JP2017134198A - Toner for electrostatic latent image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic latent image development, which can suppress occurrence of image failure even when images are continuously formed, and which has excellent fixability, hot offset resistance, glossiness and heat-resistant storage property.SOLUTION: In the toner, only transparent toner particles contain a release agent and a crystalline polyester resin. The content percentage of the crystalline polyester resin is 10 mass% or more and 30 mass% or less with respect to the total mass of the binder resin included in the transparent toner particles. A volume median diameter of the transparent toner particles is greater than that of chromatic toner particles. A difference in the volume median diameter between the transparent toner particles and the chromatic toner particles is greater than 0.0 μm and 0.2 μm or less. A number percentage of chromatic toner particles having a particle diameter of 3.0 μm or less is 5.0 number% or less. A number percentage of chromatic toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter of the chromatic toner particles is greater than a number percentage of transparent toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter of the transparent toner particles.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrostatic latent image developing toner (hereinafter sometimes referred to as toner).

  When an image is formed on a recording medium using the image forming apparatus and toner, for example, a toner image formed with toner is transferred to the recording medium. The transferred toner image is fixed on the recording medium by being heated and pressurized using, for example, a fixing roller. In order to form a high-quality image while reducing the energy required for fixing, it is desired to improve the fixing property of the toner to the recording medium. In order to improve the fixability of the toner, the electrophotographic image forming toner described in Patent Document 1 contains a crystalline polyester resin and an amorphous resin.

  Further, when a toner image is fixed on a recording medium using a fixing roller, a toner hot offset may occur. Hot offset is a phenomenon in which when a toner image is fixed on a recording medium, a part of the toner image adheres to the surface of the fixing roller, and the toner attached to the surface of the fixing roller transfers to another recording medium. In order to suppress the occurrence of hot offset, for example, toner particles may contain a release agent such as wax. However, when a release agent is contained in the toner particles, dispersion of components such as a colorant and a binder resin contained in the toner particles is likely to be hindered. As a result, a hue failure easily occurs in the formed image, and it is difficult to obtain a high-quality image. In order to suppress the occurrence of hot offset and form a high-quality image, the toner for forming a multicolor image described in Patent Document 2 contains a transparent toner in addition to the colored toner. The transparent toner contains a wax component. The colored toner does not contain a wax component.

JP 2014-174262 A JP 2006-11218 A

  The toner for forming an electrophotographic image described in Patent Document 1 contains a crystalline polyester resin. A crystalline polyester resin is easily melted at a low temperature as compared with an amorphous resin. When the toner is melted at a low temperature, the toner particles tend to aggregate when the toner is stored. Therefore, it is difficult for the toner described in Patent Document 1 to improve the heat resistant storage stability. Furthermore, the toner described in Patent Document 1 is insufficient in suppressing the occurrence of image defects, fixing properties, hot offset resistance, and glossiness.

  In order to use the toner for forming a multicolor image described in Patent Document 2, the image forming apparatus needs to include a toner hopper for transparent toner in addition to a toner hopper for colored toner. Since such an image forming apparatus has an image forming process using transparent toner in addition to an image forming process using colored toner, the number of image forming processes is one. As the number of steps for image formation increases, it becomes difficult to reduce the size of the image forming apparatus. Further, since a layer formed of transparent toner is formed on the recording medium in addition to a layer formed of colored toner, the formed image is likely to be disturbed. Therefore, with the toner described in Patent Document 2, it is difficult to suppress the occurrence of image defects particularly when images are continuously formed. In addition, the toner described in Patent Document 2 is insufficient in fixability, hot offset resistance, glossiness, and heat storage stability.

  The present invention has been made in view of the above problems, and its purpose is to suppress the occurrence of image defects even when images are continuously formed, and to achieve fixing properties, hot offset resistance, glossiness, and the like. It is to provide a toner having heat resistant storage stability.

  The electrostatic latent image developing toner according to the present invention contains a colored toner including a plurality of colored toner particles and a transparent toner including a plurality of transparent toner particles. Of the colored toner particles and the transparent toner particles, only the transparent toner particles contain a release agent and at least a crystalline polyester resin as a binder resin. The content of the crystalline polyester resin contained in the transparent toner particles is 10% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles. The volume median diameter of the transparent toner particles is larger than the volume median diameter of the colored toner particles, and the difference between the volume median diameter of the transparent toner particles and the volume median diameter of the colored toner particles is 0. It is greater than 0 μm and less than or equal to 0.2 μm. The number ratio of the colored toner particles having a particle diameter of 3.0 μm or less is 5.0% by number or less with respect to the total number of the colored toner particles. The ratio of the number of the colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of the colored toner particles to the total number of the colored toner particles is the transparent toner particles to the total number of the transparent toner particles. Is larger than the number ratio of the transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter.

  According to the present invention, it is possible to provide a toner that can suppress the occurrence of image defects even when images are continuously formed, and has both fixing property, hot offset resistance, glossiness, and heat-preserving property.

FIG. 6 is a diagram for explaining transfer of toner according to the present invention from an image carrier to a sheet. (A) is the photograph which observed the colored toner contained in the toner which concerns on this invention using the scanning electron microscope. (B) is the photograph figure which expanded the part shown by the circle in the photograph figure shown by (a). (C) is the photograph figure which mapped the titanium atom with respect to the photograph figure shown by (b). (A) is a figure which shows an example of the number distribution of the particle diameter of the transparent toner contained in the toner which concerns on this invention. (B) is a diagram showing an example of the number distribution of the particle diameter of the colored toner contained in the toner according to 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. Furthermore, acryl and methacryl are sometimes collectively referred to as “(meth) acryl”.

Hereinafter, the average value means a number average value unless otherwise specified. Further, an evaluation value (a value indicating a shape or physical property) regarding a powder (for example, toner or toner particles) 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-circle diameter of primary particles measured by 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.

<1. Toner>
This embodiment relates to a toner. The toner contains a colored toner and a transparent toner. The toner is a powder composed of a large number of colored toner particles and a large number of transparent toner particles. The colored toner includes a plurality of colored toner particles. The colored toner is a powder composed of a large number of colored toner particles. The transparent toner includes a plurality of transparent toner particles. The transparent toner is a powder composed of a large number of transparent toner particles. Hereinafter, the color toner particles and the transparent toner particles may be collectively referred to as toner particles. The toner particles may be non-capsule toner particles. The toner particles may be capsule toner particles including a toner core and a shell layer formed on the surface of the toner core.

  The toner according to the exemplary embodiment is preferably a nonmagnetic toner. When the toner is a non-magnetic toner, the toner particles do not contain magnetic powder. Toner containing magnetic powder tends to be black. By not containing magnetic powder in the toner particles, it is easy to apply to colored toner particles other than black. Further, it becomes easy to maintain the transparency of the transparent toner particles. The toner according to the present embodiment may be a magnetic toner containing magnetic powder.

  The toner according to the exemplary embodiment can be used as a one-component developer. The toner may be used in a two-component developer by mixing the toner with a desired carrier.

The toner according to the exemplary embodiment has the following configurations (1) to (6).
Configuration (1): Contains a colored toner including a plurality of colored toner particles and a transparent toner including a plurality of transparent toner particles.
Configuration (2): Only the transparent toner particles among the colored toner particles and the transparent toner particles contain a release agent and at least a crystalline polyester resin as a binder resin.
Configuration (3): The content of the crystalline polyester resin contained in the transparent toner particles is 10% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles.
Configuration (4): The volume median diameter (D ₅₀ t) of the transparent toner particles is larger than the volume median diameter (D ₅₀ c) of the colored toner particles, and the volume median diameter (D ₅₀ t) of the transparent toner particles is The difference from the volume median diameter (D ₅₀ c) of the colored toner particles is larger than 0.0 μm and not larger than 0.2 μm.
Configuration (5): The number ratio (Rcs) of colored toner particles having a particle diameter of 3.0 μm or less is 5.0% by number or less with respect to the total number of colored toner particles.
Configuration (6): The ratio (Rc1) of the number of colored toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter of the colored toner particles to the total number of colored toner particles is transparent to the total number of transparent toner particles. It is larger than the number ratio (Rt1) of transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of the toner particles.

  In the configuration (1), the color toner and the transparent toner are mixed, for example. Therefore, when the toner has the configuration (1), the image forming apparatus may not include a toner hopper for transparent toner. Therefore, the image forming apparatus can be downsized without increasing the image forming process.

  Next, since the toner has the configuration (2), the toner is considered to have the following advantages. The first advantage that the toner has the constitution (2) is as follows. When the transparent toner particles contain a release agent, the toner is easily separated from the fixing roller. This makes it difficult for a part of the toner image to adhere to the surface of the fixing roller when the toner image is fixed on the recording medium. Thereby, the hot offset resistance of the toner can be improved.

  The second advantage that the toner has the constitution (2) is as follows. It is considered that the color toner particles do not contain a release agent, so that poor dispersion of components such as a colorant and a binder resin contained in the toner particles can be suppressed. Thereby, it can be considered that the color reproducibility of the formed image can be suppressed and the occurrence of image defects can be suppressed.

  The third advantage that the toner has the constitution (2) is as follows. It is considered that the heat-resistant storage stability of the toner can be improved because the transparent toner particles contain at least a crystalline polyester resin as a binder resin and the colored toner particles do not contain a crystalline polyester resin as a binder resin. A crystalline polyester resin is easily melted at a low temperature as compared with an amorphous resin. Therefore, normally, when the toner particles contain a crystalline polyester resin, the toner particles are aggregated and the heat resistant storage stability of the toner tends to be lowered. This is because toner particles that tend to aggregate are brought into contact with each other, so that aggregation of the toner particles proceeds. However, in the toner of this embodiment, transparent toner particles containing a crystalline polyester resin and colored toner particles not containing a crystalline polyester resin are mixed. Therefore, for example, when storing toner, it is considered that transparent toner particles containing a crystalline polyester resin are covered with colored toner particles not containing a crystalline polyester resin. It is considered that the aggregation of the colored toner particles and the transparent toner particles as a whole can be suppressed by covering the transparent toner particles that are easily aggregated with the colored toner particles that are difficult to aggregate. As a result, it is considered that the heat resistant storage stability of the toner can be improved.

  Next, it is considered that the fixing property of the toner is improved when the toner has the configuration (3). Crystalline polyester resins tend to melt at low temperatures compared to amorphous resins. Therefore, when the content of the crystalline polyester resin is within the range of the configuration (3), the toner can be easily fixed on the recording medium even when the fixing temperature is low. In a normal toner, if the content of the crystalline polyester resin is within such a range, the toner particles tend to aggregate because the content of the crystalline polyester resin is high. However, since the toner of the present embodiment has the configuration (2) as described above, even if the content of the crystalline polyester resin is within such a range, the entire colored toner particles and transparent toner particles Aggregation can be suppressed. As a result, both toner fixability and heat-resistant storage stability can be achieved.

Next, the configuration (4) will be described. As described above, the volume median diameter (D ₅₀ t) of the transparent toner particles is larger than the volume median diameter (D ₅₀ c) of the colored toner particles, and the volume median diameter (D ₅₀ t) of the transparent toner particles. And the volume median diameter (D ₅₀ c) of the colored toner particles is larger than 0.0 μm and not larger than 0.2 μm. That is, D ₅₀ t (unit μm) and D ₅₀ c (unit μm) satisfy the following formula (Ia).
0.0 <D ₅₀ t−D ₅₀ c ≦ 0.2 (Ia)

  When the toner has the configuration (4), the toner is considered to have the following advantages. In order to facilitate understanding, a case where an image is formed using an image forming apparatus that employs a one-component jumping development method and a direct transfer method will be described as an example. However, the developing method and the transfer method of the image forming apparatus using the toner of the present embodiment are not limited to the one-component jumping developing method and the direct transfer method.

  Hereinafter, the advantage that the toner has the configuration (4) will be described with reference to FIG. FIG. 1 is a diagram for explaining the transfer of the toner 1 according to the present embodiment from the image carrier 10 to the paper P. FIG. The toner 1 includes a plurality of transparent toner particles 1t and a plurality of colored toner particles 1c. In the image forming process using the toner 1, for example, a charging process, an exposure process, a development process, a transfer process, and a fixing process are performed.

First, the development process will be described. When the image forming apparatus adopts the one-component jumping development method, the image force and van der Waals force are likely to act on the colored toner particles 1c having a small volume median diameter (D ₅₀ c) in the development process. Therefore, the colored toner particles 1c are difficult to be developed from the developing sleeve (not shown) to the image carrier 10 (for example, the photosensitive drum). For this reason, the transparent toner particles 1t having a larger volume median diameter (D ₅₀ t) are more easily developed from the developing sleeve to the image carrier 10 than the colored toner particles 1c having a smaller volume median diameter (D ₅₀ c). Therefore, when developing the toner 1 of the present embodiment, the transparent toner particles 1t having a large volume median diameter (D ₅₀ t) are first developed on the image carrier 10 to obtain a volume median diameter (D ₅₀ c). It is considered that the colored toner particles 1c having a small size are developed on the image carrier 10 later.

The transparent toner particles 1t and the colored toner particles 1c developed on the image carrier 10 are considered to form a laminated structure on the image carrier 10. Specifically, the transparent toner particles 1t having a large volume median diameter (D ₅₀ t) can easily form a layer of the transparent toner particles 1t on the image carrier 10 side. In addition, the colored toner particles 1c having a small volume median diameter (D ₅₀ c) can easily form a layer of the colored toner particles 1c on the developing sleeve side. That is, at the time of developing the toner 1, it is considered that a positional relationship is formed in which the layer of transparent toner particles 1t is disposed on the image carrier 10 and the layer of colored toner particles 1c is disposed on the layer of transparent toner particles 1t. It is done.

  Next, the transfer process will be described. When the image forming apparatus adopts the direct transfer method, the toner 1 is transferred from the image carrier 10 to the paper P while maintaining the positional relationship formed in the development process. Therefore, it is considered that when the toner 1 is transferred, a positional relationship is formed in which the layer of colored toner particles 1c is disposed on the paper P and the layer of transparent toner particles 1t is disposed on the layer of colored toner particles 1c. By disposing the layer of the transparent toner particles 1t on the layer of the colored toner particles 1c, an image having excellent gloss can be formed.

  Next, the fixing process will be described. The transparent toner particle 1t layer is disposed on the colored toner particle 1c layer in the development process, so that the transparent toner particle 1t layer containing a crystalline polyester resin is formed near the fixing roller (not shown) in the fixing process. Will be located. Therefore, the fixability of the toner 1 can be improved.

  Further, when the layer of the transparent toner particles 1t is arranged on the layer of the colored toner particles 1c, the layer of the transparent toner particles 1t containing a release agent is positioned near the fixing roller when the toner 1 is fixed. become. Therefore, when the toner 1 is fixed, a part of the toner image is difficult to adhere to the surface of the fixing roller. Thereby, the hot offset resistance of the toner 1 can be improved.

As described above, the difference between the volume median diameter (D ₅₀ t) of the transparent toner particles and the volume median diameter (D ₅₀ c) of the colored toner particles is greater than 0.0 μm and 0.2 μm or less. If the difference (D ₅₀ t−D ₅₀ c) exceeds 0.2 μm, a difference is likely to occur between the charge amount of the transparent toner and the charge amount of the colored toner. For this reason, the color reproducibility of the formed image is likely to be lowered, and an image defect such as unevenness of the developing sleeve layer is likely to occur. As a result, an image defect is likely to occur when images are continuously formed. Further, fog is likely to occur in the formed image. Furthermore, when the difference (D ₅₀ t−D ₅₀ c) is 0.2 μm or less, it is considered that one of the colored toner particles and the transparent toner particles can be suppressed from being buried in the other.

  The advantage of the toner having the configuration (4) has been described above with reference to FIG.

In a preferred example of the configuration (4), the difference between the volume median diameter (D ₅₀ t) of the transparent toner particles and the volume median diameter (D ₅₀ c) of the colored toner particles is 0.1 μm or more and 0.2 μm or less. is there. That is, it is preferable that D ₅₀ t (unit μm) and D ₅₀ c (unit μm) satisfy the following formula (Ib). By satisfying the mathematical formula (Ib), it is easy to form a positional relationship in which the transparent toner particle layer is disposed on the image carrier and the colored toner particle layer is disposed on the transparent toner particle layer during toner development.
0.1 ≦ D ₅₀ t−D ₅₀ c ≦ 0.2 (Ib)

The volume median diameter (D ₅₀ t) of the transparent toner particles and the volume median diameter (D ₅₀ c) of the colored toner particles are measured, for example, by the following method. Using a precise particle size distribution measuring device (for example, “Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc.), a volume distribution of the particle diameter of the measurement sample (transparent toner) is obtained. From the volume distribution of the particle diameter of the obtained transparent toner, the volume median diameter (D ₅₀ t) of the transparent toner particles is obtained. The volume median diameter (D ₅₀ c) of the colored toner particles is measured in the same manner as the volume median diameter (D ₅₀ t) of the transparent toner particles, except that the measurement sample is changed from the transparent toner to the color toner. Is done.

Next, the configuration (5) will be described. As described above, the number ratio (Rcs) of colored toner particles having a particle diameter of 3.0 μm or less is 5.0 number% or less with respect to the total number of colored toner particles. That is, Rcs satisfies the following formulas (II) and (IIIa).
Rcs (number%) = number of colored toner particles having a particle diameter of 100 × 3.0 μm or less / total number of colored toner particles (II)
Rcs ≦ 5.0 (IIIa)

Usually, toner particles having a small particle diameter have a strong adhesion to the developing sleeve and are likely to remain on the developing sleeve. Therefore, the formed image may be disturbed. In the toner of this embodiment, as described in the configuration (4), the volume median diameter (D ₅₀ c) of the colored toner particles is smaller than the volume median diameter (D ₅₀ t) of the transparent toner particles. Therefore, the number ratio of colored toner particles having a small particle diameter tends to be higher than that of transparent toner particles. However, the toner of this embodiment has the configuration (5). Therefore, it is difficult for the colored toner particles to remain on the developing sleeve, and the occurrence of image defects can be suppressed.

In a preferred example of the configuration (5), the number ratio (Rcs) of colored toner particles having a particle diameter of 3.0 μm or less is 3.5% by number or more and 4.0 number with respect to the total number of colored toner particles. % Or less. That is, Rcs preferably satisfies the following mathematical formula (IIIb).
3.5 ≦ Rcs ≦ 4.0 (IIIb)

  Hereinafter, an example of a method for measuring the number ratio (Rcs) of colored toner particles having a particle diameter of 3.0 μm or less with respect to the total number of colored toner particles will be described. First, using a scanning electron microscope, a photograph of the measurement sample (colored toner) is taken at an observation magnification of 2000 times. When the measurement sample contains an external additive, the measurement sample is subjected to elemental analysis, and atoms characteristic of the external additive (for example, a titanium atom, a silicon atom, or a zinc atom) are mapped. Thereby, a photograph of the measurement sample observed at an observation magnification of 2000 times in which atoms characteristic to the external additive are mapped is taken. By contrasting these photographs, the total number of colored toner particles and the number of colored toner particles having a particle diameter of 3.0 μm or less observed in one visual field are measured. When measuring the number of colored toner particles having a particle diameter of 3.0 μm or less, care should be taken not to count external additive particles. For example, particles to which atoms characteristic of the external additive are mapped are not counted because they are external additive particles. From the total number of colored toner particles to be measured and the number of colored toner particles having a particle diameter of 3.0 μm or less, the percentage of the number of colored toner particles having a particle diameter of 3.0 μm or less to the total number of colored toner particles (Number ratio Rcs) is calculated.

  Hereinafter, with reference to FIGS. 2A, 2B, and 2C, an example of a method for determining whether particles observed in one field of a microscope are colored toner particles or external additive particles will be described. To do. For ease of understanding, FIGS. 2A, 2B, and 2C are shown at a magnification higher than the observation magnification of the method for measuring the number ratio (Rcs) described above. FIG. 2A is a photograph of the colored toner contained in the toner according to the present embodiment observed using a scanning electron microscope. FIG. 2A is a photograph taken under the conditions of an observation magnification of 5000 times and an acceleration voltage of 20 kV. The scale bar in Fig.2 (a) shows 5 micrometers. FIG.2 (b) is the photograph figure to which the part shown by the circle in the photograph figure shown to Fig.2 (a) was expanded. FIG. 2 (c) is a photograph in which atoms characteristic to the external additive (titanium atoms in FIG. 2 (c)) are mapped to the photograph shown in FIG. 2 (b). In FIG. 2 (c), the portion where the characteristic atoms of the external additive are mapped is shown in white. When the target particles included in the circled portion in the photograph shown in FIG. 2 (a) are mapped as shown in FIG. 2 (c), it is determined that the target particles are external additive particles. The

Next, the configuration (6) will be described. As described above, the number ratio (Rc1) of the colored toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter (D ₅₀ c) of the colored toner particles with respect to the total number of the colored toner particles is the transparent toner. It is larger than the number ratio (Rt1) of transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter (D ₅₀ t) of the transparent toner particles with respect to the total number of particles. That is, Rc1 and Rt1 satisfy the following mathematical formulas (IV), (V), and (VIa).
Rc1 (number%) = 100 × number of colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of colored toner particles / total number of colored toner particles (IV)
Rt1 (number%) = 100 × number of transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of transparent toner particles / total number of transparent toner particles (V)
Rc1> Rt1 (VIa)

The colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter (D ₅₀ c) of the colored toner particles are colored toner particles having a particle diameter of “D ₅₀ c−1.0 μm” or less. is there. The transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter (D ₅₀ t) of the transparent toner particles are transparent toner particles having a particle diameter of “D ₅₀ t−1.0 μm” or less.

Here, when the range in which the particle diameter of the colored toner particles overlaps the particle diameter of the transparent toner particles is reduced, a transparent toner particle layer is disposed on the image carrier during toner development, and the transparent toner particle layer is disposed on the transparent toner particle layer. A positional relationship in which the colored toner particle layers are arranged is easily formed. As described in the configuration (4), the volume median diameter (D ₅₀ t) of the transparent toner particles is larger than the volume median diameter (D ₅₀ c) of the colored toner particles. Therefore, by reducing the number distribution on the fine powder side of the transparent toner particles having a large volume median diameter (D ₅₀ t) smaller than that of the colored toner particles, the particle diameter of the colored toner particles and the particle diameter of the transparent toner particles are reduced. It is considered that the overlapping range can be reduced. The toner of this embodiment has the configuration (6). Therefore, it is considered that the range in which the particle diameters of the colored toner particles and the transparent toner particles overlap can be reduced. Therefore, the positional relationship between the transparent toner particle layer and the colored toner particle layer is easily formed continuously. As a result, it is possible to suppress the occurrence of image defects even when images are continuously formed.

In a preferred example of the configuration (6), the number ratio (Rc1) of the colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter (D ₅₀ c) of the colored toner particles with respect to the total number of the colored toner particles. And the ratio of the number (Rt1) of transparent toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter (D ₅₀ t) of the transparent toner particles to the total number of transparent toner particles is 5 or more and 6 It is as follows. That is, Rc1 and Rt1 preferably satisfy the following mathematical formula (VIb). By satisfying the following mathematical formula (VIb), it is possible to particularly suppress the occurrence of image defects even in continuous cases.
5 ≦ Rc1−Rt1 ≦ 6 (VIb)

The number ratio (Rt1) is measured, for example, by the following method. Using a precision particle size distribution measuring apparatus (for example, “Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc.), the number distribution of the particle diameter of the measurement sample (transparent toner) is obtained. The number ratio (Rt1) is calculated from the number distribution of the particle diameter of the obtained transparent toner according to the mathematical formula (V). FIG. 3A shows an example of the number distribution of the particle diameter of the transparent toner. In FIG. 3A, the horizontal axis indicates the particle diameter (μm) of the transparent toner particles. The vertical axis represents the number ratio (number%) of transparent toner particles having a corresponding particle diameter. The number ratio (Rt1) of the transparent toner particles having a particle diameter (D ₅₀ t−1.0 μm or less) smaller than the volume median diameter of the transparent toner particles by 1.0 μm or more with respect to the total number of the transparent toner particles. This corresponds to the ratio of the area of the region indicated by diagonal lines to the area of the region surrounded by the number distribution curve and the horizontal axis.

The number ratio (Rc1) is measured by, for example, the following method. Using a precision particle size distribution measuring apparatus (for example, “Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc.), the number distribution of the particle diameter of the measurement sample (colored toner) is obtained. The number ratio (Rc1) is calculated from the number distribution of the particle diameters of the obtained colored toners according to the formula (IV). FIG. 3B shows an example of the number distribution of the particle diameter of the colored toner. In FIG. 3B, the horizontal axis indicates the particle diameter (μm) of the colored toner particles. The vertical axis represents the number ratio (number%) of colored toner particles having a corresponding particle diameter. The number ratio (Rc1) of colored toner particles having a particle diameter (D ₅₀ c−1.0 μm or less) smaller than the volume median diameter of the colored toner particles by 1.0 μm or more with respect to the total number of colored toner particles. This corresponds to the ratio of the area of the area indicated by the dots to the area of the area surrounded by the number distribution curve and the horizontal axis.

  The content of the colored toner is preferably 1.0 part by mass or more and 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner. When the content of the colored toner is 1.0 part by mass or more with respect to 1.0 part by mass of the transparent toner, the color reproducibility in the formed image can be improved and the occurrence of image defects can be suppressed. When the content of the colored toner is 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner, the toner fixability can be improved. Further, it becomes easy to improve the hot offset resistance of the toner.

  The content of the colored toner is more preferably 3.0 parts by mass or more and 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner. When the content of the colored toner is within such a range, the heat resistant storage stability of the toner can be further improved.

<2. Colored toner>
The colored toner particles contained in the colored toner do not contain a release agent and a crystalline polyester resin. When the colored toner particles do not contain a release agent, it becomes easy to improve the dispersibility of components such as a colorant and a binder resin contained in the toner particles. As a result, color reproducibility in the formed image is improved, and a high-quality image is easily formed. Further, since the colored toner particles do not contain the crystalline polyester resin, the heat resistant storage stability of the toner is easily improved.

The colored toner particles contain a binder resin different from the crystalline polyester resin and a colorant. The colored toner particles may contain a charge control agent as necessary. The volume median diameter (D ₅₀ c) of the colored toner particles satisfies the above-described configuration (4) and is preferably 5.0 μm or more and 10.0 μm or less.

<2-1. Binder resin>
The colored toner particles contain a binder resin different from the crystalline polyester resin. The binder resin contained in the colored toner particles is preferably non-crystalline. Whether the binder resin contained in the colored toner particles is crystalline or non-crystalline can be determined from the crystallinity of the binder resin, for example. In this embodiment, a binder resin having a crystallinity of 50.0% or more is made crystalline. In this embodiment, a binder resin having a crystallinity of less than 50.0% is made non-crystalline. The degree of crystallinity of the binder resin contained in the colored toner particles is preferably 0.0% or more and less than 50.0%, more preferably 0.0% or more and less than 27.0%. It is especially preferable that it is 0.0% or more and 26.5% or less. The crystallization degree of the binder resin contained in the colored toner particles is the same as the measurement of the crystallization degree of the polyester resin described later, except that the measurement sample is changed from the polyester resin to the binder resin contained in the colored toner particles. It is measured by the method.

  An example of a binder resin different from the crystalline polyester resin contained in the colored toner particles is the same as an example of another binder resin contained in the transparent toner particles described later. Among these binder resins, a styrene resin, a styrene acrylate resin, or an amorphous polyester resin can improve the dispersibility of the colorant in the toner, the chargeability of the toner, and the fixability of the toner to the recording medium. Is preferred, and an amorphous polyester resin is more preferred.

  The amorphous polyester resin that may be contained in the colored toner particles is the same as the amorphous polyester resin that may be contained in the transparent toner particles described later.

  Hereinafter, the styrene resin and styrene acrylic acid resin used as the binder resin will be described. The styrene resin is a polymer of a styrene monomer. The styrene resin may be a copolymer of a styrene monomer and other monomers (monomers other than styrene monomers and acrylic monomers). The styrene acrylic acid resin is a copolymer of a styrene monomer and an acrylic acid monomer. The styrene acrylic acid resin may be a copolymer of a styrene monomer, an acrylic acid monomer, and another monomer.

  Examples of styrenic monomers include styrene, α-methylstyrene, p-hydroxystyrene, m-hydroxystyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene or p- Ethyl styrene is mentioned.

  Examples of acrylic monomers include (meth) acrylic acid, (meth) acrylic acid alkyl ester, (meth) acrylic acid hydroxyalkyl ester, (meth) acrylic acid 2-chloroethyl, α-chloro (meth) acrylic acid methyl , Phenyl (meth) acrylate or other acrylic acid derivatives. Examples of (meth) acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, iso-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate or dodecyl (meth) acrylate. Examples of hydroxyalkyl esters of (meth) acrylic acid include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate or (meth) acrylic acid 4- Hydroxybutyl is mentioned. Examples of other acrylic acid derivatives include acrylonitrile, methacrylonitrile or acrylamide.

  Examples of other monomers include vinyl naphthalene, alkylene monoolefin, vinyl halide, vinyl esters, vinyl alkyl ethers, vinyl ketones, and N-vinyl compounds. Examples of alkylene monoolefins include alkylene (eg ethylene, propylene, butylene or isobutylene) monoolefins. Examples of the vinyl halide include vinyl chloride, vinyl bromide, and vinyl fluoride. Examples of vinyl esters include vinyl acetate, vinyl propionate, vinyl benzoate or vinyl butyrate. Examples of vinyl alkyl ethers include vinyl methyl ether or vinyl isobutyl ether. Examples of vinyl ketones include vinyl methyl ketone, vinyl ethyl ketone, or methyl isopropenyl ketone. Examples of the N-vinyl compound include N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole or N-vinyl pyrrolidene.

  When preparing a styrene acrylic acid resin, for example, by using a monomer having a hydroxyl group (for example, p-hydroxystyrene, m-hydroxystyrene or (meth) acrylic acid hydroxyalkyl ester), a hydroxyl group is added to the styrene acrylic resin. Is introduced. For example, the hydroxyl value of the resulting styrene acrylic resin is adjusted by adjusting the amount of the monomer having a hydroxyl group.

  When preparing a styrene acrylic resin, a carboxyl group is introduced into the styrene acrylic resin by using, for example, (meth) acrylic acid. For example, the acid value of the resulting styrene acrylic resin is adjusted by adjusting the amount of (meth) acrylic acid used.

  When the binder resin is a styrene resin or a styrene acrylic resin, the number average molecular weight of the styrene resin or the styrene acrylic resin is used to improve the strength of the colored toner particles and the fixing property of the toner to the recording medium. (Mn) is preferably 2000 or more and 3000 or less. The molecular weight distribution (the ratio Mw / Mn of the mass average molecular weight Mw to the number average molecular weight Mn) of the styrene resin or styrene acrylic acid resin is preferably 10 or more and 20 or less. Mn and Mw of the styrene resin or styrene acrylic acid resin are measured using, for example, gel permeation chromatography.

  The colored toner particles may contain a thermosetting resin as a binder resin. When the colored toner particles contain a thermosetting resin, a partially cross-linked structure is introduced into the binder resin, improving the toner fixability to the recording medium, while maintaining the heat resistant storage stability, shape retention and durability of the toner. It is easy to improve the property. The thermosetting resin that the colored toner particles may contain is the same as the thermosetting resin that the transparent toner particles described later may contain.

  The glass transition point (Tg) of the binder resin contained in the colored toner particles is preferably 50 ° C. or higher and 65 ° C. or lower, and more preferably 50 ° C. or higher and 60 ° C. or lower. If the glass transition point of the binder resin is 50 ° C. or higher, the toner particles and other toner particles are difficult to fuse in the developing device. Further, the toner particles hardly adhere to the image carrier. When the glass transition point of the binder resin is 65 ° C. or less, the low-temperature fixability of the toner can be easily improved. The glass transition point of the binder resin is obtained from the change point of the specific heat in the endothermic curve, for example, by measuring the endothermic curve of the binder resin using a differential scanning calorimeter.

<2-2. Colorant>
As the colorant contained in the colored toner particles, a known pigment or dye is used according to the color of the colored toner. The content of the colorant is preferably 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the binder resin.

  The colorant contained in the colored toner particles may be 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 colorant contained in the colored toner particles may be a yellow colorant, a magenta colorant, or a cyan colorant.

  Examples of yellow colorants include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, or arylamide compounds. Suitable examples of yellow colorants 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. Bat yellow is mentioned.

  Examples of magenta colorants include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinone compounds, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds or perylene compounds. Suitable examples of magenta colorants 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).

  Examples of cyan colorants include copper phthalocyanine, copper phthalocyanine derivatives, anthraquinone compounds or basic dye lake compounds. Suitable 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.

  Further, colorants other than yellow, magenta and cyan may be used. Examples of such a colorant include dyes such as Acid Violet.

<2-3. Charge Control Agent>
The colored toner particles may contain a charge control agent. The charge control agent is blended, for example, in order to improve the charge level and charge rise characteristics of the toner and to obtain a toner having excellent durability and stability. The toner charge rising characteristic is an index of whether or not the toner can be charged to a predetermined charge level in a short time. When developing using a positively charged toner, it is preferable to add a positively chargeable charge control agent. In the case of developing using a negatively charged toner, it is preferable to add a negatively chargeable charge control agent.

  Examples of positively chargeable charge control agents include pyridazine, pyrimidine, pyrazine, 1,2-oxazine, 1,3-oxazine, 1,4-oxazine, 1,2-thiazine, 1,3-thiazine, 1, 4-thiazine, 1,2,3-triazine, 1,2,4-triazine, 1,3,5-triazine, 1,2,4-oxadiazine, 1,3,4-oxadiazine, 1,2,6- Oxadiazine, 1,3,4-thiadiazine, 1,3,5-thiadiazine, 1,2,3,4-tetrazine, 1,2,4,5-tetrazine, 1,2,3,5-tetrazine, 1, Azine compounds such as 2,4,6-oxatriazine, 1,3,4,5-oxatriazine, phthalazine, quinazoline or quinoxaline; Azin Fast Red FC, Azin Fast Red 12BK, Azinba Direct dyes composed of azine compounds such as Olet BO, Azin Brown 3G, Azin Light Brown GR, Azin Dark Green BH / C, Azin Deep Black EW or Azin Dee Black 3RL; Nigrosine compounds such as nigrosine, nigrosine salts or nigrosine derivatives An acid dye comprising a nigrosine compound such as nigrosine BK, nigrosine NB or nigrosine Z; metal salts of naphthenic acid or higher fatty acids; alkoxylated amines; alkylamides; or 4 such as benzyldecylhexylmethylammonium and decyltrimethylammonium chloride; A class ammonium salt is mentioned. Two or more of these charge control agents may be combined. Of these positively chargeable charge control agents, a nigrosine compound is preferable from the viewpoint of obtaining a quicker charge rising property of the toner.

  Moreover, you may use the resin or oligomer which has a quaternary ammonium salt, carboxylate, or a carboxyl group as a functional group as a positively chargeable charge control agent. More specifically, a styrene resin having a quaternary ammonium salt, an acrylic acid resin having a quaternary ammonium salt, a styrene acrylic acid resin having a quaternary ammonium salt, a polyester resin having a quaternary ammonium salt, a carvone Styrene resin having acid salt, acrylic acid resin having carboxylate, styrene acrylic resin having carboxylate, polyester resin having carboxylate, polystyrene resin having carboxyl group, having carboxyl group Examples thereof include acrylic resins, styrene acrylic resins having a carboxyl group, and polyester resins having a carboxyl group.

  From the viewpoint of easily adjusting the charge amount to a value within the desired range, a styrene acrylic acid resin having a quaternary ammonium salt as a functional group is preferable. Examples of the acrylic monomer used in the styrene acrylic resin include methyl (meth) acrylate or alkyl (meth) acrylate. Examples of (meth) acrylic acid alkyl esters include ethyl (meth) acrylate, n-propyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, and (meth) acrylic. Examples include iso-butyl acid or 2-ethylhexyl (meth) acrylate.

  The quaternary ammonium salt is derived from, for example, a (meth) acrylic acid dialkylaminoalkyl ester through a quaternization step. Examples of the derived (meth) acrylic acid dialkylaminoalkyl ester include, for example, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, or dibutyl (meth) acrylate. Preferred are (meth) acrylic acid di (lower alkyl) aminoethyl such as aminoethyl; dimethyl (meth) acrylamide; dimethylaminopropyl (meth) acrylamide. Further, a hydroxy group-containing polymerizable monomer such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate or N-methylol (meth) acrylamide may be used in combination during polymerization. Good.

  Examples of the negatively chargeable charge control agent include organometallic complexes that are chelate compounds. As the organometallic complex, for example, an acetylacetone metal complex, a salicylic acid metal complex or a salt thereof is preferable, and a salicylic acid metal complex or a salicylic acid metal salt is more preferable. Specific examples include aluminum acetylacetonate, iron (II) acetylacetonate or chromium 3,5-di-tert-butylsalicylate.

  The content of the charge control agent is preferably 0.5 parts by mass or more and 15 parts by mass or less, and 0.5 parts by mass or more and 8.0 parts by mass or less with respect to 100 parts by mass of the total toner. Is more preferable, and most preferably 0.5 parts by mass or more and 7.0 parts by mass or less. When the content of the charge control agent is 0.5 parts by mass or more, the toner is easily and stably charged, so that the image density is easily improved. In addition, it is easy to suppress the occurrence of fog due to poor dispersion of the charge control agent, and it is easy to prevent contamination of the image carrier with toner. When the content of the charge control agent is 15 parts by mass or less, the toner can be easily and stably charged even under high temperature and high humidity. Therefore, image defects can be easily suppressed and contamination of the image carrier with the toner can be easily suppressed.

<3. Transparent toner particles>
Of the colored toner particles and transparent toner particles, only the transparent toner particles contain a release agent and a crystalline polyester resin. Thereby, as already described, the occurrence of image defects in the formed image can be suppressed, and the hot offset resistance and heat resistant storage stability of the toner can be improved. The transparent toner particles further contain a binder resin different from the crystalline polyester resin. Transparent toner particles have translucency. Therefore, it is preferable that the transparent toner particles do not contain a colorant. The transparent toner particles may contain a charge control agent as necessary. The volume median diameter (D ₅₀ t) of the transparent toner particles satisfies the above-described configuration (4), and is preferably 5.0 μm or more and 10.0 μm or less.

<3-1. Binder resin>
The transparent toner particles contain at least a crystalline polyester resin as a binder resin. The transparent toner particles further contain a binder resin different from the crystalline polyester resin (hereinafter sometimes referred to as another binder resin).

  The content of the crystalline polyester resin contained in the transparent toner particles is 10 with respect to the total mass of the binder resin contained in the transparent toner particles (total mass of the crystalline polyester resin and another binder resin). The mass is 30% by mass or more. When the content of the crystalline polyester resin contained in the transparent toner particles is less than 10% by mass, the fixability of the toner tends to be lowered. When the content of the crystalline polyester resin contained in the transparent toner particles exceeds 30% by mass, the heat resistant storage stability of the toner tends to be lowered. When the content of the crystalline polyester resin contained in the transparent toner particles exceeds 30% by mass, image defects are likely to occur when images are continuously formed. In addition, the heat resistant storage stability of the toner tends to decrease.

  The content of the crystalline polyester resin contained in the transparent toner particles is preferably 20% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles. When the content of the crystalline polyester resin contained in the transparent toner particles is within such a range, the fixing property and hot offset resistance of the toner can be particularly improved.

  Another binder resin is preferably non-crystalline. Whether another binder resin is crystalline or non-crystalline can be determined from the crystallinity of another binder resin, for example. In this embodiment, another binder resin having a crystallinity of 50.0% or more is made crystalline. In this embodiment, another binder resin having a crystallinity of less than 50.0% is made non-crystalline. The degree of crystallinity of another binder resin is measured by the same method as the measurement of the degree of crystallinity of a polyester resin described later.

  As an example of another binder resin contained in the transparent toner particles, a thermoplastic resin other than the crystalline polyester resin is preferable. Examples of such thermoplastic resins include styrene resins, acrylic resins, olefin resins (specifically, polyethylene resins or polypropylene resins), vinyl resins (specifically, vinyl chloride resins, polyvinyl alcohol resins). , Vinyl ether resin or N-vinyl resin), non-crystalline polyester resin, polyamide resin, urethane resin, styrene acrylic acid resin or styrene butadiene resin. Among these other binder resins, an amorphous polyester resin is preferable because the transparency of the transparent toner particles is excellent.

  When the other binder resin is an amorphous polyester resin, the binder resin contained in the transparent toner particles is a crystalline polyester resin and an amorphous polyester resin. In this case, the content of the crystalline polyester resin contained in the transparent toner particles is 10% by mass with respect to the total mass of the crystalline polyester resin and the amorphous polyester resin contained as the binder resin in the transparent toner particles. The content is preferably 30% by mass or less, and more preferably 20% by mass or more and 30% by mass or less.

  The crystallinity of the entire binder resin contained in the transparent toner particles is preferably 6.0% or more and 64.0% or less, more preferably 27.0% or more and 38.0% or less. It is particularly preferably 28.5% or more and 35.5% or less. The crystallinity of the entire binder resin contained in the transparent toner particles is the crystallinity of the entire crystalline polyester resin and other binder resin contained in the transparent toner particles. The crystallinity of the binder resin contained in the transparent toner particles is the same as the measurement of the crystallinity of the polyester resin described later, except that the measurement sample is changed from the polyester resin to the binder resin contained in the transparent toner particles. It is measured by the method. In addition, the crystallinity of the binder resin calculated by the method described later in the examples substantially matches the crystallinity of the binder resin measured using the binder resin as a measurement sample.

  Hereinafter, a crystalline polyester resin contained as a binder resin in transparent toner particles and an amorphous polyester resin that may be contained as a binder resin in transparent toner particles will be described. Whether the polyester resin is crystalline or non-crystalline can be determined from, for example, the degree of crystallinity of the polyester resin. In this embodiment, a polyester resin having a crystallinity of 50.0% or more is made crystalline. In this embodiment, a polyester resin having a crystallinity of less than 50.0% is made non-crystalline.

  The crystallinity of the polyester resin is measured using, for example, a differential scanning calorimeter (DSC). A specific method for measuring the crystallinity of the polyester resin is the method described later in the examples or an alternative method thereof.

  Hereinafter, properties common to the crystalline polyester resin and the amorphous polyester resin will be described. The crystalline polyester resin and the amorphous polyester resin are collectively referred to as a polyester resin. The polyester resin is obtained by polymerizing a divalent or trivalent or higher alcohol and a divalent or trivalent or higher carboxylic acid.

  Examples of the dihydric alcohol used for preparing the polyester resin include diols or bisphenols.

  Examples of diols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 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 used to prepare polyester resins 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-trihydroxymethylbenzene is mentioned.

  Examples of divalent carboxylic acids used to prepare polyester resins include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, adipic acid, sebacin Acid, azelaic acid, malonic acid, succinic acid, alkyl succinic acid (specifically, n-butyl succinic acid, isobutyl succinic acid, n-octyl succinic acid, n-dodecyl succinic acid or isododecyl succinic acid) or alkenyl succinic acid (Specific examples include n-butenyl succinic acid, isobutenyl succinic acid, n-octenyl succinic acid, n-dodecenyl succinic acid or isododecenyl succinic acid).

  Examples of trivalent or higher carboxylic acids used for preparing the polyester resin include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4. -Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid Examples include acids, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid or emporic trimer acid.

  Further, as the divalent or trivalent or higher carboxylic acid, an ester-forming derivative of a divalent or trivalent or higher carboxylic acid (for example, acid halide, acid anhydride, or lower alkyl ester) may be used. Examples of the acid anhydride of a divalent or trivalent or higher carboxylic acid include alkenyl succinic anhydride, and more specifically, dodecenyl succinic anhydride. Here, the lower alkyl means an alkyl group having 1 to 6 carbon atoms.

  When preparing the polyester resin, the acid value and the hydroxyl value of the polyester resin are adjusted by changing the amount of alcohol used and the amount of carboxylic acid used. When the molecular weight of the polyester resin is increased, the acid value and hydroxyl value of the polyester resin tend to decrease.

  When the binder resin is a polyester resin, the number average molecular weight (Mn) of the polyester resin is preferably 1000 or more and 2000 or less in order to improve the strength of the colored toner particles and the fixability of the toner to the recording medium. The molecular weight distribution of the polyester resin (ratio Mw / Mn of the mass average molecular weight Mw to the number average molecular weight Mn) is preferably 9 or more and 21 or less. The Mn and Mw of the polyester resin are measured using, for example, gel permeation chromatography.

  The softening point of the polyester resin is preferably 80 ° C. or higher and 150 ° C. or lower, and more preferably 90 ° C. or higher and 140 ° C. or lower.

  The transparent toner particles may contain a thermosetting resin as a binder resin. By containing a thermosetting resin, a partially cross-linked structure is introduced into the binder resin, improving the toner's heat-resistant storage stability, shape retention and durability while improving the toner's fixability to the recording medium. Easy to do.

  Preferable examples of the thermosetting resin used as the binder resin for the transparent toner particles include an epoxy resin or a cyanate resin. Specific examples include bisphenol A type epoxy resins, hydrogenated bisphenol A type epoxy resins, novolac type epoxy resins, polyalkylene ether type epoxy resins, cycloaliphatic type epoxy resins, and cyanate resins.

  The glass transition point (Tg) of the binder resin contained in the transparent toner particles is preferably 50 ° C. or higher and 65 ° C. or lower, and more preferably 50 ° C. or higher and 60 ° C. or lower. If the glass transition point of the binder resin is 50 ° C. or higher, the toner particles and other toner particles are difficult to fuse in the developing device. Further, the toner particles hardly adhere to the image carrier. If the glass transition point of the binder resin is 65 ° C. or less, it is easy to maintain the low-temperature fixability of the toner.

  The glass transition point of the binder resin is obtained from the change point of the specific heat in the endothermic curve, for example, by measuring the endothermic curve of the binder resin using a differential scanning calorimeter. As the measuring device, for example, a differential scanning calorimeter (“DSC-6220” manufactured by Seiko Instruments Inc.) is used. 10 mg of a measurement sample (binder resin) is placed in an aluminum pan. Use an empty aluminum pan as a reference. The measurement conditions of the measurement device are set to a measurement temperature range of 25 ° C. or more and 200 ° C. or less and a temperature increase rate of 10 ° C./min. An endothermic curve of the measurement sample is obtained using the measurement device. From the change point of specific heat in the obtained endothermic curve, the glass transition point of the measurement sample is obtained.

<3-2. Release agent>
The transparent toner particles contain a release agent. When the transparent toner particles contain a release agent, the hot offset resistance of the toner can be improved.

  Suitable examples of release agents include aliphatic hydrocarbon waxes (eg, low molecular weight polyethylene, low molecular weight polypropylene, olefin copolymers, polyolefins, microcrystalline wax, paraffin wax or Fischer-Tropsch wax), aliphatic hydrocarbon waxes. Oxides (eg, block copolymers of oxidized polyethylene wax or oxidized polyethylene wax), vegetable waxes (eg, candelilla wax, carnauba wax, wood wax, jojoba wax, or rice wax), animal waxes (eg, beeswax, lanolin) Or whale wax), mineral waxes (eg, ozokerite, ceresin or petrolatum), waxes based on fatty acid esters (eg, montanate ester wax or castor wax) or fatty acid esters. Waxes in which some or all of the de-oxidation of ether (e.g., deoxidized carnauba wax) and the like. Two or more of these release agents may be combined. When the transparent toner particles contain such a release agent, it is easy to improve the offset resistance and fixability of the toner and to easily suppress image defects such as image smearing.

  In order to improve the hot offset resistance of the toner, the content 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 whole transparent toner particles. The amount is more preferably no less than 20 parts by mass and particularly preferably no less than 1 part by mass and no greater than 10 parts by mass. When the addition amount of the release agent is 1 part by mass or more, the offset resistance of the toner is easily improved, and image defects such as image smearing are easily suppressed. When the addition amount of the release agent is 30 parts by mass or less, the toner particles are hardly fused with each other, and the heat resistant storage stability of the toner is easily improved.

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

<3-3. Charge Control Agent>
The transparent toner particles may contain a charge control agent. The charge control agent contained in the transparent toner particles is not limited as long as it is transparent. Examples of the charge control agent contained in the transparent toner particles are the same as those of the charge control agent contained in the colored toner.

<4. External additive>
If necessary, an external additive may be attached to the surface of the colored toner particles. The colored toner particles before attaching the external additive may be referred to as colored toner mother particles. Further, an external additive may be attached to the surface of the transparent toner particles as necessary. The transparent toner particles before the external additive is attached may be referred to as transparent toner base particles.

  Examples of the external additive include metal oxides (for example, alumina, titanium oxide, magnesium oxide, zinc oxide, strontium titanate or barium titanate), silicon carbide or silica. Specific examples of the silica include colloidal silica and hydrophobic silica. Examples of the external additive include a salt of a fatty acid and a metal (for example, zinc stearate). The external additive may be surface-treated with a surface treatment agent (for example, aminosilane, silicone oil, hexamethyldisilazane, titanate coupling agent or silane coupling agent) as necessary.

  The particle diameter of the external additive is preferably 0.01 μm or more and 1.0 μm or less. The amount of the external additive used is preferably 0.5 parts by mass or more and 10 parts by mass or less, preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the colored toner base particles or transparent toner base particles. Is more preferable.

<5. Toner Production Method>
The toner manufacturing method of the present embodiment includes, for example, a color toner manufacturing process, a transparent toner manufacturing process, and a color toner and transparent toner mixing process. The toner production method of the present exemplary embodiment may be implemented with appropriate modifications, and may further include another known process.

<5-1. Manufacturing process of colored toner>
Examples of the manufacturing method of the colored toner include an aggregation method or a pulverization method.

  The aggregation method includes, for example, an aggregation process and a coalescence process. In the aggregating step, fine particles containing components constituting the colored toner are aggregated in an aqueous medium to form aggregated particles. In the coalescing step, the components contained in the aggregated particles are coalesced in an aqueous medium to form colored toner base particles. According to the aggregation method, it is easy to obtain colored toner base particles having a uniform shape and a uniform particle diameter. The aggregation method may include an external addition step described later.

  Next, the grinding method will be described. According to the pulverization method, a colored toner can be prepared relatively easily. When producing a colored toner by the pulverization method, the production process of the colored toner includes, for example, a mixing step, a kneading step, a pulverizing step, a spheronizing step and a classification step. The manufacturing process of the colored toner may further include an external addition process described later. In the mixing step, for example, a binder resin, a colorant, and an internal additive (for example, a charge control agent) are mixed to obtain a mixture. In the kneading step, the obtained mixture is melted and kneaded to obtain a kneaded product. In the pulverization step, the obtained kneaded product is pulverized to obtain a pulverized product. In the spheronization step, the pulverized product is further pulverized to spheroidize the pulverized product.

In the classification step, the obtained pulverized product is classified to obtain colored toner base particles. The classification is performed using a classifier (for example, an airflow classifier). One of the zone width (ΔFc) of the fine powder zone to be removed on the fine powder side of the classifier, the zone width (ΔMc) of the coarse powder zone to be removed on the coarse powder side, and the number of classifications in the classification process of the color toner production by changing the above, the volume median diameter of the color toner particles (D ₅₀ c), small particle size 1.0μm or more than the volume median diameter of the color toner particles to the total number of color toner particles (D ₅₀ c) The number ratio (Rc1) of the colored toner particles having the above and the number ratio (Rcs) of the colored toner particles having a particle diameter of 3.0 μm or less with respect to the total number of the colored toner particles can be adjusted to desired values.

  In the classification process for producing colored toner, the zone width (ΔFc) of the fine powder zone removed on the fine powder side of the classifier is preferably 10 mm or more and 13 mm or less. The zone width (ΔMc) of the coarse powder zone removed on the coarse powder side of the classifier is preferably 20 mm or greater and 25 mm or less, and more preferably 22 mm. The number of classification is preferably two.

  In the external addition step, the color toner particles are obtained by attaching an external additive to the surface of the color toner base particles. As a suitable method for attaching the external additive, using a mixer (for example, FM mixer, Nauter mixer (registered trademark)) under the condition that the external additive is not buried in the surface of the colored toner base particles, Examples thereof include a method of mixing colored toner base particles and an external additive.

<5-2. Manufacturing process of transparent toner>
The transparent toner is manufactured in the same manner as, for example, a colored toner. When the transparent toner is manufactured by the pulverization method, the transparent toner manufacturing process includes, for example, a mixing process, a kneading process, a pulverizing process, a spheronization process, and a classification process. The manufacturing process of the transparent toner may further include an external addition process. In the mixing step, for example, a crystalline polyester resin as a binder resin, another binder resin, a release agent, and an internal additive (for example, a charge control agent) are mixed to obtain a mixture. In the kneading step, the obtained mixture is melted and kneaded to obtain a kneaded product. In the pulverization step, the obtained kneaded product is pulverized to obtain a pulverized product. In the spheronization step, the pulverized product is further pulverized to spheroidize the pulverized product.

In the classification step, the obtained pulverized product is classified to obtain transparent toner base particles. The classification is performed using a classifier (for example, an airflow classifier). One of the zone width (ΔFt) of the fine powder zone to be removed on the fine powder side of the classifier, the zone width (ΔMt) of the coarse powder zone to be removed on the coarse powder side, and the number of classifications in the classification process for producing the transparent toner By changing the above, the volume median diameter (D ₅₀ t) of the transparent toner particles and particles smaller than the volume median diameter (D ₅₀ t) of the transparent toner particles with respect to the total number of transparent toner particles by 1.0 μm or more. The number ratio (Rt1) of transparent toner particles having a diameter can be adjusted to a desired value.

  In the transparent toner classification step, the zone width (ΔFt) of the fine powder zone removed on the fine powder side of the classifier is preferably 15 mm or more and 17 mm or less. The zone width (ΔMt) of the coarse powder zone removed on the coarse powder side of the classifier is preferably 20 mm or greater and 25 mm or less, and more preferably 22 mm. The number of classifications is preferably one.

  In order to obtain a toner satisfying the configurations (4) to (6), the zone width (ΔFt) of the fine powder zone to be removed on the fine powder side of the classifier in the classification process of the production of the transparent toner, and the classification of the production of the colored toner The difference (ΔFt−ΔFc) with respect to the zone width (ΔFc) of the fine powder zone removed on the fine powder side of the classifier in the process is preferably 3 mm or more and 5 mm or less, more preferably 3 mm or more and 4 mm or less, 4 mm is particularly preferable.

<5-3. Mixing process of colored toner and transparent toner>
In the mixing step of the color toner and the transparent toner, the color toner and the transparent toner are mixed to obtain a toner. For example, an FM mixer is used to mix the color toner and the transparent toner.

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

<1. Manufacture of polyester resin>
Polyester resins A and B to be contained in colored toner particles and transparent toner particles were produced by the following method.

(Production of polyester resin A)
1960 g of bisphenol A propylene oxide adduct, 780 g of bisphenol A ethylene oxide adduct, 257 g of dodecenyl succinic anhydride, 770 g of terephthalic acid, and 4 g of dibutyltin oxide were charged into a container. The air in the container was replaced with nitrogen gas. Under a nitrogen atmosphere, the contents of the container were reacted for 8 hours under the conditions of a temperature of 235 ° C. and normal pressure. Thereafter, the container contents were reacted for 1 hour under conditions of a temperature of 235 ° C. and a pressure of 8.3 kPa. Furthermore, trimellitic anhydride was added to the contents of the container at a temperature of 180 ° C. Thereafter, the container contents were heated to 210 ° C. at a rate of temperature increase of 10 ° C./hour. As a result, polyester resin A was obtained. The crystallinity of the polyester resin A was 25.0%. From this, it was confirmed that the polyester resin A is non-crystalline.

(Production of polyester resin B)
918 g of 1,4-butanediol, 118 g of 1,6-hexanediol, 1160 g of fumaric acid, 4 g of dibutyltin oxide and 2 g of hydroquinone were charged into a container. The air in the container was replaced with nitrogen gas. Under a nitrogen atmosphere, the contents of the container were reacted for 5 hours under the conditions of a temperature of 160 ° C. and normal pressure. Thereafter, the contents of the container were reacted for 1 hour under the conditions of a temperature of 200 ° C. and normal pressure. As a result, a polyester resin B was obtained. The crystallinity of the polyester resin B was 60.0%. From this, it was confirmed that the polyester resin B is crystalline.

(Method for measuring crystallinity of polyester resin)
The crystallinity of the polyester resins A and B was measured using a differential scanning calorimeter (DSC, “DSC-6220” manufactured by Seiko Instruments Inc.). 10 mg of a measurement sample (polyester resin A or B) was placed in an aluminum pan. An empty aluminum pan was used as a reference. The DSC measurement conditions were set to a measurement temperature range of 25 ° C. or more and 200 ° C. or less and a temperature increase rate of 10 ° C./min. An endothermic curve of the measurement sample was obtained using DSC. From the area of the endothermic peak of the obtained endothermic curve, the heat of fusion (ΔHm, unit: J / g) of the measurement sample was determined. Based on the obtained ΔHm, the crystallinity (unit:%) was calculated by the following formula. In the following formula, a represents the heat of fusion of the reference sample (unit: J / g) when a reference sample having the same chemical structure as the measurement sample and having a crystallinity of 100.0% is measured by DSC. .
Crystallinity = (ΔHm / a) × 100

  A polyester resin having a measured crystallinity of 50.0% or more was judged as a crystalline polyester resin. A polyester resin having a crystallinity of less than 50.0% was judged as an amorphous polyester resin.

<2. Production of Toner A-1>
Toner A-1 was produced by the following method.

<2-1. Manufacture of colored toner>
First, a mixing step was performed. Specifically, 100 parts by mass of a polyester resin A (non-crystalline polyester resin) as a binder resin and a quaternary ammonium salt as a charge control agent (“BONTRON (registered trademark) P-51” manufactured by Orient Chemical Co., Ltd.) 2 parts by mass and 5 parts by mass of carbon black (“MA-100” manufactured by Mitsubishi Chemical Corporation) as a coloring agent are mixed using an FM mixer (“FM-20B” manufactured by Nippon Coke Industries, Ltd.) A mixture was obtained.

  Subsequently, a kneading step was performed. In the kneading step, so-called low-temperature kneading was performed on the obtained mixture in order to improve the dispersibility of the toner material and improve the color reproducibility in the formed image. Specifically, the obtained mixture was melted and kneaded using a twin screw extruder ("PCM-30" manufactured by Ikegai Co., Ltd.) under the conditions of a material charging speed of 5 kg / hour, a rotation speed of 160 rpm, and a set temperature of 160 ° C. A kneaded product was obtained. The resulting kneaded product was cooled.

  Subsequently, a pulverization step was performed. Specifically, the kneaded product was coarsely pulverized using a pulverizer (“Rohtoplex (registered trademark) 16/8 type” manufactured by Hosokawa Micron Corporation) to obtain a coarsely pulverized product. The obtained coarsely pulverized product was finely pulverized using a mechanical pulverizer (“Turbo Mill” manufactured by Freund Turbo, Inc.) under the conditions of a material input speed of 10 kg / hour and a rotational speed of 11000 rpm.

  Subsequently, a spheronization process was performed. Specifically, the pulverization conditions of a mechanical pulverizer (“Turbomill” manufactured by Freund Turbo) were changed from a material input speed of 10 kg / hour and a rotational speed of 11000 rpm in the pulverization process to a material input speed of 10 kg / hour and a rotational speed of 4000 rpm. The obtained finely pulverized product was further pulverized. This made the toner spherical.

  Subsequently, a classification process was performed. Specifically, the zone width (ΔFc) of the fine powder zone to be removed on the fine powder side of the classifier (airflow classifier, “Elbow Jet EJ-LABO type” manufactured by Nippon Steel & Mining Co., Ltd.) is set to 12 mm, and the coarse powder side The zone width (ΔMc) of the coarse powder zone to be removed was set to 22 mm. The obtained finely pulverized product was classified twice using a classifier under the condition of a material charging rate of 3.0 kg / hour. As a result, colored toner base particles were obtained.

  Subsequently, an external addition process was performed. Specifically, 97.1 parts by mass of the obtained colored toner base particles, 1.8 parts by mass of dry silica fine particles (“AEROSIL (registered trademark) REA200” manufactured by Nippon Aerosil Co., Ltd.) as an external additive, and external additives 1.0 parts by mass of conductive titanium oxide fine particles ("EC-100" manufactured by Titanium Industry Co., Ltd.) and 0.1 parts by mass of zinc stearate (manufactured by NOF Corporation) as an external additive, Mixing was performed using a mixer (“FM-20B” manufactured by Nippon Coke Industries, Ltd.). The mixing conditions were set at a rotation speed of 30 m / sec and a mixing time of 5 minutes. As a result, the external additive was adhered to the surface of the colored toner base particles. As a result, a colored toner (a plurality of colored toner particles) to be contained in the toner A-1 was obtained.

<2-2. Production of transparent toner>
First, a mixing step was performed. Specifically, 70 parts by mass of polyester resin A (non-crystalline polyester resin) as a binder resin, 30 parts by mass of polyester resin B (crystalline polyester resin) as a binder resin, and carnauba wax (as a release agent) 6 parts by mass of Hiroyuki Kato “Carnauba Wax No. 1”) and 2 parts by mass of a quaternary ammonium salt (“BONTRON (registered trademark) P-51” manufactured by Orient Chemical Co., Ltd.) as a charge control agent , FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.) was used to obtain a mixture.

  Subsequently, a kneading step was performed. Specifically, the obtained mixture was melted and kneaded using a twin screw extruder ("PCM-30" manufactured by Ikegai Co., Ltd.) under the conditions of a material charging speed of 5 kg / hour, a rotation speed of 160 rpm, and a set temperature of 150 ° C. A kneaded product was obtained. The resulting kneaded product was cooled.

  Subsequently, a pulverization step was performed. Specifically, the kneaded product was coarsely pulverized using a pulverizer (“Rohtoplex (registered trademark) 16/8 type” manufactured by Hosokawa Micron Corporation) to obtain a coarsely pulverized product. The obtained coarsely pulverized product was finely pulverized using a mechanical pulverizer (“Turbo Mill” manufactured by Freund Turbo, Inc.) under the conditions of a material input speed of 10 kg / hour and a rotational speed of 10,000 rpm.

  Subsequently, a spheronization process was performed. Specifically, the pulverization condition of the mechanical pulverizer (“Turbomill” manufactured by Freund Turbo) was changed from the material input speed of 10 kg / hour and the rotational speed of 10,000 rpm in the pulverization process to the material input speed of 10 kg / hour and the rotational speed of 4000 rpm. The obtained finely pulverized product was further pulverized. This made the toner spherical.

  Subsequently, a classification process was performed. Specifically, the zone width (ΔFt) of the fine powder zone to be removed on the fine powder side of the classifier (airflow classifier, “Elbow Jet EJ-LABO type” manufactured by Nippon Steel & Mining Co., Ltd.) is set to 15 mm, and the coarse powder side The zone width (ΔMt) of the coarse powder zone to be removed was set to 22 mm. The obtained finely pulverized product was classified only once using a classifier under the condition of a material charging rate of 3.0 kg / hour. As a result, transparent toner base particles were obtained.

  An external addition step was performed on the obtained transparent toner base particles in the same manner as in the production of colored toner particles. As a result, the external additive was adhered to the surface of the transparent toner base particles. As a result, a transparent toner (a plurality of transparent toner particles) to be contained in the toner A-1 was obtained.

<2-3. Mixing process of colored toner and transparent toner>
Using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.), 1.0 part by mass of the transparent toner and 1.0 part by mass of the colored toner were mixed. As a result, Toner A-1 was obtained. The obtained toner A-1 had a volume median diameter D ₅₀ of 6.55 μm.

<3. Production of Toners A-2 to A-6 and Toners B-1 to B-10>
Toners A-2 to A-6 and Toners B-1 to B-10 were produced in the same manner as in the production of Toner A-1, except that the following points were changed.

  In the production of the toners A-2 to A-6 and the toners B-1 to B-10, the following points were changed from the production method of the toner A-1. Regarding the color toner production classification step, the zone width (ΔFc) of 12 mm and the number of classification times in the production of the toner A-1 were changed to ΔFc and the number of color toner classification times shown in Table 1. In the classification process for producing the transparent toner, the zone width (ΔFt) 15 mm of the fine powder zone in the production of the toner A-1 was changed to ΔFt shown in Table 1. Regarding the mixing step of the colored toner and the transparent toner, 1.0 part by mass of the transparent toner and 1.0 part by mass of the colored toner in the production of the toner A-1 are added to the addition amount (Mt) of the transparent toner shown in Tables 2 to 4 and The amount of color toner added (Mc) was changed.

  For each toner, Table 1 shows the classification conditions in the classification process of the color toner production and the classification conditions in the classification process of the production of the transparent toner. ΔFc and ΔMc respectively indicate the zone width of the fine powder zone to be removed on the fine powder side of the classifier and the zone width of the coarse powder zone to be removed on the coarse powder side in the classification process for producing the colored toner. ΔFt and ΔMt respectively indicate the zone width of the fine powder zone to be removed on the fine powder side of the classifier and the zone width of the coarse powder zone to be removed on the coarse powder side in the classification process for producing the transparent toner.

  In the production of the toner A-6, the following points were also changed from the production method of the toner A-1. 70 parts by mass of polyester resin A (non-crystalline polyester resin) and 30 parts by mass of polyester resin B (crystalline polyester resin) added in the mixing step in the production of the transparent toner of toner A-1 were mixed with polyester resin A (non-crystalline). The amount was changed to 90 parts by mass of polyester resin) and 10 parts by mass of polyester resin B (crystalline polyester resin). As a result, the content of the crystalline polyester resin with respect to the total mass of the binder resin contained in the transparent toner was changed from 30% by mass to 10% by mass in the production of the toner A-1.

  In the production of the toner B-6, the following points were also changed from the production method of the toner A-1. 70 parts by mass of polyester resin A (non-crystalline polyester resin) and 30 parts by mass of polyester resin B (crystalline polyester resin) added in the mixing step in the production of the transparent toner of toner A-1 were mixed with polyester resin A (non-crystalline). Polyester resin) was changed to 100 parts by mass. As a result, the content of the crystalline polyester resin relative to the total mass of the binder resin contained in the transparent toner was changed from 30% by mass to 0% by mass in the production of the toner A-1.

  In the production of the toner B-7, the following points were also changed from the production method of the toner A-1. 100 parts by mass of the polyester resin A (non-crystalline polyester resin) added in the mixing step of the colored toner of the toner A-1, 85 parts by mass of the polyester resin A (non-crystalline polyester resin) and the polyester resin B (crystalline polyester resin) ) Changed to 15 parts by mass. Thereby, the content of the crystalline polyester resin with respect to the total mass of the binder resin contained in the colored toner was changed from 0% by mass to 15% by mass in the production of the toner A-1. Further, 70 parts by mass of the polyester resin A (non-crystalline polyester resin) and 30 parts by mass of the polyester resin B (crystalline polyester resin) added in the mixing step of the transparent toner of the toner A-1 were added to the polyester resin A (non-crystalline). The polyester resin was changed to 85 parts by mass and the polyester resin B (crystalline polyester resin) was added to 15 parts by mass. Thereby, the content of the crystalline polyester resin with respect to the total mass of the binder resin contained in the colored toner was changed from 30% by mass to 15% by mass in the production of the toner A-1.

  In the production of the toner B-8, the following points were also changed from the production method of the toner A-1. 70 parts by mass of polyester resin A (non-crystalline polyester resin) and 30 parts by mass of polyester resin B (crystalline polyester resin) added in the mixing step in the production of the transparent toner of toner A-1 were mixed with polyester resin A (non-crystalline). The amount was changed to 97 parts by mass of polyester resin and 3 parts by mass of polyester resin B (crystalline polyester resin). As a result, the content of the crystalline polyester resin relative to the total mass of the binder resin contained in the transparent toner was changed from 30% by mass to 3% by mass in the production of the toner A-1.

  In the production of the toner B-9, the following points were also changed from the production method of the toner A-1. 70 parts by mass of polyester resin A (non-crystalline polyester resin) and 30 parts by mass of polyester resin B (crystalline polyester resin) added in the mixing step in the production of the transparent toner of toner A-1 were mixed with polyester resin A (non-crystalline). The amount was changed to 60 parts by mass of polyester resin) and 40 parts by mass of polyester resin B (crystalline polyester resin). Thereby, the content of the crystalline polyester resin with respect to the total mass of the binder resin contained in the transparent toner was changed from 30% by mass to 40% by mass in the production of the toner A-1.

  In the production of the toner B-10, the color toner mixing process of the toner A-1 was changed to the following color toner mixing process. That is, 3 parts by mass of carnauba wax (“Carnauba wax No. 1” manufactured by Kato Yoko Co., Ltd.) as a release agent, 100 parts by mass of polyester resin A (amorphous polyester resin) as a binder resin, and charge control 2 parts by mass of a quaternary ammonium salt ("BONTRON (registered trademark) P-51" manufactured by Orient Chemical Co., Ltd.) as a colorant and 5 masses of carbon black ("MA-100" manufactured by Mitsubishi Chemical Corporation) as a colorant Were mixed using an FM mixer (“FM-20B” manufactured by Nippon Coke Kogyo Co., Ltd.) to obtain a mixture.

<4. Measurement of Volume Median Diameter (D ₅₀ c and D ₅₀ t) and Number Ratio of Toner Particles (Rc1 and Rt1)>
Prior to the mixing step of the color toner and the transparent toner, the particle size distribution of each color toner of the toners A-1 to A-6 and the toners B-1 to B-10 was measured. Specifically, a surfactant was added to an electrolytic solution (“ISOTON II” manufactured by Beckman Coulter, Inc.), and 10 mg of a measurement sample (colored toner) was added. The colored toner was dispersed in the electrolytic solution using an ultrasonic disperser. Using a precision particle size distribution measuring apparatus (“Coulter Counter Multisizer 3” manufactured by Beckman Coulter, Inc.), a volume distribution and a number distribution of the particle diameter of the colored toner in the electrolytic solution were obtained under the condition of an aperture diameter of 100 μm. From the volume distribution of the particle diameter of the obtained color toner, the volume median diameter (D ₅₀ c) of the color toner particles was obtained. From the number distribution of the particle diameters of the obtained colored toner, the number ratio (Rc1) of the colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of the colored toner particles with respect to the total number of the colored toner particles. Obtained.

Prior to the mixing step of the color toner and the transparent toner, the particle size distributions of the transparent toners of the toners A-1 to A-6 and the toners B-1 to B-10 were measured. The volume distribution and number distribution of the particle diameter of the transparent toner were measured in the same manner as the measurement of the particle diameter distribution of the color toner, except that the measurement sample was changed from the color toner to the transparent toner. From the volume distribution of the particle diameter of the obtained transparent toner, the volume median diameter (D ₅₀ t) of the transparent toner particles was obtained. From the number distribution of the particle diameter of the obtained transparent toner, the number ratio (Rt1) of the transparent toner particles having a particle diameter smaller by 1.0 μm or more than the volume median diameter of the transparent toner particles to the total number of transparent toner particles. Obtained.

<5. Measurement of Number Ratio (Rcs) of Toner Particles>
Prior to the mixing step of the color toner and the transparent toner, the following measurements were performed on the color toners of the toners A-1 to A-6 and the toners B-1 to B-10. Specifically, a photograph of the measurement sample (colored toner) was taken at an observation magnification of 2000 using a scanning electron microscope. Furthermore, the measurement sample was subjected to elemental analysis using an X-ray microanalyzer XMA attached to the scanning electron microscope, and titanium atoms were mapped. And the photograph which expanded the measurement sample to which the titanium atom was mapped 2000 times was image | photographed. By contrasting these photographs, the total number of colored toner particles and the number of colored toner particles having a particle diameter of 3.0 μm or less observed in one visual field were measured. When measuring the number of colored toner particles having a particle diameter of 3.0 μm or less, care was taken not to count dry silica fine particles, conductive titanium oxide fine particles and zinc stearate as external additives. In detail, since the particle | grains to which the titanium atom was mapped are electroconductive titanium oxide microparticles | fine-particles, they were not counted. Dry silica fine particles and zinc stearate were not counted based on the size of the particles. From the measured total number of colored toner particles and the number of colored toner particles having a particle diameter of 3.0 μm or less, the percentage of the number of colored toner particles having a particle diameter of 3.0 μm or less to the total number of colored toner particles ( The number ratio Rcs) was calculated.

<6. Calculation of crystallinity of binder resin>
The crystallinity of the binder resin contained in each of the transparent toners and colored toners of toners A-1 to A-6 and B-1 to B-10 was calculated by the following method. From the crystallinity of polyester resin A (non-crystalline polyester resin) and the crystallinity of polyester resin B (crystalline polyester resin) measured in the production of the polyester resin, the crystallinity of the binder resin is calculated according to the following formula: Calculated. Tables 2 to 4 show the calculated crystallinity of the binder resin.
Binder resin crystallinity (%) = [crystallinity of non-crystalline polyester resin (%) × (1-content of crystalline polyester resin with respect to total mass of binder resin (% by mass) / 100)] + [Crystallinity of crystalline polyester resin (%) × Content of crystalline polyester resin (% by mass) / 100 with respect to total mass of binder resin]

<7. Evaluation method>
The evaluation methods of the toners A-1 to A-6 and B-1 to B-10 are as follows. The image evaluation, fixability, hot offset resistance and glossiness of the formed image were evaluated using a two-component developer containing each toner. The heat resistant storage stability was evaluated using each toner.

  The two-component developer used for the evaluation was prepared by mixing 100 parts by mass of ferrite carrier (manufactured by Powder Tech Co., Ltd.) and 10 parts by mass of toner using a ball mill for 30 minutes.

<7-1. Image evaluation (initial and after printing 10,000 sheets)>
The image evaluation was performed in an environment of a temperature of 20 ° C. and a humidity of 65% RH (relative humidity). As an evaluation machine, a multifunction machine (a modified machine of “FS-C8026” manufactured by Kyocera Document Solutions Inc.) was used. The two-component developer was put into the black developing device of the evaluation machine. The replenishing toner was put into the black toner container of the evaluation machine. Image I was printed on one sheet of paper using an evaluator. Image I included a solid image portion (printing rate 100%) and a halftone image portion (printing rate 50%). The paper on which the image I was printed was used as an initial image evaluation sample.

Subsequently, the image I was continuously printed on 10,000 sheets using an evaluation machine. The paper on which the image I was printed on the 10,000th sheet was used as an image evaluation sample after printing 10,000 sheets. The obtained initial and 10,000-sheet image evaluation samples were each observed with the naked eye. From the observation results, images were evaluated according to the following criteria. A toner having an image evaluation of A to C at the initial stage and after printing 10,000 sheets was regarded as acceptable.
(Image evaluation criteria)
Evaluation A: The color was sufficiently reproduced. There were no image defects in either the solid image portion or the halftone image portion.
Evaluation B: Although the saturation is lowered, the color is sufficiently reproduced. There were no image defects in either the solid image portion or the halftone image portion.
Evaluation C: The saturation was lowered and the color was not reproduced slightly. In both the solid image portion and the halftone image portion, image defects (sleeve layer unevenness) occurred slightly for each rotation period of the sleeve roller.
Evaluation D: The color was not sufficiently reproduced. In both the solid image portion and the halftone image portion, many image defects (sleeve layer unevenness) occurred every time the sleeve roller was rotated.
Evaluation E: The color was not sufficiently reproduced. In both the solid image portion and the halftone image portion, an image defect (sleeve layer unevenness) occurred very frequently for each rotation period of the sleeve roller.

<7-2. Fixability>
After the fixing temperature of the fixing device of the evaluation machine was set to 170 ° C., the fixing device was turned off and cooled for 10 minutes in a normal environment (temperature 20 ° C., humidity 65% RH). Thereafter, turn on the fixing device, a fixing temperature of 170 ° C., linear velocity 200 mm / sec (the nip passing time 40m sec), under the conditions of toner amount 1.0 mg / cm ^2, 5 sheets (90 g / m ^2, Image II was continuously printed on (A4 size). The image II included a solid image portion (printing rate 100%) having a size of 25 mm × 25 mm.

Whether or not the toner could be fixed was confirmed by the following friction test for each of the images II formed on the five sheets. First, the image density of the image II formed on the paper was measured using a reflection densitometer (“SpectroEye (registered trademark)” manufactured by X-Rite). Next, the image II formed on the paper was subjected to 10 reciprocating frictions using a 1 kg weight covered with a cloth. The image density of the image II after friction was measured using a reflection densitometer (“SpectroEye (registered trademark)” manufactured by X-Rite). From the obtained image density before and after friction, the toner fixing rate was calculated by the formula “fixing rate of toner (%) = (image density after friction / image density before friction) × 100”. The average value of the toner fixing ratio was calculated by dividing the sum of the toner fixing ratios calculated for each of the images II formed on the five sheets by the number of measurement objects (five sheets). The average value of the calculated toner fixing ratio was used as the evaluation value. From the evaluation value (toner fixing rate), the toner fixability was evaluated according to the following criteria. A toner having a toner fixability evaluation of A to C was evaluated as acceptable.
(Fixability evaluation criteria)
Evaluation A: The toner fixing rate was 97% or more.
Evaluation B: The toner fixing rate was 95% or more and less than 97%.
Evaluation C: The toner fixing ratio was 90% or more and less than 95%.
Evaluation D: The toner fixing rate was less than 90%.

<7-3. Hot offset resistance>
Evaluation of hot offset resistance was performed in a normal environment (temperature 20 ° C., humidity 65% RH). 10 sheets of paper (90 g / m ² , A4 size) under the conditions of a fixing temperature of 230 ° C., a linear velocity of 200 mm / second (nip passage time of 40 msec) and a toner loading of 1.0 mg / cm ^2. The image III was continuously printed on. Image III was an offset pattern image. Each sheet on which the image III was formed was observed with the naked eye. From the observation results, the hot offset resistance was evaluated according to the following criteria. A toner having a hot offset resistance evaluation of A or B was considered acceptable.
(Evaluation criteria for hot offset resistance)
Evaluation A: No hot offset occurred on any of the 10 sheets.
Evaluation B: Some hot offset occurred on at least one of the 10 sheets.
Evaluation C: Hot offset clearly occurred on at least one of the 10 sheets.

<7-4. Glossiness>
The glossiness was evaluated in a normal environment (temperature 20 ° C., humidity 65% RH). A sheet of paper (90 g / m ² , A4 size) under the conditions of a fixing temperature of 180 ° C. of the fixing device of the evaluation machine, a linear speed of 200 mm / second (nip passing time 40 msec), and a toner loading of 1.0 mg / cm ² Image IV was printed on. Image IV was a solid image (printing rate 100%). The gloss value at a temperature of 60 ° C. of the image IV printed on the paper was measured using a gloss meter (“Handy Gloss Meter Gloss Checker IG-331” manufactured by Horiba, Ltd.). The glossiness was evaluated from the measured gloss value according to the following criteria. A toner having a gloss evaluation of A was determined to be acceptable.
(Evaluation criteria for glossiness)
Evaluation A: The gloss value was 6 or more.
Evaluation B: The gloss value was less than 6.

<7-5. Heat-resistant storage stability>
3 g of toner was weighed into a 20 mL capacity plastic container and allowed to stand in a thermostat set at 50 ° C. for 100 hours. As a result, a toner for heat resistant storage stability evaluation was obtained. Thereafter, the toner for heat resistant storage stability evaluation was sieved using a powder tester (“TYPE PT-E 84810” manufactured by Hosokawa Micron Corporation). Specifically, according to a manual of a powder tester (manufactured by Hosokawa Micron Corporation), a toner for heat-resistant storage stability evaluation was screened using a 200-mesh screen under the conditions of rheostat scale 5 and time 30 seconds. 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 formula “degree of aggregation (% by mass) = 100 × mass of toner remaining on the sieving / mass of toner before sieving. ”Was calculated. From the calculated degree of aggregation, heat resistant storage stability was evaluated according to the following criteria. A toner having a heat-resistant storage stability evaluation of A or B was considered acceptable.
(Evaluation criteria for heat-resistant storage stability)
Evaluation A: The degree of aggregation was less than 3% by mass.
Evaluation B: The degree of aggregation was 3% by mass or more and less than 10% by mass.
Evaluation C: The degree of aggregation was 10% by mass or more.

Tables 2 to 4 show measured values and evaluation results of the toners A-1 to A-6 and B-1 to B-10. The meaning of each term in Tables 2-4 is as follows. The “crystalline polyester resin content” of the transparent toner indicates the crystalline polyester resin content (% by mass) contained in the transparent toner particles with respect to the total mass of the binder resin contained in the transparent toner particles. “D ₅₀ t” indicates the volume median diameter of the transparent toner particles. “Rt1” represents the ratio of the number of transparent toner particles having a particle diameter of 1 μm or more smaller than the volume median diameter (D ₅₀ t) of the transparent toner particles to the total number of transparent toner particles. “Mt” indicates the addition amount of the transparent toner in the mixing step of the color toner and the transparent toner.

The “crystalline polyester resin content” of the color toner indicates the content (% by mass) of the crystalline polyester resin contained in the colored toner particles with respect to the total mass of the binder resin contained in the colored toner particles. “D ₅₀ c” indicates the volume median diameter of the colored toner particles. “Rc1” indicates the ratio of the number of colored toner particles having a particle diameter of 1 μm or more smaller than the volume median diameter (D ₅₀ c) of the colored toner particles to the total number of colored toner particles. “Rcs” indicates the ratio of the number of colored toner particles having a particle diameter of 3.0 μm or less to the total number of colored toner particles. “Mc” indicates the amount of color toner added in the mixing step of the color toner and the transparent toner.

“D ₅₀ t-D ₅₀ c” indicates a value calculated from the measured D ₅₀ t and D ₅₀ c according to the formula “D ₅₀ t-D ₅₀ c”. “Rc1-Rt1” indicates a value calculated from the measured Rc1 and Rt1 according to the mathematical expression “Rc1-Rt1”. “Mc / Mt” indicates the content of the colored toner with respect to 1.0 part by mass of the transparent toner. “Mc / Mt” is a value calculated according to the formula “Mc / Mt” from the addition amount (Mc and Mt) of the color toner and the transparent toner in the mixing step of the color toner and the transparent toner.

  Toners A-1 to A-6 had all of configurations (1) to (6). Therefore, as shown in Table 2, with toners A-1 to A-6, all evaluations of image evaluation (initial and after printing 10,000 sheets), fixability, hot offset resistance, glossiness, and heat storage stability Was a pass.

  In the toners A-1 to A-3 and A-6, in addition to the configurations (1) to (6), the content of the colored toner is 1.0 part by mass or more with respect to 1.0 part by mass of the transparent toner. It was 0 parts by mass or less. Therefore, as shown in Table 2, with toners A-1 to A-3 and A-6, image evaluation (after printing 10,000 sheets) and fixability were even better.

  In the toners A-1 to A-3, in addition to the configurations (1) to (6), the content Mc / Mt of the colored toner is 1.0 part by mass or more and 5.0 parts by mass with respect to 1.0 part by mass of the transparent toner. It was below mass parts. Further, the content of the crystalline polyester resin contained in the transparent toner particles was 20% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles. Therefore, as shown in Table 2, the fixability and the hot offset resistance were particularly good in the toners A-1 to A-3.

  In toner A-2, in addition to configurations (1) to (6), the content of the colored toner was 3.0 parts by mass or more and 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner. Further, the content of the crystalline polyester resin contained in the transparent toner particles was 20% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles. Therefore, as shown in Table 2, the toner A-2 has particularly good heat-resistant storage stability.

  From the above, it has been shown that the toner of the present invention can suppress the occurrence of image defects even when images are continuously formed. Further, it was shown that the toner of the present invention has fixing properties, hot offset resistance, glossiness and heat-resistant storage stability.

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

1 Toner 1c Colored toner particles 1t Transparent toner particles 10 Image carrier P Paper

Claims (9)

An electrostatic latent image developing toner containing a colored toner containing a plurality of colored toner particles and a transparent toner containing a plurality of transparent toner particles,
Of the colored toner particles and the transparent toner particles, only the transparent toner particles contain a release agent, and contain at least a crystalline polyester resin as a binder resin,
The content of the crystalline polyester resin contained in the transparent toner particles is 10% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles.
The volume median diameter of the transparent toner particles is larger than the volume median diameter of the colored toner particles, and the difference between the volume median diameter of the transparent toner particles and the volume median diameter of the colored toner particles is 0. Greater than 0 μm and less than or equal to 0.2 μm,
The number ratio of the colored toner particles having a particle diameter of 3.0 μm or less is 5.0% by number or less with respect to the total number of the colored toner particles,
The ratio of the number of the colored toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter of the colored toner particles to the total number of the colored toner particles is the transparent toner particles to the total number of the transparent toner particles. The toner for developing an electrostatic latent image, wherein the toner is larger than the number ratio of the transparent toner particles having a particle diameter of 1.0 μm or more smaller than the volume median diameter.   2. The electrostatic latent image developing toner according to claim 1, wherein the content of the colored toner is 1.0 part by mass or more and 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner.   The content of the crystalline polyester resin contained in the transparent toner particles is 20% by mass or more and 30% by mass or less with respect to the total mass of the binder resin contained in the transparent toner particles. Or the electrostatic latent image developing toner according to 2;   The electrostatic content according to any one of claims 1 to 3, wherein a content of the colored toner is 3.0 parts by mass or more and 5.0 parts by mass or less with respect to 1.0 part by mass of the transparent toner. Latent image developing toner.   The electrostatic latent image developing toner according to claim 1, wherein the binder resin contained in the transparent toner particles is the crystalline polyester resin and the amorphous polyester resin.   6. The electrostatic latent image developing toner according to claim 5, wherein the crystallinity of the crystalline polyester resin is 50.0% or more, and the crystallinity of the non-crystalline polyester resin is less than 50.0%. .   7. The electrostatic latent image developing according to claim 1, wherein the binder resin contained in the transparent toner particles has a crystallinity of 27.0% or more and 38.0% or less. toner. The colored toner particles contain a binder resin,
The electrostatic latent image developing according to any one of claims 1 to 7, wherein the binder resin contained in the colored toner particles has a crystallinity of 0.0% or more and less than 27.0%. toner.   The electrostatic latent image developing toner according to claim 1, wherein the electrostatic latent image developing toner is a non-magnetic toner.