JP6455485B2 - Electrostatic latent image developing toner and method for producing electrostatic latent image developing toner - Google Patents

Description

  The present invention relates to an electrostatic latent image developing toner (hereinafter sometimes referred to as toner) and a method for producing the toner.

  The toner includes a plurality of toner particles. The toner particles contain, for example, a binder resin. For example, the toner described in Patent Document 1 contains a crystalline polyester resin and an amorphous polyester resin as a binder resin.

JP 2006-078707 A

  However, the crystalline polyester resin tends to easily lose its charge. Therefore, it is difficult to improve the charging stability with the toner described in Patent Document 1 containing a crystalline polyester resin. Crystalline polyester has a relatively low melting point. Therefore, the toner described in Patent Document 1 containing a crystalline polyester resin has insufficient fixing properties (particularly, hot offset resistance) and blocking resistance.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a toner having excellent charging stability and fixing property. Another object of the present invention is to provide a toner manufacturing method capable of manufacturing such a toner.

The electrostatic latent image developing toner according to the present invention includes a plurality of toner particles. The toner particles contain at least a crystalline polyester resin and nigrosine. The content W ₁ of the crystalline polyester resin with respect to the mass of the toner particles and the content W ₂ of the crystalline polyester resin contained in the ethanol-soluble content of the toner particles with respect to the mass of the toner particles are expressed by the following formula. Satisfy (1). The ethanol-soluble component can be obtained by mixing 0.35 g of the toner particles and 4.00 g of ethanol for 3 minutes at a rotation speed of 100 rpm using a ball mill in an environment of 25 ° C. The nigrosine content C ₁ with respect to the mass of the toner particles and the nigrosine content C ₂ contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles satisfy the following formula (2). . The content rates W ₁ , W ₂ , C ₁ and C ₂ satisfy the following formula (3).
0.0010 ≦ 100 × W ₂ / W ₁ ≦ 0.1000 (1)
0.1000 ≦ 100 × C ₂ / C ₁ ≦ 10.000 (2)
1.00 ≦ (C ₂ / C ₁ ) / (W ₂ / W ₁ ) ≦ 1000.00 (3)

  The method for producing a toner for developing an electrostatic latent image according to the present invention includes a kneading step of kneading the crystalline polyester resin and the nigrosine. In the kneading step, part of the crystalline polyester resin and part of the nigrosine are dissolved together to obtain the above-described electrostatic latent image developing toner.

  According to the toner of the present invention, the charging stability and fixability of the toner can be improved. Further, according to the toner manufacturing method of the present invention, a toner having excellent charging stability and fixing property can be manufactured.

FIG. 4 is an electron micrograph showing an observation of toner particles contained in a toner according to an embodiment of the present invention. FIG. 6 is an electron micrograph showing an observation of toner particles contained in a comparative toner. FIG. 6 is an electron micrograph showing an observation of toner particles contained in a comparative toner. FIG. 6 is an electron micrograph showing an observation of toner particles contained in a comparative toner. FIG. 3 is a scanning probe microscope (SPM) photograph showing a cross section of toner particles in the toner according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described. Hereinafter, a compound and its derivatives may be generically named by adding “system” after the compound name. In addition, when “polymer” is added after the compound name to indicate the polymer name, it means that the repeating unit of the polymer is derived from the compound or a derivative thereof.

Hereinafter, the average value means a number average value unless otherwise specified. Further, an evaluation value (a value indicating a shape or physical property) relating to powder (for example, toner, toner particles, toner base particles and external additives described later) means a number average value unless specified. The number average value is a value obtained by dividing the sum of the values measured for a considerable number of measurement objects by the number of measurements. Further, the particle diameter of the powder is the equivalent area circle diameter of the primary particles measured with an electron microscope unless otherwise specified. The equivalent circle diameter is the diameter of a circle having the same area as the projected area of the particles. The volume median diameter D ₅₀ is a median diameter calculated on a volume basis using a Coulter counter method.

  This embodiment relates to a toner. The toner of the present embodiment includes a plurality of toner particles. The toner is an aggregate (powder) of a plurality of toner particles. An external additive may adhere to the surface of the toner particles as necessary. The toner particles before the external additive adheres may be referred to as toner mother particles.

The toner of this embodiment satisfies the following formulas (1), (2), and (3).
0.0010 ≦ 100 × W ₂ / W ₁ ≦ 0.1000 (1)
0.1000 ≦ 100 × C ₂ / C ₁ ≦ 10.000 (2)
1.00 ≦ (C ₂ / C ₁ ) / (W ₂ / W ₁ ) ≦ 1000.00 (3)

In formulas (1) and (3), W ₁ represents the content (mass ratio) of the crystalline polyester resin with respect to the mass of the toner particles. In the formulas (1) and (3), W ₂ represents the content (mass ratio) of the crystalline polyester resin contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles. In the formulas (2) and (3), C ₁ represents the content rate (mass ratio) of nigrosine with respect to the mass of the toner particles. In formulas (2) and (3), C ₂ represents the content (mass ratio) of nigrosine contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles. The ethanol-soluble component can be obtained by mixing 0.35 g of toner particles and 4.00 g of ethanol for 3 minutes at a rotation speed of 100 rpm using a ball mill in an environment of 25 ° C. Details of the expressions (1) to (3) will be described later.

  The toner of the present exemplary embodiment includes a plurality of toner particles containing a crystalline polyester resin and nigrosine. The inventor has intensively studied and controlled the kneading conditions (for example, kneading speed and kneading temperature) in producing the toner, so that the crystalline polyester resin and nigrosine are dissolved (compatible) with each other, and It has been found that the degree of dissolution of crystalline polyester resin by nigrosine and the degree of dissolution of nigrosine by crystalline polyester resin can be controlled. By controlling the degree of dissolution of the crystalline polyester resin by nigrosine and the degree of dissolution of nigrosine by the crystalline polyester resin within the ranges of the formulas (1), (2) and (3), the charging stability and It has been found that a toner having excellent fixability can be obtained. Hereinafter, dissolution of the crystalline polyester resin and nigrosine will be described with reference to FIGS. 1 to 4 are electron micrographs observed using a scanning electron microscope (SEM, “JSM-7401F” manufactured by JEOL Ltd.).

  FIG. 1 is an electron micrograph showing the toner particles contained in the toner of this embodiment. The photograph shown in FIG. 1 is obtained by observing at an observation magnification of 95,000 times. The toner particles shown in FIG. 1 include, as a crystalline polyester resin, a polymer of alcohol and an alkane having a molecular weight of 150 to 300 and having two carboxyl groups and having 1 to 18 carbon atoms. The toner particles shown in FIG. 1 contain a crystalline polyester resin and nigrosine and satisfy the formulas (1) to (3). The scale bar in FIG. 1 indicates 100 nm. In FIG. 1, the region of the crystalline polyester resin is shown in white. FIG. 1 confirms that in the toner of this embodiment, the crystalline polyester resin and nigrosine are dissolved (compatible) with each other.

  FIG. 2 is an electron micrograph showing the toner particles contained in the comparative toner. The photograph shown in FIG. 2 is obtained by observing at an observation magnification of 10,000 times. The toner particles shown in FIG. 2 contain a crystalline polyester resin (the crystalline polyester resin contained in the toner particles shown in FIG. 1) but do not contain nigrosine. The scale bar in FIG. 2 indicates 1 μm. In FIG. 2, the crystalline polyester resin is shown in white. In the toner particles shown in FIG. 2, it is confirmed that the crystalline polyester resin is not dissolved because nigrosine is not contained. Since the crystalline polyester is not dissolved, the crystalline polyester resin region (white region) shown in FIG. 2 is larger than the crystalline polyester resin region (white region) shown in FIG.

FIG. 3 is an electron micrograph showing the toner particles contained in the comparative toner. The photograph shown in FIG. 3 is obtained by observing at an observation magnification of 5000 times. The crystalline polyester resin contained in the toner particles shown in FIG. 3 contains an aromatic dicarboxylic acid as a carboxylic acid, has a molecular weight of 150 to 300 and has two carboxyl groups and has 1 to 18 carbon atoms. Does not contain alkanes. The toner particles shown in FIG. 3 contain a crystalline polyester resin and nigrosine, but do not satisfy the formulas (1) and (3). Specifically, the toner particle shown in FIG. 3 has a value “100 × W ₂ / W ₁ ” of 0.0008, a value “100 × C ₂ / C ₁ ” of 0.85, and a value “(C ₂ / C ₁ ) / (W ₂ / W ₁ ) ”is 1062. In FIG. 3, the crystalline polyester resin is shown in white. In the toner particles shown in FIG. 3, it is confirmed that the crystalline polyester resin and nigrosine are not dissolved in each other. Since the crystalline polyester is not dissolved, the crystalline polyester resin region (white region) shown in FIG. 3 is larger than the crystalline polyester resin region (white region) shown in FIG.

  FIG. 4 is an electron micrograph showing the toner particles contained in the comparative toner. The photograph shown in FIG. 4 is obtained by observing at an observation magnification of 20000. The toner particles shown in FIG. 4 contain a crystalline polyester resin (the crystalline polyester resin contained in the toner particles shown in FIG. 3) but do not contain nigrosine. In FIG. 4, the crystalline polyester resin is shown in white. In the toner particles shown in FIG. 4, it is confirmed that the crystalline polyester resin is not dissolved. Since the crystalline polyester is not dissolved, the crystalline polyester resin region (white region) shown in FIG. 4 is larger than the crystalline polyester resin region (white region) shown in FIG.

  1 to 4, the crystalline polyester resin and nigrosine are dissolved (compatible) with each other, and the degree of dissolution of the crystalline polyester resin by nigrosine and the degree of dissolution of nigrosine by the crystalline polyester resin are controlled. Thus, it is confirmed that a toner satisfying the formulas (1), (2) and (3) can be obtained. Next, equations (1) to (3) will be described in detail.

<Formula (1)>
The value “100 × W ₂ / W ₁ ” in the following formula (1) is an index indicating how much the crystalline polyester resin is dissolved by nigrosine.
0.0010 ≦ 100 × W ₂ / W ₁ ≦ 0.1000 (1)

In formula (1), W ₁ represents the content (unit: mass%) of the crystalline polyester resin with respect to the mass of the toner particles. W ₂ represents the content (unit: mass%) of the crystalline polyester resin contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles. The ethanol-soluble component is obtained according to the following ethanol-soluble component extraction conditions. The extraction conditions for ethanol-soluble components are conditions in which 0.35 g of toner particles and 4.00 g of ethanol are mixed for 3 minutes at a rotation speed of 100 rpm using a ball mill in an environment of 25 ° C. According to such extraction conditions for ethanol-soluble components, components contained on the surface of the toner particles can be extracted. Therefore, the components contained on the surface of the toner particles can be confirmed by analyzing the ethanol-soluble component.

When the value “100 × W ₂ / W ₁ ” is less than 0.0010, the amount of the crystalline polyester resin present on the surface of the toner particles is reduced. In this case, it is considered that the crystalline polyester resin on the surface of the toner particles is excessively dissolved by nigrosine. Since the crystalline polyester resin has a lower melting point than the amorphous polyester resin, the presence of the crystalline polyester resin on the surface of the toner particles tends to improve the low-temperature fixability of the toner. However, if the value “100 × W ₂ / W ₁ ” is less than 0.0010, the amount of the crystalline polyester resin present on the surface of the toner particles is small, so that the low-temperature fixability of the toner is lowered. Further, when the value “100 × W ₂ / W ₁ ” is less than 0.0010, the charging stability and filming resistance of the toner tend to be lowered.

When the value “100 × W ₂ / W ₁ ” exceeds 0.1000, the amount of the crystalline polyester resin present on the surface of the toner particles increases. In this case, it is considered that the crystalline polyester resin on the surface of the toner particles is hardly dissolved by nigrosine. Crystalline polyester resins tend to release charges. For this reason, if the amount of the crystalline polyester resin present on the surface of the toner particles is increased, it becomes difficult for charges to be accumulated in the toner, and the charging stability of the toner is lowered. When the charging stability of the toner is reduced, the density of the formed image and fogging may be caused in the formed image. The melting point of the crystalline polyester resin is lower than the melting point of the amorphous polyester resin. Therefore, when the amount of the crystalline polyester resin having a low melting point present on the surface of the toner particles is increased, the filming resistance and blocking resistance of the toner tend to be lowered.

The value “100 × W ₂ / W ₁ ” is adjusted by, for example, changing one or both of the kneading speed (for example, the rotational speed of the screw of the kneader) and the kneading time in the kneading step when the toner is manufactured. Is done. By changing one or both of the kneading speed and the kneading time, the degree of dissolution of the crystalline polyester resin by nigrosine can be adjusted, and the value “100 × W ₂ / W ₁ ” can be adjusted to a desired value. The kneading step will be described later.

The content W ₁ is obtained, for example, by measuring the toner using a pyrolysis gas chromatograph mass spectrometer (PY-GC-MS). Content W ₂ is obtained, for example, by measuring the ethanol soluble matter using PY-GC-MS. A specific method for measuring the contents W ₁ and W ₂ is the method described in the examples or an alternative method thereof.

When the external additive is attached to the surface of the toner particles, the content W ₁ indicates the content (unit: mass%) of the crystalline polyester resin with respect to the mass of the toner base particles. The content W ₁ can be obtained by measuring the toner base particles using PY-GC-MS. The content W ₂ indicates the content (unit: mass%) of the crystalline polyester resin contained in the ethanol-soluble content of the toner base particles with respect to the mass of the toner base particles. Ethanol solubles can be obtained by using 0.35 g toner base particles instead of 0.35 g toner particles. For the measurement of the contents W ₁ and W ₂ , a sample obtained by removing the external additive from the toner particles can be used.

<Formula (2)>
The value “100 × C ₂ / C ₁ ” in the following formula (2) is an index indicating how much nigrosine is dissolved by the crystalline polyester resin.
0.1000 ≦ 100 × C ₂ / C ₁ ≦ 10.000 (2)

In formula (2), C ₁ represents the content of nigrosine (unit: mass%) with respect to the mass of the toner particles. C ₂ represents the content (unit: mass%) of nigrosine contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles. The method for extracting the ethanol-soluble component used for calculating the content rate C ₂ is the same as the method for extracting the ethanol-soluble component used for calculating the content rate W ₂ .

When the value “100 × C ₂ / C ₁ ” is less than 0.1000, the amount of nigrosine present on the surface of the toner particles decreases. In this case, it is considered that nigrosine on the surface of the toner particles is excessively dissolved by the crystalline polyester resin. Since nigrosine is a charge control agent, if the amount of nigrosine present on the surface of the toner particles decreases, the charging stability of the toner decreases.

When the value “100 × C ₂ / C ₁ ” exceeds 10.0000, the amount of nigrosine present on the surface of the toner particles increases. In this case, it is considered that nigrosine on the surface of the toner particles is hardly dissolved by the crystalline polyester resin. Nigrosine has a relatively high melting point. Therefore, when the amount of nigrosine having a high melting point present on the surface of the toner particles is increased, the low-temperature fixability of the toner is lowered.

The value “100 × C ₂ / C ₁ ” is preferably 1.5000 or more and 10.0000 or less. When the value “100 × C ₂ / C ₁ ” is 1.5000 or more, the toner fixability can be further improved.

The value “100 × C ₂ / C ₁ ” is adjusted, for example, by changing one or both of the kneading speed (for example, the rotational speed of the screw of the kneader) and the kneading time in the kneading step when the toner is manufactured. Is done. By changing one or both of the kneading speed and the kneading time, the degree of dissolution of nigrosine by the crystalline polyester resin can be adjusted, and the value “100 × C ₂ / C ₁ ” can be adjusted to a desired value. The kneading step will be described later.

The content C ₁ is calculated from, for example, the amount of nigrosine added to the mass of toner particles when the toner is produced. Content C _2, for example, using a spectrophotometer, obtained by measuring the ethanol-soluble fraction. Absorbance is measured by irradiating the ethanol-soluble component with ultraviolet light having a wavelength that nigrosine absorbs characteristically. The specific calculation method of the content rate C _{1 and} the specific measurement method of the content rate C ₂ are the method described in the examples or an alternative method thereof.

When an external additive is attached to the surface of the toner particles, the content C ₁ is calculated from the amount of nigrosine added to the mass of the toner base particles when the toner is produced. The content C ₂ indicates the content (unit: mass%) of nigrosine contained in the ethanol-soluble content of the toner base particles with respect to the mass of the toner base particles. Ethanol solubles can be obtained by using 0.35 g toner base particles instead of 0.35 g toner particles. For the measurement of the contents C ₁ and C ₂ , a sample obtained by removing the external additive from the toner particles can be used.

<Formula (3)>
The value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” in the following formula (3) is an index indicating how much the crystalline polyester resin and nigrosine are kneaded.
W ₁ and W ₂ in the formula (3) has the same meaning as W ₁ and W ₂ in the formula (1). C ₁ and C ₂ in formula (3) has the same meaning as C ₁ and C ₂ in formula (2).
1.00 ≦ (C ₂ / C ₁ ) / (W ₂ / W ₁ ) ≦ 1000.00 (3)

When the value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” is less than 1.00, the amount of nigrosine on the surface of the toner particles is small and the amount of the crystalline polyester resin is large. Since nigrosine is a charge control agent, if the amount of nigrosine present on the surface of the toner particles decreases, the charging stability of the toner decreases. In addition, since the crystalline polyester resin easily releases charges, the charging stability of the toner decreases when the amount of the crystalline polyester resin present on the surface of the toner particles increases. Furthermore, the melting point of the crystalline polyester resin is lower than the melting point of the amorphous polyester resin. Therefore, when the amount of the crystalline polyester resin having a low melting point present on the surface of the toner particles is increased, the blocking resistance of the toner tends to be lowered.

When the value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” exceeds 1000.00, the amount of nigrosine on the surface of the toner particles is large and the amount of the crystalline polyester resin is small. Nigrosine has a relatively high melting point. Therefore, when the amount of nigrosine having a high melting point present on the surface of the toner particles is increased, the low-temperature fixability of the toner is lowered.

The value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” is preferably 50.00 or more and 1000.00 or less, and more preferably 100.00 or more and 1000.00 or less. When the value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” is 50.00 or more, the blocking resistance of the toner can be further improved.

The value “(C ₂ / C ₁ ) / (W ₂ / W ₁ )” indicates, for example, one of kneading speed (for example, the rotational speed of the screw of the kneading machine) and kneading time in the kneading step when producing the toner. Or it can be adjusted by changing both. The degree of dissolution of the crystalline polyester resin by nigrosine and the degree of dissolution of nigrosine by the crystalline polyester resin are adjusted by changing one or both of the kneading speed and the kneading time, and the value “(C ₂ / C ₁ ) / (W ₂ / W ₁ ) ”can be adjusted to a desired value. The kneading step will be described later.

<Formula (4)>
The toner of the exemplary embodiment preferably satisfies the following formula (4) in addition to the formulas (1), (2), and (3). In the kneading step at the time of producing the toner, the crystalline polyester resin region can be dispersed in the toner particles. In formula (4), R represents the dispersion diameter of the crystalline polyester resin region of the 100% by number from the smaller dispersion diameter in the dispersion diameter distribution based on the number of crystalline polyester resin regions.
0.40 μm ≦ R ≦ 0.90 μm (4)

  When the crystalline polyester resin is dissolved by nigrosine and the nigrosine is dissolved by the crystalline polyester resin, the dispersion diameter R of the crystalline polyester region (the longest diameter of the crystalline polyester region) in the toner particles becomes small. The dispersion diameter R becomes smaller as the dissolution of the crystalline polyester resin by nigrosine and the dissolution of nigrosine by the crystalline polyester resin proceed. The dispersion diameter R increases as the dissolution of the crystalline polyester resin by nigrosine and the dissolution of nigrosine by the crystalline polyester resin do not proceed. When the dispersion diameter R is 0.40 μm or more, the charging stability of the toner is improved. This is because the amount of nigrosine, which is a charge control agent, increases. Further, when the dispersion diameter R is 0.40 μm or more, the blocking resistance of the toner tends to be improved. When the dispersion diameter R is 0.90 μm or less, the toner fixing property and filming resistance are improved.

  The dispersion diameter R is preferably 0.45 μm or more and 0.90 μm or less, and more preferably 0.50 μm or more and 0.90 μm or less. When the dispersion diameter R is 0.45 μm or more, the toner fixability can be further improved. When the dispersion diameter R is 0.50 μm or more, the blocking resistance of the toner can be further improved.

  The dispersion diameter R is adjusted, for example, by changing one or both of the kneading speed (for example, the rotational speed of the screw of the kneader) and the kneading time in the kneading step when producing the toner. The dispersion diameter R tends to decrease as the kneading temperature increases. As the kneading speed increases, the dispersion diameter R tends to decrease. Further, the dispersion diameter R tends to decrease as the content of nigrosine with respect to the mass of the crystalline polyester resin increases.

  The dispersion diameter R is measured, for example, by the following method. Using SPM, an SPM image of a cross section of the toner particles is obtained. Using an image analysis software (“WinROOF” manufactured by Mitani Corporation), the SPM image of the cross section of the toner particles is binarized. An example of the SPM image of the cross section of the toner particles after binarization is shown in FIG. FIG. 5 is an SPM photograph showing a cross section of toner particles in the toner of the present embodiment. In FIG. 5, the region of the crystalline polyester resin is shown in white. In FIG. 5, toner components other than the crystalline polyester resin are shown in black. From the SPM image of the cross-section of the toner particles after binarization, the dispersion diameter (longest diameter) of the crystalline polyester resin region (the region shown in white in FIG. 5) is measured. The dispersion diameter is measured for a considerable number of crystalline polyester resin regions. From the measured dispersion diameter, the number-based dispersion diameter distribution of the crystalline polyester resin region is obtained. From the obtained dispersion diameter distribution, the dispersion diameter R of the crystalline polyester resin region of the 100% by number from the smaller dispersion diameter is obtained. In the number-based dispersion diameter distribution, the group of 100% by number from the smallest dispersion diameter is a group to which the crystalline polyester resin region having the largest dispersion diameter belongs. For example, when the dispersion diameter of the region of 1000 crystalline polyester resins is measured, the region of the crystalline polyester resin having a dispersion diameter of 991 to 1000th from the smaller one is from the smaller dispersion diameter. It is included in the group of 100% by number. In this case, the number average dispersion diameter of the crystalline polyester resin region having a dispersion diameter of 991 to 1000th from the smallest is the dispersion of the crystalline polyester resin region of the 100% by number from the smallest dispersion diameter. Diameter R. If an external additive is attached to the surface of the toner particles, the cross section of the toner base particles may be observed by SPM after the external additive is removed.

  Next, components contained in the toner base particles will be described. The toner base particles contain, for example, at least a crystalline polyester resin as a binder resin and nigrosine as a charge control agent. The toner base particles may further contain at least one of a non-crystalline polyester resin as a binder resin, magnetic powder, and a release agent, if necessary. The toner base particles may be a charge control agent other than a colorant, a binder resin other than a crystalline polyester resin and an amorphous polyester resin (hereinafter, may be referred to as other binder resin) and nigrosine as necessary. (Hereinafter, it may be described as other charge control agent). However, unnecessary components (for example, non-crystalline polyester resin, magnetic powder, release agent, colorant, other binder resin, or other charge control agent) may be omitted depending on the use of the toner.

  The toner base particles may be encapsulated. The encapsulated toner base particles have, for example, a toner core having the same structure and components as those of the toner base particles described below, and a shell layer (capsule layer) formed on the surface of the toner core.

The volume median diameter D ₅₀ of the toner base particles is preferably 5 μm or more and 10 μm or less.

<Binder resin>
The toner base particles contain a crystalline polyester resin as a binder resin. The toner base particles may further contain an amorphous polyester resin as a binder resin. The toner base particles may further contain other binder resin as required.

(Crystalline polyester resin)
Whether the polyester resin is crystalline or non-crystalline can be confirmed using differential scanning calorimetry (DSC). In the present specification, the crystalline polyester resin means a polyester resin in which the spectrum obtained by DSC has a clear endothermic peak rather than a stepwise endothermic change. Specifically, in the present specification, a polyester resin having a half-value width of an endothermic peak of 15 ° C. or less when measured at a temperature rising rate of 10 ° C./min is crystalline. In the present specification, a polyester resin in which the half-value width of the endothermic peak exceeds 15 ° C., or a polyester resin in which no clear endothermic peak is observed is amorphous (amorphous). The method for measuring the half-value width of the endothermic peak of the polyester resin is the method described in Examples or an alternative method thereof.

  The crystalline polyester resin is obtained, for example, by polymerizing alcohol and carboxylic acid. The crystalline polyester resin is a polymer of alcohol and carboxylic acid.

  Preferable examples of the alcohol used for preparing the crystalline polyester resin include diols, bisphenols, and trihydric or higher alcohols.

  Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 2-butene-1,4-diol. 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol or polytetramethylene glycol.

  Examples of bisphenols include bisphenol A, hydrogenated bisphenol A, bisphenol A ethylene oxide adduct or bisphenol A propylene oxide adduct.

  Examples of trihydric or higher alcohols include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, diglycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane or 1,3,5-trihydroxymethyl Benzene is mentioned.

  Examples of the carboxylic acid used when synthesizing the crystalline polyester resin include a divalent carboxylic acid or a trivalent or higher carboxylic acid.

  Examples of divalent carboxylic acids include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, alkanedicarboxylic acid, alkenyl succinic acid (for example, n-butenyl succinic acid). Acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid or isododecenyl succinic acid). Examples of alkane dicarboxylic acids include alkanes having 1 to 18 carbon atoms having two carboxyl groups. In an alkane having 1 to 18 carbon atoms having two carboxyl groups, two carboxyl groups are bonded to an alkane having 1 to 18 carbon atoms. Examples of alkanes having 1 to 18 carbon atoms having two carboxyl groups are malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, octanedioic acid, nonanedioic acid, sebacic acid, undecanedioic acid, Dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonanedecanedioic acid, icosanedioic acid or alkyl succinic acid (eg, n-butyl succinic acid, isobutyl succinic acid) N-octyl succinic acid, n-dodecyl succinic acid or isododecyl succinic acid).

  Examples of trivalent or higher carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, Examples include 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid or emporic trimer acid.

  Since the dissolution of the crystalline polyester resin by nigrosine and the dissolution of nigrosine by the crystalline polyester resin are likely to be caused, the carboxylic acid is preferably an alkanedicarboxylic acid and having 1 to 18 carbon atoms having two carboxyl groups. Alkanes are more preferred. For the same reason, the carboxylic acid is preferably a carboxylic acid having a molecular weight of 150 to 300, more preferably an alkane having a molecular weight of 150 to 300 and having two carboxyl groups and having 1 to 18 carbon atoms. preferable. Examples of alkanes having a molecular weight of 150 to 300 and having two carboxyl groups and having 1 to 18 carbon atoms include azelaic acid, octanedioic acid, nonanedioic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, Tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, n-butylsuccinic acid, isobutylsuccinic acid, n-octylsuccinic acid, n-dodecylsuccinic acid or isododecylsuccinic acid are preferred. Acid is more preferred. Since the dissolution of the crystalline polyester resin by nigrosine and the dissolution of nigrosine by the crystalline polyester resin are likely to be caused, the carboxylic acid constituting the crystalline polyester resin may be only a carboxylic acid having a molecular weight of 150 to 300. Preferably, it is more preferably only an alkane having a molecular weight of 150 to 300 and having two carboxyl groups and having 1 to 18 carbon atoms, and particularly preferably only dodecanedioic acid.

  The crystalline polyester resin is a polymer of alcohol and a carboxylic acid having a molecular weight of 150 to 300 because it easily causes dissolution of the crystalline polyester resin by nigrosine and dissolution of nigrosine by the crystalline polyester resin. Is preferred. It is confirmed by measuring the toner using, for example, a pyrolysis gas chromatograph mass spectrometer (PY-GC-MS) that the monomer constituting the crystalline polyester resin contains a carboxylic acid having a molecular weight of 150 to 300. be able to. Specifically, the mass spectrum of the component contained in the toner is obtained by measuring the toner using PY-GC-MS. And it is confirmed whether a peak appears in the range whose m / z value is 150-300 in a mass spectrum. The m / z value is a value obtained by dividing m (the mass of the ion represented by the atomic mass unit u) by z (the number of charges of the ion). In the ionization method used in PY-GC-MS, the number of charges of ions is usually 1. Therefore, the m / z value can be regarded as the mass of ions. Since the mass of electrons is very small compared to the mass of molecules, the mass of ions can be regarded as the molecular weight. Therefore, when a peak appears in a range where the m / z value is 150 or more and 300 or less in the mass spectrum, it is confirmed that the monomer constituting the crystalline polyester resin contains a carboxylic acid having a molecular weight of 150 or more and 300 or less. be able to.

  Alcohol and carboxylic acid may be used individually by 1 type, respectively, and may be used in combination of 2 or more type. Furthermore, the carboxylic acid may be derivatized into an ester-forming derivative. Examples of ester-forming derivatives include acid halides, acid anhydrides or lower alkyl esters. Here, the lower alkyl means an alkyl group having 1 to 6 carbon atoms.

  The content of the polyester resin is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass with respect to the mass of the entire binder resin. In order to improve the charging stability and fixability of the toner, the content of the crystalline polyester resin is based on the total mass of the polyester resin (the sum of the mass of the crystalline polyester resin and the mass of the amorphous polyester resin). It is preferably 1% by mass or more and 30% by mass or less, and more preferably 10% by mass or more and 20% by mass or less.

(Non-crystalline polyester resin)
The non-crystalline polyester resin is obtained, for example, by polymerizing alcohol and carboxylic acid. The example of alcohol used for preparation of an amorphous polyester resin is the same as the example of alcohol used for preparation of crystalline polyester resin. Examples of the carboxylic acid used for the preparation of the amorphous polyester resin are the same as the examples of the carboxylic acid used for the preparation of the crystalline polyester resin. In order to obtain an amorphous polyester resin, it is preferable to use a carboxylic acid other than an alkanedicarboxylic acid, and it is preferable to use a carboxylic acid other than an alkane having two carboxyl groups and having 1 to 18 carbon atoms. More preferred. In order to obtain an amorphous polyester resin, the carboxylic acid is preferably not a carboxylic acid having a molecular weight of 150 or more and 300 or less, and has a molecular weight of 150 or more and 300 or less and has 2 carboxyl groups and 1 carbon atom. More preferably, the alkane is not more than 18 or less.

(Other resins)
Examples of other binder resins are styrene resins, acrylic resins, styrene acrylic resins, polyethylene resins, polypropylene resins, vinyl chloride resins, polyamide resins, urethane resins, polyvinyl alcohol resins, vinyl ether resins, N-vinyl. Compound resin or styrene butadiene resin. One kind of other binder resins may be used alone, or two or more kinds may be used in combination. Moreover, you may add a crosslinking agent or a thermosetting resin to other resin.

<Charge control agent>
The toner base particles contain nigrosine as a charge control agent. Nigrosine functions as a positively chargeable charge control agent in the toner. For this reason, when an image is formed using the toner of this embodiment, it is preferable to develop the toner by positively charging the toner (as a positively chargeable toner). The toner base particles may contain other charge control agents as required.

(Nigrosine)
Nigrosine is obtained by oxidation-reduction condensation of aniline or aniline hydrochloride and nitrobenzene in the presence of hydrochloric acid and a catalyst (for example, copper or iron). Nigrosine is a compound having an azine skeleton (= C = N-N = C =) obtained by such a method or a mixture thereof. Nigrosine is a black dye. Examples of nigrosine include C.I. I. Solvent Black 5, C.I. I. Solvent Black 7, C.I. I. Examples thereof include Acid Black 2 or other compounds having an azine skeleton.

  C. I. Examples of Solvent Black 5 include SPIRIT BLACK ABL, NUBIAN (registered trademark) BLACK NH-805, or NUBIAN (registered trademark) BLACK NH-815, manufactured by Orient Chemical Industry Co., Ltd.

  C. I. Examples of Solvent Black 7 include NIGROSINE BASE SAPL, NIGROSINE BASE EX, NIGROSINE BASE EX-BP, SPECIAL BLACK EB, NUBIAN (registered trademark) BLACK TN-870, NUBLANT (registered trademark), manufactured by Orient Chemical Industry Co., Ltd. -877 or NUBIAN® BLACK TH-807.

  Other compounds having an azine skeleton include, for example, BONTRON (registered trademark) N-71, BONTRON (registered trademark) N-75, BONTRON (registered trademark) N-77, or BONTRON (registered trademark) manufactured by Orient Chemical Industries, Ltd. N-79 is mentioned.

  One type of nigrosine may be used alone, or two or more types may be used in combination. In order to improve the charging stability and fixability of the toner, the content of nigrosine is preferably 1% by mass or more and 10% by mass or less, and preferably 3% by mass or more and 6% by mass with respect to the mass of the binder resin. % Or less is more preferable. In order to improve the charging stability and fixing property of the toner, the content of nigrosine is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 50% by mass with respect to the mass of the crystalline polyester resin. It is more preferable that the amount is not more than mass%.

(Other charge control agents)
Examples of other charge control agents are quaternary ammonium salts, acidic dyes composed of quaternary ammonium salts, metal salts of naphthenic acid, metal salts of higher fatty acids, alkoxylated amines or alkylamides. One of the other charge control agents may be used alone, or two or more may be used in combination.

<Magnetic powder>
The magnetic powder is not particularly limited as long as it can be used for toner. Examples of magnetic powders include ferromagnetic metals, alloys of multiple types of ferromagnetic metals, magnetic powders composed mainly of ferromagnetic metals, magnetic powders doped with iron oxide with cobalt or nickel, and no ferromagnetic metal elements. It is an alloy or chromium dioxide that becomes ferromagnetic by heat treatment. Examples of ferromagnetic metals are iron, cobalt or nickel. Iron may be used in the form of iron oxide (eg, magnetite or ferrite). One of these magnetic powders may be used alone, or two or more thereof may be used in combination. Magnetite is preferred as the magnetic powder because the charge amount of the toner particles can be easily adjusted.

  The number average primary particle diameter of the magnetic powder is preferably 0.1 μm or more and 1.0 μm or less. When magnetic powder having a number average primary particle size in such a range is used, it is easy to uniformly disperse the magnetic powder in the binder resin. The content of the magnetic powder is preferably 1 part by mass or more and 100 parts by mass or less, and more preferably 50 parts by mass or more and 70 parts by mass or less with respect to 100 parts by mass of the binder resin.

<Release agent>
The release agent is used, for example, for the purpose of improving the toner fixing property and offset resistance. In order to improve the fixing property and offset resistance of the toner, the amount of the release agent used is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin. More preferably, it is at least 15 parts by mass.

  Examples of mold release agents include aliphatic hydrocarbon waxes, oxides of aliphatic hydrocarbon waxes, plant-derived waxes, animal-derived waxes, mineral-derived waxes, waxes based on fatty acid esters or fatty acid esters. Part or all of the wax is deoxidized. Examples of aliphatic hydrocarbon waxes are ester wax, polyethylene wax (eg, low molecular weight polyethylene), polypropylene wax (eg, low molecular weight polypropylene), polyolefin copolymer, polyolefin wax, microcrystalline wax, paraffin wax or Fischer-Tropsch wax. It is. An example of the oxide of the aliphatic hydrocarbon wax is an oxidized polyethylene wax or a block copolymer of oxidized polyethylene. Examples of waxes derived from plants are candelilla wax, carnauba wax, wood wax, jojoba wax or rice wax. Examples of animal derived waxes are beeswax, lanolin or whale wax. Examples of mineral-derived waxes are ozokerite, ceresin or petrolatum. Examples of waxes based on fatty acid esters are montanic acid ester wax or caster wax. An example of a wax in which a part or all of the fatty acid ester has been deoxidized is deoxidized carnauba wax. One of these release agents may be used alone, or two or more thereof may be used in combination.

<Colorant>
As the colorant, a known pigment or dye is used according to the color of the toner. The content of the colorant 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. In the case where the toner base particles contain magnetic powder, the magnetic powder is black, so that it is not necessary to add a colorant to the toner base particles.

  When the toner is a black toner, a black colorant is used. An example of a black colorant is carbon black. You may use the black colorant adjusted to black using the yellow colorant, magenta colorant, and cyan colorant which are mentioned later.

  When the toner is yellow toner, a yellow colorant is used. Examples of yellow colorants are condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds or arylamide compounds. More specifically, 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. Bat yellow is mentioned.

  If the toner is magenta toner, a magenta colorant is used. Examples of magenta colorants are condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds or perylene compounds. More specifically, 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).

  When the toner is cyan toner, a cyan colorant is used. Examples of cyan colorants include copper phthalocyanine, copper phthalocyanine derivatives, anthraquinone compounds or basic dye lake compounds. More specifically, 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.

<External additive>
External additives may be attached to the surface of the toner base particles. Examples of the external additive are silica or metal oxide. Examples of metal oxides are alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate or barium titanate. The surface of the external additive may be hydrophobized. One type of external additive may be used alone, or two or more types may be used in combination.

  The number average particle diameter of the external additive is preferably 1 nm or more and 1 μm or less, and more preferably 1 nm or more and 50 nm or less. The amount of the external additive used is preferably 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the toner base particles.

<Two-component developer>
The toner may be used as a one-component developer. Alternatively, the toner may be used in a two-component developer mixed with the desired carrier. When preparing a two-component developer, it is preferable to use a magnetic carrier. A carrier core coated with a resin may be used as the carrier. Further, as the carrier, a resin carrier in which a carrier core is dispersed in a resin may be used.

  Examples of carrier cores are iron, oxidized iron, reduced iron, magnetite, copper, silicon steel, ferrite, nickel or cobalt particles; alloys of these materials with metals (eg manganese, magnesium, zinc or aluminum) Particles: iron-nickel alloy particles; iron-cobalt alloy particles; ceramic particles; or particles of a high dielectric constant material. Examples of ceramics are titanium oxide, aluminum oxide, copper oxide, magnesium oxide, lead oxide, zirconium oxide, silicon carbide, magnesium titanate, barium titanate, lithium titanate, lead titanate, lead zirconate or lithium niobate. is there. Examples of high dielectric constant materials are ammonium dihydrogen phosphate, potassium dihydrogen phosphate or Rochelle salt. One of these carrier cores may be used alone, or two or more may be used in combination.

  Examples of the resin covering the carrier core are acrylic acid polymer, styrene polymer, styrene-acrylic acid copolymer, olefin polymer, polyvinyl chloride, polyvinyl acetate, polycarbonate, cellulose resin, polyester resin, An unsaturated polyester resin, polyamide resin, urethane resin, epoxy resin, silicone resin, fluororesin, phenol resin, xylene resin, diallyl phthalate resin, polyacetal resin or amino resin. Examples of olefin polymers are polyethylene, chlorinated polyethylene or polypropylene. Examples of the fluororesin are polytetrafluoroethylene, polychlorotrifluoroethylene, or polyvinylidene fluoride. One of these resins may be used alone, or two or more thereof may be used in combination.

  The particle diameter of the carrier is preferably 20 μm or more and 120 μm or less, and more preferably 25 μm or more and 80 μm or less. The particle diameter of the carrier is measured using, for example, an electron microscope.

  When the toner is used in the two-component developer, the toner content is preferably 3% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less with respect to the mass of the two-component developer. It is more preferable.

<Toner production method>
For example, the toner is manufactured by the following method. The toner manufacturing method may be arbitrarily changed according to the required configuration or characteristics of the toner. Further, unnecessary operations may be omitted. For example, when an external additive is not attached to the toner base particles, an external addition step described later may be omitted. When the external addition process is omitted, the toner base particles correspond to toner particles. In order to produce the toner efficiently, it is preferable to form a large number of toner particles simultaneously.

(Manufacturing process of toner base particles)
An example of the production method of the toner base particles is an aggregation method or a pulverization method. The pulverization method can often produce toner mother particles more easily than the aggregation method. Hereinafter, the production process of the toner base particles will be described by taking a pulverization method as an example.

  The manufacturing process of the toner base particles includes a kneading process. The production process of the toner base particles may further include one or both of a pulverization process and a classification process as necessary.

  In the kneading step, crystalline polyester resin, nigrosine and components contained as necessary (for example, non-crystalline polyester resin, magnetic powder, release agent, colorant, other binder resin and other charge control agent) Knead.

  In the kneading step, the crystalline polyester resin and nigrosine are kneaded to dissolve part of the crystalline polyester resin and part of nigrosine. Crystalline polyester resins tend to dissolve with nigrosine. Nigrosine also tends to be dissolved by the crystalline polyester resin. Due to the interaction between the crystalline polyester resin and nigrosine, a part of the crystalline polyester resin and a part of nigrosine are dissolved together, whereby the abundance ratio of the crystalline polyester resin and the abundance ratio of nigrosine in the whole toner base particles, In addition, the abundance ratio of the crystalline polyester resin and the abundance ratio of nigrosine on the surface of the toner base particles can be adjusted. As a result, toner base particles satisfying the formulas (1), (2) and (3) can be manufactured. Furthermore, there is a tendency that toner mother particles satisfying the formula (4) are obtained.

  In the kneading step, the crystalline polyester resin, nigrosine, and components to be added as necessary are kneaded to disperse the crystalline polyester resin region in the toner base particles. In the number-based dispersion diameter distribution of the crystalline polyester resin region, the crystal is dispersed until the dispersion diameter R of the crystalline polyester resin region of 100% by number from the smaller dispersion diameter becomes 0.40 μm or more and 0.90 μm or less. It is preferable to dissolve a part of the reactive polyester resin and a part of nigrosine.

  Examples of the kneader used for kneading are a single screw extruder, a twin screw extruder, a roll mill, or an open roll kneader. The kneading speed (for example, the rotational speed of the screw of the kneader) is preferably 150 rpm or more and 180 rpm or less. When the kneading speed is within such a range, toner mother particles satisfying the formulas (1) to (4) tend to be obtained. The kneading temperature is preferably 120 ° C. or higher and 170 ° C. or lower. When the kneading temperature is within such a range, toner mother particles satisfying the formulas (1) to (4) tend to be obtained.

In the pulverization step, the kneaded product obtained in the kneading step is pulverized to obtain a pulverized product. In the classification step, the pulverized product obtained in the pulverization step is classified to obtain toner base particles (for example, toner base particles having a desired volume median diameter D ₅₀ ).

(External addition process)
After the toner mother particle manufacturing process, an external addition process may be performed as necessary. In the external addition step, the toner base particles and the external additive are mixed using a mixer (for example, an FM mixer manufactured by Nippon Coke Industries, Ltd.). The mixing condition is preferably set so that the external additive is not completely buried in the toner base particles. The external additive is adhered to the surface of the toner base particles by mixing. As a result, a toner including a plurality of toner particles is obtained.

  Examples of the present invention will be described. However, the present invention is not limited to the following examples.

<Manufacture of toner>
Toners A-1 to A-5 and B-1 to B-7 were produced by the following method.

(Production of Toner A-1)
45 parts by mass of non-crystalline polyester resin AM (endothermic peak half-width: 25 ° C.) as binder resin, crystalline polyester resin CR (polymer of dodecanedioic acid and alcohol, melting start temperature: 68 ° C., melting point Tm: 73 ° C., weight average molecular weight Mw: 5500, molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) Mw / Mn: 6.0, acid value: 6.0 mgKOH / g, hydroxyl value: 29 0.0 mg KOH / g and half-value width of endothermic peak: 10 parts by mass, 5 parts by mass of nigrosine as a charge control agent ("BONTRON (registered trademark) N-71" manufactured by Orient Chemical Co., Ltd.), as a release agent Carnauba wax (manufactured by Yoko Kato “Carnauba wax No. 1”) 5 parts by mass and magnetic powder (manufactured by Toda Kogyo Co., Ltd., volume median diameter D ₅₀ : 60 nm, Holding force: 8.5 kA / m, saturation magnetization: 83 Am ² / kg, remanent magnetization: 4.9 Am ² / kg, saturation magnetization and remanent magnetization are vibration sample type magnetometers (“VSM-P7 manufactured by Toei Industry Co., Ltd.) )) With an external magnetic field of 796 kA / m (35 parts by mass) using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.) at a rotational speed of 2400 rpm for 180 seconds. Mixed. The obtained mixture was kneaded using a twin screw extruder ("PCM-30" manufactured by Ikegai Co., Ltd.). The kneading conditions were a material supply speed of 5 kg / hour, a kneading speed (rotational speed of the screw of the twin-screw extruder, that is, a rotational speed of the shaft) of 150 rpm, and a kneading temperature (cylinder temperature) of 150 ° C. After cooling the obtained kneaded material, the kneaded material was coarsely pulverized using a pulverizer (“Rotoplex 16/8 type” manufactured by Toa Machinery Co., Ltd.). The coarsely pulverized product was further pulverized using a jet mill (“Ultrasonic Jet Mill I Type” manufactured by Nippon Pneumatic Industry Co., Ltd., collision plate pulverizer). The obtained 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 were obtained. The obtained toner base particles had a volume median diameter D ₅₀ of 8.0 μm. The volume median diameter D ₅₀ of the toner base particles was measured using a precision particle size distribution measuring device (“Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc.).

  100.0 parts by mass of the obtained toner base particles and silica as an external additive (“AEROSIL (registered trademark) REA90” manufactured by Nippon Aerosil Co., Ltd.), dry-type silica particles imparted with positive charge by surface treatment, number average primary 0.5 parts by mass of particle diameter: 20 nm) was mixed for 5 minutes under the condition of a rotational speed of 2000 rpm using an FM mixer (“FM-10B” manufactured by Nippon Coke Industries, Ltd., capacity: 10 L). As a result, the external additive was adhered to the surface of the toner base particles. The toner base particles to which the external additive was adhered were sieved using a 200 mesh sieve (aperture 75 μm). As a result, toner A-1 which is an aggregate of a plurality of toner particles was obtained.

(Production of Toners A-2 to A-4 and B-1 to B-7)
Toners A-2 to A-4 and B-1 to B-7 were produced in the same manner as in the production of the toner A-1, except that the following points were changed. The kneading temperature was changed from 150 ° C. in the production of the toner A-1 to the temperature shown in Table 1. The kneading speed was changed from 150 rpm in the production of the toner A-1 to the kneading speed shown in Table 1.

(Production of Toner A-5)
A toner A-5 was produced in the same manner as in the production of the toner A-1, except that the following points were changed. The addition amount of the amorphous polyester resin AM was changed from 80 parts by mass in the production of the toner A-1 to 77 parts by mass. The addition amount of the crystalline polyester resin CR was changed from 10 parts by mass in the production of the toner A-1 to 15 parts by mass. The amount of nigrosine added was changed from 5 parts by mass in the production of toner A-1 to 3 parts by mass.

(Measurement of half width)
The method for measuring the half width of the endothermic peaks of the amorphous polyester resin AM and the crystalline polyester resin CR is as follows. The endothermic peak of the measurement sample (amorphous polyester resin AM or crystalline polyester resin CR) was measured using a differential scanning calorimeter (DSC, “DSC 6220” manufactured by Seiko Instruments Inc.). First, 10 mg of a measurement sample was put in an aluminum pan. An empty aluminum pan was used as a reference. The measurement temperature range was 25 ° C. or higher and 200 ° C. or lower. The heating rate was 10 ° C./min. Under such conditions, an endothermic peak of the measurement sample was obtained. From the obtained endothermic peak, the half width (unit: ° C.) of the measurement sample was determined.

<Measurement method and measurement result>
For each of toners A-1 to A-5 and B-1 to B-7, the content W ₁ of the crystalline polyester resin with respect to the mass of the toner base particles, the ethanol-soluble content of the toner base particles with respect to the mass of the toner base particles The content W ₂ of the crystalline polyester resin contained in the toner, the content C _{2 of} nigrosine contained in the ethanol-soluble content of the toner base particles with respect to the mass of the toner base particles, and the dispersion size distribution based on the number of crystalline polyester resins The dispersion diameter R in the region of 100% by number from the smaller diameter was measured using the following method.

<Contents W ₁ and W ₂ >
(Preparation of ethanol-soluble matter)
First, the ethanol soluble content of the toner base particles was adjusted. To the container, 0.35 g of toner base particles (toner before the external addition step) and 4.00 g of ethanol were added. The contents of the container were mixed for 3 minutes at a rotation speed of 100 rpm using a ball mill under an environment of 25 ° C. Subsequently, the container was allowed to stand for 3 minutes, and the supernatant was taken out of the contents of the container. The solid component contained in the supernatant was precipitated using a centrifuge, and the ethanol solution was taken out from the supernatant. As a result, an ethanol solution containing the ethanol-soluble component of the toner was obtained.

(Measurement by PY-GC-MS)
For the measurement of the content W ₁ , 60 μg of toner was used as a measurement sample. For the measurement of the content W ₂ , 2 μL of an ethanol solution (ethanol solution containing an ethanol-soluble component) was used as a measurement sample. As a measuring device, a gas chromatograph mass spectrometer (“GCMS-QP2010Ultra” manufactured by Shimadzu Corporation) and a thermal decomposition device (pyrolyzer, “EGA / PY-3030D” manufactured by FLONTERLAB) are integrated. A decomposition gas chromatograph mass spectrometer (PY-GC-MS) was used.

A measurement sample (toner 60 μg) was set in the thermal decomposition apparatus. The measurement sample was volatilized under the following conditions, and the volatile component was introduced into the gas chromatograph.
Pyrolyzer temperature: 600 ° C
Interface temperature: 320 ° C

Volatile components and carrier gas were introduced from the inlet of the gas chromatograph. Volatile components were separated by a column under the following conditions.
Column: DB-5MS (length 30.0 m, film thickness 0.25 μm, inner diameter 0.25 mm)
Carrier gas: Helium (He)
Flow rate: 1 mL / min Temperature of vaporization chamber: 320 ° C
Column oven temperature conditions: 40 ° C. or higher and 320 ° C. or lower, heating rate 28 ° C./min

The components separated by the gas chromatograph were ionized under the following conditions and detected by a mass spectrometer. Thereby, a mass spectrum was obtained. Crystalline polyester resin contained in measurement sample using calibration curve from peak area of peak characteristic to crystalline polyester resin appearing in mass spectrum (peak appearing in range where m / z value is 150 or more and 300 or less) The mass of was calculated. From the calculated mass of the crystalline polyester resin, the content W ₁ (unit: mass%) of the crystalline polyester resin relative to the mass of the toner base particles was calculated.
Interface temperature: 320 ° C
Ion source temperature: 200 ° C
Detection mode: Scan
Scanning mass range: range where m / z value is 45 or more and 500 or less

The content W ₂ (unit: mass%) was measured by the same method as the measurement of the content W ₁ except that the following points were changed. The measurement sample was changed from 60 μg of toner in the measurement of the content W ₁ to 2 μL of an ethanol solution (an ethanol solution containing an ethanol-soluble component).

The value “100 × W ₂ / W ₁ ” was calculated from the obtained contents W ₁ and W ₂ . The calculated value “100 × W ₂ / W ₁ ” is shown in Table 1.

<Content C ₂ >
(Measurement with a spectrophotometer)
For the measurement with the spectrophotometer, an ethanol solution containing the ethanol-soluble component obtained by the preparation of the ethanol-soluble component described above was used. The absorbance of the ethanol solution containing the ethanol-soluble component was measured using a spectrophotometer (“U-3900” manufactured by Hitachi, Ltd.). The absorbance was measured by irradiating the ethanol solution with ultraviolet rays having a wavelength of 300 nm to 800 nm. Nigrosine characteristically absorbs ultraviolet rays having a wavelength of 516 nm. From the measured absorbance, the mass of nigrosine contained in the ethanol solution (the ethanol solution containing the ethanol-soluble content of the toner) was calculated using a calibration curve. From the calculated mass of nigrosine, the content ratio C ₂ (unit: mass%) of nigrosine contained in the ethanol-soluble content of the toner base particles with respect to the mass of the toner base particles was calculated.

The content C ₁ is the mass of toner base particles (45 parts by mass of non-crystalline polyester resin AM, 10 parts by mass of crystalline polyester resin CR, 5 parts by mass of nigrosine, 5 parts by mass of carnauba wax, and 35 parts by mass of magnetic powder. 100 parts by mass which is the sum of parts) and 5 parts by mass of nigrosine added, and calculated as 5% by mass.

The value “100 × C ₂ / C ₁ ” was calculated from the contents C ₁ and C ₂ . The calculated value “100 × C ₂ / C ₁ ” is shown in Table 1.

<Dispersion diameter R>
The toner and the room temperature curable epoxy resin were mixed to obtain a mixture in which the toner was sufficiently dispersed in the resin. The obtained mixture was allowed to stand for 2 days in an environment at a temperature of 40 ° C. to be cured. As a result, a solidified product in which the toner was dispersed was obtained. Using a microtome (“EMUC6” manufactured by Leica Corporation), a slice containing toner was cut out from the cured product. Using SPM (“SPI3800N (probe station)” and “SPA400 (multifunctional unit)” manufactured by Hitachi High-Tech Science Co., Ltd.), the sliced slice was observed under the following conditions to obtain an SPM image of the cross section of the toner. It was.
Measurement mode: Micro viscoelastic mode (VE-AFM)
Scanner: FS-100N (in-plane 100 μm, vertical 15 μm)
Micro cantilever: Silicon nitride SN-AF01 (spring constant 0.08 N / m)
Measurement environment: Room temperature (25 ° C. ± 5 ° C.), excitation frequency in air: 3 kHz to 5 kHz excitation amplitude: 4 nm to 6 nm

  Four screens of amplitude A, Asin δ, and Acos δ were measured in a measurement area of 20 μm × 20 μm. An image showing a region of the crystalline resin dispersed in the toner was obtained from the obtained phase image. The image showing the crystalline resin region was binarized using image analysis software (“WinROOF” manufactured by Mitani Corporation). The dispersion diameter (longest diameter) of the crystalline resin region was measured from the binarized image. Such a dispersion diameter measurement was performed on 100 crystalline resin regions. From the measured dispersion diameters of 100 crystalline resin regions, a number-based dispersion diameter distribution was obtained. In the dispersion diameter distribution, a dispersion diameter R in a region of 100% by number from the smaller dispersion diameter was obtained. Table 1 shows the dispersion diameter R (unit: μm) in the region of the 100% number of crystalline polyester resin.

<Evaluation>
For each of toners A-1 to A-5 and B-1 to B-7, the charging stability, fixing property, filming resistance and blocking resistance of the toner were evaluated by the following methods.

(Charge stability)
The evaluation environment for charging stability was a temperature of 25 ° C. and a relative humidity of 50% RH. A printer (“FS-1370DN” manufactured by Kyocera Document Solutions Co., Ltd., printer equipped with a magnetic one-component development system) was used as an evaluation machine. Toner (any one of toners A-1 to A-5 and B-1 to B-7) was put into a developing device of an evaluation machine. Further, toner (any one of toners A-1 to A-5 and B-1 to B-7) was put into a toner container of the evaluation machine. Using an evaluation machine, image I (image with a printing rate of 4%) was continuously printed on 1000 sheets of paper. Subsequently, an image II (an image including a solid image portion with a printing rate of 100% and a blank image portion with a printing rate of 0%) was printed on one sheet of paper. The printing of 1000 images I and the printing of 1 image II were repeated 5 times in succession. Each of the images II printed after printing 1000 images, 2000 images, 3000 images, 4000 images, and 5000 images I was used as an evaluation image. The image density of the solid image portion in each image for evaluation was measured using a reflection densitometer ("SpectaEye (registered trademark) LT" sold by Sakata Inx Engineering Co., Ltd.). The image density of the blank paper image portion in each evaluation image was measured using a reflection densitometer (“SpectaEye (registered trademark) LT” sold by Sakata Inx Engineering Co., Ltd.). A value obtained by subtracting the image density of the base paper from the image density of the obtained blank paper image portion was defined as the fog density. From the measured image density and fog density, the charging stability of the toner was evaluated according to the following criteria. Table 2 shows the image density and the fog density of each of the images II printed after the 1000 sheets, 2000 sheets, 3000 sheets, 4000 sheets, and 5000 sheets of the image I are printed. Table 2 shows the evaluation results of the charging stability of the toner.

(Evaluation criteria for charging stability)
A (very good): The image for evaluation printed after printing 5000 sheets satisfied both the image density of 1.20 or more and the fog density of less than 0.010.
Good (good): The image for evaluation printed after printing 5000 sheets did not satisfy one or both of the image density of 1.20 or more and the fog density of less than 0.010. The evaluation image printed after printing 4000 sheets satisfied both an image density of 1.20 or more and a fog density of less than 0.010.
X (bad): The image for evaluation printed after printing 5000 sheets did not satisfy one or both of the image density of 1.20 or more and the fog density of less than 0.010. The evaluation image printed after printing 4000 sheets did not satisfy one or both of the image density of 1.20 or more and the fog density of less than 0.010.

(Fixability)
For the evaluation of the toner fixing property, a printer (“FS-1370DN” manufactured by Kyocera Document Solutions Co., Ltd., printer equipped with a magnetic one-component development system) was used as an evaluation machine. Toner (any one of toners A-1 to A-5 and B-1 to B-7) was put into a developing device of an evaluation machine. Further, toner (any one of toners A-1 to A-5 and B-1 to B-7) was put into a toner container of the evaluation machine. The conditions of the evaluation machine were set to a linear speed of 200 mm / second, a nip passage time of 40 milliseconds, a nip width of 8 mm, and a toner loading of 1.0 mg / cm ² . An unfixed solid image (size: 25 mm × 25 mm, printing rate: 100%) was formed on 90 g / m ² paper (A4 size paper) using an evaluation machine. Subsequently, the paper on which the unfixed solid image was formed was passed through the fixing device, and the solid image was fixed on the paper. The fixing temperature of the fixing device was set to 100 ° C. or higher and 260 ° C. or lower. Specifically, the fixing temperature of the fixing device was increased from 100 ° C. to 5 ° C., and the solid image was fixed on paper at each fixing temperature.

  Whether or not so-called cold offset occurred was confirmed by the friction test shown below. Specifically, the paper passed through the fixing device was folded in half so that the surface on which the image was formed was on the inside. The folded paper was subjected to 5 reciprocating frictions on the crease using a 1 kg weight coated 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. When the peeling length was 1 mm or more, it was determined that a cold offset occurred. The lowest temperature among the fixing temperatures at which the peeling length was less than 1 mm was defined as the lowest fixable temperature.

  Whether or not so-called hot offset has occurred is determined by whether or not the toner has been transferred to the paper in the second round of the heat roller of the fixing device. When the toner transferred to the paper on the second round of the heat roller, it was determined that hot offset occurred. Of the temperatures at which the toner does not transfer to the paper in the second round of the heat roller, the highest temperature is defined as the maximum fixable temperature.

  From the measured minimum fixable temperature, the low-temperature fixability of the toner was evaluated according to the following criteria. From the measured maximum fixing temperature, the hot offset resistance of the toner was evaluated according to the following criteria. From these evaluations, the toner fixability was comprehensively evaluated according to the following criteria. Table 3 shows the evaluation results of the minimum fixable temperature and low temperature fixability of the toner, the maximum fixable temperature, the evaluation results of hot offset resistance, and the comprehensive evaluation results of fixability.

(Evaluation criteria for low-temperature fixability)
A evaluation: The minimum fixable temperature was 125 ° C. or lower.
B evaluation: The minimum fixing temperature was more than 125 ° C. and 130 ° C. or less.
C evaluation: The lowest fixable temperature was more than 130 ° C.

(Evaluation criteria for hot offset resistance)
A evaluation: The maximum fixable temperature was 220 ° C. or higher.
B Evaluation: The maximum fixable temperature was 210 ° C. or higher and lower than 220 ° C.
C evaluation: The maximum fixable temperature was less than 210 ° C.

(Comprehensive evaluation criteria for fixability)
A (very good): Both low-temperature fixability evaluation and hot offset resistance evaluation were A evaluations.
○ (Good): There was at least one B evaluation in the evaluation of low-temperature fixability and the evaluation of hot offset resistance. There was no C evaluation in either the evaluation of low temperature fixability or the evaluation of hot offset resistance.
X (Poor): There was at least one C evaluation in the evaluation of the low-temperature fixability and the evaluation of the hot offset resistance.

(Film resistance)
The evaluation environment for the filming resistance of the toner was a temperature of 25 ° C. and a relative humidity of 50% RH. A color printer (“TASKalfa500ci” manufactured by Kyocera Document Solutions Inc., a printer employing a touch-down development method) was used as an evaluation machine. The developer for evaluation was put into the developing device of the evaluation machine. Toner (any one of toners A-1 to A-5 and B-1 to B-7) was put into a toner container of an evaluation machine. In the evaluation machine, the voltage between the developing sleeve and the magnet roll was set to 250 V, and the alternating voltage (Vpp) applied to the magnet roll was set to 2.0 kV. An image I (image with a printing rate of 4%) was continuously printed on 5000 sheets of paper using an evaluation machine. After printing 5000 sheets, 1 image III (solid image with the same size as A4 paper and 100% printing rate) and 1 image IV (halftone image with the same size as A4 paper and 50% printing rate) Printed. The obtained solid image and halftone image were visually observed to confirm the presence of color points and image omission. Further, after the solid image and the halftone image were formed, the surface of the photoconductor of the evaluator was visually observed to confirm whether the toner component adhered to the surface of the photoconductor. From these observation results, the filming resistance of the toner was evaluated according to the following criteria. Table 4 shows the evaluation results of the filming resistance of the toner.

(Filming resistance evaluation criteria)
○ (Good): No color point or missing image in the solid image and the halftone image. The toner component did not adhere to the surface of the photoreceptor.
X (bad): One or both of a color point and an image omission were found in the solid image and the halftone image. Alternatively, the toner component has adhered to the surface of the photoreceptor.

(Blocking resistance)
3 g of toner was weighed into a plastic container and allowed to stand for 3 hours in a thermostat set at 60 ° C. As a result, a toner for heat resistant storage stability evaluation was obtained. Thereafter, using a powder tester (“TYPE PT-E 84810” manufactured by Hosokawa Micron Co., Ltd.) on which a 200-mesh sieve was set, the toner for heat resistant storage stability evaluation was sieved for 30 seconds under the conditions of rheostat scale 5. After sieving, the mass of toner remaining on the sieve was measured. From the mass of the toner before sieving and the mass of the toner remaining on the sieving after sieving, the proportion of toner passing through the mesh (passage rate, unit: mass%) was calculated according to the following formula. From the calculated degree of passage, heat resistant storage stability was evaluated according to the following criteria. Table 4 shows the evaluation results of the toner mesh passage rate and the toner blocking resistance.
Passing rate (mass%) = 100 × (mass of toner before sieving−mass of toner remaining on sieving after sieving) / mass of toner before sieving

(Evaluation criteria for blocking resistance)
A (very good): The passing rate was 95% by mass or more.
○ (Good): The passing rate was 90% by mass or more and less than 95% by mass.
Δ (Normal): The passing rate was 80% by mass or more and less than 90% by mass.
X (Poor): The passing rate was less than 80% by mass.

  In toners A-1 to A-5, the toner particles contained at least a crystalline polyester resin and nigrosine. In addition, the toners A-1 to A-5 satisfy the above formulas (1), (2), and (3). Therefore, as apparent from Table 2, the evaluation of the charging stability of the toners A-1 to A-5 was ◎ (very good). Further, as is apparent from Table 3, the overall evaluation of the fixability of the toners A-1 to A-5 was ◎ (very good) and ◯ (good). From the above, it was shown that the toner of the present invention is excellent in charging stability and fixability.

  Further, as apparent from Table 4, the evaluation of the filming resistance of the toners A-1 to A-5 was “good”. Further, as apparent from Table 4, the evaluation of blocking resistance of the toners A-1 to A-5 was ◎ (very good) and ◯ (good). From the above, it has been shown that the toner of the present invention is excellent in filming resistance and blocking resistance in addition to charging stability and fixability.

  The toner according to the present invention and the toner manufactured by the manufacturing method according to the present invention can be used for forming an image with an electrophotographic image forming apparatus, for example.

Claims (8)

An electrostatic latent image developing toner comprising a plurality of toner particles,
The toner particles contain at least a crystalline polyester resin and nigrosine,
The content W ₁ of the crystalline polyester resin with respect to the mass of the toner particles and the content W ₂ of the crystalline polyester resin contained in the ethanol-soluble content of the toner particles with respect to the mass of the toner particles are expressed by the following formula. The ethanol-soluble matter satisfying (1) is obtained by mixing 0.35 g of the toner particles and 4.00 g of ethanol for 3 minutes at a rotation speed of 100 rpm using a ball mill in an environment of 25 ° C. ,
The nigrosine content C ₁ with respect to the mass of the toner particles and the nigrosine content C ₂ contained in the ethanol-soluble component of the toner particles with respect to the mass of the toner particles satisfy the following formula (2). ,
The toner for developing an electrostatic latent image, wherein the content ratios W ₁ , W ₂ , C ₁ and C ₂ satisfy the following formula (3).
0.0010 ≦ 100 × W ₂ / W ₁ ≦ 0.1000 (1)
0.1000 ≦ 100 × C ₂ / C ₁ ≦ 10.000 (2)
1.00 ≦ (C ₂ / C ₁ ) / (W ₂ / W ₁ ) ≦ 1000.00 (3) The crystalline polyester resin region is dispersed in the toner particles,
2. The electrostatic latent image developing according to claim 1, wherein a dispersion diameter R of the region of 100% by number from a smaller dispersion diameter satisfies the following formula (4) in a dispersion diameter distribution based on the number of the regions. toner.
0.40 μm ≦ R ≦ 0.90 μm (4)   The electrostatic latent image developing toner according to claim 1, wherein the crystalline polyester resin is a polymer of alcohol and a carboxylic acid having a molecular weight of 150 to 300.   4. The electrostatic latent according to claim 3, wherein the carboxylic acid having a molecular weight of 150 to 300 is an alkane having a molecular weight of 150 to 300 and having two carboxyl groups and having 1 to 18 carbon atoms. Toner for image development.   5. The electrostatic latent image developing toner according to claim 1, wherein the toner particles further contain at least one of an amorphous polyester resin, a magnetic powder, and a releasing agent. A kneading step of kneading the crystalline polyester resin and the nigrosine,
In the kneading step, a part of the crystalline polyester resin and a part of the nigrosine are dissolved together to obtain the electrostatic latent image developing toner according to any one of claims 1 to 5. A method for producing toner for developing an electrostatic latent image.   In the kneading step, while the crystalline polyester resin region is dispersed in the toner particles, the dispersion diameter of the region of 100% by number from the smaller dispersion diameter in the number-based dispersion diameter distribution of the region is 0. The method for producing a toner for developing an electrostatic latent image according to claim 6, wherein a part of the crystalline polyester resin and a part of the nigrosine are dissolved together until 40 μm or more and 0.90 μm or less.   The method for producing a toner for developing an electrostatic latent image according to claim 6 or 7, wherein in the kneading step, the kneading speed is 150 rpm to 180 rpm, and the kneading temperature is 120 ° C to 170 ° C.