JP2018072454A - Toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide toner for electrostatic latent image development which is excellent in the heat-resistant storage property, low-temperature fixability and releasability, can suppress toner adhesion in an image formation apparatus and form a high-quality image.SOLUTION: The toner for electrostatic latent image development includes a plurality of toner particles containing binder resin. The toner particle includes noncrystalline polyester resin and thermoplastic elastomer as the binder resin. The thermoplastic elastomer is a polymer of one or more kinds of styrene-based monomers and one or more kinds of olefinic monomers. The major axis diameter of the toner particle is equal to or greater than 6.0 μm and equal to or less than 10.0 μm at the number average value. The minor axis diameter of the toner particle is equal to or greater than 3.0 μm and equal to or less than 7.0 μm at the number average value. The aspect ratio of the toner particle is equal to or greater than 1.1 and equal to or less than 2.0 at the number average value. The internal cohesion of the toner is equal to or greater than 5.0 N and equal to or less than 10.0 N. The interface adhesion of the toner is equal to or greater than 10.0 nN and equal to or less than 30.0 nN.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic latent image developing toner.

  Patent Document 1 discloses a flat toner obtained by flattening secondary particles.

JP 2002-207317 A

  The flat toner disclosed in Patent Document 1 is advantageous in reducing thermal energy during fixing. However, when such flat toner is used in an image forming apparatus, toner fixation (more specifically, toner fixation to a developing sleeve, a photosensitive drum, a transfer belt, and the like) easily occurs in the image forming apparatus.

  The present invention has been made in view of the above problems, and is excellent in heat-resistant storage stability, low-temperature fixability, and releasability, and is capable of fixing toner in an image forming apparatus (more specifically, a developing sleeve, a photoreceptor). An object of the present invention is to provide a toner for developing an electrostatic latent image that can suitably suppress toner adhering to a drum, a transfer belt, and the like and can form a high-quality image.

The electrostatic latent image developing toner according to the present invention includes a plurality of toner particles containing a binder resin. The toner particles contain an amorphous polyester resin and a thermoplastic elastomer as the binder resin. The thermoplastic elastomer is a polymer of one or more styrene monomers and one or more olefin monomers. The major axis diameter of the toner particles is 6.0 μm or more and 10.0 μm or less in terms of a number average value. The minor axis diameter of the toner particles is 3.0 μm or more and 7.0 μm or less in terms of number average value. The aspect ratio of the toner particles is 1.1 to 2.0 in terms of number average value. The toner has an internal cohesive force of 5.0 N to 10.0 N. The interfacial adhesion force of the toner measured based on a force curve obtained with a scanning probe microscope is 10.0 nN or more and 30.0 nN or less.
[The internal cohesion of the toner is
A 3 mm thick aluminum stage;
A first heater for heating the stage;
From the tip side, a cylindrical indenter made of aluminum coated with a polyimide resin film, a second heater for heating the indenter, and a pressurizing unit in which a load cell is integrated in this order,
A drive unit that displaces the pressurizing unit in a vertical direction perpendicular to the surface direction of the stage;
Using a measuring device comprising
A first step of heating the pressurizing unit and the stage to 150 ° C. using the first heater and the second heater,
After the first step, 1.0 g / cm ² of the toner is placed on the stage with the temperature of the pressure unit and the stage kept at 150 ° C. A second step of pressurizing the toner on the stage for 30 seconds at a pressure of 10 N / cm ² ;
After the second step, using the load cell, the pressurizing unit is moved 10 cm from the start of pressurization while the pressurizing unit is moved away from the stage at a speed of 60 mm / sec. A third step of measuring a maximum value of a load applied between the toner and the stage as an internal cohesive force of the toner;
It is measured through. ]

  According to the present invention, excellent heat-resistant storage stability, low-temperature fixability, and releasability are obtained, and toner fixation in an image forming apparatus (more specifically, toner on a developing sleeve, a photosensitive drum, a transfer belt, etc.) It is possible to provide a toner for developing an electrostatic latent image that can suitably suppress (fixation) and can form a high-quality image.

FIG. 4 is a diagram for explaining a method for measuring each of a major axis diameter, a minor axis diameter, and an aspect ratio of toner particles. It is a figure for demonstrating the measuring method of internal cohesion force.

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

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 not specified, and the “Coulter Counter Multisizer 3” manufactured by Beckman Coulter Co., Ltd. is used. ) Measured based on. Moreover, each measured value of an acid value and a hydroxyl value is a value measured according to "JIS (Japanese Industrial Standard) K0070-1992" unless otherwise specified. Moreover, each measured value of a number average molecular weight (Mn) and a mass average molecular weight (Mw) is the value measured using the gel permeation chromatography, if not prescribed | regulated at all.

  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.

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

  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. Examples of the resin constituting the resin layer are 1 selected from the group consisting of a fluororesin (more specifically, PFA or FEP), a polyamideimide resin, a silicone resin, a urethane resin, an epoxy resin, and a phenol resin. More than one type of resin may be mentioned. 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 includes a plurality of toner particles. The toner particles may include an external additive. When the toner particles include an external additive, the toner particles include a toner base particle and an external additive. The external additive adheres to the surface of the toner base particles. The toner base particles contain a binder resin. The toner base particles may contain an internal additive (for example, at least one of a release agent, a colorant, a charge control agent, and a magnetic powder) in addition to the binder resin, if necessary. If not necessary, the external additive may be omitted. When omitting the external additive, the toner base particles correspond to the toner 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. The toner is charged by friction with the carrier or blade in the developing device before being supplied to the photoreceptor. For example, a positively chargeable toner is positively charged. In the developing process, toner (specifically, charged toner) 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 supplied to the photosensitive member, and the supplied toner is By attaching to the electrostatic latent image on the photoconductor, a toner image is formed on the photoconductor. The consumed toner is replenished to the developing device from a toner container containing replenishment toner.

  In the subsequent transfer process, 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, paper). Transcript to. 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. After the transfer step, the toner remaining on the photoreceptor is removed by a cleaning member (for example, a cleaning blade). 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 toner includes a plurality of toner particles containing a binder resin. The toner particles contain an amorphous polyester resin and a thermoplastic elastomer as a binder resin. The thermoplastic elastomer is a polymer of one or more styrene monomers and one or more olefin monomers. The major axis diameter of the toner particles is 6.0 μm or more and 10.0 μm or less in terms of a number average value. The minor axis diameter of the toner particles is 3.0 μm or more and 7.0 μm or less in terms of number average value. The aspect ratio of the toner particles is 1.1 to 2.0 in terms of number average value. The internal cohesion force of the toner is 5.0 N or more and 10.0 N or less. The interfacial adhesion force of the toner measured based on a force curve obtained with a scanning probe microscope is 10.0 nN or more and 30.0 nN or less.

The method for measuring the internal cohesive force of the toner is as follows.
The measuring device includes a stage, a first heater, a pressurizing unit, and a driving unit. The stage is an aluminum stage having a thickness of 3 mm provided with a first heater. The first heater is a heater for heating the stage. The pressurizing unit is constituted by integrating, from the front end side, an aluminum cylindrical indenter covered with a polyimide resin film, a second heater for heating the indenter, and a load cell in this order. . The drive unit is configured to displace the pressure unit in a vertical direction orthogonal to the surface direction of the stage.
Measurement is performed through the following first to third steps using the measurement apparatus.
In the first step, the pressure unit and the stage are each heated to 150 ° C. using the first heater and the second heater.
In the second step, 1.0 g / cm ² of toner is placed on the stage with the temperature of the pressure unit and the stage kept at 150 ° C., and 10 N / cm ² is used using the pressure unit. The toner on the stage is pressurized with a pressure of 30 seconds.
In the third step, the load applied between the pressurization unit and the stage from the start of pressurization until the pressurization unit rises 10 cm using the load cell while moving the pressurization unit away from the stage at a speed of 60 mm / sec. Measure the maximum value of. The maximum value of the measured load corresponds to the internal cohesive force of the toner.

  In the above basic configuration, “major axis diameter” and “minor axis diameter” are values measured based on a two-dimensional projection image (specifically, an SEM photograph) of particles. The “major axis diameter” of a particle is the length of the major axis of the particle, and more specifically corresponds to the width of the particle that maximizes the interval between two parallel lines that sandwich the particle. The “minor axis diameter” of a particle is the length of the minor axis of the particle, and more specifically, the particle measured on a straight line passing through the midpoint of the major axis and orthogonal to the major axis. It corresponds to the width of. “Aspect ratio” corresponds to a value obtained by dividing the major axis diameter by the minor axis diameter (= major axis diameter / minor axis diameter).

With reference to FIG. 1, each measuring method of a major axis diameter, a minor axis diameter, and an aspect ratio defined by the above basic configuration will be described.
The major axis diameter (number average value) defined by the above basic configuration is determined by measuring the major axis diameter D _A for each of a considerable number of toner particles 11 included in the toner 10 and adding the obtained major axis diameters D _A. The value is a value obtained by dividing the value by the number of toner particles 11 to be measured.
Minor axis defined by the basic structure (number average), measured minor axis diameter D _B for each of a substantial number of toner particles 11 contained in the toner 10, the sum of the resulting minor axis diameter D _B The value is a value obtained by dividing the value by the number of toner particles 11 to be measured.
The aspect ratio (number average value) defined in the basic configuration is obtained by obtaining the aspect ratio (= major axis diameter D _A / minor axis diameter D _B ) for each of a considerable number of toner particles 11 included in the toner 10. This is a value obtained by dividing the total value of the obtained aspect ratios by the number of toner particles 11 to be measured.

  In the toner having the above basic configuration, the major axis diameter of the toner particles is 6 μm or more and 10 μm or less in terms of the number average value, and the minor axis diameter of the toner particles is 3 μm or more and 7 μm or less in terms of the number average value. The number average value is 1.1 or more and 2.0 or less. Toner particles having such a shape (hereinafter sometimes referred to as irregularly shaped toner particles) are easier to fix at a lower temperature than true spherical toner particles. The reason is considered that the number of toner particles per unit area is reduced on the surface of the recording medium to which the toner image is transferred. In addition, the irregularly shaped toner particles are easily stretched (spread) with respect to pressure (for example, pressure by a roller) in the fixing process. The irregularly shaped toner particles can be produced, for example, by applying a shearing force to the spherical toner particles and deforming the toner particles into a flat shape using a dispersion processing device.

  As the dispersion processing apparatus, for example, a high-pressure dispersion apparatus including a pressure generation device (for example, a pump) and a bottleneck (more specifically, a portion in which a flow path such as a nozzle or an orifice is significantly narrowed) can be used. As an example of such a high-pressure dispersion device, a high-pressure emulsification device (formerly “NANO3000” manufactured by Mie Co., Ltd.) can be mentioned. This high-pressure emulsifying device (NANO3000) includes a pump, a nozzle unit, a dispersion processing unit (multistage screen space), and a multistage decompression module from upstream to downstream, and the following dispersion processing is applied to the processing target (dispersion). Configured to apply.

  A dispersion (processing target) containing powder (toner) to be processed is supplied to the nozzle portion by a pump. That is, the dispersion liquid (processing object) pressurized by the pump located upstream from the nozzle part is pumped to the nozzle part and further downstream thereof. The dispersion processing unit positioned downstream of the nozzle unit is filled with a dispersion liquid (processing target) to which back pressure is applied. The dispersion liquid (processing target) passes through the nozzle portion and is converted into a jet flow (high-speed fluid) according to Bernoulli's law. The jet stream is jetted downstream of the nozzle portion. The jet stream (processing target) from the nozzle unit collides with the dispersion liquid (processing target) existing in the dispersion processing unit, and loses kinetic energy while giving a large shearing force to the liquid existing around. By causing the processing objects to collide with each other, distributed processing with high energy efficiency becomes possible. In addition, since back pressure is applied to the dispersion processing unit, cavities (bubbles) do not occur in the dispersion liquid present in the dispersion processing unit. The back pressure force filling the cavity corresponds to cavitation. The distributed processing unit is divided into a plurality of screen spaces by being partitioned by a plurality of screens. The generation of bubbles is effectively suppressed by gradually reducing the back pressure through the multistage screen space. Furthermore, the multistage decompression module located downstream of the dispersion processing unit is a stepwise process that reduces the pressure (back pressure) of the dispersion subjected to the dispersion treatment to a pressure that does not generate bubbles even when released to the atmosphere. Depressurize to. As a result, the dispersion liquid that has been subjected to the dispersion treatment in the apparatus can be taken out of the apparatus without bubbles.

  When the aspect ratio of the toner particles is too large, an area that easily rubs against the surface of the toner particles (for example, an area that easily contacts the carrier when mixing the two-component developer) and an area that does not easily rub (for example, mixing two-component developer). In some cases, a region that is difficult to come into contact with the carrier) is present, and the charge amount of the toner tends to be insufficient. Also, the charge distribution on the surface of the toner particles tends to be non-uniform. When the aspect ratio of the toner particles is too small, the shape of the toner particles is close to a true sphere, and it becomes difficult to ensure sufficient low-temperature fixability of the toner, and the toner cleaning property tends to be insufficient. Specifically, the toner tends to pass through the cleaning member and remain on the photoreceptor.

  In the toner having the above-described basic configuration, the internal cohesive force of the toner is 5.0 N or more and 10.0 N or less. The inventor of the present application makes it easy to ensure sufficient low-temperature fixability of the toner by setting the internal cohesion of the toner containing the above-mentioned irregularly shaped toner particles to 5.0 N or more and 10.0 N or less, and the recording medium is fixed during fixing. It has been found that it is difficult to wind around a fixing roller (for example, a heating roller). It is considered that the internal cohesion force of the toner is mainly caused by the intermolecular force of the polyester molecular chain. Specifically, the internal cohesive force of the toner is mainly caused by hydrogen bonds between ester groups (—COO—) or between the ester groups and hydroxyl groups (—OH) in the amorphous polyester resin. Conceivable. If the internal cohesive force of the toner is too large, it is considered that the amorphous polyester resin does not melt at a low temperature. In addition, if the internal cohesive force of the toner is too small, it is considered that the recording medium is easily wound around the fixing roller at the time of fixing.

  In the toner having the above-described basic configuration, the interfacial adhesion force of the toner is 10.0 nN or more and 30.0 nN or less. The inventor of the present application ensures sufficient heat storage stability and adhesion resistance (and hence cleaning properties) of the toner by setting the interfacial adhesion force of the toner including the above-mentioned irregularly shaped toner particles to 10.0 nN or more and 30.0 nN or less. It has been found that toner scattering can be suppressed in the developing device. If the adhesion force of the toner interface is too great, the toner particles tend to aggregate when storing the toner (particularly when stored in a high temperature environment), or the toner tends to adhere to the developing roller and the fixing roller during image formation. It is thought that. Further, it is considered that if the interfacial adhesion force of the toner is too small, the toner is easily scattered in the developing device during image formation.

  The internal cohesive force and interfacial adhesion force of the toner tend to decrease as the content of the thermoplastic elastomer in the toner particles increases. Therefore, by changing the content of the thermoplastic elastomer in the toner particles, it is possible to adjust the internal cohesion force and the interfacial adhesion force of the toner. However, when an excessive amount of a thermoplastic elastomer is contained in the toner particles, the influence of the viscosity derived from the elastomer appears on the surface of the toner particles, and the adhesion force of the toner tends to increase. When a thermoplastic elastomer that is particularly susceptible to the internal cohesive force of the toner and a thermoplastic elastomer that is particularly susceptible to the interfacial adhesion of the toner are used in combination, by changing the blending ratio of these thermoplastic elastomers, The internal cohesion force and the interfacial adhesion force of the toner can be adjusted separately.

  In order to bring both the internal cohesive force and the interfacial adhesion force of the toner within the range defined by the above basic constitution, the non-crystalline polyester resin contains one or more bisphenols and one or more aromatic dicarboxylic acids. One or more styrenic monomers and one or more carbons in which the thermoplastic elastomer contains a styrenic monomer in a proportion of 15% by mass to 35% by mass with respect to the total amount of the monomers. It is a polymer with an olefin monomer having a number of 2 or more and 4 or less, and the amount of the thermoplastic elastomer is preferably 2.0 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin. Further, it is more preferable that the toner particles contain a crystalline polyester resin having the following components in the following ratio (amount).

  Suitable crystalline polyester resins include one or more α, ω-alkanediols having 2 to 8 carbon atoms, fumaric acid, one or more styrene monomers, and 1 to 4 carbon atoms in the ester portion. It is a polymer with 1 or more types of (meth) acrylic-acid alkylester which has the following alkyl group. A suitable amount of the crystalline polyester resin is 5.0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin.

  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.

  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.

  The toner having the above basic configuration is preferably a pulverized toner. The pulverized toner is toner prepared by a pulverization method. After the toner base particles are produced by a pulverization method, an external addition step may be performed. The pulverization method is a method of obtaining a powder through a step of obtaining a kneaded product by melting and kneading a plurality of types of materials (resins and the like) and a step of pulverizing the obtained kneaded product. Note that the pulverized toner and the polymerized toner (so-called chemical toner) are generally distinguished from each other, and can be easily distinguished from the particle shape and the state of the particle surface. The pulverized toner is produced by a pulverization method (dry method), and the polymerized toner is produced by a wet method. Due to the difference in manufacturing method, generally, the pulverized toner is more environmentally friendly than the polymerized toner.

  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.

  Next, the non-capsule toner base particles (binder resin and internal additive) and the 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. Capsule toner base particles may be produced by forming a shell layer on the surface of the following non-capsule toner base particles (toner core).

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

  In the toner having the above-described basic configuration, the toner base particles contain an amorphous polyester resin and a thermoplastic elastomer as a binder resin. The toner base particles may contain a crystalline polyester resin in addition to the amorphous polyester resin and the thermoplastic elastomer. By containing a crystalline polyester resin in the toner base particles, sharp melt properties can be imparted to the toner base particles.

  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.

  As a first preferred example of the amorphous polyester resin contained in the toner base particles, one or more bisphenols (more specifically, bisphenol A ethylene oxide adduct or bisphenol A propylene oxide adduct, etc.) are used. And at least one alkenyl succinic acid (more specifically, dodecenyl succinic acid and the like) having an alkenyl group having 10 to 16 carbon atoms and at least one aromatic dicarboxylic acid (more specifically, terephthalic acid). Etc.).

  As a second preferred example of the amorphous polyester resin contained in the toner base particles, one or more bisphenols (more specifically, bisphenol A ethylene oxide adduct or bisphenol A propylene oxide adduct, etc.) are used. And a polymer of one or more aromatic dicarboxylic acids (more specifically, terephthalic acid or the like).

  In order to ensure sufficient toner fixability even during high-speed fixing, an amorphous polyester resin in the toner base particles (when the toner base particles contain a plurality of types of non-crystalline polyester resins, the mass basis The most common non-crystalline polyester resin) has a softening point (Tm) of 105 ° C. or higher and 150 ° C. or lower, and a glass transition point (Tg) of 50 ° C. or higher and 70 ° C. or lower.

  Preferred examples of the crystalline polyester resin contained in the toner base particles include one or more α, ω-alkanediols having 2 to 8 carbon atoms (for example, two aliphatic diols: 1,4-butane). Diol and 1,6-hexanediol), fumaric acid, one or more styrene-based monomers, and one or more (meth) acrylic acid alkyl esters having an alkyl group having 2 to 6 carbon atoms in the ester portion, These polymers are mentioned.

  The thermoplastic elastomer contained in the toner base particles is a polymer of one or more styrene monomers and one or more olefin monomers. Suitable examples of styrene monomers and olefin monomers for synthesizing such thermoplastic elastomers are shown below. A thermoplastic elastomer having a number average molecular weight of 1,000 to 100,000 is particularly preferred.

  Preferable examples of the styrenic monomer include styrene and alkyl styrene (more specifically, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, ethyl styrene, 2,3-dimethyl styrene). 2,4-dimethylstyrene, o-tert-butylstyrene, m-tert-butylstyrene, or p-tert-butylstyrene), or halogenated styrene (more specifically, monochlorostyrene, dichlorostyrene, p -Bromostyrene, 2,4,5-tribromostyrene, or 2,4,6-tribromostyrene).

In order to impart reactivity to the thermoplastic elastomer, one or more functional groups selected from the group consisting of a hydroxyl group (—OH), a carboxyl group (—COOH), a sulfo group (—SO ₃ H), and an amino group are used. It is preferable to introduce a repeating unit derived from a styrenic monomer having a group into the thermoplastic elastomer. The amino group includes both “—NH ₂ ” and a functional group substituted with hydrogen in “—NH ₂ ”. Preferable examples of the styrene monomer having a hydroxyl group, a carboxyl group, or a sulfo group include styrene sulfonic acid, carboxystyrene, hydroxystyrene, or a salt of any of these styrene monomers. Further, suitable examples of the styrenic monomer having an amino group include aminostyrene, alkylaminostyrene (more specifically, N-methylaminostyrene, N, N-dimethylaminostyrene, N-ethylaminostyrene, or N, N-diethylaminostyrene etc.).

Preferable examples of the olefin monomer include alkenes having only one double bond or conjugated diene compounds having two double bonds. Preferable examples of the alkene include ethylene, propylene, 1-butene, 2-butene, isobutene (CH ₂ ═C (CH ₃ ) ₂ ), 1-pentene, 2-pentene, 1-hexene, 2-hexene, 1 -Heptene, 2-heptene, 1-octene, or 2-octene. In addition, preferable examples of the conjugated diene compound include butadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene.

(Coloring agent)
The toner base particles may contain a colorant. As the colorant, a known pigment or dye can be used according to the color of the toner. In order to 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 base particles may contain a black colorant. An example of a black colorant is carbon black. The black colorant may be a colorant that is toned to black using a yellow colorant, a magenta colorant, and a cyan colorant.

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

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

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

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

(Release agent)
The toner base particles may contain a release agent. The release agent is used, for example, for the purpose of improving the fixing property or offset resistance of the toner. In order to 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 base particles may contain a charge control agent. The charge control agent is used, for example, for the purpose of improving the charge stability or charge rising property of the toner. The charge rising characteristic of the toner is an index as to whether or not the toner can be charged to a predetermined charge level in a short time.

  By adding a negatively chargeable charge control agent (more specifically, an organometallic complex or a chelate compound) to the toner base particles, the anionicity of the toner base particles 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 base particles, the cationicity of the toner base particles can be increased. However, if sufficient chargeability is ensured in the toner, it is not necessary to add a charge control agent to the toner base particles.

(Magnetic powder)
The toner base particles may contain magnetic powder. Examples of magnetic powder materials include ferromagnetic metals (more specifically, iron, cobalt, nickel, or alloys containing one or more of these metals), ferromagnetic metal oxides (more specifically, Ferrite, magnetite, chromium dioxide, or the like) or a material subjected to ferromagnetization treatment (more specifically, a carbon material or the like imparted with ferromagnetism by heat treatment) can be suitably used. One type of magnetic powder may be used alone, or a plurality of types of magnetic powder may be used in combination.

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

[External additive]
An external additive (specifically, a powder containing a plurality of external additive particles) may be adhered to the surface of the toner base particles. 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). For example, by stirring together the toner base particles (powder) and the external additive (powder), the external additive particles can be attached to the surface of the toner base particles. The toner base particles and the external additive particles do not chemically react with each other and are physically bonded instead of chemically. The strength of the bond between the toner base particles and the external additive particles depends on the stirring conditions (more specifically, the stirring time, the rotation speed of the stirring, etc.), the particle diameter of the external additive particles, and the shape of the external additive particles. And the surface condition of the external additive particles.

  In order to fully perform the functions of the external additive while suppressing the detachment of the external additive particles from the toner particles, the amount of the external additive (if multiple types of external additive particles are used, The total amount of external additive particles) 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.

  The external additive particles are preferably inorganic particles such as silica particles or metal oxide particles (more specifically, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate, or barium titanate). Particularly preferred. However, particles of an organic acid compound such as a fatty acid metal salt (more specifically, zinc stearate) or resin particles may be used as the external additive particles. Moreover, you may use the composite particle which is a composite of a multiple types of material as external additive particle | grains. One type of external additive particles may be used alone, or a plurality of types of external additive particles may be used in combination.

  In order to improve the fluidity of the toner, it is preferable to use inorganic particles (powder) having a number average primary particle diameter of 5 nm to 30 nm as external additive particles. In order to make the external additive function as a spacer between the toner particles to improve the heat-resistant storage stability of the toner, resin particles (powder) having a number average primary particle diameter of 50 nm to 200 nm are used as the external additive particles. It is preferable to do.

  The external additive particles may be surface-treated. For example, when silica particles are used as the external additive particles, hydrophobicity and / or positive chargeability may be imparted to the surface of the silica particles by the 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), a silazane compound (for example, a chain silazane compound or a cyclic silazane compound). ) Or silicone oil (more specifically, dimethyl silicone oil or the like) can be preferably used. As the surface treatment agent, a silane coupling agent or a silazane compound is particularly preferable. Preferable examples of the silane coupling agent include silane compounds (more specifically, methyltrimethoxysilane or aminosilane). A preferred example of the silazane compound is HMDS (hexamethyldisilazane). 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.

  Examples of the present invention will be described. Tables 1 and 2 show toners TA-1 to TA-9 and TB-1 to TB-11 (each toner for developing an electrostatic latent image) according to Examples or Comparative Examples. Table 3 shows crystalline polyester resins CPES-1 to CPES-3 used for the production of the toners shown in Tables 1 and 2. Table 4 shows non-crystalline polyester resins APES-1 to APES-3 used in the production of the toners shown in Tables 1 and 2.

  In Tables 1 and 2, the unit of “amount” is parts by mass. The “ER ratio” indicates the ratio of the mass of the thermoplastic elastomer to the mass of the amorphous polyester resin. For example, in the toner TA-1, the amount of the thermoplastic elastomer is 3.7 parts by mass with respect to 100 parts by mass of the amorphous polyester resin.

  Hereinafter, the production methods, evaluation methods, and evaluation results of the toners TA-1 to TA-9 and TB-1 to TB-11 will be described in order. In the evaluation in which an error occurs, a considerable number of measurement values with sufficiently small errors are obtained, and the arithmetic average of the obtained measurement values is used as the evaluation value. Moreover, the measuring methods of Tg (glass transition point) and Tm (softening point) are as follows unless otherwise specified.

<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 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.

[Preparation of materials]
(Synthesis of crystalline polyester resins CPES-1 to CPES-3)
In a 5 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirrer, the alcohol components (1,4-butanediol and 1,6- (Hexanediol), an acid component (fumaric acid) in an amount shown in Table 3, and 2.5 parts by mass of 1,4-benzenediol were added. For example, in the synthesis of the crystalline polyester resin CPES-1, 990 parts by mass of 1,4-butanediol, 242 parts by mass of 1,6-hexanediol, and 1480 parts by mass of fumaric acid are added as a resin raw material (monomer). did.

  Next, in a normal pressure (atmospheric pressure) environment, the temperature of the flask contents is raised to 170 ° C. while stirring the contents of the flask, and the contents of the flask are reacted at that temperature (170 ° C.) for 5 hours. It was. Subsequently, the flask contents were heated and reacted at a temperature of 210 ° C. for an additional 1.5 hours (90 minutes). Subsequently, the inside of the flask was placed in a reduced pressure atmosphere (pressure 8 kPa), and the contents of the flask were reacted for 1 hour under the reduced pressure atmosphere (pressure 8 kPa) and temperature 210 ° C.

  Subsequently, the atmosphere was returned to normal pressure, and St-Ac-based components (styrene and n-butyl methacrylate) in the amounts shown in Table 3 were placed in the flask. For example, in the synthesis of the crystalline polyester resin CPES-1, 68 parts by mass of styrene and 54 parts by mass of n-butyl methacrylate were added as a resin raw material (monomer).

  Subsequently, the inside of the flask was placed in a reduced pressure atmosphere (pressure 8 kPa), and the contents of the flask were reacted for 1 hour under the reduced pressure atmosphere (pressure 8 kPa) and temperature 210 ° C. As a result, crystalline polyester resins CPES-1 to CPES-3 having physical properties shown in Table 3 were obtained. For example, regarding crystalline polyester resin CPES-1, Tm was 82 ° C., acid value was 3.1 mgKOH / g, hydroxyl value was 19 mgKOH / g, Mw was 27500, and Mn was 3620.

(Synthesis of amorphous polyester resins APES-1 to APES-3)
An alcohol component (bisphenol A propylene oxide adduct and bisphenol A ethylene oxide) in the amounts shown in Table 4 was placed in a 5 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirring device. Adduct), an acid component in the amount shown in Table 4 (APES-1 and APES-2: n-dodecenyl succinic anhydride and terephthalic acid, APES-3: terephthalic acid), and 4 parts by mass of dibutyltin oxide. It was. For example, in the synthesis of the amorphous polyester resin APES-1, 1700 parts by mass of BPA-PO (bisphenol A propylene oxide adduct) and 650 masses of BPA-EO (bisphenol A ethylene oxide adduct) are used as a resin raw material (monomer). Part, 500 parts by mass of n-dodecenyl succinic anhydride, and 400 parts by mass of terephthalic acid were added.

  Subsequently, in a normal pressure (atmospheric pressure) environment, the temperature of the flask contents was increased to 220 ° C. while stirring the flask contents, and the flask contents were reacted at a temperature of 220 ° C. for 9 hours. Subsequently, the inside of the flask was placed in a reduced pressure atmosphere (pressure 8 kPa), and the contents of the flask were reacted for 2 hours in a reduced pressure atmosphere (pressure 8.3 kPa) and a temperature of 220 ° C. As a result, amorphous polyester resins APES-1 to APES-3 having physical properties shown in Table 4 were obtained. For example, regarding the amorphous polyester resin APES-1, Tm was 124.8, Tg was 57.2 ° C., acid value was 6 mgKOH / g, hydroxyl value was 41 mgKOH / g, Mw was 76800, and Mn was 3737. .

[Toner Production Method]
(Preparation of toner base particles)
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.), the first binder resin of the type and amount shown in Table 1 or Table 2 (crystalline polyester resin CPES-1 defined for each toner) ~ Any of CPES-3) and the second binder resin of the type and amount shown in Table 1 or Table 2 (any of the non-crystalline polyester resins APES-1 to APES-3 determined for each toner). A third binder resin (any one of elastomers ER-1 to ER-4) of the type and amount shown in Table 1 or Table 2, 120 parts by mass of carbon black ("MA100" manufactured by Mitsubishi Chemical Corporation), 20 parts by mass of ester wax (“Nissan Electol (registered trademark) WEP-3” manufactured by NOF Corporation) was mixed. For example, in the production of toner TA-1, 180 parts by mass of crystalline polyester resin CPES-1, 1620 parts by mass of amorphous polyester resin APES-1, 60 parts by mass of elastomer ER-4, 120 parts by mass Carbon black (MA100) and 20 parts by mass of ester wax (Nissan Electol WEP-3) were mixed. Further, in the production of the toner TB-1, no third binder resin (thermoplastic elastomer) was added.

Elastomer ER-1 was a thermoplastic elastomer ("Tuftec (registered trademark) M1943" manufactured by Asahi Kasei Corporation, component: acid-modified styrene / ethylene / butylene / styrene block copolymer).
The elastomer ER-2 was a thermoplastic elastomer ("Tuftec (registered trademark) M1941" manufactured by Asahi Kasei Corporation, component: acid-modified styrene / ethylene / butylene / styrene block copolymer).
Elastomer ER-3 was a thermoplastic elastomer (“Tuftec (registered trademark) M1911” manufactured by Asahi Kasei Corporation, component: acid-modified styrene / ethylene / butylene / styrene block copolymer).
The elastomer ER-4 was a thermoplastic elastomer (“Tuftec (registered trademark) MP10” manufactured by Asahi Kasei Corporation, component: amine-modified styrene / ethylene / butylene / styrene block copolymer).
Table 5 shows the physical properties of the elastomers ER-1 to ER-4.

ISO 1183 is a standard that prescribes “a method for measuring the density and specific gravity of plastic-non-foamed plastic”.
ISO 1133 is a standard that stipulates “Plastic-thermoplastic melt mass flow rate (MFR) and melt volume flow rate (MVR) test methods”.
ISO7619 is a standard that prescribes “vulcanized rubber and thermoplastic rubber—how to obtain hardness”.
ISO 37 is a standard that prescribes “vulcanized rubber and thermoplastic rubber—how to obtain tensile properties”.
ISO 527 is a standard that prescribes “plastics—test method for tensile properties”.

  Each of the elastomers ER-1 to ER-4 is a polymer of one or more styrene monomers and one or more olefin monomers having 2 to 4 carbon atoms (more specifically, styrene / ethylene / butylene / styrene block) Copolymer). Elastomer ER-1 contained a styrenic monomer in a proportion of 20% by mass relative to the total amount of monomers (see “Styrene / Ethylene / Butylene (mass ratio)” in Table 5). Each of the elastomers ER-2 to ER-4 contained a styrene monomer at a ratio of 30% by mass with respect to the total amount of the monomers (see “styrene / ethylene butylene (mass ratio)” in Table 5).

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 170 rpm, and a set temperature (cylinder temperature) of 95 ° C. Was melt kneaded. Thereafter, the obtained kneaded material was cooled. Subsequently, the cooled kneaded material was coarsely pulverized using a pulverizer (“Rotoplex 16/8” manufactured by Toa Machinery Co., Ltd.). Subsequently, the obtained coarsely pulverized product was finely pulverized using a pulverizer (“Turbo Mill RS type” manufactured by Freund Turbo 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, substantially spherical pre-treatment particles (toner mother particles before mechanical treatment described later) were obtained. The volume-median diameter (D ₅₀ ) of the obtained pre-treatment particles (powder) was 10 μm.

  After the preparation of the pre-treatment particles, 200 parts by mass of the pre-treatment particles (powder) were put into 1000 parts by mass of a 10 mass% aqueous sodium dodecyl sulfate solution to obtain a dispersion of pre-treatment particles. Using a high-pressure emulsifier (formerly “NANO3000” manufactured by Miki Co., Ltd.), the pre-treatment particles in the dispersion were subjected to a dispersion treatment (more specifically, a treatment for applying a shearing force). As a result, toner base particles (powder) having the shapes (major axis diameter, minor axis diameter, and aspect ratio) shown in Table 6 described later were obtained. The aspect ratio can be adjusted by changing the dispersion processing conditions (processing temperature, processing pressure, and processing time). For example, in the production of the toner TA-1, a dispersion process was performed for 10 minutes under the conditions of a temperature of 80 ° C. and a pressure of 80 MPa. As the processing pressure is increased and the processing time is increased, the aspect ratio of the processed particles (toner base particles) tends to increase. In the production of the toner TB-9, the dispersion process was not performed, and the pre-treatment particles were used as toner base particles as they were.

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

(Drying process)
Subsequently, the washed wet cake-like toner mother 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 toner base particles (powder) were obtained.

(External addition process)
Subsequently, 100 parts by mass of toner base particles and dry silica particles (“HDK (registered trademark) H30TA” manufactured by Wacker Chemie), surface treatment agent: Dimethylsiloxane, BET specific surface area: about 300 m ² / g) 2 parts by mass were mixed for 5 minutes. As a result, the external additive (silica particles) adhered to the surface of the toner base particles. Then, sieving was performed using a 300 mesh sieve (aperture 48 μm). As a result, toners containing a large number of toner particles (toners TA-1 to TA-9 and TB-1 to TB-11 shown in Tables 1 and 2) were obtained.

  As a result of measuring the major axis diameter, minor axis diameter, aspect ratio, internal cohesive force, and interfacial adhesion of each of toners TA-1 to TA-9 and TB-1 to TB-11 obtained as described above. Was as shown in Table 6.

  For example, for toner TA-1, the major axis diameter was 7.2 μm, the minor axis diameter was 6.8 μm, the aspect ratio was 1.1, the internal cohesion was 5.1 N, and the interfacial adhesion was 17.5 nN. The measuring methods of the major axis diameter, minor axis diameter, aspect ratio, internal cohesive force, and interfacial adhesion force were as follows.

<Measurement method of major axis diameter, minor axis diameter, and aspect ratio>
A sample (toner) is uniformly dispersed on the upper surface of a smooth plate, and the upper surface of the plate is enlarged 1000 times from above the plate using a scanning electron microscope (“JSM-6700F” manufactured by JEOL Ltd.). Photographing was performed to obtain a two-dimensional projection image (specifically, an SEM photograph) of the toner particles on the plate. The major axis diameter, minor axis diameter, and aspect ratio (= major axis diameter / minor axis diameter) were measured for each of 100 toner particles (each measurement object) included in the sample (toner). The total value of the 100 major axis diameters obtained was divided by the number (100) of toner particles to be measured to obtain the major axis diameter (number average value) of the toner particles in the sample (toner). Further, the total value of the 100 short axis diameters obtained is divided by the number (100) of toner particles to be measured to obtain the short axis diameter (number average value) of the toner particles in the sample (toner). It was. Further, the total value of the 100 aspect ratios obtained was divided by the number (100) of toner particles to be measured to obtain the aspect ratio (number average value) of the toner particles in the sample (toner).

<Measurement method of internal cohesive force>
As a measuring apparatus, an apparatus 100 as shown in FIG. 2 was used. The apparatus 100 includes a fixed unit 400, a pressure unit (movable unit) 200, a drive unit 101, and a control unit 102 for controlling the drive unit 101. The fixing unit 400 includes a stage 401, a thermocouple 402, and a heater 403 (first heater). The stage 401 was an aluminum stage having a thickness of 3 mm. A thermocouple 402 for detecting the temperature of the stage 401 was attached to the stage 401. The heater 403 was a heater for heating the stage 401. The pressurizing unit 200 is configured such that an aluminum cylindrical indenter 204, a heater 202 (second heater) for detecting the temperature of the indenter 204, and a load cell 201 are integrated in this order from the front end side. It had been. The tip surface of the indenter 204 was covered with a polyimide resin film 205 (thickness: 5 mm, surface roughness: 1.5 μm). A thermocouple 203 for detecting the temperature of the indenter 204 was attached to the indenter 204. The drive unit 101 is configured to drive the pressure unit 200 to displace the pressure unit 200 in a vertical direction (Z direction) orthogonal to the surface direction of the stage 401 (the direction of the XY plane). . The control unit 102 is a computer, and includes a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM). The control unit 102 is configured to control the displacement (displacement amount and displacement speed) of the pressurizing unit 200 in the Z direction by controlling the drive unit 101 based on the input signal. The temperature (electric signal) detected by the thermocouple 402, the temperature (electric signal) detected by the thermocouple 203, and the load (electric signal) detected by the load cell 201 are input to the control unit 102. It was.

Using the apparatus 100, the interfacial adhesion force of the toner was measured by the following procedure. First, the pressurizing unit 200 and the stage 401 are moved using the heater 403 and the heater 202 in a state where the pressurizing unit 200 is sufficiently raised (that is, the pressurizing unit 200 is sufficiently separated from the stage 401). Each was heated to 150 ° C. Subsequently, with the temperature of each of the pressure unit 200 and the stage 401 maintained at 150 ° C., 1.0 g / cm ² of toner (sample 301) is placed on the stage 401, and the pressure unit 200 is placed on the stage. The toner (sample 301) on the stage 401 was pressurized for 30 seconds with a pressure of 10 N / cm ² using the pressure unit 200. Subsequently, the pressurizing unit 200 is moved away from the stage 401 at a speed of 60 mm / second (while being raised) and the load cell 201 is used until the pressurizing unit 200 rises by 10 cm from the start of pressurization. The maximum load applied between the stage 401 and the stage 401 was measured. The maximum value of the measured load corresponds to the internal cohesive force of the toner.

<Measurement method of interfacial adhesion>
As a measuring device, an SPM probe station (“NanoNaviReal” manufactured by Hitachi High-Tech Science Co., Ltd.) equipped with a scanning probe microscope (SPM) (“Multifunctional Unit AFM5200S” manufactured by Hitachi High-Tech Science Co., Ltd.) was used. Prior to the measurement, an average toner particle is selected from the toner particles contained in the sample (toner) using a scanning electron microscope (SEM) (“JSM-6700F” manufactured by JEOL Ltd.). Toner particles were measured.

(SPM measurement conditions)
・ Moveable range of measurement unit (size of sample that can be measured): 100 μm (Small Unit)
Measurement probe: Cantilever ("SI-DF3-R" manufactured by Hitachi High-Tech Science Co., Ltd., tip radius: 30 nm, probe coating material: rhodium (Rh), spring constant: 1.6 N / m, resonance frequency: 26 kHz)
Measurement mode: SIS-DFM (SIS: sampling intelligent scan, DFM: dynamic force mode)
・ Measurement range (one field of view): 1μm × 1μm
・ Resolution (X data / Y data): 256/256

  In the environment of temperature 25 ° C. and humidity 50% RH, the measurement range (XY plane: 1 μm × 1 μm) of the surface of the measurement object (toner particles) is scanned horizontally with a cantilever in the measurement mode (SIS-DFM). The AFM force curve was measured to obtain a mapping image regarding the interfacial adhesion force. The AFM force curve is a curve showing the relationship between the distance between the probe (tip end of the cantilever) and the toner particles and the force (deflection amount) acting on the cantilever. From the AFM force curve, the interfacial adhesion force of the toner particles (the force necessary for the cantilever to move away from the surface of the toner particles) is obtained. In the measurement apparatus, the pressing force (deflection signal) of the cantilever is detected by an optical lever method. Specifically, the semiconductor laser device emits laser light toward the back surface of the cantilever, and the position sensor detects the laser light (flex signal) reflected from the back surface of the cantilever.

  Based on the mapping image relating to the interfacial adhesion obtained as described above, the interfacial adhesion of the toner base particles was determined. In the above measurement, with the external additive attached to the surface of the toner base particle, a cantilever is applied to the surface area of the toner base particle where the external additive is not attached, and a mapping image regarding the interfacial adhesion force is obtained. Obtained. For the five toner particles contained in the sample (toner), the interfacial adhesion force was measured at 10 locations per sample, and 50 measured values were obtained per sample (toner). Then, the arithmetic average of 50 measurement values was used as the evaluation value (interface adhesion force) of the sample (toner).

[Evaluation method]
The evaluation method of each sample (toners TA-1 to TA-9 and TB-1 to TB-11) is as follows.

(Heat resistant storage stability)
2 g of the sample (toner) was put in a 20 mL polyethylene container, and the container was left in a thermostat set at 60 ° C. for 3 hours. Thereafter, the toner taken out from the thermostat was cooled to room temperature to obtain an evaluation toner.

Subsequently, the obtained toner for evaluation was placed on a sieve having a known mass of 200 mesh (aperture 75 μm). Then, the mass of the sieve containing the toner was measured, and the mass of the toner on the sieve (the mass of the toner before sieving) was determined. Subsequently, a sieve was set on a powder tester (manufactured by Hosokawa Micron Co., Ltd.), 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 evaluation toner was sieved. Then, the mass of the toner remaining on the sieve (the mass of the toner after sieving) was determined by measuring the mass of the sieve containing the toner after sieving. From the mass of the toner before sieving and the mass of the toner after sieving, the degree of aggregation (unit: mass%) was determined based on the following formula.
Aggregation degree = 100 × mass of toner after sieving / mass of toner before sieving

  When the degree of aggregation was less than 10% by mass, it was evaluated as “good”, and when the degree of aggregation was 10% by mass or more, it was evaluated as “poor” (not good).

(Preparation of developer for evaluation)
100 parts by weight of a developer carrier (carrier for “TASKalfa 5550ci” manufactured by Kyocera Document Solutions Co., Ltd.) and 10 parts by weight of a sample (toner) are mixed for 30 minutes using a ball mill, and a developer for evaluation (two components) Developer) was prepared.

(Releasability, low temperature fixability)
An image was formed using the developer for evaluation (two-component developer) prepared as described above, and the releasability and low-temperature fixability of the toner were evaluated. As an evaluator, a printer having a Roller-Roller type heat and pressure type fixing device (an evaluator in which “FS-C5250DN” manufactured by Kyocera Document Solutions Co., Ltd. was modified to change the fixing temperature) was used. The evaluation developer 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 above-mentioned evaluation machine, a linear speed of 200 mm / second and a toner applied amount of 1.0 mg / cm on a paper having a basis weight of 90 g / m ² (A4 size printing paper) in an environment of a temperature of 25 ° C. and a humidity of 50% RH. ^Under the condition ² , a solid image having a size of 25 mm × 25 mm (specifically, an unfixed toner image) was formed. Subsequently, the paper on which the image was formed was passed through the fixing device of the evaluation machine. The nip passage time was 40 milliseconds.

  The measuring range of the fixing temperature was 100 ° C. or higher and 200 ° C. or lower. Specifically, the fixing temperature of the fixing device is increased from 100 ° C. by 5 ° C., and at each fixing temperature, it is determined whether or not the paper is wound around the fixing roller (heating roller), and the solid image (toner image) is displayed on the paper. It was determined whether or not it was able to be fixed.

  Whether or not the toner could be fixed was confirmed by a rubbing test as shown below. 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. If the measured peeling length was 1 mm or less, it was determined that the toner image was fixed on the paper.

  The lowest fixing temperature at which the toner image could be fixed on the paper was defined as the lowest fixing temperature. With regard to toner releasability, when the paper is wound around the fixing roller at a fixing temperature lower than the minimum fixing temperature (that is, before measuring the minimum fixing temperature), it is evaluated as x (not good), and the paper is fixed. When the minimum fixing temperature could be measured without winding around a roller, it was evaluated as “good”. When the paper was wound around the fixing roller, it could not be determined whether or not the toner image was fixed on the paper.

  Regarding the low-temperature fixability of the toner, it was evaluated as good (good) if the minimum fixing temperature was 135 ° C. or lower, and evaluated as x (not good) if the minimum fixing temperature exceeded 135 ° C.

(Image density, cleanability, toner scattering)
An image was formed using the developer for evaluation (two-component developer) prepared by the above-described method, and the image density, cleaning property, and toner scattering were evaluated. A multifunction machine (“TASKalfa 500ci” manufactured by Kyocera Document Solutions Inc.) was used as an evaluation machine. The evaluation developer 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, a printing durability test was performed in which 200,000 sheets were continuously printed at a printing rate of 5.0% under a normal temperature and normal humidity environment (temperature 20 ° C., humidity 50% RH).

After the printing durability test, a sample image including a solid portion and a blank portion is formed on a recording medium (evaluation paper) using an evaluation machine, and a reflection densitometer (“RD914” manufactured by X-Rite) is used. The image density (ID) of the solid part was measured. The measured image density was evaluated according to the following criteria.
When the image density was 1.3 or more, it was evaluated as ◯ (good), and when the image density was less than 1.3, it was evaluated as bad (x).

After the printing durability test, the photosensitive drum was taken out of the evaluator, the state of fixing of the sample (toner) to the photosensitive drum was visually confirmed, and the toner cleaning property was evaluated according to the following criteria.
Good (◯): The toner did not adhere to the surface of the photosensitive drum.
Bad (x): Toner adhered to the surface of the photosensitive drum.

After the printing durability test, the entire sample (toner) scattered in the developing device of the evaluation machine was collected. Then, the mass of the collected toner was measured, and the measured mass of toner (toner scattering amount) was evaluated according to the following criteria.
Good (◯): The amount of toner scattering was 100 mg or less.
Not good (x): Toner scattering amount was more than 100 mg.

[Evaluation results]
For each of toners TA-1 to TA-9 and TB-1 to TB-11, heat-resistant storage stability (aggregation degree), low-temperature fixability (minimum fixing temperature), releasability (whether paper is wound around the fixing roller) Table 7 shows the results of evaluation of image density, cleanability (whether toner adheres to the surface of the photosensitive drum), and toner scattering (whether the toner scattering amount is within an allowable range).

  The toners TA-1 to TA-9 (toners according to Examples 1 to 9) each had the above-described basic configuration. Specifically, in toners TA-1 to TA-9, the toner particles each contained an amorphous polyester resin and a thermoplastic elastomer as a binder resin. The thermoplastic elastomer was a polymer of one or more styrene monomers and one or more olefin monomers (specifically, a styrene / ethylene / butylene / styrene block copolymer). The major axis diameter of the toner particles is 6.0 μm or more and 10.0 μm or less in terms of the number average value, the minor axis diameter of the toner particles is 3.0 μm or more and 7.0 μm or less in terms of the number average value, and the aspect ratio of the toner particles is The number average value was 1.1 or more and 2.0 or less (see Table 6). The internal cohesion force of the toner was 5.0 N or more and 10.0 N or less (see Table 6). The interfacial adhesion force of the toner was 10.0 nN or more and 30.0 nN or less (see Table 6).

  As shown in Table 7, each of the toners TA-1 to TA-9 was excellent in heat resistant storage stability, low-temperature fixability, and releasability. Further, in continuous printing using these toners, an image having an appropriate image density is formed while suppressing toner fixation (specifically, toner adhesion to the surface of the photosensitive drum) and toner scattering in the image forming apparatus. I was able to.

  The toners TB-1 and TB-2 (the toners according to Comparative Examples 1 and 2) were inferior in low-temperature fixability as compared with the toners TA-1 to TA-9, respectively. It is presumed that the toners TB-1 and TB-2 did not use the thermoplastic elastomer (or used a small amount).

  Toner TB-3 (toner according to Comparative Example 3) was inferior in releasability as compared with toners TA-1 to TA-9. By including an excessive amount of the thermoplastic elastomer in the toner particles, the influence of the viscosity derived from the elastomer appears on the surface of the toner particles, and it is considered that the interfacial adhesion force of the toner is increased.

  The toners TB-4, TB-6, TB-10, and TB-11 (the toners according to Comparative Examples 4, 6, 10, and 11) each had a large amount of toner scattering. This reason is presumed to be because the interfacial adhesion force of the toner was insufficient.

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

DESCRIPTION OF SYMBOLS 10 Toner 11 Toner particle 100 Apparatus 101 Drive part 102 Control part 200 Pressurization part 201 Load cell 202 Heater (2nd heater)
203 Thermocouple 204 Indenter 400 Fixed part 401 Stage 402 Thermocouple 403 Heater (first heater)

Claims (4)

An electrostatic latent image developing toner comprising a plurality of toner particles containing a binder resin,
The toner particles contain an amorphous polyester resin and a thermoplastic elastomer as the binder resin,
The thermoplastic elastomer is a polymer of one or more styrene monomers and one or more olefin monomers,
The major axis diameter of the toner particles is 6.0 μm to 10.0 μm in terms of number average value,
The minor axis diameter of the toner particles is 3.0 μm or more and 7.0 μm or less in terms of number average value,
The aspect ratio of the toner particles is a number average value of 1.1 or more and 2.0 or less,
The toner has an internal cohesion force of 5.0 N to 10.0 N,
The toner for developing an electrostatic latent image, wherein the adhesion force of the toner interface measured based on a force curve obtained with a scanning probe microscope is 10.0 nN or more and 30.0 nN or less.
[The internal cohesion of the toner is
A 3 mm thick aluminum stage;
A first heater for heating the stage;
From the tip side, a cylindrical indenter made of aluminum coated with a polyimide resin film, a second heater for heating the indenter, and a pressurizing unit in which a load cell is integrated in this order,
A drive unit that displaces the pressurizing unit in a vertical direction perpendicular to the surface direction of the stage;
Using a measuring device comprising
A first step of heating the pressurizing unit and the stage to 150 ° C. using the first heater and the second heater,
After the first step, 1.0 g / cm ² of the toner is placed on the stage with the temperature of the pressure unit and the stage kept at 150 ° C. A second step of pressurizing the toner on the stage for 30 seconds at a pressure of 10 N / cm ² ;
After the second step, using the load cell, the pressurizing unit is moved 10 cm from the start of pressurization while the pressurizing unit is moved away from the stage at a speed of 60 mm / sec. A third step of measuring a maximum value of a load applied between the toner and the stage as an internal cohesive force of the toner;
It is measured through. ] The non-crystalline polyester resin is a polymer of monomers containing one or more bisphenols and one or more aromatic dicarboxylic acids,
The thermoplastic elastomer includes at least one styrene monomer and at least one olefin monomer having 2 to 4 carbon atoms, including a styrene monomer at a ratio of 15% by mass to 35% by mass with respect to the total amount of monomers. And a polymer
2. The electrostatic latent image developing toner according to claim 1, wherein an amount of the thermoplastic elastomer is 2.0 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin. The toner particles further contain a crystalline polyester resin,
The crystalline polyester resin includes one or more α, ω-alkanediol having 2 to 8 carbon atoms, fumaric acid, one or more styrene monomers, and 1 to 4 carbon atoms in the ester portion. It is a polymer with one or more (meth) acrylic acid alkyl esters having an alkyl group,
The electrostatic latent image developing toner according to claim 2, wherein the amount of the crystalline polyester resin is 5.0 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin.   The electrostatic latent image developing toner according to claim 1, wherein the toner is a pulverized toner.

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