JP2017227698A - Two-component developer and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue to continuously form an image of high picture quality using a two-component developer.SOLUTION: A toner particle comprises a toner mother particle 10, and silica particles 12a and resin particle 12b present on a surface of the toner mother particle 10. A resin particle 12b contains a copolymer of two or more kinds of vinyl compound including (meth)acrylic acid ester of monohydric alcohol. A cationic surfactant sticks on a surface of the resin particle 12b. At respective timings after initial and continuous printing of images of 5% in printing rate in characteristic evaluation on the two-component developer, relational expressions (A) A-A<A-A<0.10% and (B) B-B<0.010%≤B-Bhold for a carrier sticking quantity (A, A, A) of silica particles 12a and a carrier sticking quantity (B, B, B) of resin particles 12b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a two-component developer and a method for producing the same, and more particularly to a two-component developer that can be suitably used for developing an electrostatic latent image and a method for producing the two-component developer.

  Patent Document 1 discloses a two-component developer containing magnetic particles, colorant-containing resin particles, a flow improver (inorganic oxide), and spherical resin fine particles (polyvinylidene fluoride resin fine particles). .

Japanese Patent Laid-Open No. 2-67567

  However, it is difficult to sufficiently prevent the flow improver from adhering to the surfaces of the magnetic particles (carrier particles) only by the technique disclosed in Patent Document 1. For this reason, when used for continuous printing, it is difficult to ensure sufficient charge imparting properties of magnetic particles (carrier particles).

  The present invention has been made in view of the above problems, and provides a two-component developer capable of continuously forming a high-quality image over a long period of time even when used for continuous printing, and a method for producing the same. The purpose is to do.

The two-component developer according to the present invention includes a toner including a plurality of toner particles and a carrier including a plurality of carrier particles. The toner particles include toner base particles, silica particles and resin particles present on the surface of the toner base particles. The resin particles contain a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol. A cationic surfactant is attached to the surface of the resin particles. In the characteristic evaluation of the two-component developer, the amount of the silica particles attached to the surface of the carrier particles at the initial stage and the timing after continuous printing of the image with a printing rate of 5%, and the surface of the carrier particles When the adhesion amount of the adhered resin particles is measured, the relational expressions (A) and (B) are satisfied.
A ₁₀₀₀₀ -A ₁₀₀₀ <A ₁₀₀₀ -A _i <0.10% (A)
_{B 10000 -B 1000 <0.010% ≦} B 1000 -B i ... (B)
In the formula (A), A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ are the silica particles in the carrier in the two-component developer at the initial timing, the cumulative number of printed sheets 1000 sheets, and the cumulative number of printed sheets 10,000 sheets, respectively. The adhesion amount is expressed as a mass ratio with respect to the mass of the carrier. In the formula (B), B _i , B ₁₀₀₀ , and B ₁₀₀₀₀ are the resin particles in the carrier in the two-component developer at the initial timing, the cumulative number of printed sheets of 1000, and the cumulative number of printed sheets of 10,000, respectively. The adhesion amount is expressed as a mass ratio with respect to the mass of the carrier. The measurement methods for A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ are each a fluorescent X-ray analysis. Each B _i, B _1000, and a measuring method of B ₁₀₀₀₀ is GC / MS method.

  The method for producing a two-component developer according to the present invention includes a preparation step, a first external addition step, a second external addition step, and a mixing step. In the preparation step, toner base particles, silica particles, and resin particles are prepared. The resin particles contain a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol. A cationic surfactant is attached to the surface of the resin particles. In the first external addition step, the silica particles are adhered to the toner base particles. In the second external addition step, toner particles are obtained by further attaching the resin particles to the toner base particles to which the silica particles are attached. In the mixing step, the toner particles are mixed with carrier particles to obtain a two-component developer.

  According to the present invention, it is possible to provide a two-component developer capable of continuously forming a high-quality image for a long period of time even when used for continuous printing, and a method for producing the same.

FIG. 3 is a diagram illustrating an example of the surface of toner particles contained in a two-component developer according to an embodiment of the present invention.

  Embodiments of the present invention will be described in detail. Note that the evaluation results (values indicating shape, physical properties, etc.) regarding the powder (more specifically, toner base particles, external additives, toner, carrier, etc.) are average values 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 measured using a laser diffraction / scattering particle size distribution measuring device (“LA-750” manufactured by Horiba, Ltd.) unless otherwise specified. It is the value. Moreover, the softening point (Tm) is a value measured using a Koka type flow tester (“CFT-500D” manufactured by Shimadzu Corporation) unless otherwise specified. In the S curve (horizontal axis: temperature, vertical axis: stroke) measured with the Koka type flow tester, the temperature that becomes "(baseline stroke value + maximum stroke value) / 2" is Tm (softening point). Equivalent to. Further, the measured value of the acid value is a value measured according to “JIS (Japanese Industrial Standard) K0070-1992” unless otherwise specified. Moreover, each measured value of a number average molecular weight (Mn) and a mass average molecular weight (Mw) is the value measured using the gel permeation chromatography, if not prescribed | regulated at all.

  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 (CH ₂ ═CHCN) and methacrylonitrile (CH ₂ ═C (CH ₃ ) CN) may be collectively referred to as “(meth) acrylonitrile”. Further, the “main component” of a material means a component that is contained most in the material on a mass basis unless otherwise specified. 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. In addition, a group represented by a predetermined symbol may be represented by the symbol. For example, the group represented by R ₁₁ may be simply referred to as “R ₁₁ ”.

  The developer according to the present embodiment is a two-component developer including a toner and a carrier. The toner and the carrier are each a powder composed of a large number of particles. The toner includes a plurality of toner particles having the configuration described below. The carrier includes a plurality of carrier particles having the configuration described below. The developer according to this embodiment can be suitably used for developing an electrostatic latent image. The toner contained in the developer according to this embodiment can be used as, for example, a positively chargeable toner. The positively chargeable toner is positively charged by friction with the carrier.

  The toner particles contained in the toner include toner base particles and an external additive. The external additive adheres to the surface of the toner base particles. The toner base particles contain a binder resin. The toner base particles may contain an internal additive (for example, at least one of a release agent, a colorant, a charge control agent, and a magnetic powder) in addition to the binder resin, if necessary. Hereinafter, the toner particles before the external additive adheres are referred to as toner mother particles.

  The toner particles contained in the toner may be toner particles not having a shell layer (hereinafter referred to as non-capsule toner particles) or toner particles having a shell layer (hereinafter referred to as capsule toner particles). There may be. In the capsule toner particles, the toner base particles include a core and a shell layer that covers the surface of the core. The shell layer is substantially composed of a resin. For example, by covering a core that melts at a low temperature with a shell layer having excellent heat resistance, it is possible to achieve both heat-resistant storage stability and low-temperature fixability of the toner. Additives may be dispersed in the resin constituting the shell layer. The shell layer may cover the entire surface of the core, or may partially cover the surface of the core. In order to improve the fixing property of the toner, it is preferable that the core of the capsule toner particle is substantially composed of a thermoplastic resin. The shell layer may be substantially composed of a thermosetting resin, may be substantially composed of a thermoplastic resin, or may contain both a thermoplastic resin and a thermosetting resin. Good.

  Carrier particles contained in the carrier have magnetism. In order to impart magnetism to the carrier particles, at least a part of the carrier particles may be formed of a magnetic material (for example, a ferromagnetic material such as ferrite), or the carrier particles may be formed of a resin in which the magnetic particles are dispersed. You may form at least one part.

  The carrier particles contained in the carrier may be carrier particles without a coat layer (for example, ferrite carrier particles), or may be carrier particles with a coat layer (hereinafter referred to as coated carrier particles). . In order to form a high-quality image over a long period of time using a developer, it is preferable to use coated carrier particles. The coated carrier particles include a carrier core and a coat layer that covers the surface of the carrier core. The coat layer is substantially composed of a resin. Additives may be dispersed in the resin constituting the coat layer. The coat layer may cover the entire surface of the carrier core, or may partially cover the surface of the carrier core. Hereinafter, the material for forming the coating layer is referred to as a coating material.

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

  First, an electrostatic latent image is formed on a photoconductor (for example, a surface layer portion of a photoconductor drum) based on image data. Next, the formed electrostatic latent image is developed using a developer (toner and carrier). In the developing process, a developer is carried on a developing roller (for example, a developing roller incorporating a magnet roll) disposed near the photosensitive drum, and toner in the developer (for example, toner charged by friction with a carrier) To the electrostatic latent image. As a result, a toner image is formed on the photoreceptor. 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 developer according to this embodiment is a two-component developer having the following configuration (hereinafter referred to as a basic configuration).

(Basic configuration of two-component developer)
The developer includes a toner including a plurality of toner particles and a carrier including a plurality of carrier particles. The toner particles include toner base particles, silica particles and resin particles present on the surface of the toner base particles. The resin particles contain a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol. A cationic surfactant is attached to the surface of the resin particles. In the characteristics evaluation of the developer, the amount of silica particles adhering to the surface of the carrier particles and the amount of resin particles adhering to the surface of the carrier particles at the initial stage and after each continuous printing of the image with a printing rate of 5% Are measured, the relational expressions of the formulas (A) and (B) are satisfied.
A ₁₀₀₀₀ -A ₁₀₀₀ <A ₁₀₀₀ -A _i <0.10% (A)
_{B 10000 -B 1000 <0.010% ≦} B 1000 -B i ... (B)

In the formula (A), A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ respectively represent the adhesion amount of silica particles on the carrier in the developer at each of the initial timing, the cumulative number of printed sheets 1000, and the cumulative number of printed sheets 10,000. It is expressed as a mass ratio relative to the mass of the carrier (including a substance attached to the surface of the carrier particle). The measurement methods for A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ are each a fluorescent X-ray analysis. The measurement conditions of the fluorescent X-ray analysis are the same conditions as the examples described later or alternative conditions thereof.

In the formula (B), B _i , B ₁₀₀₀ , and B ₁₀₀₀₀ respectively represent the adhesion amount of the resin particles on the carrier in the developer at each of the initial timing, the cumulative number of printed sheets 1000, and the cumulative number of printed sheets 10,000. Expressed as a mass ratio to the mass of the carrier. Each B _i, B _1000, and a measuring method of B ₁₀₀₀₀ is GC / MS method. The measurement conditions of the GC / MS method are the same conditions as the examples described later or alternative conditions thereof.

  In Formula (A) and Formula (B), the adhesion amount of specific particles (silica particles or resin particles) (the amount of specific particles present on the surface of carrier particles) is the carrier extracted from the developer at each of the above timings. Measured. The adhesion amount of specific particles corresponds to “adhesion amount of specific particles = 100 × (mass of specific particles present in carrier) / (mass of all carriers)”. “Mass of all carriers” corresponds to the sum of the mass of all carrier particles contained in the carrier and the mass of the substance attached to the surface of each of the carrier particles.

  In the above basic configuration, “initial” means an unused state (for example, at the time of product sales). Further, the continuous printing conditions are the same conditions as in the embodiments described later or alternative conditions thereof.

  When continuous printing is performed using a two-component developer, the particles (toner particles and carrier particles) in the developer collide, the particles collide with an apparatus (for example, a developing device), or the heat generated by the collision. For example, a phenomenon in which the external additive of toner particles adheres to the surface of carrier particles (carrier contamination) may occur. When carrier contamination occurs, the charge imparting property of the carrier particles tends to decrease.

  The inventor compared the influence of carrier contamination between the case where silica particles are used as an external additive for toner particles and the case where resin particles are used as an external additive for toner particles. It has been found that fog is more likely to occur when it occurs than when carrier contamination with resin particles occurs. Such a tendency becomes particularly strong when silica particles to which positive chargeability is imparted by the surface treatment agent (for example, silica particles having an amino group on the surface) are used.

  In addition, when the silica particles and the resin particles are used as external additives for the toner particles contained in the two-component developer, the inventor used a sufficient amount of specific resin particles (specifically, the following resin particles). By adhering to the surface of the carrier particle before the silica particle, the resin particle (resin particle adhering to the surface of the carrier particle) adheres to the surface of the carrier particle (hereinafter referred to as carrier). It has been found that it works to suppress (sometimes described as adhesion). The specific resin particles are resin particles containing a copolymer of two or more kinds of vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol and having a cationic surfactant attached to the surface. Such specific resin particles have excellent positive chargeability.

  For the developer satisfying the formula (B), a sufficient amount of the specific resin particles are detached from the toner particles and adhere to the surface of the carrier particles at an early stage after the use of the developer is started. Even if it continues, it has the characteristic that there is little increase in the adhesion amount of a specific resin particle. A developer including the specific resin particles as an external additive of toner particles can satisfy the formula (B) relatively easily. A developer satisfying the formula (B) is easy to ensure sufficient charge imparting property of carrier particles. Moreover, when a developer satisfy | fills Formula (B), it is easy to satisfy | fill Formula (A) by the effect | action of the above specific resin particles. When the developer satisfies the formula (A), fog is less likely to occur.

  In order for the developer to satisfy the above formulas (A) and (B), the silica particles and the specific resin particles have a laminated structure in which the silica particles and the specific resin particles are laminated in this order from the toner base particle side. Is preferred. When the specific resin particles are located outside the silica particles in the toner particles, the specific resin particles easily adhere to the surface of the carrier particles before the silica particles.

  Hereinafter, an example of silica particles and resin particles having the above-described laminated structure (lower layer: silica particles, upper layer: resin particles) on the surface of the toner base particles will be described with reference to FIG.

  Silica particles 12a and resin particles 12b exist on the surface of the toner base particles 10 shown in FIG. The resin particles 12b correspond to the aforementioned “specific resin particles”. The silica particles 12a and the resin particles 12b have a laminated structure in which the silica particles 12a and the resin particles 12b are laminated in this order from the toner base particle 10 side. That is, the silica particles 12a are located closer to the toner base particles 10 than the resin particles 12b. Silica particles 12 a are attached to the surface of toner base particles 10. The resin particles 12b are attached to the surface of the silica particles 12a (however, in the surface area of the toner base particles 10 where the silica particles 12a are not present). In the example of FIG. 1, the number average particle diameter of the resin particles 12b is larger than the number average particle diameter of the silica particles 12a.

  In order to attach a sufficient amount of the specific resin particles to the surface of the carrier particles before the silica particles, the number average primary particle size of the specific resin particles is larger than the number average primary particle size of the silica particles, And it is preferable that the number average primary particle diameter of specific resin particles is 40 nm or more and 200 nm or less. If the number average primary particle diameter of the specific resin particles is too large, the specific resin particles are likely to be excessively detached from the toner particles. Moreover, when the number average primary particle diameter of the specific resin particles is too small, the amount of the specific resin particles adhering to the surface of the carrier particles before the silica particles tends to be insufficient.

  In order for the developer to satisfy the formula (A) and the formula (B), the resin particles (external additives) in the above-described basic configuration are allowed to stand before and after standing at a temperature of 80 ° C. for 3 hours. The change rate of the BET specific surface area is preferably less than 3.0%, particularly preferably less than 1.0%.

In the toner having the basic structure described above, the resin particles (external additive) contain a copolymer of two or more kinds of vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol. 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).

  The (meth) acrylic acid ester of monohydric alcohol becomes a repeating unit represented by, for example, the following formula (1) (hereinafter referred to as repeating unit (1)) by addition polymerization to constitute a copolymer.

In formula (1), R ¹¹ represents a hydrogen atom or a methyl group, and R ¹² represents an alkyl group having 1 to 8 carbon atoms which may have a substituent. In the repeating unit derived from butyl acrylate, R ¹¹ represents a hydrogen atom, and R ¹² represents a butyl group (an alkyl group having 4 carbon atoms). In the repeating unit derived from methyl mesylate, R ¹¹ represents a methyl group, and R ¹² represents a methyl group (an alkyl group having 1 carbon atom).

In the above basic configuration, in order for the resin particles (external additive) to have sufficiently strong chargeability and appropriate strength, the resin constituting the resin particles preferably includes the repeating unit (1). In formula (1), R ¹² is particularly preferably an alkyl group having 1 to 4 carbon atoms.

In the above basic configuration, in order for the resin particles (external additive) to have sufficiently strong chargeability and appropriate strength, the resin constituting the resin particles is derived from a (meth) acrylic acid ester of a monohydric alcohol. preferably comprises two or more repeating units, the repeating unit (1) an alkyl group R ¹² = C 1 or 2, R ¹² = the repeating units of the alkyl group having a carbon number of 3 or 4 (1) It is particularly preferred to include combinations.

  In the above basic configuration, in order for the resin particles (external additives) to have sufficiently strong chargeability and appropriate strength, the resin constituting the resin particles is derived from the (meth) acrylic acid ester of the monohydric alcohol. In addition to the repeating unit, it is preferable to further include at least one of a repeating unit derived from a (meth) acrylic acid ester of a polyhydric alcohol and a repeating unit derived from a styrenic monomer.

  The (meth) acrylic acid ester of a polyhydric alcohol is obtained by polycondensing one or more polyhydric alcohols and one or more (meth) acrylic acids. As preferable examples of the polyhydric alcohol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1, Examples include diols such as 4-diol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.

  In the basic structure described above, the resin constituting the resin particles (external additive) is an alkylene represented by the following formula (2) as a repeating unit derived from the (meth) acrylic acid ester of the polyhydric alcohol. It is particularly preferred to contain a repeating unit derived from a (meth) acrylic acid ester of glycol or a derivative thereof.

In formula (2), R ²¹ represents a hydrogen atom or a methyl group, R ²² represents a hydrogen atom or a methyl group, and R ³ represents an alkylene group which may have a substituent. R ³ is preferably an alkylene group having 1 to 8 carbon atoms, and more preferably an alkylene group having 1 to 4 carbon atoms. In the repeating unit derived from ethylene glycol dimethacrylate, each of R ²¹ and R ²² represents a methyl group, and R ³ represents an ethylene group (— (CH ₂ ) ₂ —).

  In the basic structure described above, the resin constituting the resin particles (external additive) particularly preferably contains a repeating unit represented by the following formula (3) as a repeating unit derived from the styrene monomer.

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 to achieve both the heat-resistant storage stability and the low-temperature fixability of the toner, the volume median diameter (D ₅₀ ) of the toner is preferably 4 μm or more and less than 10 μm.

  Next, a preferred example of the configuration of non-capsule toner particles will be described. Resins suitable for forming toner particles are as follows.

<Preferable thermoplastic resin>
Suitable examples of thermoplastic resins include styrene resins, acrylic resins (more specifically, acrylic ester polymers or methacrylic ester polymers), olefin resins (more specifically, polyethylene). Resin or polypropylene resin), vinyl chloride resin, polyvinyl alcohol, vinyl ether resin, N-vinyl resin, polyester resin, polyamide resin, or urethane resin. 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 used. May be.

  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). A combination of a polyhydric alcohol and a polyhydric carboxylic acid to be a 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.

  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 polycondensation of one or more polyhydric alcohols and one or more polyhydric 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.

  Preferable examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4. -Diol, 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.

  Hereinafter, the toner base particles (binder resin and internal additive), the external additive, and the carrier particles will be described in order.

[Toner mother particles]
(Binder resin)
In the toner base particles, generally, the binder resin 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 base particles. By using a combination of a plurality of types of resins as the binder resin, the properties of the binder resin (more specifically, the hydroxyl value, acid value, Tg, Tm, etc.) can be adjusted. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner base particles tend to be anionic, and the binder resin has an amino group or an amide group. In some cases, the toner base particles tend to be cationic.

  In order to improve the fixing property of the toner, the toner base particles preferably contain a thermoplastic resin (more specifically, the above-mentioned “suitable thermoplastic resin”) as a binder resin. It is particularly preferable to contain a resin. In order to improve the fixing property of the toner, 80% by mass or more of the binder resin contained in the toner base particles is preferably a polyester resin, and 90% by mass or more of the resin is a polyester resin. It is more preferable that 100% by mass of the resin is a polyester resin.

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

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

  The toner base particles 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 base particles 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 base particles 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 base particles, it is preferable to prepare the toner base particles using an anionic wax. In order to improve the fixing property or offset resistance of the toner, the amount of the release agent is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.

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

  In order to improve the compatibility between the binder resin and the release agent, a compatibilizing agent may be added to the toner base particles.

(Charge control agent)
The toner base particles 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 base particles, the anionicity of the toner base particles can be enhanced. Further, by adding a positively chargeable charge control agent to the toner base particles, the cationic property of the toner base particles can be enhanced. However, if sufficient chargeability is ensured in the toner, it is not necessary to add a charge control agent to the toner base particles.

(Magnetic powder)
The toner base particles may contain magnetic powder. Examples of magnetic powder materials include ferromagnetic metals (more specifically, iron, cobalt, nickel, or alloys containing one or more of these metals), ferromagnetic metal oxides (more specifically, Ferrite, magnetite, chromium dioxide, or the like) or a material subjected to ferromagnetization treatment (more specifically, a carbon material or the like imparted with ferromagnetism by heat treatment) 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 base particles under acidic conditions, if the metal ions are eluted on the surface of the toner base particles, the toner base particles are easily fixed to each other. It is considered that fixing of toner mother particles can be suppressed by suppressing elution of metal ions from the magnetic powder.

[External additive]
The toner base particles include silica particles and resin particles (specifically, the above-mentioned “specific resin particles”) as external additives. 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.

Hydrophobicity and / or positive chargeability may be imparted to the surface of the silica particles by the surface treatment agent. As the surface treatment agent, for example, a coupling agent (more specifically, a silane coupling agent, a titanate coupling agent, an aluminate coupling agent, or the like) or silicone oil can be suitably used. As the silane coupling agent, a silane compound (more specifically, aminosilane or the like) may be used, or a silazane compound (more specifically, HMDS (hexamethyldisilazane) or the like) may be used. . When the surface of the silica particles is treated with the surface treatment agent, a plurality of hydroxyl groups (—OH) present on the surface of the silica particles are partially or entirely substituted with functional groups derived from the surface treatment agent. As a result, silica particles having a functional group derived from the surface treating agent (specifically, a functional group that is more hydrophobic and / or positively charged than the hydroxyl group) on the surface can be obtained. For example, when the surface of the silica particles is treated with a silane coupling agent having an amino group, the hydroxyl group of the silane coupling agent (for example, a hydroxyl group generated by hydrolysis of the alkoxy group of the silane coupling agent with moisture) A dehydration condensation reaction (“A (silica particle) —OH” + “B (coupling agent) —OH” → “AO—B” + H ₂ O) occurs with a hydroxyl group present on the surface of the silica particle. By such a reaction, the amino group is imparted to the surface of the silica particle by chemically bonding the silane coupling agent having an amino group and the silica particle. More specifically, the hydroxyl group present on the surface of the silica particles is substituted with a functional group having an amino group at the end (more specifically, —O—Si— (CH ₂ ) ₃ —NH ₂ or the like). Silica particles provided with amino groups tend to have a stronger positive charge than untreated silica particles. When a silane coupling agent having an alkyl group is used, a hydroxyl group present on the surface of the silica particle is converted into a functional group having an alkyl group at the end (more specifically, − it can be replaced by O-Si-CH _3, etc.). Thus, the silica particle to which the hydrophobic group (alkyl group) was provided instead of the hydrophilic group (hydroxyl group) tends to have stronger hydrophobicity than the untreated silica particle.

  Preferable examples of the resin constituting the specific resin particles include a copolymer of methyl methacrylate, n-butyl acrylate, and ethylene glycol dimethacrylate, or a copolymer of methyl methacrylate, n-butyl acrylate, and styrene. A polymer is mentioned.

  A cationic surfactant is attached to the surface of the specific resin particles. Examples of the cationic surfactant present on the surface of the specific resin particles include amine salts (more specifically, acetates of primary amines) or quaternary ammonium salts (more specifically, alkyltrimethylammonium salts). , Dialkyldimethylammonium salt, alkylbenzyldimethylammonium salt, benzethonium chloride and the like), and alkyltrimethylammonium salts having an alkyl group having 12 to 20 carbon atoms (for example, dodecyltrimethylammonium chloride) are particularly preferable. In order to impart appropriate positive charge to specific resin particles, the amount of cationic surfactant present on the surface of specific resin particles is the total mass of specific resin particles (including substances adhering to the surface of resin particles). On the other hand, it is preferably 100 ppm or more and 500 ppm or less. The amount of the cationic surfactant can be measured by, for example, the GC / MS method. In addition, that the quantity of a cationic surfactant is 1 ppm means that 0.001 mg of cationic surfactant is contained per 1 g of specific resin particles.

  Resin particles having a cationic surfactant attached to the surface can be obtained, for example, by emulsion polymerization of an unsaturated monomer in an aqueous medium containing a cationic surfactant and drying the resulting emulsion. The cationic surfactant added to the aqueous medium remains on the surface of the resin particles. 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). As a polar medium in the aqueous medium, for example, alcohol (more specifically, methanol or ethanol) can be used.

  In order to make the adhesion of each of the silica particles and the resin particles to the toner base particles appropriate, the number average primary particle diameter of the resin particles is larger than the number average primary particle diameter of the silica particles, and The number average primary particle diameter of the resin particles is preferably 40 nm or more and 200 nm or less. The number average primary particle diameter of the silica particles is preferably 12 nm or more and 30 nm or less, for example. Further, in order to make the adhesion of each of the silica particles and the resin particles to the toner base particles appropriate, the amount of the silica particles is 0.5 parts by mass or more and 5 parts by mass with respect to 100 parts by mass of the toner base particles. The amount of the resin particles is preferably 50 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the silica particles.

  The toner base particles may include external additive particles that are neither silica particles nor resin particles (hereinafter referred to as other external additive particles) as external additives. Other external additive particles include metal oxide particles (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, or barium titanate), or fatty acid metal salts (more specifically, Specifically, particles of zinc stearate or the like) can be preferably used.

[Toner Production Method]
(Preparation of toner mother particles)
In order to easily obtain suitable toner base particles, the toner base particles are 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, toner base particles having a desired particle diameter are obtained.

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

(External addition process)
In order for the silica particles and the specific resin particles having the above-mentioned “laminated structure” (lower layer: silica particles, upper layer: specific resin particles) to be present on the surface of the toner base particles, the silica particles and the specific resin particles with respect to the toner base particles It is preferable to perform the external addition in the following procedure. First, toner base particles and silica particles are mixed using a mixing device, and the silica particles are adhered to the surface of the toner base particles. Subsequently, specific resin particles are further adhered to the surface of the toner base particles to which the silica particles are adhered using a mixing device. Thus, the silica particles adhering to the surface of the toner base particles and the specific particles are added by performing the external addition of the silica particles (first external addition) and the external addition of the specific resin particles (second external addition) in this order. The resin particles have the aforementioned “laminated structure” (lower layer: silica particles, upper layer: specific resin particles).

  As the mixing device, for example, an FM mixer (manufactured by Nippon Coke Kogyo Co., Ltd.) can be used. The FM mixer includes a mixing tank with a temperature adjusting jacket, and further includes a deflector, a temperature sensor, an upper blade, and a lower blade in the mixing tank. When mixing the material (more specifically, powder or slurry, etc.) charged into the mixing tank using an FM mixer, the material in the mixing tank is swung in the vertical direction by rotating the lower blade. To flow. This causes convection of the material in the mixing tank. The upper blade rotates at a high speed and gives a shearing force to the material. The FM mixer applies a shearing force to the material, thereby allowing the material to be mixed with a strong mixing force.

[Carrier particles]
Hereinafter, suitable examples of the coated carrier particles will be described. The coated carrier particle includes a carrier core and a coat layer. In addition, you may use the carrier core which has the following structure as carrier particles as it is, without covering with a coating layer.

(Career core)
In order to impart magnetism to the coated carrier particles, the carrier core preferably contains a magnetic material. Examples of such magnetic materials include metal oxides such as magnetite, barium ferrite, maghemite, Mn—Zn ferrite, Ni—Zn ferrite, Mn—Mg ferrite, Ca—Mg ferrite, Li ferrite, or Cu—Zn ferrite. preferable. One kind of magnetic material may be used alone, or two or more kinds of magnetic materials may be used in combination. A commercially available product may be used as the carrier core. Also, the carrier core may be made by pulverizing and firing the magnetic material.

(Coat layer)
The coat layer is formed on the surface of the carrier core so as to cover the carrier core. Examples of the method for forming the coating layer include a method of immersing the carrier core in a liquid containing the coating material, or a method of spraying the liquid containing the coating material onto the carrier core in the fluidized bed.

  In order to make the adhesion of the external additives (silica particles and resin particles) to the toner base particles appropriate, the coat layer preferably contains a fluorine-containing resin. Of the resins contained in the coat layer, 60% by mass or more of the resin is preferably a fluorine-containing resin. Fluorine-containing resins include polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polytrifluoroethylene (more specifically, polychlorotrifluoroethylene, etc.), polyhexafluoropropylene, tetrafluoroethylene- One or more resins selected from the group consisting of hexafluoropropylene copolymer (FEP) and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) are preferred, and FEP or PFA is particularly preferred.

[Developer production method]
A two-component developer can be obtained by mixing the toner and the carrier using a mixing device. In order to form a high-quality image using a developer, the amount of toner is preferably 3 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the carrier.

  Examples of the present invention will be described. Table 1 shows developers DA-1 to DA-6 and DB-1 to DB-5 (two-component developers for electrostatic latent image development, respectively) according to examples or comparative examples. Table 2 shows the resin particles A to I used in the production of the developer shown in Table 1.

  Hereinafter, production methods, evaluation methods, and evaluation results of developers DA-1 to DA-6 and DB-1 to DB-5 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. A transmission electron microscope (TEM) was used for the measurement of the number average primary particle size.

[Developer production method]
(Preparation of toner base particles)
Using an FM mixer (Nippon Coke Kogyo Co., Ltd.), 4000 g of a polyester resin (acid value: 5.1 mg KOH / g, Tm: 120 ° C.) and a colorant (CI Pigment Blue 15: 3, component: copper) 200 g of phthalocyanine pigment, 200 g of ester wax (“Nissan Electol (registered trademark) WEP-3” manufactured by NOF Corporation), and quaternary ammonium salt (“BONTRON (registered trademark) P-51 manufactured by Orient Chemical Industry Co., Ltd.) )) 40 g. Subsequently, the obtained mixture was melt-kneaded using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.). Thereafter, the obtained melt-kneaded product was cooled. Subsequently, the melt-kneaded material was coarsely pulverized using a hammer mill (impact type screen crusher: “Hama Mill H” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized using a mechanical pulverizer (“Turbo Mill T250” manufactured by Freund Turbo Inc.). 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, toner mother particles having a volume median diameter (D ₅₀ ) of 6.83 μm were obtained.

(Preparation of resin particles A for external additives)
200 g of ion-exchanged water and 2.5 g of dodecyltrimethylammonium chloride (cationic surfactant) were placed in a 500 mL flask equipped with a dropping funnel, a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser. . Subsequently, while stirring the flask contents in a nitrogen atmosphere, the temperature of the flask contents was raised to 80 ° C., and 1 g of ammonium persulfate was added to the flask during the temperature increase. Subsequently, a mixture of 30 g of methyl methacrylate, 30 g of n-butyl acrylate, and 40 g of ethylene glycol dimethacrylate was dropped into the flask over 1 hour. After completion of dropping, the flask contents were further stirred for 1 hour. Subsequently, the flask contents were cooled to room temperature (about 25 ° C.) and then sieved using a 300-mesh sieve to obtain an emulsion of resin particles A. Subsequently, the obtained emulsion was dried to obtain resin particles A (powder).

(Preparation of resin particles B for external additives)
The production method of the resin particles B (powder) was the same as the production method of the resin particles A except that the amount of dodecyltrimethylammonium chloride added was changed from 2.5 g to 5.0 g.

(Preparation of resin particles C for external additives)
The production method of the resin particles C (powder) was the same as the production method of the resin particles A except that the amount of dodecyltrimethylammonium chloride added was changed from 2.5 g to 0.8 g.

(Preparation of resin particles D for external additives)
The production method of the resin particles D (powder) was the same as the production method of the resin particles A except that the amount of dodecyltrimethylammonium chloride added was changed from 2.5 g to 8.0 g.

(Preparation of resin particles E for external additives)
The production method of the resin particles E (powder) was the same as the production method of the resin particles A except that the amount of dodecyltrimethylammonium chloride added was changed from 2.5 g to 0.4 g.

(Preparation of resin particles F for external additives)
Resin particles F (powder) were prepared by using 40 g of methyl methacrylate, 40 g of n-butyl acrylate and styrene instead of a mixture of 30 g of methyl methacrylate, 30 g of n-butyl acrylate and 40 g of ethylene glycol dimethacrylate. It was the same as the preparation method of the resin particle A except having used the mixture with 20g.

(Preparation of resin particles G for external additives)
The production method of the resin particles G (powder) was the same as the production method of the resin particles A except that 2.5 g of dodecyltrimethylammonium chloride was not added.

(Preparation of resin particles H for external additives)
The resin particle H (powder) was prepared in the same manner as the resin particle A except that 3.0 g of sodium lauryl sulfate (anionic surfactant) was added instead of 2.5 g of dodecyltrimethylammonium chloride. It was.

(Preparation of resin particles I for external additives)
The production method of the resin particle I (powder) is a production method of the resin particle A, except that the addition amount of methyl methacrylate is changed from 30 g to 50 g and the addition amount of n-butyl acrylate is changed from 30 g to 50 g. Was the same.

  In Table 1, “resin A” to “resin I” indicate the resin particles A to I obtained as described above, respectively. The result of measuring the number average primary particle size of each of the resin particles A to I is as shown in “Particle size (unit: nm)” in Table 2. Table 2 also shows the results of measuring the change rate of the BET specific surface area. For example, regarding the resin particle A, the number average primary particle diameter was 75 nm, and the rate of change of the BET specific surface area was 0.31%. The measuring method of the change rate of the BET specific surface area was as follows.

(Change rate of BET specific surface area)
The change rate of the BET specific surface area of the resin particles before and after the heat resistance storage test was measured. In the heat-resistant storage test, the sample (resin particles) was allowed to stand for 3 hours in an environment of a temperature of 80 ° C. and a humidity of 20% RH. Before and after such a heat-resistant storage test, the BET specific surface area of the resin particles contained in the sample was measured using a fully automatic BET specific surface area measuring apparatus (“Macsorb (registered trademark) HM MODEL-1208” manufactured by Mountec Co., Ltd.). From the BET specific surface area S _A of the resin particles contained in the sample before the heat-resistant storage test and the BET specific surface area S _{B of the} resin particles contained in the sample after the heat-resistant storage test, the expression “change rate of BET specific surface area = 100 × The change rate (unit:%) of the BET specific surface area represented by (S _A −S _B ) / S _A ”was determined.

(Preparation of silica particles for external additives)
30 g of dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd.) and 15 g of 3-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) were dissolved in 200 g of toluene to obtain a solution. Subsequently, the resulting solution was diluted 10 times. Subsequently, while the obtained diluted solution is gradually added dropwise to 200 g of silica particles (“AEROSIL (registered trademark) 130, manufactured by Nippon Aerosil Co., Ltd., hydrophilic fumed silica)”, the silica particles are stirred to obtain a mixture. Obtained. Furthermore, the mixture was subjected to ultrasonic irradiation for 30 minutes while stirring the mixture.

  Subsequently, the ultrasonically irradiated mixture was heated to 150 ° C. using a thermostatic bath. Subsequently, toluene was distilled off from the mixture using a rotary evaporator. As a result, a solid was obtained.

  Subsequently, the obtained solid was dried using a vacuum dryer at a set temperature of 50 ° C. until the weight was not reduced. Subsequently, the dried solid was heated for 3 hours using an electric furnace in a nitrogen stream at a set temperature of 200 ° C. Subsequently, the heated solid was pulverized using a jet mill and collected with a bag filter to obtain silica particles (powder). The number average primary particle diameter of the obtained silica particles was 18 nm.

  In Table 1, “silica” indicates the silica particles obtained as described above.

(External addition to toner base particles)
Using a 10 L capacity FM mixer (manufactured by Nippon Coke Kogyo Co., Ltd.) equipped with a temperature control jacket, while circulating water at 20 ° C. through the jacket, 1000 g of toner base particles prepared by the above procedure, and the above procedure 15 g of the external additive silica particles prepared in (1) were mixed for a predetermined time (the time shown in Table 1 defined for each toner). The mixing at this timing corresponds to the “first external addition” in Table 1. For example, in the production of the toner TA-1, toner mother particles and silica particles are mixed for 10 minutes using an FM mixer. In addition, in the production of the toner TB-4, at this timing, in addition to the toner base particles 1000 g and the silica particles 15 g, 10 g of resin particles for external additives (resin particles A prepared in the above-described procedure) were also added. In the production of the toner TB-4, in the first external addition, toner base particles, silica particles, and resin particles were mixed for 20 minutes using an FM mixer.

  Subsequently, 10 g of resin particles for external additives (any one of the resin particles A to I shown in Table 1 defined for each toner) prepared in the above-described procedure were put into the FM mixer. For example, in the production of the toner TA-1, 10 g of the resin particles A were put into the FM mixer. In the production of the toner TB-1, 10 g of resin particles G were put into the FM mixer. In the production of toner TB-4, resin particles were not added at this timing.

  Subsequently, mixing by the FM mixer was performed for a predetermined time (the time shown in Table 1 determined for each toner). The mixing at this timing corresponds to the “second external addition” in Table 1. For example, in the production of the toner TA-1, the toner base particles having silica particles adhered to the surface and the resin particles A were further mixed for 10 minutes using an FM mixer. In the production of the toner TB-4, mixing (second external addition) at this timing was not performed.

  By the first external addition and the second external addition (however, in the production of the toner TB-4, only the first external addition), the external additives (silica particles and resin particles) are adhered to the surface of the toner base particles. A powder containing the toner particles was obtained. Thereafter, the obtained powder was sieved using a 200-mesh (aperture 75 μm) sieve. As a result, toners (toners TA-1 to TA-6 and TB-1 to TB-4) containing a large number of toner particles were obtained.

(Preparation of carrier C-1)
30 g of polyamideimide resin (copolymer of trimellitic anhydride and 4,4′-diaminodiphenylmethane) and 120 g of FEP (tetrafluoroethylene-hexafluoropropylene copolymer) were added to 1350 g of ion-exchanged water and dissolved. A resin solution was obtained. Subsequently, 3 g of silica particles were dispersed in the obtained resin solution to obtain 1503 g of a carrier coating solution.

  Subsequently, 1503 g of the obtained carrier coating solution and 10 kg of Mn—Mg—Sr ferrite core (“EF-35” manufactured by Powder Tech Co., Ltd., particle diameter: 35 μm) are mixed with a fluidized bed coating apparatus (“Freund Sangyo Co., Ltd.” Spiral Flow (registered trademark) SFC-5 "), and the surface of the Mn-Mg-Sr ferrite core was coated with a resin using a coating apparatus. Thereafter, the obtained resin-coated particles (powder) were heated at 250 ° C. for 1 hour using a box-type shelf dryer to obtain a developer carrier (carrier C-1).

(Production of Carrier C-2)
A resin solution was obtained by dissolving 150 g of methyl silicone resin in 300 mL of toluene. Subsequently, 22.5 g of 3-aminopropyltriethoxysilane, 1.5 g of 3-glycidoxypropyltrimethoxysilane, and titanium dioctyloxybis (octylene glycolate) 37. 5 g and 1.5 g of methyltris (methylethylketoxime) silane were added to obtain a carrier coat solution.

  Subsequently, the obtained carrier coat liquid and 10 kg of Mn—Mg—Sr ferrite core (“EF-35” manufactured by Powder Tech Co., Ltd., particle diameter: 35 μm) are mixed with a fluidized bed coating apparatus (“Spira” manufactured by Freund Corporation). Flow SFC-5 ") and the surface of the Mn-Mg-Sr ferrite core was coated with a resin using a coating apparatus. Thereafter, the obtained resin-coated particles (powder) were heated at 280 ° C. for 2 hours using a box-type shelf dryer to obtain a developer carrier (carrier C-2).

(Mixing of toner and carrier)
In a polyethylene container having a capacity of 500 mL, 24 g of toner (any one of toners TA-1 to TA-6 and TB-1 to TB-4 shown in Table 1 specified for each developer) and a carrier (each developer) 300 g of carrier C-1 or C-2 shown in Table 1 defined in the agent, and powder mixer ("Rocking Mixer (registered trademark)" manufactured by Aichi Electric Co., Ltd.), mixing method: container rotation The container was mixed for 30 minutes using a rocking system. As a result, two-component developers (developers DA-1 to DA-6 and DB-1 to DB-5) were obtained. For example, in the production of developer DA-1, toner TA-1 and carrier C-1 were mixed. In the production of developer DB-5, toner TA-1 and carrier C-2 were mixed.

  In the characteristic evaluation of each of the developers DA-1 to DA-6 and DB-1 to DB-5 obtained as described above, at each timing after the initial printing and continuous printing of an image with a printing rate of 5%, The amount of silica particles adhering to the surface of the carrier particles (silica particle adhesion amount) and the amount of resin particles adhering to the surface of the carrier particles (adhesion amount of resin particles) were measured. The measurement results are shown in Table 3.

In Table 3, “A _i ”, “A ₁₀₀₀ ”, “A ₁₀₀₀₀ ”, “B _i ”, “B ₁₀₀₀ ”, and “B ₁₀₀₀₀ ” respectively indicate the following contents.
A _i : Adhesion amount of silica particles measured for the carrier in the initial developer (unused developer) A ₁₀₀₀ : Removed from the developer at the timing of 1000 sheets of accumulated prints after continuous printing adhesion of the silica particles to be measured for carrier · a _10000: deposited amount of the silica particles to be measured for the carrier that is removed from the developer by the cumulative number of printed sheets 10,000 sheets timing running continuous printing · B _i: initial Adhesion amount of resin particles measured for carrier in developer (unused developer) of B · B ₁₀₀₀ : Measured for carrier taken out from developer at the timing of 1000 cumulative prints after continuous printing that the adhesion amount of the resin particles · B _10000: trees measured for carrier taken out from the developer at 10,000 cumulative number of printed sheets running continuous printing Adhesion amount of particles

In Table 3, the numerical value in parentheses “A ₁₀₀₀₀ ” indicates the amount of change from “A ₁₀₀₀ ” (that is, A ₁₀₀₀₀ −A ₁₀₀₀ ). The numerical value in parentheses “B ₁₀₀₀₀ ” indicates the amount of change from “B ₁₀₀₀ ” (that is, B ₁₀₀₀₀ −B ₁₀₀₀ ).

  As the initial developer (unused developer), a developer that was left for 24 hours in an environment of a temperature of 20 ° C. and a humidity of 65% RH after the above-mentioned “mixing of toner and carrier” was used. It was. Details of the continuous printing were as follows.

<Continuous printing>
As an evaluation machine, a color multifunction machine (“TASKalfa 5500ci” manufactured by Kyocera Document Solutions Co., Ltd., development method: touch-down system) was used. The sample (unused developer) was put into the developing device of the evaluation machine, and the replenishment toner (unused toner) corresponding to the sample (developer) was put into the toner container of the evaluation machine. In addition, to perform color printing, a toner for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd., and a developer other than the sample (magenta, yellow, and black) and a replenishment toner are prepared. It was thrown into.

Using the above-mentioned evaluation machine in an environment of a temperature of 20 ° C. and a humidity of 65% RH, a printing rate (“ColorCopy (registered trademark)” manufactured by Mondi, size: A4 size, basis weight: 90 g / m ² ) is printed. 5% image (character pattern) was continuously printed. The conditions for continuous printing (image forming conditions) were as follows.

(Image formation conditions)
・ Photosensitive drum diameter (diameter): 30 mm
・ Developing roller diameter (diameter): 20 mm
-Linear speed of photosensitive drum: 288 mm / second-Linear speed ratio of developing sleeve / photosensitive drum: 1.6
_Gp (distance between developing sleeve and photosensitive drum): 0.1 mm
-Toner amount on the developing roller: 0.4 mg / cm ²
・ Development bias (DC component): 300V
Development bias (AC component): rectangular wave, frequency 4.6 kHz, duty 43%, V _pp (potential difference between peaks) 2500 V
V ₀ (charge potential of photoconductor): 230V
・ V _L (potential after exposure of photoreceptor): 15V

Regarding the initial developer, the developer in the developing device at the time when 1000 sheets have been printed by the continuous printing, and the developer in the developing device at the time when 10,000 sheets have been printed by the continuous printing, A _i , _A1000 , _A10000 , _Bi , _B1000 , and _B10000 were measured. Prior to the measurement, the developer was sieved using a 795 mesh (aperture 16 μm) sieve to separate the toner and carrier in the developer. For the carrier taken out from the developer, the adhesion amount of silica particles and the adhesion amount of resin particles were measured. The measurement method of the adhesion amount (A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ ) of silica particles was X-ray fluorescence analysis under the following conditions. The adhesion amount of silica particles corresponds to the mass ratio (= mass of silica particles present in the carrier / mass of all carriers) in the measurement target (carrier). The measurement method of the adhesion amount (B _i , B ₁₀₀₀ , and B ₁₀₀₀₀ ) of the resin particles was a GC / MS method under the following conditions. The adhesion amount of the resin particles corresponds to a mass ratio (= mass of resin particles present in the carrier / mass of all carriers) in the measurement target (carrier). Obtained measurement values (fluorescence X-ray analysis: intensity of peaks derived from silica particles for external additives, GC / MS method: area of peaks derived from resin particles for external additives), and calibration prepared in advance Based on a line (specifically, a calibration curve prepared using a standard substance), the adhesion amount of silica particles and the adhesion amount of resin particles were determined.

(Fluorescence X-ray analysis conditions)
・ Analyzer: X-ray fluorescence analyzer (“ZSX-100e” manufactured by Rigaku Corporation)
・ X-ray tube (X-ray source): Rh (Rhodium)
Excitation conditions: tube voltage 50 kV, tube current 50 mA
・ Measurement area (X-ray irradiation range): Diameter 30mm
・ Measurement element: Si (silicon)

(GC / MS conditions)
Measurement apparatus: gas chromatograph mass spectrometer (“GCMS-QP2010 Ultra” manufactured by Shimadzu Corporation) and multi-shot pyrolyzer (“PY-3030D” manufactured by Frontier Laboratories)
Column: Metal capillary column (“Ultra ALLOY (registered trademark) -5 (MS / HT)” manufactured by Frontier Laboratories, Inc., inner diameter: 0.25 mm, film thickness: 0.25 μm, length: 30 m)
・ Pyrolysis temperature: Furnace “600 ° C”, interface part “320 ° C”
-Temperature conditions: After holding at 40 ° C for 15 minutes, the temperature was raised to 320 ° C at a rate of 14 ° C / min and held at 320 ° C for 15 minutes.
Carrier gas: Helium (He) gas Column head pressure: 49.7 kPa
Injection mode: split injection (split ratio 1:50)
Carrier flow rate: Total flow rate “14.1 mL / min”, column flow rate “1 mL / min”, purge flow rate “3 mL / min”

[Evaluation method]
The evaluation method of each sample (Developers DA-1 to DA-6 and DB-1 to DB-5) is as follows.

(Preparation of evaluation machine)
A color multifunction machine (“TASKalfa 5500ci” manufactured by Kyocera Document Solutions Inc.) was used as an evaluation machine. The sample (unused developer) was put into the developing device of the evaluation machine, and the replenishment toner (unused toner) corresponding to the sample (developer) was put into the toner container of the evaluation machine. In addition, to perform color printing, a toner for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd., and a developer other than the sample (magenta, yellow, and black) and a replenishment toner are prepared. It was thrown into.

(Fogging resistance)
Under the environment of temperature 20 ° C. and humidity 65% RH, using the above-mentioned evaluation machine, the printing rate is 2% on 5000 sheets of printing paper (“ColorCopy” manufactured by Mondi, size: A4 size, basis weight: 90 g / m ² ). Images (character patterns) were continuously printed. Continuously, printing paper (“ColorCopy” manufactured by Mondi, size: A4 size, basis weight: 90 g / m ² ) on a sheet of 50% printing image (test pattern: a plurality of linear patterns having different thicknesses) Was continuously printed. For each of 1000 printed sheets, the reflection density of the blank portion of the test pattern is measured using a reflection densitometer (“SpectroEye (registered trademark)” manufactured by X-Rite), and the fog density (FD) is calculated. Calculated. The fog density (FD) corresponds to a value obtained by subtracting the reflection density of the base paper (unprinted paper) from the reflection density of the blank portion of the printed paper.

  The highest fog density among all the fog densities (FD) measured for each of 1000 printed sheets was taken as an evaluation value (maximum fog density: maximum FD). The fog resistance of the toner was evaluated based on the obtained evaluation value (maximum fog density). When the maximum fog density was less than 0.010, it was evaluated as ◯ (good), and when it was 0.010 or more, it was evaluated as x (not good).

(Toner charge amount)
Printing paper (manufactured by Mondi, Inc.) using the above-mentioned evaluation machine under a predetermined environment (R / R environment: temperature 20 ° C. and humidity 65% RH, H / H environment: temperature 32.5 ° C. and humidity 80% RH) “ColorCopy”, size: A4 size, basis weight: 90 g / m ² ) Continuous printing of images (character patterns) with 5% coverage was performed on 10,000 sheets. After completion of continuous printing of 10,000 sheets, the developer is taken out from the developing device of the evaluation machine, and the toner in the developer is charged by the following method using a Q / m meter (“MODEL 210HS-1” manufactured by Trek). The amount was measured. For the initial sample (unused developer), the charge amount of the toner in the developer was measured by the following method. As an initial sample, a developer was used which was allowed to stand for 24 hours in an environment of a temperature of 20 ° C. and a humidity of 65% RH after performing the above-mentioned “mixing of toner and carrier”.

<Measurement method of charge amount of toner in developer>
0.10 g of developer (carrier and toner) was charged into a Q / m meter measurement cell, and only the toner out of the charged developer was sucked through a sieve (metal mesh) for 10 seconds. Then, based on the formula “total electric amount of sucked toner (unit: μC) / mass of sucked toner (unit: g)”, the charge amount of toner in the developer (unit: μC / g) is calculated. Calculated.

The toner charge amount measured for the initial sample (unused developer) was evaluated according to the following criteria.
○ (Good): The charge amount was 20 μC / g or more and less than 40 μC / g.
X (not good): The charge amount was less than 20 μC / g or 40 μC / g or more.

The toner charge amount measured after continuous printing in an R / R environment (temperature 20 ° C. and humidity 65% RH) was evaluated according to the following criteria.
○ (Good): The charge amount was 20 μC / g or more and less than 40 μC / g.
X (not good): The charge amount was less than 20 μC / g or 40 μC / g or more.

The toner charge amount measured after continuous printing in an H / H environment (temperature 32.5 ° C. and humidity 80% RH) was evaluated according to the following criteria.
○ (Good): The charge amount was 10 μC / g or more and less than 40 μC / g.
X (not good): The charge amount was less than 10 μC / g or 40 μC / g or more.

[Evaluation results]
For each of developers DA-1 to DA-6 and DB-1 to DB-5, the fog resistance (maximum fog density) and the toner charge amount (initial value, after continuous printing in an R / R environment) Table 4 shows the results of evaluation of the values and values after continuous printing in an H / H environment.

Developers DA-1 to DA-6 (developers according to Examples 1 to 6) each had the basic configuration described above. Specifically, each of developers DA-1 to DA-6 includes toner (a plurality of toner particles) and a carrier (a plurality of carrier particles). The toner particles were provided with toner mother particles and silica particles and resin particles present on the surface of the toner mother particles. Specifically, the silica particles and the resin particles had the above-described laminated structure (lower layer: silica particles, upper layer: resin particles). The resin particles contained a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol. A cationic surfactant adhered to the surface of the resin particles. In the characteristics evaluation of the developer, the amount of silica particles adhering to the surface of the carrier particles and the amount of resin particles adhering to the surface of the carrier particles at the initial stage and after each continuous printing of the image with a printing rate of 5% Were measured, respectively, the relational expressions of the formulas (A) and (B) were satisfied (see Table 3).
A ₁₀₀₀₀ -A ₁₀₀₀ <A ₁₀₀₀ -A _i <0.10% (A)
_{B 10000 -B 1000 <0.010% ≦} B 1000 -B i ... (B)

  As shown in Table 4, for the developers DA-1 to DA-6, good results were obtained in the respective evaluations of fog resistance and toner charge amount.

Developer DB-1 (developer according to Comparative Example 1) did not satisfy Formula (B). Specifically, as shown in Table 3, “B ₁₀₀₀₀ −B ₁₀₀₀ ” was 0.010% or more. The reason for this is considered to be that the particle diameter of the resin particles (resin particles G) is too large and the resin particles are excessively detached from the toner particles (see Table 2). The developer DB-1 had a poor evaluation result of the toner charge amount as compared with the developers DA-1 to DA-6 (see Table 4).

Developer DB-2 (developer according to Comparative Example 2) did not satisfy Formula (A) and Formula (B). Specifically, as shown in Table 3, for example, “A ₁₀₀₀₀ -A ₁₀₀₀ ” was “A ₁₀₀₀ -A _i ” or more. This reason is considered that the cationic surfactant was not adhering to the surface of the resin particle (resin particle H). It is considered that the resin particles attached to the surface of the carrier particles attracted the silica particles not yet attached to the carrier particles with an electric force. Developer DB-2 was poor in evaluation results of fog resistance and toner charge amount (particularly, initial stage) as compared with developers DA-1 to DA-6 (see Table 4).

Developer DB-3 (developer according to Comparative Example 3) did not satisfy Formula (A). Specifically, as shown in Table 3, “A ₁₀₀₀ -A _i ” was 0.10% or more. The use of resin particles (resin particles I) having a large change rate of the BET specific surface area is considered to make it easier for silica particles to adhere to soft resin particles. Developer DB-3 had a poor fog resistance evaluation result compared to Developers DA-1 to DA-6 (see Table 4).

Developer DB-4 (developer according to Comparative Example 4) did not satisfy the expressions (A) and (B). Specifically, as shown in Table 3, for example, “B ₁₀₀₀ -B _i ” was less than 0.010%. In Developer DB-4, silica particles and resin particles were adhered to the surface of the toner base particles by one external addition (see Table 1). For this reason, it is considered that the silica particles and the resin particles did not have a laminated structure (lower layer: silica particles, upper layer: resin particles). In each of the developers DA-1 to DA-6, the resin particles adhere to the surface of the carrier particles prior to the silica particles, and the resin particles attached to the surface of the carrier particles cause the carrier adhesion of the silica particles (of the carrier particles). It is thought that it worked to suppress adhesion to the surface. On the other hand, in Developer DB-4, the amount of the resin particles adhering to the surface of the carrier particles prior to the silica particles is small, and it is considered that most of the resin particles did not function as described above.

Developer DB-5 (Developer according to Comparative Example 5) did not satisfy Formula (A) and Formula (B). Specifically, as shown in Table 3, for example, “B ₁₀₀₀ -B _i ” was less than 0.010%. In developer DB-5, the coat layer covering the surface of the carrier core did not contain a fluorine-containing resin. For this reason, it is considered that the silica particles easily adhere to the surface of the carrier particles before the resin particles.

  The developer according to the present invention can be used to form an image in, for example, a copying machine, a printer, or a multifunction machine.

10 Toner mother particles 12a Silica particles 12b Resin particles

Claims (13)

A two-component developer comprising a toner comprising a plurality of toner particles and a carrier comprising a plurality of carrier particles,
The toner particles include toner base particles, silica particles and resin particles present on the surface of the toner base particles,
The resin particles contain a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol,
A cationic surfactant is attached to the surface of the resin particles,
In the characteristic evaluation of the two-component developer, the amount of the silica particles attached to the surface of the carrier particles at the initial stage and the timing after continuous printing of the image with a printing rate of 5%, and the surface of the carrier particles When the adhesion amount of the adhered resin particles is measured, the relational expressions of the formulas (A) and (B) are satisfied,
A ₁₀₀₀₀ -A ₁₀₀₀ <A ₁₀₀₀ -A _i <0.10% (A)
_{B 10000 -B 1000 <0.010% ≦} B 1000 -B i ... (B)
In the formula (A), A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ are the silica particles in the carrier in the two-component developer at the initial timing, the cumulative number of printed sheets 1000 sheets, and the cumulative number of printed sheets 10,000 sheets, respectively. Is expressed as a mass ratio to the mass of the carrier,
In the formula (B), B _i , B ₁₀₀₀ , and B ₁₀₀₀₀ are the resin particles in the carrier in the two-component developer at the initial timing, the cumulative number of printed sheets of 1000, and the cumulative number of printed sheets of 10,000, respectively. Is expressed as a mass ratio to the mass of the carrier,
A _i , A ₁₀₀₀ , and A ₁₀₀₀₀ are each measured by fluorescent X-ray analysis,
B _i, respectively B _1000, and a measuring method of B ₁₀₀₀₀ is GC / MS method, two-component developer.   The two-component developer according to claim 1, wherein the silica particles and the resin particles have a laminated structure in which the silica particles and the resin particles are laminated in this order from the toner base particle side.   The two-component developer according to claim 1, wherein the silica particles are surface-treated silica particles having an amino group on a surface thereof.   The amount of the silica particles is 0.5 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the toner base particles, and the amount of the resin particles is 50 parts by mass with respect to 100 parts by mass of the silica particles. The two-component developer according to any one of claims 1 to 3, wherein the two-component developer is not less than 80 parts by mass and not more than 80 parts by mass. The number average primary particle diameter of the resin particles is larger than the number average primary particle diameter of the silica particles,
5. The two-component developer according to claim 1, wherein the number average primary particle diameter of the resin particles is 40 nm or more and 200 nm or less.   6. The change rate of the BET specific surface area of the resin particles is less than 1.0% before and after the resin particles are left to stand at a temperature of 80 ° C. for 3 hours, according to claim 1. Two-component developer.   The two components according to any one of claims 1 to 6, wherein the copolymer contained in the resin particles includes two or more repeating units derived from a (meth) acrylic acid ester of a monohydric alcohol. Developer.   The two-component developer according to any one of claims 1 to 7, wherein the copolymer contained in the resin particles includes a repeating unit derived from a (meth) acrylic acid ester of a polyhydric alcohol.   The two-component developer according to any one of claims 1 to 7, wherein the copolymer contained in the resin particles includes a repeating unit derived from a styrene monomer.   The two-component developer according to any one of claims 1 to 9, wherein the toner base particles contain a polyester resin. The carrier particles include a carrier core and a coat layer covering the surface of the carrier core,
The two-component developer according to claim 1, wherein the coat layer contains a fluorine-containing resin.   The two-component developer according to claim 1, wherein the toner is a positively chargeable toner that is positively charged by friction with the carrier. Prepare toner base particles, silica particles, and resin particles containing a copolymer of two or more vinyl compounds including a (meth) acrylic acid ester of a monohydric alcohol and having a cationic surfactant attached to the surface. And
Attaching the silica particles to the toner base particles;
Further attaching the resin particles to the toner base particles to which the silica particles are adhered to obtain toner particles;
Mixing the toner particles with carrier particles to obtain a two-component developer;
A method for producing a two-component developer.

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