JP2018072453A - Toner for developing electrostatic latent image and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic latent image development which is excellent in heat-resistant storage property and low-temperature fixability and can suppress filming, and a method for producing the same. SOLUTION: A toner for electrostatic latent image development includes a plurality of toner particles having at least a resin-containing toner mother particle in a surface layer portion and an external additive adhering to the surface of the toner mother particle. The external additive contains a plurality of resin particles. Each of the plurality of resin particles is fixed to the toner mother particles by physical fusion with the resin on the surface layer portion that rises from the surface of the toner mother particles toward the resin particles. The desorption rate of resin particles measured after 10 minutes of ultrasonic treatment under the conditions of an oscillation frequency of 50 kHz and an output of 100 W in liquid is 0.1% or more and 5.0 in terms of the peak intensity ratio of the FT-IR spectrum. % Or less. [Selection diagram] Fig. 2

Description

  The present invention relates to an electrostatic latent image developing toner and a method for producing the same.

  As a method for attaching an external additive to toner base particles, a dry external addition method is known (for example, see Patent Document 1). In the external addition method described in Patent Document 1, the toner base particles and the external additive are mixed using an FM mixer (formerly Henschel mixer), and the external additive is adhered to the surface of the toner base particles. Further, in the external addition method described in Patent Document 1, the resin fine particles having a chargeability opposite to that of the toner raw powder are used as the external additive, thereby promoting the fixation of the resin fine particles to the toner raw powder. doing.

JP 2011-90168 A

  In the technique described in Patent Document 1, it is necessary to use resin fine particles (external additive) having chargeability opposite to that of the toner raw powder. In a two-component developer (toner and carrier mixture) containing toner produced by such a method, a phenomenon (filming) in which resin fine particles (external additive) detached from toner particles are fixed to the carrier easily occurs.

  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 that is excellent in heat-resistant storage and low-temperature fixability and can suppress filming, and a method for producing the same. To do.

  The electrostatic latent image developing toner according to the present invention includes a plurality of toner particles including toner base particles containing a resin at least in a surface layer portion and an external additive attached to the surface of the toner base particles. The external additive includes a plurality of resin particles. Each of the plurality of resin particles is fixed to the toner base particles by physical fusion with the resin of the surface layer portion rising from the surface of the toner base particles toward the resin particles. The desorption rate of the resin particles measured after ultrasonic treatment for 10 minutes under conditions of an oscillation frequency of 50 kHz and an output of 100 W in a liquid is 0.1% or more as a peak intensity ratio of an FT-IR spectrum. 0% or less.

  The method for producing a toner for developing an electrostatic latent image according to the present invention includes a melting step and a fixing step. In the melting step, the resin existing in the surface layer portion of the toner base particles is melted by heating a liquid containing toner base particles containing a resin at least in the surface layer portion and a plurality of resin particles. The resin is brought into contact with the resin particles. In the fixing step, the plurality of resin particles are fixed to the surface of the toner base particles by physical fusion with the resin by cooling the liquid after the melting step.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the toner for electrostatic latent image development which is excellent in heat-resistant storage property and low-temperature fixability, and can suppress filming, and its manufacturing method.

FIG. 3 is a diagram illustrating an example of a configuration of toner particles contained in an electrostatic latent image developing toner according to an embodiment of the present invention. FIG. 2 is a diagram showing a first example of a surface state of toner particles shown in FIG. 1. FIG. 4 is a diagram showing a second example of the surface state of the toner particles shown in FIG. 1. 5 is an SEM photograph showing an example of resin particles fixed on the surface of toner base particles by a general dry external addition method. 4 is an SEM photograph showing a first example of resin particles fixed on the surface of toner base particles by the method for producing a toner for developing an electrostatic latent image according to the embodiment of the present invention. 6 is an SEM photograph showing a second example of resin particles fixed to the surface of toner base particles by the method for producing toner for developing an electrostatic latent image according to the embodiment of the present invention.

  An embodiment of the present invention will be described. 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. Moreover, each measured value of an acid value and a hydroxyl value is a value measured according to "JIS (Japanese Industrial Standard) K0070-1992" unless otherwise specified.

Unless otherwise specified, the number average particle diameter of the powder is the number average of the equivalent-circle diameters of primary particles (Haywood diameter: the diameter of a circle having the same area as the projected area of the particles) measured using a microscope. Value. 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.

  The glass transition point (Tg) is a value measured according to “JIS (Japanese Industrial Standard) K7121-2012” using a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) unless otherwise specified. It is. In the endothermic curve (vertical axis: heat flow (DSC signal), horizontal axis: temperature) at the second temperature rise measured by the differential scanning calorimeter, the change point of the specific heat (outside the extrapolated line of the baseline and the falling line) The temperature (onset temperature) at the intersection with the insertion line corresponds to Tg (glass transition point). 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. Moreover, the measured value of the melting point (Mp) is an endothermic curve (vertical axis: heat flow (DSC) measured using a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.), unless otherwise specified). Signal), horizontal axis: temperature) is the maximum endothermic peak temperature.

  The chargeability means the chargeability in frictional charging unless otherwise specified. The strength of positive chargeability (or strength of negative chargeability) in frictional charging can be confirmed by a known charge train or the like.

  The “main component” of a material means a component most contained in the material on a mass basis unless otherwise specified.

  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.

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

  The toner according to this embodiment is a powder containing a plurality of toner particles. The toner particles include toner base particles and an external additive. 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. The external additive is attached to the surface of the toner base particles.

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

  First, an image forming unit (charging device and exposure device) of an electrophotographic apparatus forms an electrostatic latent image on a photosensitive member (for example, a surface layer portion of a photosensitive drum) based on image data. Subsequently, a developing device of the electrophotographic apparatus (specifically, a developing device in which a developer containing toner is set) supplies the toner to the photoconductor to develop the electrostatic latent image formed on the photoconductor. Specifically, 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 electrostatically charged. A toner image is formed on the photoreceptor by being attached to the latent image. In the subsequent transfer step, after the transfer device of the electrophotographic apparatus transfers the toner image on the photosensitive member to an intermediate transfer member (for example, a transfer belt), the toner image on the intermediate transfer member is further transferred to a recording medium (for example, Transfer to paper. Thereafter, the toner is heated and pressed by a fixing device (fixing method: nip formed by a heating roller and a pressure roller) of the electrophotographic apparatus 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 transfer method may be a direct transfer method in which the toner image on the photosensitive member is directly transferred to the recording medium without using the intermediate transfer member. The fixing method may be a belt fixing method.

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

(Basic toner configuration)
The electrostatic latent image developing toner includes a plurality of toner particles including toner base particles containing a resin at least on a surface layer portion and an external additive attached to the surface of the toner base particles. Hereinafter, the resin present in the surface layer portion of the toner base particles is referred to as a surface layer resin. The external additive includes a plurality of resin particles. Each of the plurality of resin particles is fixed to the toner base particles by physical fusion with a surface layer resin (resin on the surface layer of the toner base particles) rising from the surface of the toner base particles toward the resin particles. The desorption rate of the resin particles in the toner measured after ultrasonic treatment for 10 minutes under the conditions of an oscillation frequency of 50 kHz and an output of 100 W in the liquid is 0.1% or more in terms of the peak intensity ratio of the FT-IR spectrum. 0.0% or less.

  Hereinafter, the resin particle desorption rate defined by the basic configuration may be simply referred to as “resin particle desorption rate”, omitting measurement conditions and the like. The method for measuring the resin particle desorption rate is the same method as in the examples described later or an alternative method thereof. The desorption rate of the resin particles corresponds to the ratio of the peak intensity derived from the resin particles in the FT-IR spectrum of the toner after ultrasonic treatment to the peak intensity derived from the resin particles in the FT-IR spectrum of the initial toner. The peak intensity corresponds to the distance from the peak apex to the baseline.

  The toner base particles may be toner base particles without a shell layer (hereinafter referred to as non-capsule toner base particles), or toner base particles with a shell layer (hereinafter referred to as capsule toner base particles). It may be. The capsule toner base particles include a toner core containing a binder resin and a shell layer that covers the toner core. Capsule toner base particles can be produced by forming a shell layer on the surface of non-capsule toner base particles (toner core). The shell layer is substantially composed of a resin. For example, by covering a toner 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 toner core or may partially cover the surface of the toner core. Hereinafter, a material for forming the shell layer is referred to as a shell material.

  The non-capsule toner base particles can be produced by, for example, a pulverization method or an aggregation method. In these methods, the internal additive is easily dispersed well in the binder resin of the non-capsule toner base particles.

  In an example of the pulverization method, first, a binder resin, a colorant, a charge control agent, and a release agent are mixed. Subsequently, the obtained mixture is melt-kneaded using a melt-kneading apparatus (for example, a single-screw or twin-screw extruder). Subsequently, the obtained melt-kneaded product is pulverized, and the obtained pulverized product is classified. Thereby, non-encapsulated toner base particles having a desired particle diameter are obtained. When the pulverization method is used, the toner base particles can often be produced more easily than when the aggregation method is used.

  In an example of the aggregation method, first, these fine particles are aggregated in an aqueous medium containing fine particles of the binder resin, the release agent, and the 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. Thereby, non-encapsulated toner base particles having a desired particle diameter are obtained.

  When the capsule toner base particles are manufactured, the shell layer can be formed by any method. For example, the shell layer can be formed on the surface of the toner core (non-encapsulated toner base particles) by an in-situ polymerization method, a liquid-cured coating method, or a coacervation method.

  The inventor of the present application includes a method for producing an electrostatic latent image developing toner according to the present embodiment including the following steps (hereinafter referred to as basic steps) (hereinafter may be referred to as a production method according to the present embodiment). Thus, the toner having the above basic configuration was successfully manufactured.

(Basic manufacturing process)
In the basic step A, a resin (surface layer resin) existing in the surface layer portion of the toner base particles is dissolved by heating a liquid containing at least the toner base particles containing the resin in the surface layer portion and a plurality of resin particles, This is a step (melting step) of bringing the melted surface layer resin into contact with the resin particles.
The basic process B is a process (fixing process) of fixing a plurality of resin particles on the surface of the toner base particles by physical fusion with a surface layer resin by cooling the liquid after the melting process.

  In addition, you may add arbitrary processes between processes as needed.

  The manufacturing method of the present embodiment is a method that can be realized relatively easily both in terms of cost and technology, but with toner base particles and resin particles (external additives), rather than a general dry external addition method. Can be strongly coupled. In a general dry external addition method, it is difficult to make the resin particle detachment rate 5.0% or less (see Toner TB-6 in Examples described later). In a general dry external addition method, when toner base particles and resin particles (external additives) are strongly bonded by an excessively strong impact force, the resin particles are embedded in the toner base particles, and the resin particles are The original role (specifically, the role of improving toner fluidity) cannot be achieved.

  As a method of firmly bonding the toner base particles and the resin particles (external additive), the toner base particles have a strong negative chargeability, and the resin particles (external additive) have a strong positive chargeability, A method of strengthening the bond between the toner base particles and the resin particles by electrostatic force is also conceivable. However, in the two-component developer containing toner produced by such a method, filming is likely to occur (specifically, resin particles detached from the toner particles are likely to adhere to the carrier). When filming occurs, the image density tends to decrease. Further, in such a method, since it is necessary to set the charging properties of the toner base particles and the resin particles so that the toner base particles and the resin particles are firmly bonded, the degree of freedom in designing the toner is narrowed. It will be. Specifically, it becomes necessary to design the toner (selection of materials, etc.) under the above-described restrictions, and it becomes difficult to ensure the chargeability of the toner suitable for image formation.

  In the manufacturing method of the present embodiment, the toner base particles and the resin particles are bonded by physical fusion without chemically reacting the toner base particles and the resin particles (external additive). By applying the above basic configuration to the toner, the resin particles can be fixed to the surface of the toner base particles with a sufficiently strong adhesive force without embedding the resin particles on the surface of the toner base particles. For example, even when 80% or more of the resin particles protrude from the surface of the toner base particles in the depth direction (direction perpendicular to the surface of the toner base particles), the resin particles are adhered to the toner with a sufficiently strong adhesive force. Can be fixed on the surface of the mother particle. The resin particles fixed on the surface of the toner base particles by the manufacturing method of this embodiment sufficiently protrude from the surface of the toner base particles. For this reason, the resin particles function as spacers between the toner particles. Since the resin particles function as spacers, the fluidity of the toner is improved and aggregation of the toner particles is suppressed. Further, it is considered that the heat resistant storage stability of the toner is improved by suppressing aggregation of the toner particles.

  In the basic process A of the manufacturing method of the present embodiment, the surface layer resin (resin existing in the surface layer portion of the toner base particles) is dissolved by heating a liquid containing toner base particles and a plurality of resin particles. By dissolving the resin in the toner base particles (specifically, the surface layer resin) (melting step) in the liquid, the surface layer resin of the toner base particles was dissolved and dissolved while suppressing aggregation of the toner base particles. The surface layer resin can be brought into contact with the resin particles (at least the bottom of the resin particles). In order to suppress aggregation of the toner base particles, it is preferable to heat the liquid containing the toner base particles and the plurality of resin particles while stirring.

  In the basic step A, the surface layer resin of the toner base particles rises (plastically deforms) from the surface of the toner base particles toward the resin particles (external additive). Then, the raised surface layer resin is cured in the basic process B. Hereinafter, the configuration of toner particles contained in the toner having the above-described basic configuration will be described with reference to FIGS. FIG. 1 is a diagram showing an example of the configuration of toner particles contained in the toner having the basic configuration described above. 2 and 3 are enlarged views of the surface of the toner particles. 2 and 3, the cured product R corresponds to a surface layer resin that has gone up from the surface F of the toner base particles 11 and has been cured through the basic steps A and B.

  A toner particle 10 shown in FIG. 1 includes toner base particles 11 and a plurality of resin particles 12. Each of the plurality of resin particles 12 has a spherical outer shape and adheres to the surface of the toner base particles 11. As shown in FIG. 2 or FIG. 3, the resin particles 12 are fixed to the toner base particles 11 by physical fusion with a cured product R (surface layer resin that has been cured from the surface F of the toner base particles 11). Yes.

  The cured product R may completely cover the resin particles 12 as shown in FIG. 2, or may contact only the bottom of the resin particles 12 without covering the resin particles 12 as shown in FIG. 3. Good. However, in order to make the resin particle detachment rate 0.1% or more and 5.0% or less, the surface of the toner base particle is covered with the resin particle 12 (see FIG. 2) covered with the cured product R, and the bottom portion. It is preferable that both the resin particles 12 (see FIG. 3) with which the cured product R is in contact only exist. When only the resin particles 12 covered with the cured product R are present on the surface of the toner base particles, the resin particle detachment rate tends to be too small. In addition, when only the resin particles 12 having the cured product R in contact with only the bottom are present on the surface of the toner base particles, the resin particle detachment rate tends to be too large.

  In addition, when the surface layer resin rises up to the upper part (upper half) of the resin particle, even if the resin particle is partially exposed (for example, the top of the resin particle is exposed), the resin The particles correspond to resin particles covered with a surface layer resin (hereinafter may be referred to as strongly fused particles). Also, when the surface layer resin of the toner base particles rises from the surface of the toner base particles, but does not rise to the top of the resin particles, and the surface layer resin is in contact only with the bottom of the resin particles. The resin particles correspond to resin particles (hereinafter sometimes referred to as weakly fused particles) in which the surface layer resin is in contact only with the bottom.

  FIG. 4 is an SEM photograph showing an example of resin particles fixed on the surface of toner base particles by a general dry external addition method. 5 and 6 are SEM photographs showing examples of resin particles fixed on the surface of toner base particles by the manufacturing method of the present embodiment. The SEM imaging conditions were an acceleration voltage of 0.50 kV, a WD (working distance) of about 3.0 mm, and a magnification of 100,000.

  In the example shown in FIG. 4, the surface layer resin of the toner base particles is not raised. Further, in each of the examples shown in FIGS. 5 and 6, resin particles (strongly coated on the surface of the toner base particles with a surface layer resin (specifically, a surface layer resin that rises and hardens from the surface of the toner base particles). Fused particles) and resin particles (weakly fused particles) in which the surface layer resin (specifically, the surface layer resin that has risen from the surface of the toner base particles and hardened) are in contact only at the bottom.

  In order to make the desorption rate of the resin particles (external additive) 0.1% or more and 5.0% or less, the glass transition point of the resin particles (external additive) is 5 ° C. higher than the glass transition point of the surface layer resin. Higher than the above (Tg of the resin particle ≧ Tg of the surface layer resin + 5 ° C.), the temperature of the liquid in the basic step A (melting step) is not less than “the glass transition point of the surface layer resin—2 ° C.” ) Glass transition point of −6 ° C. ”or less. If the temperature of the liquid in the basic process A (melting process) is too low with respect to the glass transition point of the surface layer resin, the desorption rate of the resin particles (external additive) tends to be too high. If the temperature of the liquid in the basic process A (melting process) is too high with respect to the glass transition point of the resin particles (external additive), the resin particles (external additive) may be deformed and may not function as a spacer. There is. For example, when the glass transition point of the surface layer resin is 68 ° C. and the glass transition point of the resin particles (external additive) is 73 ° C., the temperature of the liquid in the basic step A (melting step) is 66 ° C. or more and 67 ° C. It is preferable that it is below ℃. In order to perform appropriate cooling easily, the temperature of the liquid in the basic process B (fixing process) is preferably around room temperature (for example, 20 ° C. or more and 35 ° C. or less).

  In the basic step A (melting step), only the surface layer resin of the surface layer resin and resin particles of the toner base particles is melted, and in the subsequent basic step B (fixing step), the resin is applied to the surface of the toner base particles by the dissolved surface layer resin. In order to fix the particles, in the toner having the basic structure described above, the glass transition point of the resin particles (external additive) is preferably 70 ° C. or higher. In order to ensure sufficient low-temperature fixability of the toner, the glass transition point of the resin particles (external additive) is preferably 150 ° C. or lower in the toner having the above-described basic configuration.

  In order for the resin particles (external additive) to have a glass transition point of 70 ° C. or higher and 150 ° C. or lower, the resin particles (external additive) contain a cross-linked styrene-acrylonitrile resin mainly composed of an acrylonitrile monomer. Is preferred. The crosslinked styrene-acrylonitrile resin is a polymer of one or more styrene monomers, one or more acrylonitrile monomers, and one or more crosslinking monomers (crosslinking agents). In the cross-linked styrene-acrylonitrile resin mainly composed of an acrylonitrile monomer, the repeating unit having the highest mass ratio among all repeating units contained in the resin is a repeating unit derived from the acrylonitrile monomer. Examples of the styrenic monomer include styrene, alkyl styrene (more specifically, α-methyl styrene, p-ethyl styrene, 4-tert-butyl styrene, etc.), hydroxy styrene (more specifically, p- Hydroxystyrene, m-hydroxystyrene, etc.), or halogenated styrene (more specifically, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.). Examples of acrylonitrile monomers include acrylonitrile, methacrylonitrile, hydroxyacrylonitrile, or halogenated acrylonitrile (more specifically, chloroacrylonitrile and the like). In order to form a uniform cross-linked structure in the styrene-acrylonitrile-based resin, an aromatic compound having two or more “C═C” (carbon double bond portion) as a cross-linking agent (more specifically, divinyl It is preferable to use benzene or the like.

  In the basic configuration described above, when the toner base particles are non-capsule toner base particles, the surface layer resin of the toner base particles (resin existing on the surface layer portion of the toner base particles) is the binder resin contained in the toner base particles. It is considered to be. In the basic step A (melting step), only the surface layer resin of the surface layer resin and resin particles of the toner base particles is melted, and in the subsequent basic step B (fixing step), the resin is applied to the surface of the toner base particles by the dissolved surface layer resin. In order to fix the particles, the glass transition point of the non-capsule toner base particles is preferably 50 ° C. or higher and 65 ° C. or lower. In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner using non-capsule toner base particles having such a glass transition point, the non-capsule toner base particles are used as a binder resin and have a glass transition point of 60. It is preferable to contain a first polyester resin having a glass transition temperature of 65 ° C. or lower and a second polyester resin having a glass transition point of 65 ° C. or higher.

  In the basic configuration described above, when the toner base particles are non-capsule toner base particles, the number average primary order of the resin particles is used in order to make the resin particle detachment rate 0.1% to 5.0%. The particle diameter is preferably 10 nm or more and 30 nm or less, and the amount of the resin particles is preferably 1.00 part by mass or more and 1.80 parts by mass or less with respect to 100 parts by mass of the toner base particles. As the number average primary particle diameter of the resin particles increases, the resin particles tend to be easily detached from the surface of the toner base particles. On the other hand, when the amount of the resin particles is too large, the flow of the melted surface layer resin is hindered, and the fixing of the resin particles by the raised surface layer resin tends to be insufficient. If the particle diameter of the resin particles is too small or the amount of the resin particles is too small, it is considered that the resin particles do not function as a spacer.

  In the basic configuration described above, when the toner base particles are capsule toner base particles, the surface layer resin of the toner base particles (resin existing in the surface layer portion of the toner base particles) is considered to be a resin constituting the shell layer. In the basic step A (melting step), only the surface layer resin of the surface layer resin and resin particles of the toner base particles is melted, and in the subsequent basic step B (fixing step), the resin is applied to the surface of the toner base particles by the dissolved surface layer resin. In order to fix the particles, the glass transition point of the toner core is preferably 40 ° C. or higher and 55 ° C. or lower, and the glass transition point of the shell layer is preferably 65 ° C. or higher and 80 ° C. or lower.

  In the above basic configuration, when the toner base particles are capsule toner base particles, the number average primary particles of the resin particles is used in order to make the resin particle detachment rate 0.1% or more and 5.0% or less. The diameter is preferably 10 nm or more and 30 nm or less, and the amount of the resin particles is preferably 0.50 part by mass or more and 1.00 part by mass or less with respect to 100 parts by mass of the toner core. As the number average primary particle diameter of the resin particles increases, the resin particles tend to be easily detached from the surface of the toner base particles. On the other hand, when the amount of the resin particles is too large, the flow of the melted surface layer resin is hindered, and the fixing of the resin particles by the raised surface layer resin tends to be insufficient. If the particle diameter of the resin particles is too small or the amount of the resin particles is too small, it is considered that the resin particles do not function as a spacer.

  When producing the capsule toner base particles, prior to the basic step A (melting step), a liquid to be used in the melting step is prepared, and the toner core and shell layer materials are put into the liquid. It is preferable to further include a shell layer forming step of forming a shell layer on the surface of the toner core. In such a production method, the toner mother particles are not taken out from the liquid after the shell layer is formed, and both the melting step and the shell layer forming step can be performed in the same liquid, and therefore, the toner can be manufactured with high productivity. In order to further increase the productivity of the toner, it is preferable to perform both the shell layer forming step and the melting step in a state where the temperature of the liquid is maintained at 60 ° C. or higher and 70 ° C. or lower. As the liquid, an aqueous medium which is relatively inexpensive and easily available and has stable properties can be preferably used.

  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. The boiling point of the aqueous medium is about 100 ° C.

In order to obtain a toner suitable for image formation, it is preferable that the volume median diameter (D ₅₀ ) of the toner is 4 μm or more and 9 μm or less.

  Next, the toner core (binder resin and internal additive), shell layer, and external additive will be described in order. Depending on the toner application, unnecessary components (for example, an internal additive or an external additive) may be omitted. The toner core may be used as non-capsule toner base particles.

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

  Examples of the binder resin include a styrene resin, an acrylic acid resin (more specifically, an acrylate polymer or a methacrylic acid ester polymer), an olefin resin (more specifically, a polyethylene resin or Polypropylene resin, etc.), 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.

  As the binder resin, an amorphous polyester resin is particularly preferable. The toner core may contain a crystalline polyester resin. By containing a crystalline polyester resin in the toner core, sharp melt properties can be imparted to the toner core.

  The polyester resin is composed of one or more polyhydric alcohols (more specifically, aliphatic diol, bisphenol, trihydric or higher alcohol as shown below) and one or more polyhydric carboxylic acids (more specifically). Specifically, it can be obtained by polycondensation with a divalent carboxylic acid or a trivalent or higher carboxylic acid as shown below. The polyester resin may contain a repeating unit derived from another monomer (a monomer that is neither a polyhydric alcohol nor a polyvalent carboxylic acid).

  Suitable examples of the aliphatic diol include diethylene glycol, triethylene glycol, neopentyl glycol, 1,2-propanediol, α, ω-alkanediol (more specifically, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,12-dodecanediol, etc. ), 2-butene-1,4-diol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, or polytetramethylene glycol.

  Preferable examples of 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.

  Preferable examples of the divalent carboxylic acid include aromatic dicarboxylic acid (more specifically, phthalic acid, terephthalic acid, or isophthalic acid), α, ω-alkanedicarboxylic acid (more specifically, malonic acid). Succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, or 1,10-decanedicarboxylic acid), alkyl succinic acid (more specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid) Acid, n-dodecyl succinic acid, or isododecyl succinic acid), alkenyl succinic acid (more specifically, n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid, or isodode Senylsuccinic acid, etc.), maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, or cyclohexanedicarboxylic acid Examples include acids.

  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.

  The amorphous polyester resin having a glass transition point of 45 ° C. or more and 60 ° C. or less includes at least bisphenol (more specifically, bisphenol A ethylene oxide adduct or bisphenol A propylene oxide adduct) as an alcohol component, As the acid component, an amorphous polyester resin containing at least fumaric acid is preferable.

  As an amorphous polyester resin having a glass transition point of 65 ° C. or more and 80 ° C. or less, one or more bisphenols (more specifically, bisphenol A ethylene oxide adduct or bisphenol A propylene oxide adduct) and one kind are used. Polymers with the above aromatic dicarboxylic acids (more specifically, terephthalic acid and the like) are preferred.

  In order to ensure sufficient toner strength and fixability, the amorphous polyester resin contained in the toner core has a number average molecular weight (Mn) of 1000 or more and 2000 or less, and a molecular weight distribution (number average molecular weight ( The ratio Mw / Mn) of the mass average molecular weight (Mw) to Mn) is preferably 9 or more and 21 or less.

  Preferred examples of the crystalline polyester resin include one or more α, ω-alkanediols having 2 to 6 carbon atoms (for example, ethylene glycol having 2 carbon atoms) and one or more carbon atoms (two carboxyls). And a polymer with 6 or more and 10 or less α, ω-alkanedicarboxylic acid (for example, suberic acid having 8 carbon atoms).

  In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner, the amount of the crystalline polyester resin contained in the toner core is the total amount of the polyester resin in the toner core (the sum of the crystalline polyester resin and the amorphous polyester resin). It is preferable that they are 5 mass% or more and 20 mass% or less with respect to quantity. For example, when the total amount of the polyester resin in the toner core is 100 g, the amount of the crystalline polyester resin contained in the toner core is preferably 5 g or more and 20 g or less.

  In order for the toner core to have an appropriate sharp melt property, it is preferable to contain a crystalline polyester resin having a crystallinity index of 0.90 or more and 1.20 or less in the toner core. The crystallinity index of the resin corresponds to the ratio (= Tm / Mp) of the softening point (Tm) of the resin to the melting point (Mp) of the resin. For amorphous resins, it is often impossible to measure a clear Mp. The measuring method of each of Mp and Tm of the resin is the same method as the examples described later or its alternative method. The crystallinity index of the crystalline polyester resin can be adjusted by changing the type or amount (blending ratio) of the material for synthesizing the crystalline polyester resin. The toner core may contain only one type of crystalline polyester resin, or may contain two or more types of crystalline polyester resins.

  In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner, it is particularly preferable that the toner core contains a crystalline polyester resin having a melting point (Mp) of 70 ° C. or higher and 85 ° C. or lower.

(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 obtain a toner suitable for image formation, the amount of the colorant is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the binder resin.

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

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

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

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

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

(Release agent)
The toner core may contain a release agent. The release agent is used, for example, for the purpose of improving the fixing property or offset resistance of the toner. In order to 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 two or more types of release agents may be used in combination.

(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 (more specifically, an organometallic complex or a chelate compound) to the toner core, the anionicity of the toner core can be enhanced. Further, by adding a positively chargeable charge control agent (more specifically, pyridine, nigrosine, quaternary ammonium salt, or the like) to the toner core, the toner core can be made more cationic. However, if sufficient chargeability is ensured in the toner, it is not necessary to include a charge control agent in the toner core.

(Magnetic powder)
The toner core may contain magnetic powder. Examples of magnetic powder materials include ferromagnetic metals (more specifically, iron, cobalt, nickel, 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 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 above basic configuration, the shell layer is preferably substantially composed of a monomer polymer (resin) containing one or more vinyl compounds. The monomer polymer containing one or more vinyl compounds contains a repeating unit derived from the vinyl compound. By polymerizing a vinyl compound having a functional group corresponding to the performance to be imparted to the toner to obtain a shell layer (or shell material), it is possible to impart desired performance to the shell layer easily and accurately. 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, butadiene, vinyl chloride, acrylic acid, acrylic Acid methyl, methacrylic 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 order to suppress charge attenuation of the toner, it is preferable that the resin constituting the shell layer includes a repeating unit derived from an acrylonitrile monomer. Preferable examples of the repeating unit derived from the acrylonitrile monomer include a repeating unit represented by the following formula (1).

In formula (1), R ¹¹ and R ¹² each independently represent a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, or an alkoxy group that may have a substituent. A combination in which R ¹¹ represents a hydrogen atom and R ¹² represents a hydrogen atom or a methyl group is particularly preferred. In the repeating unit derived from acrylonitrile, R ¹¹ and R ¹² each independently represent a hydrogen atom.

  In order to ensure sufficient heat-resistant storage stability and low-temperature fixability of the toner while suppressing charge decay of the toner, the resin constituting the shell layer is added to the styrene monomer in addition to the repeating unit derived from the acrylonitrile monomer. It is preferable to include the derived repeating unit. Preferable examples of the repeating unit derived from the styrene monomer include a repeating unit represented by the following formula (2).

In formula (2), R ^{21 to} R ²⁵ each independently represent a hydrogen atom, a halogen atom, an alkyl group that may have a substituent, an alkoxy group that may have a substituent, or a substituent. The aryl group which may have is represented. R ²⁶ and R ²⁷ each independently represent a hydrogen atom, a halogen atom, or an alkyl group that may have a substituent. R ^{21 to} R ²⁵ 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 ²⁶ and R ²⁷ are each independently preferably a hydrogen atom or a methyl group, particularly preferably a combination in which R ²⁷ represents a hydrogen atom and R ²⁶ represents a hydrogen atom or a methyl group. In the repeating unit derived from styrene, each of R ^{21 to} R ²⁷ represents a hydrogen atom.

  In order to set the glass transition point of the shell layer to 65 ° C. or more and 80 ° C. or less, the shell layer preferably contains a styrene-acrylonitrile resin mainly composed of an acrylonitrile monomer. In such a styrene-acrylonitrile resin, the repeating unit having the highest mass ratio among all repeating units contained in the resin is a repeating unit derived from an acrylonitrile monomer.

  In order to achieve both heat-resistant storage stability and low-temperature fixability of the toner, the thickness of the shell layer is preferably 1 nm or more and 20 nm or less. The thickness of the shell layer can be measured by analyzing a TEM (transmission electron microscope) 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 shell layer 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. The thickness of the shell layer is measured at each of the four points where the straight line intersects the shell layer, and the arithmetic average of the four measured values obtained is taken as the evaluation value of the toner particles (shell layer thickness). The boundary between the toner core and the shell layer can be confirmed, for example, by selectively dyeing only the shell layer of the toner core and the shell layer. When the boundary between the toner core and the shell layer is unclear in the TEM photographed image, a characteristic element contained in the shell layer in the TEM photographed image is formed by combining TEM and electron energy loss spectroscopy (EELS). By performing the mapping, the boundary between the toner core and the shell layer can be clarified.

[External additive]
Unlike the internal additive, the external additive does not exist inside the toner base particles, but selectively exists only on the surface of the toner base particles (surface layer portion of the toner particles). In the toner having the above basic configuration, resin particles (external additives) are fixed on the surface of the toner base particles. Inorganic particles (external additives) may be further adhered to the surface of the toner base particles. For example, toner mother particles (specifically, a powder containing a plurality of toner mother particles) and an external additive (specifically, a powder containing a plurality of inorganic particles) are agitated together to obtain the surface of the toner base particles. Inorganic particles (external additive particles) can be adhered to the surface. The toner base particles and the inorganic particles (external additive particles) do not chemically react with each other and are physically bonded instead of chemically. In order to fully exert the function of the external additive while suppressing the detachment of the external additive particles from the toner particles, the amount of the inorganic particles (if a plurality of types of inorganic particles are used, The total amount) 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 inorganic particles is preferably 0.01 μm or more and 1.0 μm or less.

  As inorganic particles (external additive particles), particles of silica particles or metal oxides (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, barium titanate, etc.) are suitable. Can be used for In order to improve the fluidity of the toner, it is preferable to use silica particles. In order to improve the abrasiveness of the toner, it is preferable to use titanium oxide particles. One type of inorganic particles may be used alone, or a plurality of types of inorganic particles may be used in combination.

The inorganic particles may be surface treated. For example, when silica particles are used as the inorganic particles, hydrophobicity and / or positive chargeability may be imparted to the surface of the silica particles by a surface treatment agent. Examples of the surface treatment agent include a coupling agent (more specifically, a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent), or silicone oil (more specifically, dimethyl silicone oil). Etc.) can be suitably used. As the silane coupling agent, a silane compound (more specifically, methyltrimethoxysilane, 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 substrate (untreated silica particles) is treated with the surface treatment agent, a large number of hydroxyl groups (—OH) present on the surface of the silica substrate are partially or entirely derived from the surface treatment agent. Substituted with a functional group. 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 a silica substrate is treated with a silane coupling agent having an amino group, a hydroxyl group of the silane coupling agent (for example, a hydroxyl group generated by hydrolysis of an alkoxy group of the silane coupling agent with moisture) A dehydration condensation reaction (“A (silica substrate) —OH” + “B (coupling agent) —OH” → “A—O—B” + H ₂ O) occurs with a hydroxyl group present on the surface of the silica substrate. By such a reaction, a silane coupling agent having an amino group is chemically bonded to silica, whereby an amino group is imparted to the surface of the silica particles. More specifically, the hydroxyl group present on the surface of the silica substrate 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 positive chargeability stronger than that of a silica substrate. When a silane coupling agent having an alkyl group is used, a hydroxyl group present on the surface of the silica substrate 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 a stronger hydrophobicity than the silica substrate.

As the external additive particles, inorganic particles having a conductive layer may be used. The conductive layer is, for example, a metal oxide film (hereinafter, referred to as a doped metal oxide) provided with conductivity by doping (specifically, an Sb-doped SnO ₂ film). The conductive layer may be a layer containing a conductive material other than the doped metal oxide (more specifically, a metal, a carbon material, a conductive polymer, or the like).

  Examples of the present invention will be described. Table 1 shows toners TA-1 to TA-8 and TB-1 to TB-6 (toners for electrostatic latent image development, respectively) produced by the production methods of Examples or Comparative Examples. In Table 1, the amount of the resin particles (unit: part by mass) is the relative amount with respect to 100 parts by mass of the toner core with respect to the capsule toner base particle (toner TA-8), and the amount of non-capsule toner base particle (other than toner TA-8) ), The relative amounts with respect to 100 parts by mass of the toner base particles are shown.

  Hereinafter, the production methods, evaluation methods, and evaluation results of the toners TA-1 to TA-8 and TB-1 to TB-6 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, Tg (glass transition point), Tm (softening point), and Mp (melting point) were measured by the following methods.

<Measurement method of Tg>
As a measuring device, a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) was used. The Tg (glass transition point) of the sample was determined by measuring the endothermic curve of the sample using a measuring device. Specifically, about 10 mg of a sample (for example, resin) was placed in an aluminum dish (aluminum container), and the aluminum dish was set in the measurement unit of the measuring device. In addition, an empty aluminum dish was used as a reference. In the measurement of the endothermic curve, the temperature of the measurement part was increased from the measurement start temperature of 25 ° C. to 200 ° C. at a rate of 10 ° C./min (RUN1). Thereafter, the temperature of the measurement part was lowered from 200 ° C. to 25 ° C. at a rate of 10 ° C./min. Subsequently, the temperature of the measurement part was again raised from 25 ° C. to 200 ° C. at a rate of 10 ° C./min (RUN 2). An endothermic curve (vertical axis: heat flow (DSC signal), horizontal axis: temperature) of the sample was obtained by RUN2. The Tg of the sample was read from the obtained endothermic curve. In the endothermic curve, the temperature (onset temperature) of the specific heat change point (intersection of the extrapolation line of the base line and the extrapolation line of the falling line) 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 S-curve, if the maximum stroke value is S ₁ and the low-temperature baseline stroke value is S ₂ , the temperature at which the stroke value in the S-curve is “(S ₁ + S ₂ ) / 2” Corresponds to the Tm (softening point) of the sample.

<Measurement method of Mp>
As a measuring device, a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) was used. The Mp (melting point) of the sample was determined by measuring the endothermic curve of the sample using a measuring device. Specifically, about 15 mg of a sample (for example, resin) was put in an aluminum dish (aluminum container), and the aluminum dish was set in the measurement unit of the measuring device. In addition, an empty aluminum dish was used as a reference. In the measurement of the endothermic curve, the temperature of the measurement part was increased from a measurement start temperature of 30 ° C. to 170 ° C. at a rate of 10 ° C./min. During the temperature increase, the endothermic curve (vertical axis: heat flow (DSC signal), horizontal axis: temperature) of the sample was measured. The Mp of the sample was read from the obtained endothermic curve. In the endothermic curve, the maximum peak temperature due to the heat of fusion corresponds to the Mp (melting point) of the sample.

[Preparation of materials]
(First binder resin: synthesis of amorphous polyester resin PES-1)
In a 10 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirrer, 370 g of bisphenol A propylene oxide adduct, 3059 g of bisphenol A ethylene oxide adduct, terephthalic acid 1194 g, 286 g of fumaric acid, 10 g of tin (II) 2-ethylhexanoate, and 2 g of gallic acid were added. Subsequently, the contents of the flask were reacted in a nitrogen atmosphere and at a temperature of 230 ° C. until the reaction rate reached 90% by mass or more. The reaction rate was calculated according to the formula “reaction rate = 100 × actual amount of reaction product water / theoretical product water amount”. Subsequently, the flask contents were reacted under a reduced pressure atmosphere (pressure 8.3 kPa) and a temperature of 230 ° C. until the Tm of the reaction product (resin) reached a predetermined temperature (89 ° C.). As a result, an amorphous polyester resin PES-1 having a Tm of 89 ° C. and a Tg of 50 ° C. was obtained.

(Second binder resin: synthesis of non-crystalline polyester resin PES-2)
The method for synthesizing the non-crystalline polyester resin PES-2 is to replace 370 g of bisphenol A propylene oxide adduct, 3059 g of bisphenol A ethylene oxide adduct, 1194 g of terephthalic acid, and 286 g of fumaric acid, 1286 g of bisphenol A propylene oxide adduct, bisphenol. A It was the same as the synthesis method of the non-crystalline polyester resin PES-1 except that 2218 g of ethylene oxide adduct and 1603 g of terephthalic acid were used. Regarding the obtained amorphous polyester resin PES-2, Tm was 111 ° C. and Tg was 69 ° C.

(Third binder resin: synthesis of amorphous polyester resin PES-3)
In a 10 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirring device, 4907 g of bisphenol A propylene oxide adduct, 1942 g of bisphenol A ethylene oxide adduct, and fumaric acid 757 g, 2078 g of dodecyl succinic anhydride, 30 g of tin (II) 2-ethylhexanoate, and 2 g of gallic acid were added. Subsequently, the contents of the flask were reacted in a nitrogen atmosphere and at a temperature of 230 ° C. until the reaction rate represented by the above formula reached 90% by mass or more. Subsequently, the contents of the flask were reacted for 1 hour in a reduced pressure atmosphere (pressure 8.3 kPa) and a temperature of 230 ° C. Subsequently, 548 g of trimellitic anhydride is added to the flask, and Tm of the reaction product (resin) reaches a predetermined temperature (127 ° C.) under a reduced pressure atmosphere (pressure 8.3 kPa) and a temperature of 220 ° C. The flask contents were reacted. As a result, an amorphous polyester resin PES-3 having a Tm of 127 ° C. and a Tg of 51 ° C. was obtained.

(Fourth binder resin: synthesis of crystalline polyester resin)
In a 10 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirring device, 2231 g of ethylene glycol, 5869 g of suberic acid, and 40 g of tin (II) 2-ethylhexanoate And 3 g of gallic acid. Subsequently, the contents of the flask were reacted for 4 hours under conditions of a nitrogen atmosphere and a temperature of 180 ° C. Subsequently, the contents of the flask were heated and reacted at a temperature of 210 ° C. for 10 hours. Subsequently, the contents of the flask were reacted for 1 hour in a reduced pressure atmosphere (pressure 8.3 kPa) and a temperature of 210 ° C. As a result, a crystalline polyester resin having Tm of 78 ° C. and Mp of 74 ° C. was obtained.

(External additive: Preparation of suspension DA)
A round bottom flask equipped with an anchor type stirring blade was set in a water bath at a temperature of 30 ° C., and 20 parts by mass of styrene, 80 parts by mass of acrylonitrile, 10 parts by mass of divinylbenzene, potassium persulfate (water solution) 4.5 parts by mass of a polymerization polymerization initiator) and 100 parts by mass of ion-exchanged water. And the temperature in a flask was heated up to 70 degreeC using the water bath, stirring the flask contents at a rotational speed of 100 rpm using the anchor type stirring blade. Thereafter, emulsion polymerization (soap-free) is carried out at a temperature of 70 ° C. for 8 hours while stirring at a rotational speed of 100 rpm, and a dispersion of resin particles (specifically, particles of crosslinked styrene-acrylonitrile resin) is obtained in the flask. It was. The obtained dispersion was filtered (solid-liquid separation), and the resulting resin particles were washed, and then redispersed in an aqueous solution of sodium alkyl ether sulfate having a concentration of 10% by mass. As a result, a suspension DA of resin particles having a solid content concentration of 8% by mass was obtained. Regarding the resin particles (crosslinked styrene-acrylonitrile resin particles) contained in the obtained suspension DA, the number average primary particle diameter was 20 nm, and Tg was 73 ° C.

(Shell material: Preparation of suspension DB)
3. A round bottom flask equipped with an anchor type stirring blade is set in a water bath at a temperature of 30 ° C., and 20 parts by mass of styrene, 80 parts by mass of acrylonitrile, and potassium persulfate (water-soluble polymerization initiator) are contained in the flask. 5 parts by mass and 100 parts by mass of ion-exchanged water were added. And the temperature in a flask was heated up to 70 degreeC using the water bath, stirring the flask contents at a rotational speed of 100 rpm using the anchor type stirring blade. Thereafter, emulsion polymerization (soap-free) is carried out at a temperature of 70 ° C. for 5 hours while stirring at a rotational speed of 100 rpm, and a dispersion of resin particles (specifically, particles of non-crosslinked styrene-acrylonitrile resin) is placed in the flask. Obtained. The obtained dispersion was filtered (solid-liquid separation), and the resulting resin particles were washed, and then redispersed in an aqueous solution of sodium alkyl ether sulfate having a concentration of 10% by mass. As a result, a suspension DB of resin particles having a solid content concentration of 8% by mass was obtained. Regarding the resin particles (styrene-acrylonitrile resin particles) contained in the obtained suspension DB, the number average primary particle diameter was 20 nm, and Tg was 68 ° C.

(Preparation of toner mother particle MA)
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.), 300 g of the first binder resin (amorphous polyester resin PES-1 prepared by the above procedure) and the second binder resin (as described above). 100 g of the non-crystalline polyester resin PES-2 prepared by the above procedure, 600 g of the third binding resin (non-crystalline polyester resin PES-3 prepared by the above-described procedure), and the fourth binding resin (the above-described procedure). 100 g of the crystalline polyester resin prepared in the above, 144 g of a colorant (“Colortex (registered trademark) Blue B1021” manufactured by Sanyo Dye Co., Ltd., component: phthalocyanine blue), and a first release agent (manufactured by Hiroyuki Kato “ Carnauba Wax No. 1 ", component: Carnauba wax 12g, and second mold release agent (" Nissan Electol (registered trademark) WEP-3 "manufactured by NOF Corporation) : A synthetic ester wax) 48 g, were mixed at a rotational speed 2400 rpm.

Subsequently, the obtained mixture was subjected to conditions using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.) at a material supply speed of 5 kg / hour, a shaft rotation speed of 160 rpm, and a set temperature (cylinder temperature) of 100 ° C. Was melt kneaded. Thereafter, the obtained kneaded material was cooled. Subsequently, the cooled kneaded material was coarsely pulverized using a pulverizer (“Rohtoplex (registered trademark)” 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, toner base particles MA (powder) having a glass transition point (Tg) of 55 ° C. and a volume median diameter (D ₅₀ ) of 6.8 μm were obtained. Toner mother particles MA were non-capsule toner mother particles.

(Preparation of toner mother particle MB)
The toner base particle MB is prepared by using a non-crystalline polyester resin PES instead of 300 g of non-crystalline polyester resin PES-1 (Tg: 50 ° C.) and 100 g of non-crystalline polyester resin PES-2 (Tg: 69 ° C.). -2 (Tg: 69 ° C.) Except that 400 g was added, it was the same as the production method of the toner mother particles MA. In producing the toner base particles MB, the non-crystalline polyester resin PES-1 was not used. With respect to the obtained toner base particles MB (powder), the volume median diameter (D ₅₀ ) was 6.8 μm, and the glass transition point (Tg) was 61 ° C. The toner base particles MB were non-capsule toner base particles.

[Method for Producing Toners TA-1 to TA-7 and TB-1 to TB-5]
(First external addition step: wet external addition)
A 1 L three-necked flask equipped with a thermometer and a stirring blade was prepared, and the flask was set in a water bath. Subsequently, 300 mL of ion-exchanged water was put in the flask, and the temperature in the flask was kept at 30 ° C. using a water bath. Subsequently, in the flask, 1 g of an anionic surfactant (“Emar (registered trademark) 0” manufactured by Kao Corporation, component: sodium lauryl sulfate) and toner base particles shown in Table 1 (the toner defined for each toner) 300 g of mother particles MA or MB) was added, and the flask contents were stirred for 1 hour under the conditions of a temperature of 30 ° C. and a rotation speed (stirring blade) of 200 rpm. Subsequently, dilute hydrochloric acid was added to the flask to adjust the pH of the flask contents to 4.

  Subsequently, suspension DA (solid content concentration: 8% by mass) containing resin particles (crosslinked styrene-acrylonitrile resin particles) having a glass transition point of 73 ° C. was added to the flask. The amount of suspension DA added was such that the amount of resin particles was the amount shown in Table 1. For example, in the production of toner TA-1, 56.25 g of suspension DA is added to 300 g of toner base particles. As a result, 1.50 parts by mass (= 56.25 × 0.08 × 100/300) of resin particles (solid content in the suspension DA) was added to 100 parts by mass of toner base particles.

  Subsequently, 300 mL of ion exchange water was added to the flask, and the temperature in the flask was adjusted at a rate of 1.0 ° C./min using a water bath while stirring the flask contents at a rotation speed (stirring blade) of 100 rpm. The temperature is increased to the temperature shown in “External Addition Temperature” in Table 1 (for example, 57 ° C. in the production of toner TA-1), and the temperature (57 ° C. in the production of toner TA-1) and the rotation speed (stirring blade) are 100 rpm. The contents of the flask were stirred for 1 hour under the following conditions. By stirring while keeping the liquid in the flask at a high temperature (57 ° C. in the production of toner TA-1), the resin (binder resin) on the surface layer of the toner base particles was melted and rose from the surface of the toner base particles. . The raised resin (binder resin) was in contact with the resin particles. Thereafter, the contents of the flask were cooled to a temperature of 30 ° C. using a water bath. As a result, the resin (binder resin) rising from the surface of the toner base particles is cured, and a plurality of resin particles (first external additive) are formed on the surface of the toner base particles by physical fusion with the raised resin. Was fixed (fused and fixed). As a result, a dispersion of first external additive particles (toner base particles to which a plurality of resin particles were externally added) was obtained.

(Washing process)
The dispersion of the first external additive particles obtained as described above was filtered (solid-liquid separation) using a Buchner funnel. As a result, wet cake-like first external additive particles were obtained. Thereafter, the obtained wet cake-like first external additive particles were redispersed in 1.5 L of ion-exchanged water. Dispersion and filtration were repeated until the electrical conductivity of the filtrate after washing (washing water) reached 3 μS / cm to wash the first external additive particles. An electrical conductivity meter “HORIBA ES-51” manufactured by HORIBA, Ltd. was used for the measurement of conductivity.

(Drying process)
Subsequently, the washed wet cake-like first external additive particles were put in a vacuum shelf dryer and dried for 24 hours under the conditions of a vacuum degree of 1 kPa and a temperature of 40 ° C. As a result, dried first external additive particles (powder) were obtained.

(Second external addition process: dry external addition)
Subsequently, 100 parts by mass of the first external additive particles and positively-charged silica particles (“AEROSIL (registered trademark) REA90” manufactured by Nippon Aerosil Co., Ltd.) were used using a 10-L FM mixer (manufactured by Nippon Coke Industries, Ltd.). , Contents: Dry silica particles imparted with a positive charge by surface treatment, number average primary particle diameter: 20 nm, 1.0 part by mass, conductive titanium oxide particles (“EC-100” manufactured by Titanium Industry Co., Ltd.) Substrate: TiO ₂ particles, coating layer: Sb-doped SnO ₂ film, number average primary particle diameter: about 0.35 μm) and 0.5 parts by mass were mixed for 5 minutes. As a result, the second external additive (silica particles and titanium oxide particles) adhered to the surface of the first external additive particles. Thereafter, sieving was performed using a 200 mesh sieve (aperture 75 μm). As a result, toners containing a large number of toner particles (toners TA-1 to TA-7 and TB-1 to TB-5 shown in Table 1) were obtained.

[Production Method of Toner TA-8]
(Production of toner core)
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.), 450 g of the first binder resin (amorphous polyester resin PES-1 prepared by the above procedure) and the second binder resin (as described above). 100 g of the non-crystalline polyester resin PES-2 prepared by the above procedure, 450 g of the third binder resin (non-crystalline polyester resin PES-3 prepared by the above procedure), and the fourth binder resin (the above procedure). 100 g of the crystalline polyester resin prepared in step 1), 144 g of a colorant (“Colortex Blue B1021” manufactured by Sanyo Dye Co., Ltd., component: phthalocyanine blue), and a first release agent (“Carnauba Wax 1” manufactured by Hiroyuki Kato) No. ", component: Carnauba wax 12g, second release agent (" Nissan Electol WEP-3 "manufactured by NOF Corporation), component: synthetic ester wax And 48 g, were mixed at a rotational speed 2400 rpm.

Subsequently, the obtained mixture was subjected to conditions using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.) at a material supply speed of 5 kg / hour, a shaft rotation speed of 160 rpm, and a set temperature (cylinder temperature) of 100 ° C. Was melt kneaded. Thereafter, the obtained kneaded material was cooled. Subsequently, the cooled kneaded material was coarsely pulverized using a pulverizer (“Rotoplex” 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 (powder) having a glass transition point (Tg) of 48 ° C. and a volume median diameter (D ₅₀ ) of 6.8 μm was obtained.

(First external addition step: wet external addition)
A 1 L three-necked flask equipped with a thermometer and a stirring blade was prepared, and the flask was set in a water bath. Subsequently, 300 mL of ion-exchanged water was put in the flask, and the temperature in the flask was kept at 30 ° C. using a water bath. Subsequently, 1 g of an anionic surfactant (“Emar 0” manufactured by Kao Corporation, component: sodium lauryl sulfate) and 300 g of the toner core prepared by the above-described procedure were charged into the flask, and the temperature was 30 ° C. and the rotation speed ( Stirring blade) The contents of the flask were stirred for 1 hour under the condition of 200 rpm. Subsequently, dilute hydrochloric acid was added to the flask to adjust the pH of the flask contents to 4.

  Subsequently, suspension DB (solid content concentration: 8% by mass) containing resin particles (non-crosslinked styrene-acrylonitrile resin particles) having a glass transition point of 68 ° C. was added into the flask. Specifically, 75 g of suspension DB was added to 300 g of toner core. Thus, 2.0 parts by mass (= 75 × 0.08 × 100/300) of resin particles (solid content in the suspension DB) was added to 100 parts by mass of the toner core.

  Subsequently, 300 mL of ion exchange water was added to the flask, and the temperature in the flask was adjusted to 68 ° C. at a rate of 1.0 ° C./min using a water bath while stirring the flask contents at a rotation speed (stirring blade) of 100 rpm. The flask contents were stirred for 1 hour at a temperature of 68 ° C. and a rotational speed (stirring blade) of 100 rpm. As a result, film formation and fixation of the shell material (or resin particles) proceeded, and a shell layer was formed on the surface of the toner core. As a result, toner mother particles (toner mother particles MC: capsule toner mother particles) having a toner core and a shell layer were obtained. In the obtained toner base particles, the shell layer completely covered the surface of the toner core (with a coverage of 100%).

  Subsequently, the temperature in the flask was adjusted to 67 ° C. Subsequently, suspension DA (solid content concentration: 8% by mass) containing resin particles having a glass transition point of 73 ° C. (cross-linked styrene-acrylonitrile resin particles) was added to the flask, and the temperature was 67 ° C. and the rotation speed (stirring blade). The flask contents were further stirred for 1 hour under the condition of 100 rpm. The amount of suspension DA added was such that the amount of resin particles was the amount shown in Table 1. Specifically, 26.25 g of suspension DA was added to 300 g of toner core. As a result, 0.7 parts by mass (= 26.25 × 0.08 × 100/300) of resin particles (solid content in the suspension DA) was added to 100 parts by mass of the toner core.

  By stirring the liquid in the flask while maintaining a high temperature (temperature: 67 ° C.), the resin of the surface layer portion of the toner base particles (resin constituting the shell layer) was melted and rose from the surface of the toner base particles. The raised resin (resin constituting the shell layer) was in contact with the resin particles. Thereafter, the contents of the flask were cooled to a temperature of 30 ° C. using a water bath. Thereby, the resin (surface layer resin) rising from the surface of the toner base particles is cured, and a plurality of resin particles (first external additives) are formed on the surface of the toner base particles by physical fusion with the raised resin. Fixed (fused and fixed). As a result, a dispersion of first external additive particles (toner base particles to which a plurality of resin particles were externally added) was obtained.

  Thereafter, a second external additive (silica particles and titanium oxide particles) is formed on the surface of the first external additive particles through the washing step, the drying step, and the second external addition step, which are the same as the method for producing the toner TA-1. Was adhered to obtain a toner (toner TA-8 shown in Table 1) containing a large number of toner particles.

[Production Method of Toner TB-6]
(External additive: Preparation of resin particles)
The resin particles in the suspension DA prepared by the above procedure were taken out and dried. As a result, resin particles (powder) for external additives were obtained. The obtained resin particles were resin particles having a glass transition point of 73 ° C. (crosslinked styrene-acrylonitrile resin particles).

(External addition process: dry external addition)
Using an FM mixer with a capacity of 10 L (manufactured by Nihon Coke Kogyo Co., Ltd.), 100 parts by mass of toner base particles (toner base particles MA prepared by the above procedure) and resin particles for external additives prepared by the above procedure (Powder) 1.5 parts by mass, positively charged silica particles (“AEROSIL REA90” manufactured by Nippon Aerosil Co., Ltd.), content: dry silica particles imparted with positive charge by surface treatment, number average primary particle size: 20 parts by weight, conductive titanium oxide particles (“EC-100” manufactured by Titanium Industry Co., Ltd.), substrate: TiO ₂ particles, coating layer: Sb-doped SnO ₂ film, number average primary particle size: about 0 .35 μm) and 0.5 parts by mass were mixed for 5 minutes. As a result, external additives (resin particles, silica particles, and titanium oxide particles) adhered to the surface of the toner base particles (toner base particles MA). Thereafter, sieving was performed using a 200 mesh sieve (aperture 75 μm). As a result, a toner (toner TB-6 shown in Table 1) containing a large number of toner particles was obtained.

  With respect to the toners TA-1 to TA-8 and TB-1 to TB-6 obtained as described above, the measurement results of the resin particle detachment rate and the toner particle surface state are shown in Table 1. It was as shown in. For example, in the toner TA-1, the resin particle detachment rate was 3.3%, and the surface state of the toner particle was “B” (for the meaning, see “Method for Measuring Surface State of Toner Particle” below). . Each measurement method of the resin particle desorption rate and the surface state of the toner particles was as follows.

<Measurement method of resin particle desorption rate>
The resin particle detachment rate was measured for the toner dispersion in a state where ultrasonic treatment with an oscillation frequency of 50 kHz and an output of 100 W was performed for 10 minutes. Specifically, after ultrasonic treatment, the toner dispersion is filtered to remove the toner, and the obtained toner (hereinafter referred to as “sample after ultrasonic treatment”) is subjected to FT-IR analysis to obtain an FT-IR spectrum. It was. In addition to the sample after ultrasonic treatment, a sample before ultrasonic treatment (hereinafter referred to as “initial sample”) was also subjected to FT-IR analysis to obtain an FT-IR spectrum. Then, the FT-IR spectrum of the sample after sonication was compared with the FT-IR spectrum of the initial sample to obtain the resin particle desorption rate. The details of the ultrasonic treatment, FT-IR analysis, and how to determine the desorption rate were as follows.

(Sonication)
2.0 g of a sample (toner) was dispersed in 500 mL of a 2% strength by weight aqueous solution of a surfactant (sodium alkyl ether sulfate) to obtain a toner dispersion. Subsequently, the obtained toner dispersion was subjected to ultrasonic treatment for 10 minutes using an ultrasonic liquid mixing apparatus ("Supersonic VS-F100" sold by ASONE Corporation, high frequency output: 100 W, oscillation frequency: 50 kHz). . Subsequently, the toner dispersion liquid subjected to ultrasonic treatment as described above was subjected to suction filtration using a suction filtration apparatus in which a filter cloth having an opening diameter of 2 μm was set.

  Thereafter, using a vacuum constant temperature dryer, the toner remaining on the filter cloth was dried under vacuum and at a temperature of 40 ° C. for 12 hours. As a result, a sample after sonication was obtained.

(FT-IR analysis)
As a measuring device, FT-IR (Fourier transform infrared spectroscopic analyzer) ("Frontier" manufactured by Perkin Elmer) was used. The measurement mode was an ATR (total reflection measurement method) mode. Using a measuring device equipped with an ATR crystal, after measuring the background under the conditions of a measuring range of 4000 to 400 cm ⁻¹ , a resolution of 4.0 cm ⁻¹ and 16 times of integration, an initial sample and a sample after ultrasonic treatment FT-IR spectra (horizontal axis: irradiated infrared wave number, vertical axis: absorbance) were measured.

(How to determine the desorption rate of resin particles)
Based on the FT-IR spectrum obtained for each of the sample after sonication and the initial sample by the FT-IR analysis, the desorption rate of the resin particles (external additive) was calculated. Specifically, from the peak intensity X _A derived from the resin particles (external additive) of the sample after sonication and the peak intensity X _B derived from the resin particles (external additive) of the initial sample, the formula “X _T = 100 × (X _The desorption rate X _T of the resin particles (external additive) was calculated according to “ _B− X _A ) / X _B ”.

<Method for measuring surface condition of toner particles>
The surface of the toner particle is observed by using a scanning electron microscope (SEM) (“JSM-6700F” manufactured by JEOL Ltd.), and the surface state of the toner particle belongs to any of the following states A to D: It was judged.
A: The resin particles were completely embedded in the toner base particles and included in the toner base particles. Therefore, no resin particles were present on the surface of the toner base particles.
B: Both weakly fused particles and strongly fused particles were present.
C: There were weakly fused particles, but no strongly fused particles.
D: There was no rise.

  The presence / absence of “raised” indicates whether or not the resin (surface layer resin) in the toner base particles was raised from the surface of the toner base particles toward the resin particles (external additive). Further, the strongly fused particles mean resin particles (external additive) covered with the raised surface layer resin, and the weakly fused particles are resin particles (the raised surface layer resin is in contact with only the bottom portion ( Means external additive). The surface layer resin (resin existing in the surface layer portion of the toner base particles) corresponds to the resin constituting the shell layer in the capsule toner base particles (toner TA-8), and the non-capsule toner base particles (other than the toner TA-8) Toner) corresponds to a binder resin.

[Evaluation method]
The evaluation method of each sample (toners TA-1 to TA-8 and TB-1 to TB-6) is as follows.

(Heat resistant storage stability)
3 g of the sample (toner) was put in a 20 mL polyethylene container and sealed, and the sealed container was allowed to stand for 3 hours in a thermostatic bath set at 58 ° C. (“DKN302” sold by Yamato Scientific Co., Ltd.). Thereafter, the toner taken out from the thermostat was cooled to room temperature (about 25 ° C.) to obtain an evaluation toner (heat-treated toner).

Subsequently, the obtained toner for evaluation was placed on a 200-mesh sieve having a known mass. Then, the mass of the sieve containing the evaluation toner was measured, and the mass of the toner on the sieve (the mass of the toner before sieving) was determined. Subsequently, the sieve was set in a powder tester (manufactured by Hosokawa Micron Corporation), and the sieve for evaluation was sieved by vibrating the sieve for 30 seconds under the conditions of the rheostat scale 5 according to the manual of the powder tester. After sieving, the mass of toner that did not pass through the sieve (toner remaining on the sieve) was measured. Based on the mass of the toner before sieving and the mass of the toner after sieving (the mass of the toner that did not pass through the sieving), the toner aggregation rate (unit: mass%) was determined according to the following formula. .
Toner aggregation rate = 100 × toner mass after sieving / toner mass before sieving

  When the toner aggregation rate was 20% by mass or less, it was evaluated as good (good), and when the toner aggregation rate was higher than 20% by mass, it was evaluated as x (not good).

(Preparation of developer for evaluation)
100 parts by weight of a developer carrier (FS-C5250DN carrier) and 5 parts by weight of a sample (toner) were mixed for 30 minutes using a ball mill to prepare a developer for evaluation (two-component developer).

(Low temperature fixability)
An image was formed using the developer for evaluation (two-component developer) prepared as described above, and the low-temperature fixability of the sample (toner) was evaluated. As an evaluation machine, a printer having a Roller-Roller type heating and pressing type fixing device (an evaluation machine in which “FS-C5250DN” manufactured by Kyocera Document Solutions Co., Ltd. was modified to change the fixing temperature) was used. The evaluation developer prepared as described above was charged into the developing device of the evaluation machine, and the sample (replenishment toner) was charged into the toner container of the evaluation machine.

Using the evaluation machine, the paper (Fuji Xerox Co., Ltd. “C290”: A4 size, plain paper with a basis weight of 90 g / m ² ) from the rear end to 10 mm in an environment of a temperature of 23 ° C. and a humidity of 60% RH. A solid image (specifically, an unfixed toner image) having a size of 25 mm × 25 mm was formed on the portion under the conditions of a linear speed of 200 mm / second and a toner applied amount of 1.0 mg / cm ² . Subsequently, the paper on which the image was formed was passed through the fixing device of the evaluation machine.

  The minimum fixing temperature was measured in the range of the fixing temperature from 100 ° C. to 200 ° C. Specifically, the fixing temperature of the fixing device was increased from 100 ° C. by 5 ° C., and the lowest temperature (minimum fixing temperature) at which a solid image (toner image) can be fixed on paper was measured. Whether or not the toner could be fixed was confirmed by a rub test. Specifically, the evaluation paper passed through the fixing device was bent so that the surface on which the image was formed was on the inside, and the image on the fold was rubbed 5 times with a 1 kg weight coated with a cloth. Subsequently, the paper was spread and the bent portion of the paper (the portion where the solid image was formed) was observed. Then, the length (peeling length) of toner peeling at the bent portion was measured. The lowest temperature among the fixing temperatures at which the peeling length was 1 mm or less was defined as the lowest fixing temperature. When the minimum fixing temperature was 155 ° C. or lower, it was evaluated as “good”, and when the minimum fixing temperature exceeded 155 ° C., it was evaluated as “poor” (not good).

(Film resistance)
As an evaluation machine, a multifunction machine (“TASKalfa 5550ci” manufactured by Kyocera Document Solutions Inc.) was used. The evaluation developer (two-component developer) prepared in the above-described procedure was put into the developing device of the evaluation machine, and the sample (replenishment toner) was put into the toner container of the evaluation machine.

Using the evaluation machine, continuous printing at a printing rate of 5% was performed on 10,000 sheets of paper (A4 size printing paper) in an environment of a temperature of 32 ° C. and a humidity of 80% RH. During continuous printing, the evaluation paper (“ColorCopy (registered trademark)” manufactured by Mondi, Inc. was used every 200 sheets up to 1000 sheets from the start of printing and every 1000 sheets thereafter, under the condition of a toner loading of 0.5 mg / cm ^2. , A4 size, 90 g / m ² ), an unfixed solid image was formed, and the formed solid image was visually observed. Further, the surface of the developing sleeve of the evaluator was visually observed. The filming resistance of the sample (toner) was evaluated according to the following criteria.
○ (Good): Through the continuous printing of 10,000 sheets, coloring by the toner was not observed on the surface of the developing sleeve, and no image defect was observed in the solid image.
X (not good): At any timing during continuous printing of 10,000 sheets, coloring by toner is observed on the surface of the developing sleeve, or image defects (for example, vertical stripes) are observed in the solid image. It was.

(Heat stress resistance)
The developing device was taken out from the multifunction machine (“TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd.), and the developer for evaluation (two-component developer) prepared by the above-described procedure was put into the taken out developing device. Subsequently, the developing device was put in an oven in a drivable state, and the temperature in the oven was adjusted to 45 ° C. After confirming that the temperature in the oven reached 45 ° C., the developing device was continuously driven in the oven for 1 hour. During the driving of the developing device, the developer for evaluation was stirred in the developing device. Thereafter, the developing device was taken out from the oven, and 10 g of the developer for evaluation was taken out from the taken out developing device.

10 g of the developer for evaluation thus taken out was placed on a sieve having a known mass of 200 mesh (aperture 75 μm). Then, the mass of the sieve containing the developer for evaluation was measured, and the mass of the developer for evaluation on the sieve (the mass of the developer before sieving) was determined. Subsequently, the above sieve was set on a powder tester (manufactured by Hosokawa Micron Corporation), and according to the manual of the powder tester, the sieve was vibrated for 30 seconds under the conditions of the rheostat scale 5, and the developer for evaluation was sieved. After sieving, the mass of the developer that did not pass through the sieve (developer remaining on the sieve) was measured. Based on the mass of the developer before sieving and the mass of the developer after sieving (the mass of the developer that has not passed through the sieve), the developer aggregation rate (unit: mass%) according to the following formula: )
Developer aggregation rate = 100 × mass of developer after sieving / mass of developer before sieving

  When the developer aggregation rate was 2.0% by mass or less, it was evaluated as “good”, and when the developer aggregation rate was over 2.0% by mass, it was evaluated as “x” (not good).

[Evaluation results]
For each of toners TA-1 to TA-8 and TB-1 to TB-6, heat-resistant storage stability (toner aggregation rate), low-temperature fixability (minimum fixing temperature), filming resistance (◯: no filming, × : Filming occurrence) and heat stress resistance (developer aggregation rate) were evaluated.

  The toners TA-1 to TA-8 (toners according to Examples 1 to 8) each had the above-described basic configuration. Specifically, in each of the toners TA-1 to TA-8, a plurality of resin particles adhering to the surface of the toner base particle are respectively surface resin (toner base particle of the toner base particle) rising from the surface of the toner base particle toward the resin particle. It was fixed to the toner base particles by physical fusion with the resin of the surface layer portion. The desorption rate of the resin particles in the toner measured after ultrasonic treatment for 10 minutes under the conditions of an oscillation frequency of 50 kHz and an output of 100 W in the liquid is 0.1% or more in terms of the peak intensity ratio of the FT-IR spectrum. 0.0% or less (see Table 1).

  In any of the toners TA-1 to TA-8, the resin particles (external additive) maintained a spherical shape. In any of the toners TA-1 to TA-8, the thickness of the shell layer was 1 nm or more and 20 nm or less.

  Each of the production methods of the toners TA-1 to TA-8 included the basic steps A and B described above (see “first external addition step”). In the basic step A, a resin (surface layer resin) existing in the surface layer portion of the toner base particles is dissolved by heating a liquid containing at least the toner base particles containing the resin in the surface layer portion and a plurality of resin particles, This is a step (melting step) of bringing the melted surface layer resin into contact with the resin particles. The basic process B is a process (fixing process) of fixing a plurality of resin particles on the surface of the toner base particles by physical fusion with a surface layer resin by cooling the liquid after the melting process.

  In addition, the toner TA-8 is produced by preparing the liquid (aqueous medium) prior to the melting step, putting the toner core and the shell layer material in the liquid, and forming the shell layer on the surface of the toner core in the liquid. A shell layer forming step to be formed was further included. And the shell layer formation process and the melting process were performed in a state where the temperature of the liquid was maintained at 60 ° C. or higher and 70 ° C. or lower (specifically, 67 ° C. to 68 ° C.).

  As shown in Table 2, toners TA-1 to TA-8 were excellent in heat-resistant storage stability, low-temperature fixability, and heat-resistant stress, and could suppress filming.

  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.

10 Toner Particles 11 Toner Base Particles 12 Resin Particles R Cured Product (Surface Layer Resin)

Claims (13)

A plurality of toner particles comprising toner base particles containing a resin at least in a surface layer portion and an external additive attached to the surface of the toner base particles;
The external additive includes a plurality of resin particles,
Each of the plurality of resin particles is fixed to the toner base particles by physical fusion with the resin of the surface layer portion rising from the surface of the toner base particles toward the resin particles,
The desorption rate of the resin particles measured after ultrasonic treatment for 10 minutes under conditions of an oscillation frequency of 50 kHz and an output of 100 W in a liquid is 0.1% or more as a peak intensity ratio of an FT-IR spectrum. An electrostatic latent image developing toner of 0% or less.   The electrostatic latent image developing toner according to claim 1, wherein the resin particles have a glass transition point of 70 ° C. or higher and 150 ° C. or lower.   The electrostatic latent image developing toner according to claim 2, wherein the resin particles contain a cross-linked styrene-acrylonitrile resin mainly composed of an acrylonitrile monomer. The toner base particles are non-capsule toner base particles,
The toner base particles contain a binder resin,
The resin present in the surface layer portion of the toner base particles is the binder resin;
The electrostatic latent image developing toner according to claim 2, wherein the toner base particles have a glass transition point of 50 ° C. or more and 65 ° C. or less.   5. The electrostatic latent image according to claim 4, wherein the toner base particles contain, as the binder resin, a first polyester resin having a glass transition point of 60 ° C. or lower and a second polyester resin having a glass transition point of 65 ° C. or higher. Toner for image development. The number average primary particle diameter of the resin particles is 10 nm or more and 30 nm or less,
6. The electrostatic latent image developing toner according to claim 4, wherein an amount of the resin particles is 1.00 parts by mass or more and 1.80 parts by mass or less with respect to 100 parts by mass of the toner base particles. The toner base particle is a capsule toner base particle comprising a toner core containing a binder resin and a shell layer covering the toner core;
The toner core has a glass transition point of 40 ° C. or more and 55 ° C. or less,
The electrostatic latent image developing toner according to claim 2, wherein the shell layer has a glass transition point of 65 ° C. or more and 80 ° C. or less. The number average primary particle diameter of the resin particles is 10 nm or more and 30 nm or less,
The electrostatic latent image developing toner according to claim 7, wherein the amount of the resin particles is 0.50 parts by mass or more and 1.00 parts by mass or less with respect to 100 parts by mass of the toner core.   The surface of the toner base particles includes the resin particles covered with the raised resin and the resin particles in which the raised resin contacts only a bottom portion. The electrostatic latent image developing toner according to one item. By heating a liquid containing at least a toner mother particle containing a resin in the surface layer portion and a plurality of resin particles, the resin present in the surface layer portion of the toner mother particle is dissolved, and the melted resin is A melting step for contacting the resin particles;
Fixing the plurality of resin particles on the surface of the toner base particles by physical fusion with the resin by cooling the liquid after the melting step;
A method for producing a toner for developing an electrostatic latent image, comprising: The toner base particle is a capsule toner base particle comprising a toner core containing a binder resin and a shell layer covering the toner core;
Prior to the melting step, the liquid is prepared, and the shell layer forming step of forming the shell layer on the surface of the toner core in the liquid by adding the toner core and the material of the shell layer into the liquid The method for producing a toner for developing an electrostatic latent image according to claim 10. The prepared liquid is an aqueous medium,
The method for producing a toner for developing an electrostatic latent image according to claim 11, wherein the shell layer forming step and the melting step are performed in a state where the temperature of the liquid is maintained at 60 ° C. or higher and 70 ° C. or lower. The glass transition point of the resin particles is 5 ° C. or more higher than the glass transition point of the resin present in the surface layer portion of the toner base particles,
The temperature of the liquid in the melting step is not less than “the glass transition point of the resin existing in the surface layer portion of the toner base particles −2 ° C.” and not more than “the glass transition point of the resin particles −6 ° C.”. The method for producing a toner for developing an electrostatic latent image according to any one of claims 10 to 12.