JP2019020690A - toner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner excellent in heat-resistant storage property, low-temperature fixability, and document offset resistance. SOLUTION: Toner particles contain an amorphous polyester resin, a crystalline polyester resin, and a styrene-acrylic acid-based resin. The crystalline polyester resin is a polymer of a monomer containing an alcohol monomer, a carboxylic acid monomer, an acrylic acid-based monomer, and a styrene-based monomer. The temperature of the toner having a storage elastic modulus of 1.0 × 108 Pa is 55 ° C. or higher. The temperature of the toner having a storage elastic modulus of 1.0 × 105 Pa is 80 ° C. or lower. The dispersion diameter of the crystalline polyester resin in the toner particles is 100 nm or more and 500 nm or less. In the differential scanning calorimetry of the toner, the endothermic amount of the CPES endothermic peak measured at the second temperature rise is 80% or more of the heat absorption of the CPES endothermic peak measured at the first temperature rise. [Selection diagram] Fig. 3

Description

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

  Patent Document 1 discloses a technique in which toner particles contain an amorphous polyester resin, a crystalline polyester resin, and a styrene-acrylic acid resin.

Japanese Patent Laying-Open No. 2015-4722

  However, it is difficult to provide a toner excellent in heat-resistant storage stability, low-temperature fixability, and document offset resistance only by the technique disclosed in Patent Document 1. For example, in Patent Document 1, although low-temperature fixability of the toner is studied, sufficient investigation has not been made on the poor dispersion of the toner component (internal additive).

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a toner excellent in heat-resistant storage stability, low-temperature fixability, and document offset resistance.

The toner according to the present invention includes a plurality of toner particles containing an amorphous polyester resin and a crystalline polyester resin. The toner particles further contain a styrene-acrylic acid resin. The crystalline polyester resin is a polymer of monomers including an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer. The temperature of the toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa is 55 ° C. or higher. The temperature of the toner having a storage elastic modulus of 1.0 × 10 ⁵ Pa is 80 ° C. or less. A dispersion diameter of the crystalline polyester resin in the toner particles is 100 nm or more and 500 nm or less. The endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin, measured at the second temperature increase by differential scanning calorimetry of the toner, is measured at the first temperature increase by differential scanning calorimetry of the toner. 80% or more of the endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin. The measurement conditions of the differential scanning calorimetry are a measurement range of 20 ° C. to 150 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 100 ° C./min, and an interval between the first time and the second time of 10 minutes.

  According to the present invention, it is possible to provide a toner excellent in heat-resistant storage stability, low-temperature fixability, and document offset resistance.

6 is a graph showing an endothermic curve measured at the time of temperature increase in the first test of differential scanning calorimetry for the toner according to the embodiment of the present invention. 6 is a graph showing an endothermic curve measured at the time of temperature increase in a second test of differential scanning calorimetry for the toner according to the embodiment of the present invention. 6 is a graph showing a G ′ temperature dependency curve of a toner according to an exemplary embodiment of the present invention.

  An embodiment of the present invention will be described. Note that evaluation results (values indicating shape, physical properties, etc.) relating to powder (more specifically, toner base particles, external additives, toner, etc.) are included in the powder unless otherwise specified. It is the number average of the values measured for a considerable 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 measured using a laser diffraction / scattering particle size distribution measuring device (“LA-750” manufactured by Horiba, Ltd.) unless otherwise specified. It is the value. Moreover, 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.

The SP value (solubility parameter) is calculated according to the Fedors calculation method (R. F. Fedors, “Polymer Engineering and Science”, 1974, Vol. 14, No. 2, p 147-154) unless otherwise specified. Value (unit: (cal / cm ³ ) ^1/2 , temperature: 25 ° C.). The SP value is represented by the formula “SP value = (E / V) ^1/2 ” (E: molecular cohesive energy [cal / mol], V: molecular volume [cm ³ / mol]).

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

  The toner according to the exemplary embodiment can be suitably used for developing an electrostatic latent image, for example, as a positively chargeable toner. The toner of the present exemplary embodiment is a powder that includes a plurality of toner particles (each having a configuration described later). The toner may be used as a one-component developer. Alternatively, a two-component developer may be prepared by mixing toner and carrier using a mixing device (for example, a ball mill).

  In order to form a high-quality image, it is preferable to use a ferrite carrier (specifically, a powder of ferrite particles) 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 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, the developing sleeve, or the 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, a fixing device (fixing method: nip fixing with a heating roller and a pressure roller) of the electrophotographic apparatus heats and pressurizes the toner 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 this embodiment 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 particles contained in the toner according to the present embodiment may be toner particles not having a shell layer (hereinafter referred to as non-capsule toner particles), or toner particles having a shell layer (hereinafter referred to as capsule toner particles). May be described). In the capsule toner particles, the toner base particles include a toner core and a shell layer formed on the surface of the 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 shell layer may be substantially composed of a thermosetting resin, may be substantially composed of a thermoplastic resin, or may contain both a thermoplastic resin and a thermosetting resin. .

  Non-capsule toner particles can be produced, for example, by 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 particles. In general, toner is roughly classified into pulverized toner and polymerized toner (also called chemical toner). The toner obtained by the pulverization method belongs to the pulverized toner, and the toner obtained by the aggregation method belongs to the polymerized toner.

  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, toner mother particles 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 one example of the agglomeration method, first, these fine particles are aggregated in an aqueous medium containing fine particles of a binder resin, fine particles of a release agent, fine particles of a charge control agent, and fine particles of a colorant until a desired particle size is obtained. Let Thereby, aggregated particles containing a binder resin, a release agent, a charge control agent, and a colorant are formed. Subsequently, the obtained aggregated particles are heated to unite the components contained in the aggregated particles. Thereby, toner mother particles having a desired particle diameter are obtained.

  When producing the capsule toner particles, the method for forming the shell layer is arbitrary. For example, the shell layer may be formed using any one of an in-situ polymerization method, a submerged cured coating method, and a coacervation 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 an amorphous polyester resin and a crystalline polyester resin. The toner particles further contain a styrene-acrylic acid resin. The crystalline polyester resin is a polymer of a monomer (resin raw material) containing an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer. The temperature of a toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa (hereinafter sometimes referred to as “melting initial temperature TM _A ”) is 55 ° C. or higher. Storage modulus 1.0 × 10 ⁵ Pa toner temperature (hereinafter, may be referred to as "melting end temperature TM _B") is 80 ° C. or less. The dispersion diameter of the crystalline polyester resin in the toner particles is 100 nm or more and 500 nm or less. The endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin, which is measured at the second temperature increase by the differential scanning calorimetry of the toner, is measured at the first temperature increase by the differential scanning calorimetry of the toner. It is 80% or more of the endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin. The measurement conditions of the differential scanning calorimetry are a measurement range of 20 ° C. to 150 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 100 ° C./min, and an interval between the first time and the second time of 10 minutes.

Hereinafter, a storage elastic modulus temperature dependency curve (vertical axis: storage elastic modulus, horizontal axis: temperature) of a toner measured by a rheometer at a temperature rising rate of 2 ° C./min and a frequency of 6.28 radians / second is expressed as “ It is described as “G ′ temperature dependence curve”. In the basic configuration described above, the melting initial temperature TM _A and melt end temperature TM _B are each a value measured from the G 'temperature dependence curve. In addition, the measuring method of a G 'temperature dependence curve is the same method as the Example mentioned later, or its alternative method.

  In the above basic configuration, the dispersion diameter of the crystalline polyester resin in the toner particles is the number average value of the equivalent circle diameters of the crystalline polyester resin domains in the cross-sectional image of the toner particles.

  Generally, a toner having excellent heat-resistant storage stability can be obtained by adding an amorphous polyester resin to toner particles. However, it is difficult to obtain a toner excellent in both heat-resistant storage stability and low-temperature fixability.

  As a method for obtaining a toner excellent in both heat-resistant storage stability and low-temperature fixability, it is conceivable to add a crystalline polyester resin to the toner particles in addition to the amorphous polyester resin. However, unless the compatibility between the amorphous polyester resin and the crystalline polyester resin contained in the toner particles is high, the effect of the crystalline polyester resin (specifically, the effect of improving the low-temperature fixability of the toner) is small. In order to improve the low-temperature fixability of the toner, it is preferable to sufficiently reduce the dispersion diameter (specifically, the domain diameter) of the crystalline polyester resin in the toner particles. However, if the non-crystalline polyester resin and the crystalline polyester resin are too compatible in the toner particles, document offset is likely to occur. The document offset is a phenomenon in which after the toner is fixed on the recording medium by heating, the next recording medium is placed on the recording medium while the recording medium is still warm, so that the overlapping recording media adhere to each other. In order to increase the printing speed (and hence throughput) of the image forming apparatus, it is desirable to use toner that is less likely to cause document offset.

In the basic configuration described above, the measurement conditions of the differential scanning calorimetry are a measurement range of 20 ° C. to 150 ° C., a temperature rising rate of 10 ° C./min, a temperature falling rate of 100 ° C./min, and an interval between the first and second times of 10 minutes. . That is, after the temperature of the toner is increased from 20 ° C. to 150 ° C. at a temperature increase rate of 10 ° C./min, a temperature increase / decrease test is repeatedly performed twice. The second test is started after the first test is completed and the toner is allowed to stand for 10 minutes while maintaining the toner temperature at 20 ° C. An endothermic curve (vertical axis: heat flow, horizontal axis: temperature) is obtained by such differential scanning calorimetry. When the toner contains a crystalline polyester resin in a crystallized state, the endothermic peak derived from the crystallization site of the crystalline polyester resin (hereinafter referred to as “CPES endothermic peak” may be described in the endothermic curve of the toner. Appears). The endothermic amount of the CPES endothermic peak corresponds to the endothermic amount accompanying dissolution of the crystallization site of the crystalline polyester resin, and can be determined from the area of the CPES endothermic peak. In the following, the endothermic amount of the CPES endothermic peak appearing in the endothermic curve obtained during the temperature increase in the first test is “ΔH ₁ ”, and the endothermic amount of the CPES endothermic peak appearing in the endothermic curve obtained during the temperature rise in the second test. The amount of heat may be described as “ΔH ₂ ”, respectively. A value obtained by dividing ΔH ₂ by ΔH ₁ may be referred to as “CPES crystallinity index”. In the differential scanning calorimetric analysis of the toner, when all of the crystalline polyester resin dissolved by the temperature increase in the first test is crystallized again by the temperature decrease in the first test, “ΔH ₂ = ΔH ₁ ” is obtained. On the other hand, when at least a part of the melted crystalline polyester resin does not crystallize, ΔH ₂ becomes smaller than ΔH ₁ . A large CPES crystallinity index (ΔH ₂ / ΔH ₁ ) of the toner means that the crystalline polyester resin in the toner is easily crystallized.

The toner having the above-described basic configuration satisfies the relationship of the expression “ΔH ₂ ≧ 0.8 × ΔH ₁ ”. This means that in the differential scanning calorimetry analysis of the toner, most of the crystalline polyester resin dissolved by the temperature increase in the first test was recrystallized by the temperature decrease in the first test. The temperature drop rate of the differential scanning calorimetry is very fast, 100 ° C./min. The crystalline polyester resin that can be crystallized even when the temperature is lowered at this rate is the crystalline polyester resin in the basic configuration described above. That is, in the toner having the above basic configuration, the toner particles contain a crystalline polyester resin that is easily crystallized. Crystallization of the crystalline polyester resin in the toner particles lowers the compatibility between the amorphous polyester resin and the crystalline polyester resin contained in the toner particles, thereby suppressing document offset.

  Crystalline polyester resins that are easily crystallized tend to be less compatible with non-crystalline polyester resins. If the compatibility between the amorphous polyester resin and the crystalline polyester resin is insufficient, it is difficult to sufficiently reduce the dispersion diameter of the crystalline polyester resin in the toner particles. The inventor of the present application uses a polymer of monomers including an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer as the crystalline polyester resin, and the amorphous polyester resin and the crystalline polyester resin. In addition to the above, by further incorporating a styrene-acrylic acid resin into the toner particles, the dispersion diameter of the crystalline polyester resin that is easily crystallized in the toner particles has been sufficiently reduced. This is because the styrene-acrylic acid resin is compatible with the crystalline polyester resin (specifically, a polymer of monomers including an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer). It is thought that. In the basic configuration described above, the difference (absolute value) between the SP value of the styrene-acrylic acid resin and the SP value of the crystalline polyester resin is the difference between the SP value of the amorphous polyester resin and the SP value of the crystalline polyester resin. It tends to be smaller than the difference (absolute value). The presence of the crystalline polyester resin in the toner particles having a sufficiently small and not too small dispersion diameter (specifically, 100 nm or more and 500 nm or less) is considered to cause the toner to have a sharp melt property.

In general, as the toner dissolves, the storage elastic modulus of the toner tends to decrease. In the basic configuration described above, the storage elastic modulus of the toner being 1.0 × 10 ⁸ Pa means that the toner has started to melt. In a toner having a sharp melt property, when the toner starts to melt, the storage elastic modulus of the toner tends to rapidly decrease. Further, a storage elastic modulus of the toner of 1.0 × 10 ⁵ Pa means that the toner has sufficiently dissolved. When the melting initial temperature TM _A (specifically, the temperature of a toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa) is too low, the heat resistant storage stability and document offset resistance of the toner tend to be insufficient. If the end-of-melting temperature TM _B (specifically, the temperature of a toner having a storage modulus of 1.0 × 10 ⁵ Pa) is too high, the low-temperature fixability of the toner tends to be insufficient. Melt initial temperature TM _A is at temperatures above 55 ℃, and it is melting end temperature TM _B is 80 ° C. or less, in approximately temperatures above 55 ℃ 80 ° C. in a temperature range of the toner is started to melt, and the toner It means that the dissolution proceeds sufficiently. In addition, after the toner is fixed, when the toner (specifically, a toner image) fixed on the recording medium is left in a room temperature (for example, 25 ° C.) environment, the temperature of the toner quickly decreases to around 55 ° C. However, after that, the temperature of the toner tends to gradually decrease. When the melt initial temperature TM _A toner is temperatures above 55 ℃ after toner fixing quickly because the storage modulus of the toner is sufficiently large, so that the document offset is suppressed. In order to obtain a toner excellent in heat-resistant storage stability, low-temperature fixability and document offset resistance, the storage elastic modulus of the toner at a temperature of 30 ° C. is 3.0 × 10 ⁸ Pa or more, and the storage elastic modulus is 1.0 ×. It is particularly preferable that the temperature of the 10 ⁸ Pa toner is 55 ° C. or more and 60 ° C. or less, and the temperature of the toner having a storage modulus of 1.0 × 10 ⁵ Pa is 75 ° C. or more and 80 ° C. or less. In the low temperature region around 30 ° C., the storage elastic modulus of the toner tends to be substantially constant. The storage elastic modulus of the toner at a temperature of 30 ° C. corresponds to the storage elastic modulus of the toner before heating (during storage).

The melt initial temperature TM _A be at least 55 ° C., and, in order to melt the end temperature TM _B to 80 ° C. or less, in the basic configuration described above, the amount of the crystalline polyester resin in the toner particles, non-crystalline polyester 10 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the resin, and the amount of the styrene-acrylic resin in the toner particles is 30 parts by mass or more and 50 parts by mass with respect to 100 parts by mass of the amorphous polyester resin. It is particularly preferred that When the amount of the styrene-acrylic resin is too large, the dispersibility of the toner component (internal additive) is deteriorated and the sharp melt property of the toner tends to be insufficient (the toner TB-1 and TB- described later). 7). Styrene - the amount of acrylic resin is too small, a styrene to reduce the dispersion diameter of the crystalline polyester resin - the action of acrylic acid-based resin is not sufficiently obtained, that the melting end temperature TM _B to 80 ° C. or less (Refer to toners TB-3, TB-5, and TB-9 described later). If the amount of the crystalline polyester resin is too small, that the melting end temperature TM _B to 80 ° C. or less difficult (see Toner TB-2 and TB-4 will be described later). When the amount of the crystalline polyester resin is too large, many large crystalline polyester resin domains are present in the toner particles, and the sharp melt property of the toner tends to be insufficient (the toner TB-6 and the toner TB described later). TB-8). In addition, when the amount of the crystalline polyester resin is too large, the pulverizability of the toner tends to deteriorate.

In order to obtain a toner suitable for image formation, the SP value of the styrene-acrylic acid resin is smaller than the SP value of the crystalline polyester resin, the SP value of the styrene-acrylic acid resin and the SP value of the crystalline polyester resin. Is preferably smaller than the difference (absolute value) between the SP value of the amorphous polyester resin and the SP value of the crystalline polyester resin. In a particularly preferred example, the SP value of the amorphous polyester resin is 10.0 (cal / cm ³ ) ^1/2 or more and 11.0 (cal / cm ³ ) ^1/2 or less, and the SP value of the crystalline polyester resin. Is 9.2 (cal / cm ³ ) ^1/2 or more and 9.9 (cal / cm ³ ) ^1/2 or less, and the SP value of the styrene-acrylic acid resin is 9.0 (cal / cm ³ ) ^{1. / 2 to} 9.7 (cal / cm ³ ) ^1/2 or less.

  In order to suppress poor dispersion of the toner component (internal additive) in the pulverized toner, the amorphous polyester resin contains an aliphatic diol having 2 to 6 carbon atoms as an alcohol component, does not contain bisphenol, and does not contain acid. It is preferable that an aromatic dicarboxylic acid is included as a component and the crystalline polyester resin does not include an aromatic monomer as an alcohol component or an acid component.

  1 and 2 each show an endothermic curve (vertical axis: heat flow (DSC signal), horizontal axis: temperature) measured for an example of the toner having the above-described basic configuration using a differential scanning calorimeter. . The measurement conditions are a temperature range of 20 ° C. to 150 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 100 ° C./min, and an interval between the first and second times of 10 minutes. FIG. 1 shows a CPES endothermic peak in an endothermic curve measured at the time of temperature increase in the first test. FIG. 2 shows a CPES endothermic peak in the endothermic curve measured at the time of temperature increase in the second test.

From the area S1 of the CPES endothermic peak shown in FIG. 1, ΔH _{1 of} the toner (specifically, the endothermic amount of the CPES endothermic peak appearing in the endothermic curve obtained at the time of temperature increase in the first test) can be obtained. Further, from the area S2 of the CPES endothermic peak shown in FIG. 2, ΔH _{2 of} the toner (specifically, the endothermic amount of the CPES endothermic peak appearing in the endothermic curve obtained at the time of temperature increase in the second test) can be obtained. .

FIG. 3 shows a G ′ temperature dependency curve (vertical axis: storage elastic modulus, horizontal axis: temperature) measured for an example of the toner having the above-described basic configuration using a rheometer. Specifically, FIG. 3 shows the storage elasticity of toner at each temperature under the condition of frequency 6.28 radians / second while increasing the toner temperature at a constant rate (temperature increase rate 2 ° C./min) using a rheometer. It is the result of measuring the rate. In the G ′ temperature dependence curve shown in FIG. 3, the storage elastic modulus decreases as the toner temperature increases. As shown in FIG. 3, the initial melting temperature TM _A (specifically, the temperature of a toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa) is 55 ° C. or more, and the final melting temperature TM _B (specifically, the storage elastic modulus). The temperature of the toner of 1.0 × 10 ⁵ Pa is 80 ° C. or less. That is, both the melt initial temperature TM _A and the melting end temperature TM _B is present in the temperature range of 80 ° C. 55 ° C. or higher. The storage elastic modulus of the toner at a temperature of 30 ° C. was 3.0 × 10 ⁸ Pa. In the G ′ temperature dependence curve shown in FIG. 3, the storage elastic modulus of the toner is substantially constant in a low temperature region around 30 ° C.

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

  Next, the configuration of the non-capsule toner particles will be described. Specifically, the toner base particles (binder resin and internal additive) and the external additive will be described in order. In the capsule toner particles, the toner base particles in the non-capsule toner particles shown below can be used as the toner core.

[Toner mother particles]
The toner base particles contain a binder resin. The toner base particles may contain an internal additive (for example, a colorant, a release agent, a charge control agent, and a magnetic powder).

(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. For example, when the binder resin has an ester group, a hydroxyl group, an ether group, an acid group, or a methyl group, the toner base particles tend to be anionic, and when the binder resin has an amino group, The toner base particles tend to be cationic.

  In the toner having the basic configuration described above, the toner base particles contain a crystalline polyester resin, an amorphous polyester resin, and a styrene-acrylic acid resin as a binder resin.

  The polyester resin is obtained by polycondensation of one or more polyhydric alcohols and one or more polyhydric carboxylic acids. However, in order to obtain the crystalline polyester resin defined by the basic constitution described above, it is necessary to polycondensate acrylic monomers and styrene monomers in addition to alcohol and carboxylic acid. As the alcohol for synthesizing the polyester resin, for example, a dihydric alcohol (more specifically, an aliphatic diol or bisphenol) or a trihydric or higher alcohol as shown below can be preferably used. As the carboxylic acid for synthesizing the polyester resin, for example, divalent carboxylic acids or trivalent or higher carboxylic acids as shown below can be suitably used.

  Suitable examples of 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), unsaturated dicarboxylic acid (more specifically, maleic acid, fumaric acid, citraconic acid, itaconic acid, Or glutaconic acid or the like), or cycloalkane dicarboxylic acid (more specifically, cyclohexane dicarboxylic acid or the like).

  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 styrene-acrylic acid resin is a copolymer of one or more styrene monomers and one or more acrylic monomers.

  In order to synthesize the crystalline polyester resin and the styrene-acrylic acid resin contained in the toner base particles, for example, styrene monomers and acrylic monomers as shown below can be preferably used.

  Preferable examples of the styrene monomer include styrene, alkyl styrene (more specifically, α-methyl styrene, p-ethyl styrene, 4-tert-butyl styrene, etc.), p-hydroxy styrene, m-hydroxy styrene. , Halogenated styrene (more specifically, monochlorostyrene, dichlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, 2,4,6-tribromostyrene, or the like).

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

  In order to obtain a toner suitable for image formation, in the above-mentioned basic structure, the non-crystalline polyester resin comprises 1,2-propanediol, aromatic dicarboxylic acid (for example, terephthalic acid) and trivalent carboxylic acid (for example, A monomer (resin raw material) containing α, ω-alkanediol (preferably α, ω-alkanediol having 4 to 10 carbon atoms). A divalent carboxylic acid (preferably an unsaturated dicarboxylic acid having 4 to 10 carbon atoms), a styrene monomer (for example, styrene), and a (meth) acrylic acid alkyl ester (preferably having 2 to 8 carbon atoms in the ester moiety). A methacrylic acid alkyl ester having the following alkyl group) and a polymer of a monomer (resin raw material), Tylene monomer (for example, styrene), (meth) acrylic acid aminoalkyl ester (more specifically, aminoethyl acrylate or 2- (dimethylamino) ethyl methacrylate) and a crosslinking agent (for example, divinylbenzene) Particularly preferred is a polymer of a monomer (resin raw material) containing

  As the 1,2-propanediol for synthesizing the amorphous polyester resin (binder resin), plant-derived 1,2-propanediol is particularly preferable. Plant-derived 1,2-propanediol can be produced using, for example, chemical synthesis, fermentation, or a combination of these methods. In an example of a method for producing a plant-derived 1,2-propanediol, plant biomass containing a saccharide such as glucose is hydrolyzed to obtain glycerin. Subsequently, plant-derived 1,2-propanediol is obtained by reacting glycerin with hydrogen. As the plant biomass, for example, one or more vegetable oils and fats selected from the group consisting of soybean oil, palm oil, palm oil, castor oil, and cacao oil can be used. As a method for hydrolyzing plant biomass, a chemical method using an acid or a base may be employed, a biological method using an enzyme or a microorganism may be employed, or another method may be employed. Also good.

(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 multiple 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.

[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. 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. 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.

  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. Table 1 shows toners TA-1 to TA-6 and TB-1 to TB-9 (respectively positively chargeable toners) according to Examples or Comparative Examples.

In Table 1, regarding the crystalline polyester resin, “CPES-1” and “CPES-2” were respectively crystalline polyester resins CPES-1 and CPES-2 prepared by the method described later.
In Table 1, regarding styrene-acrylic acid resins, “SAc-1” and “SAc-2” were crosslinked styrene-acrylic resins SAc-1 and SAc-2 prepared by the methods described later, respectively. .
“Amount (unit: part by mass)” in Table 1 indicates a relative amount 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-6 and TB-1 to TB-9 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.

[Preparation of materials]
(Preparation method of non-crystalline polyester resin)
First, palm oil which is a vegetable oil was hydrolyzed to obtain glycerin. Specifically, palm oil and a 10% by weight aqueous sodium hydroxide solution having a concentration twice as much as that required to completely saponify the palm oil were added to the reaction vessel. Subsequently, the container contents were heated to completely saponify palm oil (vegetable oil) at a temperature of 150 ° C. The glycerin aqueous solution was separated from the saponified container contents, and the resulting glycerin aqueous solution was distilled. Activated carbon treatment was performed on the glycerin after distillation to purify glycerin.

Next, 200 g of ethylene glycol and 76 g of cupric nitrate trihydrate were added into a reaction vessel equipped with a reflux condenser. Subsequently, after the container contents were stirred at a temperature of 80 ° C. for 2 hours, 52 g of tetraethoxysilane was added dropwise, and the container contents were further stirred at a temperature of 80 ° C. for 2 hours. Thereafter, 18 g of water was dropped into the container, and then the contents of the container were stirred at a temperature of 80 ° C. for 3 hours to obtain a precipitate in the container. The obtained precipitate was dried at a temperature of 120 ° C. and then calcined in air at a temperature of 400 ° C. for 2 hours to obtain a copper / silica catalyst (copper content: 50 mass%). An aqueous solution containing 29.8 mg of tetraammineplatinum (II) nitrate [Pt (NH ₃ ) ₄ (NO ₃ ) ₂ ] was added to 3 g of the obtained copper / silica catalyst, and the mixture was dried to dryness using a rotary evaporator. The obtained solid was dried at a temperature of 120 ° C. and then calcined in the air at a temperature of 400 ° C. for 2 hours. /0.5/17).

Subsequently, 2 g of the copper-platinum / silica catalyst obtained as described above and 200 g of glycerin (purified glycerin) obtained by the above procedure were added to a 500 mL iron autoclave with a stirrer, and the air in the autoclave Was replaced with hydrogen. Subsequently, the temperature inside the autoclave is raised to 230 ° C., and hydrogen gas is introduced into the autoclave at a rate of 5 L / min, while the autoclave is in a hydrogen (H ₂ ) atmosphere, a pressure of 2 MPa, and a temperature of 25 ° C. The inner material (liquid) was reacted for 7 hours to obtain a reaction product (liquid). The resulting reaction product was purified according to a conventional method to obtain plant-derived 1,2-propanediol.

  A 5-L four-necked flask equipped with a stirrer (As One Co., Ltd. “SM-104”), a nitrogen introducing tube, a thermocouple, a dehydrating tube, and a rectifying column was used as a reaction vessel. In this reaction vessel, 1142 g of plant-derived 1,2-propanediol (alcohol component) prepared as described above, 1743 g of terephthalic acid (carboxylic acid component), and 4 g of tin (II) dioctanoate (condensation catalyst) And added. While removing water produced by the reaction, the contents of the container were reacted at a temperature of 230 ° C. for 15 hours under an atmospheric pressure of a nitrogen atmosphere. Thereafter, the pressure in the container was reduced to 8.3 kPa, and the contents of the container were further reacted for 1 hour under conditions of a pressure of 8.3 kPa and a temperature of 230 ° C.

  Subsequently, the pressure in the container was returned to atmospheric pressure, the temperature in the container was lowered to 180 ° C., and 288 g of trimellitic anhydride was added to the container. Thereafter, the temperature in the container was raised to 210 ° C. at a rate of 10 ° C./hour. Subsequently, the contents of the container were reacted for 10 hours at 210 ° C. under atmospheric pressure. Subsequently, the pressure in the container was reduced to 20 kPa, and the contents of the container were further reacted for 1 hour under the conditions of a pressure of 20 kPa and a temperature of 230 ° C. After completion of the reaction, the contents of the container were taken out and cooled. As a result, an amorphous polyester resin was obtained.

(Method for Preparing Crystalline Polyester Resin CPES-1)
In a 5 L four-necked flask equipped with a thermometer (thermocouple), dehydration tube, nitrogen introduction tube, and stirrer, 990 g of 1,4-butanediol (alcohol component) and 242 g of 1,6-hexanediol (Alcohol component), 1480 g of fumaric acid (acid component), and 2.5 g of 1,4-benzenediol were added. Subsequently, the contents of the flask were reacted at a temperature of 170 ° C. for 5 hours. Subsequently, the flask contents were reacted at a temperature of 210 ° C. for 1.5 hours. Subsequently, the contents of the flask were reacted for 1 hour in a reduced pressure atmosphere (pressure 8 kPa) and a temperature of 210 ° C. Subsequently, the atmosphere was returned to normal pressure, and 69 g of styrene (styrene-acrylic acid component) and 54 g of n-butyl methacrylate (styrene-acrylic acid component) were placed in the flask. Subsequently, the flask contents were reacted at a temperature of 210 ° C. for 1.5 hours. Subsequently, the contents of the flask were reacted for 1 hour in a reduced pressure atmosphere (pressure 8 kPa) and a temperature of 210 ° C. As a result, a crystalline polyester resin CPES-1 having an SP value of 9.9 (cal / cm ³ ) ^1/2 was obtained.

(Method for preparing crystalline polyester resin CPES-2)
In the “Preparation Method of Crystalline Polyester Resin CPES-1”, the monomer composition ratio was changed to obtain a crystalline polyester resin CPES-2 having an SP value of 9.6 (cal / cm ³ ) ^1/2 .

(Method for Preparing Crosslinked Styrene-Acrylic Acid Resin SAc-1)
In a reaction vessel equipped with a stirrer and a thermometer, 5058 g of ion-exchanged water, 14 g of sodium sulfate, and an antifoaming agent (polyoxyalkylene pentaerythritol ether: NODIS Corporation (registered trademark) CE-457) ) 60g. Subsequently, 6740 g of 2- (dimethylamino) ethyl methacrylate, 2136 g of styrene, 10 g of a crosslinking agent (divinylbenzene having a purity of 56.5%), 75 g of a polymerization initiator (BPO: benzoyl peroxide), and t-butyl 14 g of peroxy-2-ethylhexyl monocarbonate (“Trigonox (registered trademark) 117” manufactured by Kayaku Akzo Co., Ltd.) was added. The temperature of the container contents was 40 ° C. Subsequently, while stirring the container contents, the temperature of the container contents is increased from 40 ° C. to 130 ° C. over 65 minutes, and the container contents are further heated for 2 hours after the temperature of the container contents reaches 130 ° C. The product was reacted (specifically, polymerization reaction). Thereafter, the contents of the container were cooled to obtain a dispersion of a crosslinked styrene-acrylic acid resin. The obtained dispersion was filtered (solid-liquid separation) with a metal mesh having an opening of 2 mm to obtain resin particles (powder). Subsequently, fine powder in the obtained resin particles (powder) was removed using a nylon filter cloth. Thereafter, a crosslinked styrene-acrylic acid resin SAc-1 having an SP value of 9.6 (cal / cm ³ ) ^1/2 was obtained through a washing step and a drying step.

(Method for Preparing Crosslinked Styrene-Acrylic Acid Resin SAc-2)
In the above-mentioned “Preparation Method of Crosslinked Styrene-Acrylic Acid Resin SAc-1,” the monomer composition ratio was changed, and the crosslinked styrene-acrylic acid resin SAc- having an SP value of 9.4 (cal / cm ³ ) ^1/2 was obtained. 2 was obtained.

[Toner Production Method]
(Preparation of toner base particles)
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.), 100 parts by mass of an amorphous polyester resin (amorphous polyester resin obtained by the above-mentioned procedure) and the types and amounts shown in Table 1 Crystalline polyester resin (one of crystalline polyester resins CPES-1 and CPES-2 defined for each toner) and the type and amount of crosslinked styrene-acrylic acid resin (specified for each toner) shown in Table 1 Cross-linked styrene-acrylic acid resin SAc-1 or SAc-2), 3 parts by mass of ester wax (“Nissan Electol (registered trademark) WEP-9” manufactured by NOF Corporation), carbon black (Mitsubishi 5 parts by mass of “MA-100” manufactured by Chemical Co., Ltd. and quaternary ammonium salt (“BONTRON (registered trademark) P-” manufactured by Orient Chemical Co., Ltd.) 1 ") were mixed with 1 part by weight. For example, in the production of the toner TA-1, 100 parts by mass of an amorphous polyester resin, 10 parts by mass of a crystalline polyester resin CPES-1, 30 parts by mass of a crosslinked styrene-acrylic acid resin SAc-1, 3 parts by mass of ester wax (Nissan Electol WEP-9), 5 parts by mass of carbon black (MA-100), and 1 part by mass of a quaternary ammonium salt (BONTRON P-51) were mixed.

  Subsequently, the obtained mixture was melt-kneaded using a twin-screw extruder (“PCM-30” manufactured by Ikegai Co., Ltd.). Thereafter, the obtained kneaded material was cooled. Subsequently, the cooled kneaded material was coarsely pulverized using a pulverizer (“Rohtoplex (registered trademark)” manufactured by Hosokawa Micron Corporation). Subsequently, the obtained coarsely pulverized product was finely pulverized using a pulverizer (“Turbo Mill RS Model” 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, toner mother particles having a volume median diameter of 7 μm were obtained.

(External addition process)
Using an FM mixer (“FM-10B” manufactured by Nippon Coke Kogyo Co., Ltd.) under the conditions of a rotational speed of 3000 rpm and a jacket temperature of 20 ° C., 100 parts by mass of toner base particles and silica fine particles (“AEROSIL (manufactured by Nippon Aerosil Co., Ltd.)” (Registered trademark) RA-200H ”, content: 1.2 parts by mass of dry silica particles surface-modified with trimethylsilyl group and amino group, number average primary particle size: about 12 nm), conductive titanium oxide fine particles (titanium industry stock) “EC-100” manufactured by company, substrate: TiO ₂ particles, coating layer: Sb-doped SnO ₂ layer, volume median diameter: about 0.35 μm) and 0.8 parts by mass were mixed for 2 minutes. As a result, external additives (silica particles and titanium oxide 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 (toners TA-1 to TA-6 and TB-1 to TB-9) containing a large number of toner particles were obtained.

Regarding the toners TA-1 to TA-6 and TB-1 to TB-9 obtained as described above, the CPES dispersion diameter (specifically, the dispersion diameter of the crystalline polyester resin in the toner particles) and the storage elastic modulus. Table 2 shows the measurement results of the temperature characteristics (melting initial temperature TM _A and melting end temperature TM _B ) and CPES crystallinity index (ΔH ₂ / ΔH ₁ ).

For example, for toner TA-1, the CPES dispersion diameter is 260 nm, the initial melting temperature TM _A (specifically, the temperature of the toner having a storage modulus of 1.0 × 10 ⁸ Pa) is 58 ° C., and the final melting temperature TM _B (specifically, the temperature of a toner having a storage modulus of 1.0 × 10 ⁵ Pa) was 79 ° C., and the CPES crystallinity index (ΔH ₂ / ΔH ₁ ) was 0.88 (= 88%). . These measuring methods were as follows.

<Measurement method of CPES dispersion diameter>
A toner (measuring object: any of toners TA-1 to TA-6 and TB-1 to TB-9) is dispersed in a room temperature curable epoxy resin and cured in an atmosphere at a temperature of 40 ° C. for 2 days to obtain a cured product. Got. Subsequently, the obtained cured product was dyed with osmium tetroxide, and then cut out using an ultramicrotome (“EM UC6” manufactured by Leica Microsystems Co., Ltd.) equipped with a diamond knife, and a thin piece sample having a thickness of 250 μm. Got. Subsequently, a cross-section of the obtained flake sample (particularly, a cross-section of the toner base particles) was scanned with a scanning electron microscope (“JSM-7401F” manufactured by JEOL Ltd., method: FE-SEM, FE electron source: conical FE. Photographed using an electron gun). Then, the dispersion diameter (equivalent circle diameter) of the crystalline polyester resin was measured by analyzing the SEM photographed image (cross-sectional image of the toner particles) using image analysis software (“WinROOF” manufactured by Mitani Corporation).

  The number average dispersion diameter of the crystalline polyester resin domains in the cross section of the toner particles was measured. Specifically, a measurement value of the dispersion diameter of 10 crystalline polyester resin domains is obtained for a cross-sectional image of one toner particle, and the crystallinity in the cross section of the toner particle is determined based on the obtained 10 measurement values. The number average dispersion diameter of the polyester resin domain was calculated. Further, for each of the 10 toner particles contained in the toner, the number average dispersion diameter of the crystalline polyester resin domains in the cross section of the toner particles is obtained, and the arithmetic average of the 10 measured values obtained is the evaluation value of the toner ( CPES dispersion diameter).

<Measurement method of temperature characteristics of storage modulus>
0.1 g of toner (measuring object: any of toners TA-1 to TA-6 and TB-1 to TB-9) is set in a pellet molding machine, and a load of 20 kN is applied to the toner at room temperature (about 25 ° C.) for 2 minutes. In addition, a cylindrical pellet having a diameter of 10 mm and a thickness of 1 mm was obtained. Subsequently, the obtained pellets were set in a measuring device. As a measuring device, a rheometer (“ARES” manufactured by TA Instruments Japan Co., Ltd.) was used. A circular parallel plate having a diameter of 10 mm was used as the measurement plate. Then, the G ′ temperature dependency curve (vertical axis: storage elastic modulus, horizontal axis: temperature) of the toner was measured under the following conditions.

(Measurement condition)
Measurement temperature range: 50 ° C to 200 ° C
Temperature increase rate: 2 ° C./min Frequency: 6.28 radians / second Measurement interval: 15 seconds Applied strain: Automatic measurement mode (initial value: 0.1%)
Extension compensation: Automatic measurement mode

From the G ′ temperature dependency curve obtained as described above, the initial melting temperature TM _A (specifically, the temperature of a toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa) and the final melting temperature TM _B (specifically, The temperature of the toner having a storage elastic modulus of 1.0 × 10 ⁵ Pa was read.

<Measuring method of ΔH ₁ and ΔH ₂ >
As a measuring device, a TG-DSC system (“TAS-100” manufactured by Rigaku Corporation) was used. By performing the temperature rising and falling test twice using this measuring device, the endothermic curve of the toner (measuring object: any of toners TA-1 to TA-6 and TB-1 to TB-9) is measured, From the obtained endothermic curve, ΔH ₁ and ΔH ₂ of the toner were determined. Specifically, 10 mg of toner was put in an aluminum dish (aluminum container), and the aluminum dish was set in the measuring unit of the measuring device. In the measurement of the endothermic curve, the temperature of the measurement part was increased from the measurement start temperature of 20 ° C. to 150 ° C. at a rate of 10 ° C./min (RUN1). With RUN1, an endothermic curve (the vertical axis: heat flow (DSC signal) and the horizontal axis: temperature) of the toner at the first temperature increase was obtained. Thereafter, the temperature of the measurement part was lowered from 150 ° C. to 20 ° C. at a rate of 100 ° C./min. The temperature was kept at 20 ° C. for 10 minutes after the temperature reached 20 ° C. (interval between the first measurement and the second measurement). Subsequently, the temperature of the measurement part was increased again from 20 ° C. to 150 ° C. at a rate of 10 ° C./min (RUN2). With RUN2, an endothermic curve (the vertical axis: heat flow (DSC signal) and the horizontal axis: temperature) of the toner at the second temperature increase was obtained. From each of the endothermic curve of the toner at the first temperature increase and the endothermic curve of the toner at the second temperature increase obtained as described above, ΔH ₁ and ΔH _{2 of the} toner (respectively at the crystallization site of the crystalline polyester resin). The endothermic peak of the derived endothermic peak) was read. ΔH ₁ of the toner was obtained from the area of the CPES endothermic peak in the endothermic curve of the toner at the first temperature rise. The ΔH ₂ of the toner was obtained from the area of the CPES endothermic peak in the endothermic curve of the toner at the second temperature increase. Then, ΔH ₂ was divided by ΔH ₁ to obtain the CPES crystallinity index (ΔH ₂ / ΔH ₁ ) of the toner.

[Evaluation method]
The evaluation method of each sample (toners TA-1 to TA-6 and TB-1 to TB-9) is as follows.

(Heat resistant storage stability)
2 g of toner (evaluation target: any of toners TA-1 to TA-6 and TB-1 to TB-9) is put in a 20 mL polyethylene container, and the container is set in a thermostatic chamber set at a temperature of 60 ° C. It was allowed to stand for 3 hours. Thereafter, the toner taken out from the thermostat was cooled to room temperature (about 25 ° C.) to obtain an evaluation toner.

Subsequently, the obtained toner for evaluation was placed on a sieve having a known mass of 140 mesh (aperture 105 μm). 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 above sieve is set in a powder property evaluation apparatus (“Powder Tester (registered trademark)” manufactured by Hosokawa Micron Corporation), and according to the manual of the powder tester, the sieve is vibrated for 30 seconds under the conditions of the rheostat scale 5 for evaluation. The toner was sieved. After sieving, the mass of toner remaining on the sieve without passing through the sieve (the mass of toner after sieving) was measured. Based on the mass of the toner before sieving and the mass of the toner after sieving, the degree of toner aggregation (unit: mass%) was determined according to the following formula.
Toner aggregation degree = 100 × mass of toner after sieving / mass of toner before sieving

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

(Low temperature fixability)
Using a ball mill, 100 parts by mass of a developer carrier (FS-C5200DN carrier) and 5 parts by mass of a toner (evaluation target: any of toners TA-1 to TA-6 and TB-1 to TB-9) are used. Were mixed for 30 minutes to prepare a two-component developer.

  As an evaluator, a printer having a Roller-Roller type heat and pressure type fixing device (an evaluator in which “FS-C5200DN” manufactured by Kyocera Document Solutions Co., Ltd. was modified to change the fixing temperature) was used. The two-component developer prepared as described above is put into a developing device of an evaluation machine, and a replenishing toner (evaluation object: any one of toners TA-1 to TA-6 and TB-1 to TB-9) is evaluated. Into the toner container of the machine.

Using an evaluation machine under the environment of a temperature of 23 ° C. and a humidity of 50% RH, an evaluation paper (“ColorCopy (registered trademark)” manufactured by Mondi, A4 size, basis weight 90 g / m ² ) is applied to a linear speed of 105 mm / second. A black solid image (specifically, an unfixed toner image) having a size of 25 mm × 25 mm was formed under the condition of a toner loading of 1.3 mg / cm ² . Subsequently, the paper on which the image was formed was passed through the fixing device of the evaluation machine.

  In the evaluation of the minimum fixing temperature, the measuring range of the fixing temperature was 100 ° C. or higher and 150 ° C. or lower. Specifically, the fixing temperature of the fixing device was lowered from 150 ° C. by 2 ° C., and whether or not fixing was possible was determined for each fixing temperature, 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 rubbing test as shown below. Specifically, the evaluation paper passed through the fixing device was folded in half so that the surface on which the image was formed was inside, and the image on the crease was rubbed 5 times with a 1 kg brass weight covered with a fabric. . 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 130 ° C. or lower, it was evaluated as “good”, and when the minimum fixing temperature exceeded 130 ° C., it was evaluated as “poor” (not good).

(Document offset)
Of the solid images formed in the evaluation of the low-temperature fixability, the document offset was evaluated for a solid image (toner image after fixing) fixed at the minimum fixing temperature (for example, 126 ° C. for toner TA-1). Specifically, two sheets of paper on which an image (toner image fixed at the minimum fixing temperature) was formed were overlapped with the surface on which the image was formed in contact. The image formed on one paper was overlaid so as to contact both the image area and the non-image area of the other paper. Then, two stacked papers were placed on a table and a load was applied. In a state where a pressure of 16 g / cm ² was applied to the two stacked sheets, the two sheets were left in an oven set at a temperature of 75 ° C. for 1 hour. Thereafter, the two sheets of paper taken out from the oven were left in a room temperature (about 25 ° C.) atmosphere for 30 minutes. Thereafter, the two overlapped sheets were peeled off, the state of the image on each sheet was confirmed, and the document offset was evaluated according to the following criteria.
○ (Good): There was no image defect in any of the two sheets of paper.
X (not good): Image defect occurred in at least one of the two sheets.

[Evaluation results]
Table 3 shows the evaluation results for each sample (toners TA-1 to TA-6 and TB-1 to TB-9). In Table 3, “L-fixing” means low-temperature fixing property, “storability” means heat-resistant storage property, and “DO” means document offset. The evaluation results shown in Table 3 are the minimum fixing temperature for low-temperature fixability, the toner aggregation degree for heat-resistant storage stability, and the presence or absence of image defects (◯: no, x: yes) for document offset.

The toners TA-1 to TA-6 (toners according to Examples 1 to 6) each had the above-described basic configuration. Specifically, in toners TA-1 to TA-6, the toner particles contained an amorphous polyester resin, a crystalline polyester resin, and a styrene-acrylic acid resin, respectively. The crystalline polyester resin is a polymer of monomers including an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer (specifically, 1,4-butanediol, 1,6-hexanediol, and fumaric acid. And a polymer of styrene and n-butyl methacrylate) (see “Preparation Method of Crystalline Polyester Resin CPES-1” above). The initial melting temperature TM _A (specifically, the temperature of the toner having a storage elastic modulus of 1.0 × 10 ⁸ Pa) is 55 ° C. or more, and the final melting temperature TM _B (specifically, the storage elastic modulus is 1.0 × 10 ⁵ Pa). The temperature of the toner was 80 ° C. or less (see Table 2). The dispersion diameter of the crystalline polyester resin in the toner particles was 100 nm or more and 500 nm or less (see Table 2). The CPES crystallinity index (ΔH ₂ / ΔH ₁ ) of the toner was 0.80 or more (see Table 2). That is, the endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin, which is measured at the second temperature increase by the differential scanning calorimetry of the toner, is measured at the first temperature increase by the differential scanning calorimetry of the toner. It was 80% or more of the endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin.

  As shown in Table 3, the toners TA-1 to TA-6 were excellent in heat-resistant storage stability, low-temperature fixability, and document offset resistance.

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

Claims (7)

A toner comprising a plurality of toner particles containing an amorphous polyester resin and a crystalline polyester resin,
The toner particles further contain a styrene-acrylic acid resin,
The crystalline polyester resin is a polymer of monomers including an alcohol monomer, a carboxylic acid monomer, an acrylic acid monomer, and a styrene monomer,
The temperature of the toner having a storage modulus of 1.0 × 10 ⁸ Pa is 55 ° C. or higher;
The temperature of the toner having a storage modulus of 1.0 × 10 ⁵ Pa is 80 ° C. or less,
The dispersion diameter of the crystalline polyester resin in the toner particles is 100 nm or more and 500 nm or less,
The endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin, measured at the second temperature increase by differential scanning calorimetry of the toner, is measured at the first temperature increase by differential scanning calorimetry of the toner. The toner is 80% or more of the endothermic amount of the endothermic peak derived from the crystallization site of the crystalline polyester resin.
[The measurement conditions of the differential scanning calorimetry are a measurement range of 20 ° C. to 150 ° C., a temperature increase rate of 10 ° C./min, a temperature decrease rate of 100 ° C./min, and an interval between the first time and the second time of 10 minutes. ] The storage elastic modulus of the toner at a temperature of 30 ° C. is 3.0 × 10 ⁸ Pa or more,
The temperature of the toner having a storage modulus of 1.0 × 10 ⁸ Pa is 55 ° C. or higher and 60 ° C. or lower;
The toner according to claim 1, wherein the toner having a storage elastic modulus of 1.0 × 10 ⁵ Pa has a temperature of 75 ° C. or higher and 80 ° C. or lower. The amount of the crystalline polyester resin in the toner particles is 10 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin.
3. The toner according to claim 1, wherein an amount of the styrene-acrylic acid resin in the toner particles is 30 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the amorphous polyester resin. The SP value of the styrene-acrylic acid resin is smaller than the SP value of the crystalline polyester resin,
The difference between the SP value of the styrene-acrylic acid resin and the SP value of the crystalline polyester resin is smaller than the difference between the SP value of the amorphous polyester resin and the SP value of the crystalline polyester resin. Item 4. The toner according to Item 3. The toner is a pulverized toner;
The non-crystalline polyester resin contains an aliphatic diol having 2 to 6 carbon atoms as an alcohol component, does not contain bisphenol, and contains an aromatic dicarboxylic acid as an acid component,
The toner according to claim 3, wherein the crystalline polyester resin does not contain an aromatic monomer as an alcohol component or an acid component. The amorphous polyester resin is a polymer of monomers including 1,2-propanediol, aromatic dicarboxylic acid and trivalent carboxylic acid,
The crystalline polyester resin is a polymer of monomers including an α, ω-alkanediol, a divalent carboxylic acid, a styrene monomer, and a (meth) acrylic acid alkyl ester,
5. The toner according to claim 3, wherein the styrene-acrylic acid resin is a polymer of a monomer including a styrene monomer, a (meth) acrylic acid aminoalkyl ester, and a crosslinking agent.   The toner according to any one of claims 1 to 6, which is a positively chargeable toner.

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