toners A to I, charge decay characteristics (charge decay constant), N / N charge amount (charge amount of toner left in a normal temperature / humidity environment), H / H charge amount (high temperature / high humidity environment) Table 2 shows the evaluation results of the charge amount of the toner left still) and the fog density.

  Toners A to E and I (toners according to Examples 1 to 6) had the above-described “basic configuration” and “preferable shell configuration”, respectively. Specifically, in each of the toners according to Examples 1 to 6, the shell layer had a resin film and a plurality of resin particles. In addition, each of the toners according to Examples 1 to 6 generally had a form as illustrated in FIG. The shell layer of the toner particles contained in each toner has a plurality of dot-like regions and a planar region having a stronger hydrophobic property than the dot-like regions on the surface thereof. Each of the plurality of dot-like regions had a charging property stronger than that of the planar region.

Each of the toners A to E and I was confirmed by image analysis of the SEM photographed image. As a result, the total area S _B of all the dot-like regions was compared with the total area S _A of all the planar regions on the surface of the shell layer. The ratio (= S _B / S _A ) was 0.01 or more and 0.20 or less. Further, more than half of the dotted regions had an equivalent circle diameter of 20 nm to 150 nm. The shell layer covered an area of 50% to 95% of the entire surface of the toner core. Moreover, when it confirmed by the image analysis of the TEM image, the thickness of the resin film was 1 nm or more and 30 nm or less.

  As shown in Table 2, each of the toners according to Examples 1 to 6 had a sufficient positive charge property in both a normal temperature and normal humidity environment and a high temperature and high humidity environment. In addition, each of the toners according to Examples 1 to 6 was able to form an image with a low fog density even in a high temperature and high humidity environment.

  In the toner F (the toner according to Comparative Example 1), a region having charging properties was formed on the entire surface of the shell layer. This is presumably because in the toner F, the shell layer did not contain the hydrophobic resin and the chargeable resin as separate resins.

  Toner G (toner according to Comparative Example 2) did not have the basic configuration described above. In the toner G, it is presumed that water molecules are adsorbed on the entire surface of the toner particles in a high temperature and high humidity environment because the functional groups having charging property and hydrophilicity are uniformly distributed on the surface of the toner particles.

  In the toner H (toner according to Comparative Example 3), the region having the charging property on the surface of the shell layer was too wide to be formed in a dot shape. In Toner H, since the hydrophobicity of the toner particles is weak, it is presumed that the toner is poorly charged in a high-temperature and high-humidity environment, and fog is generated in the formed image.

  As shown in Table 2, the toners F to H (the toners according to Comparative Examples 1 to 3) are higher in temperature and humidity than the toners A to E and I (the toners according to Examples 1 to 6), respectively. It was inferior in charging property below. In addition, each of the toners F to H (toners according to Comparative Examples 1 to 3) could not form an image with a low fog density in a high temperature and high humidity environment.

  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.

DESCRIPTION OF SYMBOLS 10 Toner mother particle 11 Toner core 12 Shell layer 12a 2nd resin particle 12b 1st resin particle R1 Point area | region R2 Planar area | region

Claims (16)

A plurality of toner particles having a core and a shell layer formed on the surface of the core;
The shell layer is substantially composed of a resin, and has a plurality of dotted regions and a planar region having a stronger hydrophobic property than the dotted regions on the surface thereof,
The electrostatic latent image developing toner, wherein each of the plurality of dot-like regions has a charging property stronger than that of the planar region. The dotted regions are scattered on the surface of the shell layer,
The electrostatic latent image developing toner according to claim 1, wherein each of the dotted regions is surrounded by the planar region. The shell layer has a resin film substantially composed of a first resin and a plurality of resin particles substantially composed of a second resin, respectively.
The first resin has a stronger hydrophobicity than the second resin,
The second resin has a stronger charging property than the first resin,
The portion of the resin film exposed on the surface of the shell layer corresponds to the planar region,
The electrostatic latent image developing toner according to claim 1, wherein a portion of the resin particles exposed from the resin film corresponds to the dot-like region.   The electrostatic latent image developing toner according to claim 3, wherein the first resin contains one or more repeating units derived from a styrene monomer.   The electrostatic latent image developing toner according to claim 4, wherein the first resin is a copolymer of one or more styrene monomers and one or more acrylic monomers.   6. The electrostatic latent image developing toner according to claim 4, wherein the repeating unit having the highest molar fraction among the repeating units contained in the first resin is a repeating unit derived from a styrene monomer.   The said 2nd resin is a polymer of the monomer containing 1 or more types of vinyl compounds which do not contain nitrogen, and 1 or more types of nitrogen-containing vinyl compounds, It is any one of Claims 3-6. Toner for developing electrostatic latent image.   The electrostatic latent image developing toner according to claim 3, wherein the second resin contains one or more repeating units derived from a quaternary ammonium compound.   The electrostatic latent image developing toner according to claim 8, wherein the second resin is a copolymer of one or more quaternary ammonium compounds and one or more (meth) acrylic acid esters.   The electrostatic latent image developing toner according to claim 3, wherein the second resin contains one or more repeating units having a sulfo group and / or a salt thereof.   11. The electrostatic latent image developing toner according to claim 3, wherein the second resin is a thermoplastic resin into which a repeating unit derived from a charge control agent is introduced.   The ratio of the repeating unit which has the functional group which can ionize and can form a salt among all the repeating units contained in the said 1st resin, or its salt is 10 mass% or less, Any one of Claims 3-11 The electrostatic latent image developing toner according to one item.   The electrostatic latent image developing toner according to claim 3, wherein the shell layer further contains a thermosetting resin.   The electrostatic latent image development according to claim 13, wherein the shell layer includes, as the thermosetting resin, at least one resin selected from the group consisting of a melamine resin, a urea resin, and a glyoxal resin. Toner.   The ratio of the total mass of the resin constituting all the resin particles to the total mass of the resin constituting all the resin films is 1% by mass or more and 20% by mass or less. The toner for developing an electrostatic latent image according to the item.   The electrostatic latent image developing toner according to claim 3, wherein the resin film has a thickness of 1 nm to 30 nm.

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