JP6834298B2 - Toner set for static charge image development, static charge image developer set, toner cartridge set, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

The present invention relates to an electrostatic charge image developing toner set, an electrostatic charge image developing agent set, a toner cartridge set, a process cartridge, an image forming apparatus, and an image forming method.

Methods for visualizing image information, such as electrophotographic methods, are currently used in various fields. In the electrophotographic method, an electrostatic charge image is formed as image information on the surface of an image holder by forming a charged and electrostatic charge image. Then, a toner image is developed on the surface of the image holder with a developer containing toner, the toner image is transferred to a recording medium, the toner image is fixed on the recording medium, and the image information is visualized as an image.

For example, Patent Document 1 states, "A toner containing at least a binder resin and a wax, the wax exposure rate on the surface of the toner is 15% or less, and the melting point of the wax is in the range of 80 ° C. to 100 ° C. Toner "is disclosed.

Further, Patent Document 2 states that "at least a yellow toner composed of a yellow colorant, a binder resin and an external additive, at least a magenta toner composed of a magenta colorant, a binder resin and an external additive, and at least cyan". A full-color toner that combines cyan toner consisting of a colorant, a binder resin, and an external additive, and at least a black toner composed of carbon black, a binder resin, and an external additive, in any one color other than black toner. Alternatively, "a full-color toner for static charge image development in which the amount of wax exposure on the toner surface required for extraction of two colors of toner with hexane is less than the amount of wax exposure on the toner surface required for extraction of the remaining toner with hexane" is disclosed. There is.

Japanese Unexamined Patent Publication No. 2013-003225 Japanese Unexamined Patent Publication No. 2014-106517

The problem to be solved by the present invention is that the exposure rate of the release agent on the surface of the colored toner particles is less than 1.2 times the exposure rate of the release agent on the surface of the black toner particles, or It is an object of the present invention to provide a toner set for static charge image development in which scattering of toner on a recording medium is suppressed as compared with a case where the amount exceeds 10 times.

The above problem is solved by the following means.

< 1 > is
Black toner particles containing a black colorant, a binder resin and a mold release agent, the content is 1% by mass or more with respect to the black toner particles, and the volume resistance is 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less. Black toner for static charge image development containing inorganic particles having an average primary particle size of 10 nm or more and 50 nm, and colored toner particles containing a colored colorant, a binder resin, and a mold release agent. Inorganic particles having an amount of 1% by mass or more with respect to the colored toner particles, a volume resistance of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less, and an average primary particle size of 10 nm or more and 50 nm. It has a colored toner for static charge image development, and the exposure rate of the mold release agent on the surface of the colored toner particles is 1.2 times the exposure rate of the mold release agent on the surface of the black toner particles. This is a toner set for static charge image development that is 10 times or more.

< 2 > is
The toner set for static charge image development according to < 1 > , which has cyan toner as the colored toner for static charge image development.

< 3 > is
The exposure rate of the release agent on the surface of the black toner particles is 0.1% or more and 3.2% or less, and the exposure rate of the release agent on the surface of the colored toner particles is 0.12% or more and 10. The toner set for static charge image development according to < 1 > or < 2 > , which is 0% or less.

< 4 > is
The contrast ratio due to the inorganic particles in the exposed portion of the release agent is less than 90% 30% <1> to <3> developing an electrostatic charge image according to any one of the surface of the colored toner particles Toner set for.

< 5 > is
Wherein the inorganic particles are titania particles <1> to <4> any one The toner set according to the.

< 6 > is
<1> to the black electrostatic charge image developer containing a black toner for developing an electrostatic image contained in the toner set for electrostatic image development according to any one of <5>, <1> to <5 > is any one electrostatic image developer set comprising a colored electrostatic image developer containing the color toner for developing electrostatic images contained in the electrostatic image developing toner set forth in the.

< 7 > is
<1> to accommodate a black toner for developing an electrostatic image that is included in the electrostatic image developing toner set according to any one of <5>, and black toner cartridge that is removably to an image forming apparatus, < 1> to accommodate the color toner for developing an electrostatic image that is included in the electrostatic image developing toner set according to any one of <5>, containing a color toner cartridge that is removably to an image forming apparatus, a It is a toner cartridge set.

< 8 > is
A first developing unit that accommodates the black electrostatic charge image developer of the electrostatic image developer set according to <6>, wherein the colored electrostatic image of the electrostatic image developer set according to <6> development It is a process cartridge including a second developing means containing an agent and attached to and detached from an image forming apparatus.

< 9 > is
<1> to a first image forming means for forming a black image by the electrostatic image developing black toner of the toner set for electrostatic image development according to any one of <5>, <1> to < 5> and the second image forming means for forming a color image by the electrostatic image developing color toner of any one toner set for electrostatic image development according to the, the black image and a recording medium the color image An image forming apparatus including a transfer means for transferring onto the image and a fixing means for fixing the black image and the colored image on the recording medium.

< 10 > is
<1> to the first image forming step of forming a black image by the electrostatic image developing black toner of the toner set for electrostatic image development according to any one of <5>, <1> to < 5> and the second image forming step of forming a color image by the electrostatic image developing color toner of any one toner set for electrostatic image development according to the, the black image and a recording medium the color image It is an image forming method including a transfer step of transferring onto the image and a fixing step of fixing the black image and the colored image on the recording medium.

According to < 1 > , the exposure rate of the mold release agent on the surface of the colored toner particles is less than 1.2 times the exposure rate of the mold release agent on the surface of the black toner particles, or 10 Provided is a toner set for static charge image development in which toner scattering on a recording medium is suppressed as compared with the case where the amount exceeds double.
According to < 2 > , as the colored toner, a toner set for static charge image development is provided in which scattering of toner on a recording medium is further suppressed as compared with the case where cyan toner is not provided.
According to < 3 >, when the exposure rate of the release agent on the surface of the black toner particles is less than 0.1% or exceeds 3.2%, or the release agent on the surface of the colored toner particles Provided is a toner set for static charge image development, which is superior in releasability in a fixed image as compared with the case where the exposure rate is less than 0.12% or more than 10.0%.
According to < 4 > , the concealment rate of the exposed portion of the release agent on the surface of the colored toner particles by the external agent is less than 30% or more than 90% on the recording medium. Provided is a toner set for developing an electrostatic charge image, in which the scattering of toner in the above is further suppressed and the releasability of the fixed image is excellent.
According to < 5 > , a toner set for static charge image development is provided, in which the scattering of toner on a recording medium is further suppressed as compared with the case where only silica particles are contained as the inorganic particles, and the releasability of the fixed image is excellent. Will be done.

According to < 6 > , < 7 > , < 8 > , < 9 > or < 10 > , the exposure rate of the release agent on the surface of the colored toner particles is the exposure of the release agent on the surface of the black toner particles. Static charge image developer set, toner cartridge set, process cartridge, image formation that suppresses toner scattering on the recording medium compared to the case where the rate is less than 1.2 times or more than 10 times. An apparatus or image forming method is provided.

It is a schematic block diagram which shows an example of the image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment. It is a schematic diagram for demonstrating the power feed addition method.

Hereinafter, embodiments that are an example of the present invention will be described in detail.

[Toner set for static charge image development]
The toner set for static charge image development according to the present embodiment includes a black toner for static charge image development (hereinafter, also simply referred to as “black toner” or “black toner”) and a colored toner for static charge image development (hereinafter, simply “color”). Also referred to as "toner").
The black toner contains black toner particles containing a black colorant, a binder resin and a mold release agent, a volume resistivity of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less, and an average primary particle size of 10 nm or more and 50 nm. It contains inorganic particles which are.
The content of the inorganic particles in the black toner is 1% by mass or more with respect to the total mass of the black toner particles.
The color toner includes colored toner particles containing a colored colorant, a binder resin and a mold release agent, a volume resistivity of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less, and an average primary particle size of 10 nm or more and 50 nm. It contains inorganic particles that are.
The content of the inorganic particles in the color toner is 1% by mass or more with respect to the total mass of the colored toner particles.
The exposure rate of the release agent on the surface of the colored toner particles is 1.2 times or more and 10 times or less with respect to the exposure rate of the release agent on the surface of the black toner particles.

Here, the colored toner (color toner) for developing an electrostatic charge image, the colored toner particles, and the colored colorant refer to the toner, the toner particles, and the colorant having a color other than black. Examples of the color toner include yellow toner, magenta toner, cyan toner and the like.

In the present embodiment, when a plurality of color toners are used together as the color toner (for example, when three color toners of yellow toner, magenta toner and cyan toner are used together), at least one color toner is the above-mentioned. The requirements may be satisfied, but it is preferable that the color toners of all the colors used in combination satisfy the above requirements.

Further, in the following, when both black toner and color toner are referred to, they are simply referred to as toner. Further, when both the black toner particles and the colored toner particles are referred to, the toner particles are simply referred to, and when both the black colorant and the colored toner particles are referred to, the colorant is simply referred to as a black toner image and the colored toner. When referring to both the image and the image, it is simply called a toner image.

In the toner set for static charge image development according to the present embodiment, the above-mentioned configuration suppresses the scattering of toner on the recording medium. The reason is presumed as follows.

When a toner having toner particles with a release agent exposed on the surface is used, the releasability in the fixed image is improved.
A mold release agent exposed on the surface of toner particles such as the toner tends to increase the cohesiveness between the toner particles and deteriorate the powder fluidity, but the volume resistance of titanium oxide particles and the like is high. The powder fluidity is improved by adding inorganic particles having an average primary particle size of 10 nm or more and 50 nm or less and 1 × 10 ⁹ Ωcm or more and 1 × 10 ^{14 Ωcm or less.} By adhering the external additive in a nearly uniform state, the viscosity of the exposed portion of the release agent on the surface of the toner particles is appropriately adjusted, and the effect of suppressing aggregation can be obtained. For external additives other than inorganic particles having a volume resistivity of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less and an average primary particle size of 10 nm or more and 50 nm, adhesion between the external agents on the surface of the release agent Since aggregates are easily formed, they are unevenly distributed and adhere to each other, so that sufficient fluidity may not be obtained.

However, a toner having inorganic particles as an external additive having a volume resistance of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less and an average primary particle size of 10 nm or more and 50 nm has a long color image such as a photograph. When an image in which a black solid image portion is present in the color image is printed after time printing, toner may be scattered at the boundary line between the black solid image portion and the color image portion.
It is presumed that the toner scattering is caused by the following causes.
^{Inorganic toner having a volume resistivity of 1 × 10 9} Ωcm or more and 1 × 10 ¹⁴ Ωcm or less and an average primary particle size of 10 nm or more and 50 nm due to a stirring load of black toner from a stirrer such as an auger in a developing machine. Many particles adhere to the exposed portion of the release agent on the surface of the toner particles. When a large amount of the inorganic particles gather in the exposed portion of the release agent, an electric conduction path is generated on the surface of the toner particles, and electric charges escape from the surface of the toner particles. Since black colorants such as carbon black have higher conductivity than colorants of other colors, the charge of black toner particles in particular is significantly reduced by the stirring load of the stirring device.
Due to the decrease in charge of black toner due to the stirring load, charge injection occurs from the color toner to the black toner, and the charge balance of the toner is lost when the intermediate transfer material is secondarily transferred onto the recording medium, resulting in the recording medium. The phenomenon that black toner scatters on the top occurs.

Therefore, in order to suppress the scattering of the black toner on the recording medium, an electrical conduction path is generated on the surface of the black toner particles, and charge injection is generated from the color toner to the black toner to be generated from the surface of the black toner particles. By setting an appropriate ratio between the exposure rate of the release agent on the surface of the colored toner particles and the exposure rate of the release agent on the surface of the black toner particles so that the charge does not decrease, the occurrence of the toner scattering is suppressed. Will be done.

Specifically, as described above, the toner set for static charge image development according to the present embodiment contains toner particles containing a colorant, a binder resin and a mold release agent, and a content of 1% by mass with respect to the toner particles. It has black toner and color toner containing inorganic particles having a volume resistance of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less and an average primary particle size of 10 nm or more and 50 nm. The exposure rate of the release agent on the surface of the colored toner particles is 1.2 times or more and 10 times or less the exposure rate of the release agent on the surface of the black toner particles.
When the exposure rate of the release agent on the surface of the colored toner particles exceeds 10 times the exposure rate of the release agent on the surface of the black toner particles, the charge reduction width of the color toner is too large, so that the black toner The relationship between the charging characteristics of the color toner and that of the color toner is reversed, and charge injection from the black toner to the color toner occurs, which causes the color toner to scatter.
When the exposure rate of the release agent on the surface of the colored toner particles is less than 1.2 times the exposure rate of the release agent on the surface of the black toner particles, the charge of the color toner equivalent to that of the black toner is reduced. No effect is obtained, and black toner is scattered on the recording medium.
Further, when the volume resistance is 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less, and the content of inorganic particles having an average primary particle size of 10 nm or more and 50 nm is less than 1% by mass with respect to the toner particles. Since the amount of the inorganic particles adhering to the surface of the black toner particles other than the exposed portion of the release agent is small, the amount of the inorganic particles transferred to the exposed portion of the release agent on the surface of the color toner particles is reduced, and the particles are sufficiently charged. The lowering effect cannot be obtained, and toner is scattered on the recording medium.

Hereinafter, the details of the toner set for static charge image development according to the present embodiment will be described.

In the toner set for static charge image development according to the present embodiment, the exposure rate of the release agent on the surface of the colored toner particles is 1.2 times or more the exposure rate of the release agent on the surface of the black toner particles. It is 10 times or less, preferably 1.3 times or more and 10 times or less, and more preferably 3.0 times or more and 10 times or less from the viewpoint of suppressing toner scattering on the recording medium.
Further, from the viewpoint of suppressing toner scattering on the recording medium and releasability of the fixed image, the exposure rate of the mold release agent on the surface of the black toner particles is 0.01% or more and 5.0% or less. It is preferably 0.05% or more and 4.0% or less, and particularly preferably 0.1% or more and 3.2% or less.
Further, from the viewpoint of suppressing toner scattering on the recording medium and releasability of the fixed image, the exposure rate of the mold release agent on the surface of the colored toner particles is 0.05% or more and 12.0% or less. It is preferably 0.12% or more and 10.0% or less, and particularly preferably 3.0% or more and 10.0% or less.
The exposure rate of the release agent on the surface of the toner particles in the present embodiment represents the exposure area rate.

The exposure rate of the release agent on the surface of the toner particles in the present embodiment (referred to as the release agent surface exposure rate) shall be measured by the following method.
The exposure rate of the release agent is a value measured by XPS (X-ray photoelectron spectroscopy). XPS (X-ray photoelectron spectroscopy) measurement is performed using toner particles as a measurement sample. As the XPS measuring device, JPS-9000MX manufactured by JEOL Ltd. is used, and the measurement is carried out by using MgKα ray as the X-ray source and setting the acceleration voltage to 10 kV and the emission current to 30 mA. Here, the amount of mold release agent on the surface of the toner particles is quantified by the peak separation method of the C1s spectrum. In the peak separation method, the measured C1s spectrum is separated into each component by using curve fitting by the least squares method. For the component spectrum that is the base of separation, the C1s spectrum obtained by independently measuring the release agent and the resin used for producing the toner particles is used.
When the toner is externally added by an external additive, for example, the toner is dispersed in ion-exchanged water to which a dispersant such as a surfactant is added, and an ultrasonic homogenizer (US-300T: Co., Ltd .) The external additive and toner particles are separated by applying ultrasonic waves (manufactured by Nissei Tokyo Office). Then, only the toner particles from which the external additive has been separated are taken out by drying and recovering through a filtration treatment and a washing treatment, and the toner particles are used as a measurement sample.

Further, in the toner set for static charge image development according to the present embodiment, the release agent is exposed on the surface of the colored toner particles from the viewpoint of suppressing the scattering of toner on the recording medium and the releasability of the fixed image. The concealment rate of the portion by the inorganic particles is preferably 30% or more and 90% or less, and more preferably 50% or more and 70% or less.

The concealment rate of the exposed portion of the release agent on the surface of the colored toner particles in the present embodiment by the inorganic particles shall be measured by the following method.
Due to the difference in crystallinity, the material is contrasted between the release agent and the other parts by the ruthenium tetroxide staining method, observed with a scanning electron microscope (SEM), and the image is captured in an image analyzer. It is possible to obtain the area of the release agent portion and the projected area of the existing external additive, calculate the average value of the observed toner, and calculate the concealment rate from each value. A more specific method of ruthenium tetroxide staining is as follows.

-Staining-
As a sample for electron microscope observation, an aluminum stage for electron microscope observation to which carbon tape is attached is prepared, toner powder is adhered on the carbon tape, and then ruthenium tetroxide (ruthenium tetroxide) is used in an environment of temperature 25 ° C. and humidity 55%. It was placed in a desiccator together with Soekawa Rikagaku Co., Ltd. and subjected to an oxidation reaction treatment for 2 hours for staining (the degree of dyeing was judged by the degree of dyeing of the tape left at the same time).

-Observation-
From the stained observation sample, the surface of the stained toner was observed with a scanning electron microscope (S-4800 manufactured by Hitachi High-Technologies Corporation). By emphasizing the composition signal at the time of observation, the binder resin, the external additive, and the release agent component on the toner surface can be discriminated from the difference in image shading. Specifically, using image analysis software (Win ROOF (manufactured by Mitani Shoji Co., Ltd.)), observe the image so that one particle of toner fits in one field of view, and perform binarization processing on the toner surface. The area is calculated by extracting the exposed part of the release agent. Further, only the exposed part of the release agent is selected and projected in one field of view, and the area of the inorganic particles on the release agent is calculated by binarizing. From the above, the areas of each of the exposed part of the release agent and the inorganic fine particle part were calculated, and the ratio was calculated. This was performed for 100 or more toner particles, and the average value was taken as the concealment rate.

-Method of controlling the exposure rate of the release agent in the colored toner particles and the black toner particles The method of controlling the exposure rate of the release agent on the surface of the colored toner particles and the black toner particles is not particularly limited.
Examples of the method for increasing the exposure rate of the release agent on the surface include the following methods.
(1) Method of unevenly distributing the release agent on the surface side of the toner particles (2) Method of increasing the amount of the release agent contained in the toner particles

The content of the release agent contained in the toner particles has a preferable range from the viewpoint of the charging performance of the toner (for example, it is preferably 1% by mass or more and 20% by mass or less with respect to the entire toner particles). Therefore, from the viewpoint of obtaining the charging performance of the toner and increasing the exposure rate of the release agent, the method (1) is preferable. That is, in the present embodiment, the colored toner particles are subjected to the method (1). It is preferable to increase the exposure rate of the release agent.
Here, as a method of (1) unevenly distributing the release agent on the surface side of the toner particles, for example, a method of producing the toner particles by a power feed addition method described later can be mentioned.

On the other hand, as a method for reducing the exposure rate of the release agent on the surface, for example, the following method can be mentioned.
(I) A method of dispersing the release agent in a state of high uniformity over the entire toner particles (ii) A method of reducing the amount of the release agent contained in the toner particles (iii) A method of dispersing the release agent near the surface of the toner particles A method of controlling the release agent from being unevenly distributed and reducing the exposure of the release agent on the surface.

From the viewpoint of suppressing offset (adhesion of toner to the fixing member) when fixing the toner image to the recording medium, the surface of the toner particles is used to allow the release agent to exude satisfactorily during fixing. It is preferable that the release agent is unevenly distributed in the vicinity. Therefore, from the viewpoint of suppressing the offset at the time of fixing and reducing the exposure rate of the release agent, the method of (iii) above is preferable. That is, in the present embodiment, the method of (iii) above is used to obtain black toner particles. It is preferable to reduce the exposure rate of the release agent.
Here, as a method of unevenly distributing the release agent on the surface side of the (iii) toner particles and reducing the exposure of the release agent on the surface, for example, the toner particles are prepared by the power feed addition method described later and the surface side. After the release agent is unevenly distributed, a method of forming a shell layer containing no release agent or having a low content of the release agent can be mentioned.

-Domain of mold release agent The colored toner particles and black toner particles in the present embodiment preferably have a domain of a mold release agent on the surface, that is, a sea part containing a binder resin and an island part containing a mold release agent. It is preferable to have a sea-island structure having and.

Here, the average particle size of the release agent domain (islands containing the release agent) on the surface of the colored toner particles is preferably 2.0 μm or less, more preferably 1.7 μm or less. It is more preferably 1.5 μm or less.
When the average particle size of the release agent domain of the colored toner particles is 2.0 μm or less, the generation of color spots due to the aggregation of the toners is suppressed.

The average particle size of the release agent domain (islands containing the release agent) on the surface of the black toner particles is preferably 2.0 μm or less, more preferably 1.7 μm or less. It is more preferably .5 μm or less.
When the average particle size of the release agent domain of the black toner particles is 2.0 μm or less, the reproducibility of fine lines in a black image is excellent.

Here, the average particle size of the release agent domain on the surface of the colored toner particles and the average particle size of the release agent domain on the surface of the black toner particles are both measured by the following methods.
Due to the difference in crystallinity, the material is contrasted between the release agent and the other parts by the ruthenium tetroxide staining method, observed with a scanning electron microscope (SEM), and the image is captured in an image analyzer. , The equivalent circle diameter of the mold release agent was calculated. A more specific method of ruthenium tetroxide staining is as follows.

-Staining-
As a sample for electron microscope observation, an aluminum stage for electron microscope observation with carbon tape attached was prepared, toner powder was adhered on the carbon tape, and then ruthenium tetroxide (ruthenium tetroxide) under an environment of temperature 25 ° C. and humidity 55%. It was placed in a desiccator together with Soekawa Rikagaku Co., Ltd. and subjected to an oxidation reaction treatment for 2 hours for staining (the degree of dyeing was judged by the degree of dyeing of the tape left at the same time).

-Observation-
From the stained observation sample, the surface of the stained toner was observed with a scanning electron microscope (S-4800 manufactured by Hitachi High-Technologies Corporation). By emphasizing the composition signal at the time of observation, the binder resin on the toner surface and the release agent component are discriminated from the difference in image shading. Specifically, using image analysis software (Win ROOF (manufactured by Mitani Shoji Co., Ltd.)), observe the image so that one particle of toner fits in one field of view, and perform binarization processing on the toner surface. The exposed part of the release agent was extracted, and the equivalent circle diameter was calculated. This was performed for 100 or more toner particles, and the average value was taken as the average particle size of the release agent domain.

-Method of controlling the average particle size of the release agent domain As a method of controlling the average particle size of the release agent domain on the surface of the black toner particles and the colored toner particles, for example, the following method can be mentioned.
For the release agent dispersion, for example, a mixture of a release agent and a dispersant is heated to a temperature equal to or higher than the melting point of the release agent, emulsified using a high-pressure type emulsifier, and then cooled. Obtained by solidifying the release agent particles.
The prepared release agent particle dispersion is centrifuged using a centrifuge device, and the release agent particles having a particle size of 2.0 μm or less and the release agent particles having a larger size are separated. Then, the supernatant after centrifugation, that is, the release agent dispersion having a particle size of 2.0 μm or less is collected and provided to the release agent particle dispersion in the subsequent stage. Since the conditions differ depending on the type of mold release agent and the particle size distribution, it is appropriately selected, but it is separated by applying a centrifugal force of 500 G to 1,000 G.
By using the release agent particle dispersion prepared as described above, the exposure average particle size of the release agent is controlled to 2.0 μm or less.

From the viewpoint of transparency and concealment of each color image, among the color toners, the cyan toner often comes into contact with the black toner. Therefore, the toner set for static charge image development according to the present embodiment is a toner set on a recording medium. From the viewpoint of suppressing scattering, it is preferable to have at least cyan toner as the colored toner. Due to the light absorption rate of the toner, there are many embodiments in which the black toner and the cyan toner come into contact with each other at the time of fixing or intermediate transfer, and when the cyan toner is used as the colored toner, the toner is scattered on the recording medium. More suppressed.

The black toner for static charge image development (black toner) and the colored toner for static charge image development (color toner) included in the toner set according to the present embodiment contain the inorganic particles, and the colorant contained therein is contained. The configuration may be freely adopted except that it is different and the exposure rate of the release agent on the surface meets the above-mentioned requirements. For example, the same configuration may be adopted between the black toner and the color toner except for the difference in the colorant and the difference in the exposure rate of the release agent.

Hereinafter, the constituent components of the toner (black toner and color toner) contained in the toner set according to the present embodiment will be described.
The toner in the present embodiment is composed of toner particles and an external additive.

(Toner particles)
The toner particles are composed of a binder resin, a colorant, and a release agent, and may further contain other additives.

-Bound resin-
Examples of the binder resin include styrenes (for example, styrene, parachlorostyrene, α-methylstyrene, etc.) and (meth) acrylic acid esters (for example, methyl acrylate, ethyl acrylate, n-propyl acrylate, acrylic acid). n-butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (eg, acrylonitrile, Methacrylic acid, etc.), vinyl ethers (eg, vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (eg, ethylene, propylene, butadiene, etc.), etc. Examples thereof include a homopolymer of the above-mentioned monomer and a vinyl-based resin composed of a copolymer obtained by combining two or more kinds of these monomers.
Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosins, mixtures of these with the vinyl resins, or these. Examples thereof include a graft polymer obtained by polymerizing a vinyl-based monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

As the binder resin, a polyester resin is suitable.
Examples of the polyester resin include known polyester resins.

Examples of the polyester resin include a condensed polymer of a polyvalent carboxylic acid and a polyhydric alcohol. As the polyester resin, a commercially available product may be used, or a synthetic resin may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenyl succinic acid, adipic acid, sebacic acid, etc.). , Alicyclic dicarboxylic acid (eg cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acid (eg terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), these anhydrides, or their lower grades (eg, 1 or more carbon atoms) (5 or less) Alkyl ester can be mentioned. Among these, as the polyvalent carboxylic acid, for example, an aromatic dicarboxylic acid is preferable.
As the polyvalent carboxylic acid, a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure may be used in combination with the dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, 1 to 5 carbon atoms) alkyl esters thereof.
The polyvalent carboxylic acid may be used alone or in combination of two or more.

Examples of the polyhydric alcohol include aliphatic diols (for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (for example, cyclohexanediol, cyclohexanedimethanol, etc.). Hydrogenated bisphenol A, etc.), aromatic diols (for example, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.) can be mentioned. Among these, as the polyhydric alcohol, for example, an aromatic diol and an alicyclic diol are preferable, and an aromatic diol is more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used in combination with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
The polyhydric alcohol may be used alone or in combination of two or more.

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is obtained from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically described in JIS K 7121-1987 "Method for measuring transition temperature of plastics". It is obtained by the "external glass transition start temperature" of.

The weight average molecular weight (Mw) of the polyester resin is preferably 5000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less.
The number average molecular weight (Mn) of the polyester resin is preferably 2000 or more and 100,000 or less.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed using a Tosoh GPC / HLC-8120GPC as a measuring device, a Tosoh column / TSKgel SuperHM-M (15 cm), and a THF solvent. The weight average molecular weight and the number average molecular weight are calculated from this measurement result using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

The polyester resin is obtained by a well-known manufacturing method. Specifically, for example, the polymerization temperature is set to 180 ° C. or higher and 230 ° C. or lower, the pressure inside the reaction system is reduced as necessary, and the reaction is carried out while removing water and alcohol generated during condensation.
When the raw material monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a dissolution aid to dissolve the monomer. In this case, the polycondensation reaction is carried out while distilling off the dissolution aid. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility, the monomer, and the acid or alcohol to be polycondensed are condensed in advance, and then weighted together with the main component. It is good to condense.

The content of the binder resin is, for example, preferably 40% by mass or more and 95% by mass or less, more preferably 50% by mass or more and 90% by mass or less, and 60% by mass or more and 85% by mass or less with respect to the entire toner particles. More preferred.

-Colorant-
Colorants include, for example, carbon black, chrome yellow, Hansa yellow, benzine yellow, slene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliant carmine 3B, brilliant. Carmin 6B, Dupont Oil Red, Pyrazolon Red, Resole Red, Rhodamin B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultra Marine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, or aclysine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black Examples thereof include various dyes such as system, polymethine type, triphenylmethane type, diphenylmethane type and thiazole type.

In addition to the carbon black and aniline black dyes, examples of the black colorant include copper oxide, manganese dioxide, activated carbon, non-magnetic ferrite, and magnetite.
The black colorants listed above are relatively highly conductive colorants, and black toners containing these black colorants tend to have lower resistance than color toners.
One type of colorant may be used alone, or two or more types may be used in combination.

As the colorant, a surface-treated colorant may be used if necessary, or may be used in combination with a dispersant. Further, a plurality of kinds of colorants may be used in combination.

The content of the colorant is, for example, preferably 1% by mass or more and 30% by mass or less, and more preferably 3% by mass or more and 15% by mass or less with respect to the entire toner particles.

-Release agent-
Examples of the release agent include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester waxes such as fatty acid esters and montanic acid esters. ; And so on. The release agent is not limited to this.

Among the above-mentioned mold release agents, hydrocarbon wax, fatty acid ester wax, or amide wax is more preferable from the viewpoint of suppressing toner scattering on the recording medium and releasability of the fixed image.

The melting temperature of the release agent is preferably 50 ° C. or higher and 110 ° C. or lower, and more preferably 60 ° C. or higher and 100 ° C. or lower.
The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) by the "melting peak temperature" described in the method for determining the melting temperature in JIS K 7121-1987 "Method for measuring transition temperature of plastics". ..

The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less with respect to the entire toner particles.

-Other additives-
Examples of other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are contained in the toner particles as an internal additive.

-Characteristics of toner particles, etc.-
The toner particles may be toner particles having a single layer structure, or are toner particles having a so-called core-shell structure composed of a core portion (core particles) and a coating layer (shell layer) covering the core portion. You may.
Here, the toner particles having a core-shell structure include, for example, a core portion composed of a binder resin, a colorant, and a mold release agent, and if necessary, other additives, and a binder resin. It may be composed of a composed coating layer and.

The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 3 μm or more and 8 μm or less, from the viewpoint of suppressing toner scattering on the recording medium.

The various average particle sizes and various particle size distribution indexes of the toner particles were measured using Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolytic solution was measured using ISOTON-II (manufactured by Beckman Coulter). Toner.
At the time of measurement, 0.5 mg or more and 50 mg or less of the measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate) as a dispersant. This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolytic solution in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm or more and 60 μm or less is obtained by using a 100 μm aperture with a Coulter Multisizer II. Measure. The number of particles to be sampled is 50,000.
Cumulative distribution of volume and number is drawn from the small diameter side for each particle size range (channel) divided based on the measured particle size distribution, and the cumulative 16% particle size is volume particle size D16v and number particle size. The particle size with D16p and cumulative 50% is defined as volume average particle size D50v and cumulative number average particle size D50p, and the particle size with cumulative 84% is defined as volume particle size D84v and number particle size D84p.
Using these, the volume particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 , and the number particle size distribution index (GSDp) is calculated as ^{(D84p / D16p) 1/2.}

The average circularity of the toner particles is preferably 0.94 or more and 1.00 or less, and more preferably 0.95 or more and 0.98 or less.

The average circularity of the toner particles is obtained by (circumferential peripheral length) / (peripheral length) [(circumferential length of a circle having the same projected area as the particle image) / (peripheral length of the particle projected image)]. Specifically, it is a value measured by the following method.
First, a flow-type particle image analyzer (Cysmex) that captures a particle image as a still image by sucking and collecting toner particles to be measured, forming a flat flow, and instantly causing strobe light emission to analyze the particle image. Obtained by FPIA-2100) manufactured by the company. Then, the number of samples for obtaining the average circularity is set to 3500.
When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additive has been removed. ..

(External agent)
In the present embodiment, both the black toner and the color toner have a volume resistivity of 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less and an average primary particle size of 10 nm or more and 50 nm as an external additive. Inorganic particles (hereinafter, also referred to as specific inorganic particles) are contained in an amount of 1% by mass or more based on the total mass of the toner particles.

Examples of the material of the specific inorganic particles include titania, metatitanic acid, zirconia, alumina, Celica, and a mixture thereof.
Among these, as the specific inorganic particles, the inorganic particles containing titanium oxide are preferable, and the titania particles are particularly preferable, from the viewpoint of suppressing the scattering of toner on the recording medium and the releasability of the fixed image.
In addition, ordinary silica particles have a high volume resistivity and do not satisfy the above range.

The volume resistivity of the specific inorganic particles is 1 × 10 ⁹ Ωcm or more and 1 × 10 ¹⁴ Ωcm or less, and from the viewpoint of suppressing toner scattering on the recording medium, it is 1 × 10 ¹⁰ Ωcm or more and 1 × 10 ¹³ Ωcm or less. Is preferable.
The method for measuring the volume resistivity of particles in this embodiment is as follows.
^{A layer of particles is formed on a pair of 20 cm 2} circular plates connected to an electrometer (KEYTHLEY610C, manufactured by KEYTHLEY) and a high-voltage power supply (trade name: FLUKE415B, manufactured by FKUKE), and an upper pole is formed on the layer. After arranging the plate, the thickness of the particle layer is measured with a weight of 4 kg placed on it to remove voids in the particles. Next, a voltage of 1,000 V is applied to both electrode plates, the current value is measured, and the volume resistivity ρ is calculated by the formula ρ = V × S / {(AA ₀ ) × d}. In addition, V = applied voltage, S = plate area, A = measured voltage, A ₀ = initial current value when applied voltage 0V, d = particle layer thickness.

The average primary particle size of the specific inorganic particles is 10 nm or more and 50 nm, and is preferably 15 nm or more and 30 nm or less from the viewpoint of suppressing toner scattering on the recording medium.
The method for measuring the average primary particle size of the inorganic particles in the present embodiment is as follows.
The primary particles of the inorganic particles were observed with a scanning electron microscope SEM (Scanning Electron Microscope) device (manufactured by Hitachi, Ltd .: S-4100, acceleration voltage 5 kV, 30,000 times), and an image was taken. Is taken into an image analyzer (LUZEXIII, manufactured by Nireco Co., Ltd.), the area of each particle is measured by image analysis of the primary particles, and the equivalent circle diameter is calculated from this area value. This circle-equivalent diameter is calculated for 100 inorganic particles. Then, the 50% diameter (D50) of the obtained volume-based cumulative frequency of the equivalent circle diameter is defined as the average primary particle diameter (average equivalent circle diameter D50) of the inorganic particles. In the electron microscope, the magnification is adjusted so that about 10 or more and 50 or less inorganic particles are captured in one field of view, and the equivalent circle diameter of the primary particles can be obtained by combining the observations of a plurality of fields of view.

Examples of the method for separating the external additive such as specific inorganic particles from the toner include the following methods.
A preferred method is to add toner to tetrahydrofuran (THF), dissolve only the toner particles, separate the external additive from the toner particles, and then separate the external additive with a centrifuge. When a plurality of external additives are used in combination, the external additive species can be separated and recovered by changing the conditions for centrifugation.

The surface of the specific inorganic particles may be hydrophobized. The hydrophobizing treatment is performed, for example, by immersing inorganic particles in a hydrophobizing agent. The hydrophobizing agent is not particularly limited, and examples thereof include a silane-based coupling agent, a silicone oil, a titanate-based coupling agent, and an aluminum-based coupling agent. These may be used alone or in combination of two or more.
The amount of the hydrophobizing agent is preferably 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the specific inorganic particles.

The content of the specific inorganic particles with respect to the toner particles is 1% by mass or more in both the black toner and the color toner, and is preferably 1% by mass or more and 5% by mass or less from the viewpoint of suppressing the scattering of the toner on the recording medium. 1, 1% by mass or more and 3% by mass or less is more preferable, and 1.0% by mass or more and 2.0% by mass or less is particularly preferable.

-Other external additives-
In the present embodiment, both the black toner and the color toner may contain an external additive other than the specific inorganic particles (for example, inorganic particles having an average primary particle size of more than 50 nm (large diameter external additive)).

Examples of other external additives include inorganic particles. As the inorganic particles, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO. _{SiO 2, K 2 O · (} TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.
Other external additives include resin particles (resin particles such as polystyrene, polymethylmethacrylate (PMMA), and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, and fluorine-based highs. Particles of molecular weight) and the like.

The surface of the inorganic particles as the other external additive may be hydrophobized, as in the case of the specific inorganic particles.

As the external addition amount of the other external additive, for example, 0.01% by mass or more and 5% by mass or less is preferable, and 0.01% by mass or more and 2.0% by mass or less is more preferable with respect to the toner particles.

(Toner manufacturing method)
Next, a method for producing toner (black toner and color toner) in the present embodiment will be described.
The toner in the present embodiment can be obtained by externally adding an external additive to the toner particles after producing the toner particles.

The toner particles may be produced by any of a dry production method (for example, a kneading and pulverizing method, etc.) and a wet production method (for example, an agglomeration coalescence method, a suspension polymerization method, a dissolution suspension method, etc.). The method for producing the toner particles is not particularly limited to these production methods, and a well-known production method is adopted.
Among these, it is preferable to obtain toner particles by the aggregation and coalescence method.

In particular, the colored toner particles and the black toner particles are shown below from the viewpoint of obtaining toner particles having a composition in which the exposure rate of the release agent on the surface of the colored toner particles is larger than the exposure rate of the release agent on the surface of the black toner particles. It may be manufactured by the coagulation coalescence method and then controlled so that the exposure of the release agent on the surface to the black toner particles is reduced.

First, the aggregation and coalescence method will be described.
Specifically, a step of preparing each dispersion (dispersion preparation step) and
Obtained by mixing a first resin particle dispersion liquid in which first resin particles to be a binder resin are dispersed and a colorant particle dispersion liquid in which colorant particles (hereinafter, also referred to as “colorant particles”) are dispersed. A step of aggregating each particle to form a first agglomerated particle (first agglomerated particle forming step) in the dispersion liquid.
After obtaining the first agglomerated particle dispersion liquid in which the first agglomerated particles are dispersed, a mixture in which the second resin particles to be the binder resin and the particles of the release agent (hereinafter, also referred to as “release agent particles”) are dispersed. The dispersion is sequentially added to the first agglomerated particle dispersion while gradually increasing the concentration of the release agent particles in the mixed dispersion, and the second resin particles and the release agent particles are further added to the surface of the first agglomerated particles. A step of aggregating to form a second agglomerated particle (second agglomerated particle forming step) and
A step of heating the second agglomerated particle dispersion liquid in which the second agglomerated particles are dispersed to fuse and coalesce the second agglomerated particles to form toner particles (fusion and coalescence step).
It is preferable to produce toner particles through the above.

The method for producing toner particles is not limited to the above. For example, the resin particle dispersion liquid and the colorant particle dispersion liquid are mixed, and each particle is agglomerated in the obtained mixed dispersion liquid. Next, in the aggregation process, the release agent particle dispersion is added to the mixed dispersion while gradually increasing the addition rate or increasing the concentration of the release agent particles, and the aggregation of each particle is further promoted. To form aggregated particles. Then, the aggregated particles may be fused and united to form toner particles.

The details of each step will be described below.

-Each dispersion preparation process-
First, it is prepared with each dispersion used in the aggregation and coalescence method. Specifically, the first resin particle dispersion liquid in which the first resin particles to be the binder resin are dispersed, the colorant particle dispersion liquid in which the colorant particles are dispersed, and the second resin particles to be the binder resin are dispersed. A second resin particle dispersion and a release agent particle dispersion in which the release agent particles are dispersed are prepared.
In each dispersion liquid preparation step, the first resin particles and the second resin particles will be referred to as "resin particles".

Here, the resin particle dispersion liquid is prepared, for example, by dispersing the resin particles in a dispersion medium with a surfactant.

Examples of the dispersion medium used in the resin particle dispersion liquid include an aqueous medium.
Examples of the aqueous medium include distilled water, water such as ion-exchanged water, alcohols, and the like. These may be used alone or in combination of two or more.

Examples of the surfactant include anionic surfactants such as sulfate ester salt type, sulfonate type, phosphoric acid ester type and soap type; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol. Examples thereof include nonionic surfactants such as systems, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
The surfactant may be used alone or in combination of two or more.

Examples of the method for dispersing the resin particles in the dispersion medium in the resin particle dispersion liquid include general dispersion methods such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, and a dyno mill. Further, depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion liquid by, for example, a phase inversion emulsification method.
In the phase inversion emulsification method, the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and a base is added to the organic continuous phase (O phase) to neutralize the resin, and then the aqueous medium is used. A method in which the (W phase) is charged to convert the resin from W / O to O / W (so-called phase inversion) to discontinue the phase, and the resin is dispersed in an aqueous medium in the form of particles. Is.

The volume average particle diameter of the resin particles dispersed in the resin particle dispersion is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less. preferable.
The volume average particle size of the resin particles is determined by using the particle size distribution obtained by the measurement of a laser diffraction type particle size distribution measuring device (for example, manufactured by Horiba Seisakusho, LA-700) with respect to the divided particle size range (channel). , The cumulative distribution is subtracted from the small particle size side for the volume, and the particle size that is cumulatively 50% of all particles is measured as the volume average particle size D50v. The volume average particle diameter of the particles in the other dispersion is also measured in the same manner.

The content of the resin particles contained in the resin particle dispersion is, for example, preferably 5% by mass or more and 50% by mass or less, and more preferably 10% by mass or more and 40% by mass or less.

In the same manner as the resin particle dispersion, for example, a colorant particle dispersion and a release agent particle dispersion are also prepared. That is, regarding the volume average particle size, dispersion medium, dispersion method, and particle content of the particles in the resin particle dispersion, the colorant particles dispersed in the colorant particle dispersion and the release agent particle dispersion are used. The same applies to the disperse of the release agent particles.

-First aggregate particle formation step-
Next, the first resin particle dispersion liquid and the colorant particle dispersion liquid are mixed.
Then, in this mixed dispersion, the first resin particles and the colorant particles are hetero-aggregated to form the first agglutinated particles containing the first resin particles and the colorant particles.

Specifically, for example, a flocculant is added to the mixed dispersion, the pH of the mixed dispersion is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. Particles that have been heated to the glass transition temperature of the first resin particles (specifically, for example, the glass transition temperature of the first resin particles is -30 ° C or higher and the glass transition temperature is -10 ° C or lower) and dispersed in the mixed dispersion. To agglomerate to form first agglomerated particles.
In the first agglomerated particle forming step, for example, the mixed dispersion is stirred with a rotary shear type homogenizer, the above-mentioned flocculant is added at room temperature (for example, 25 ° C.), and the pH of the mixed dispersion is acidic (for example, pH is 2 or more). 5 or less), and if necessary, a dispersion stabilizer may be added, and then the above heating may be performed.

Examples of the flocculant include a surfactant used as a dispersant added to the mixed dispersion, a surfactant having the opposite polarity, an inorganic metal salt, and a divalent or higher metal complex. In particular, when a metal complex is used as the flocculant, the amount of the surfactant used is reduced and the charging characteristics are improved.
Additives that form a complex or similar bond with the metal ions of the flocculant may be used as needed. As this additive, a chelating agent is preferably used.

Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride and aluminum sulfate, and inorganics such as polyaluminum chloride, polyaluminum hydroxide and calcium polysulfide. Examples include metal salt polymers.
As the chelating agent, a water-soluble chelating agent may be used. Examples of the chelating agent include oxycarboxylic acids such as tartrate acid, citric acid and gluconic acid, iminodic acid (IDA), nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid (EDTA).

The amount of the chelating agent added is, for example, preferably 0.01 parts by mass or more and 5.0 parts by mass or less, and more preferably 0.1 parts by mass or more and less than 3.0 parts by mass with respect to 100 parts by mass of the first resin particles. ..

-Second aggregate particle formation step-
Next, after obtaining the first agglomerated particle dispersion liquid in which the first agglomerated particles are dispersed, the mixed dispersion liquid in which the second resin particles and the release agent particles are dispersed is subjected to the release agent particles in the mixed dispersion liquid. The particles are sequentially added to the first agglomerated particle dispersion while gradually increasing the concentration.
The second resin particles may be of the same type as the first resin particles or may be of different types.

Then, the second resin particles and the release agent particles are aggregated on the surface of the first agglomerated particles in the dispersion liquid in which the first agglomerated particles, the second resin particles, and the release agent particles are dispersed. Specifically, for example, in the first agglomerated particle forming step, when the first agglomerated particles reach the target particle size, while gradually increasing the concentration of the release agent particles in the first agglomerated particle dispersion liquid, A mixed dispersion in which the second resin particles and the release agent particles are dispersed is added, and the dispersion is heated below the glass transition temperature of the second resin particles.
Then, by setting the pH of the dispersion liquid in the range of, for example, 6.5 or more and 8.5 or less, the progress of aggregation is stopped.

Through this step, agglomerated particles in which the second resin particles and the release agent particles are attached to the surface of the first agglomerated particles are formed. That is, the second agglomerated particles to which the agglomerates of the second resin particles and the release agent particles are attached are formed on the surface of the first agglomerated particles. At this time, the mixed dispersion in which the second resin particles and the release agent particles are dispersed is sequentially added to the first agglomerated particle dispersion while gradually increasing the concentration of the release agent particles in the mixed dispersion. On the surface of the first agglomerated particles, the concentration (absence) of the release agent particles gradually increases toward the outside in the particle size direction, and agglomerates of the second resin particles and the release agent particles adhere to the surface.

Here, as a method of adding the mixed dispersion liquid, it is preferable to use a power feed addition method. By utilizing this power feed addition method, the mixed dispersion can be added to the first agglomerated particle dispersion while gradually increasing the concentration of the release agent particles in the mixed dispersion.

Hereinafter, a method of adding the mixed dispersion liquid using the power feed addition method will be described with reference to the drawings.

FIG. 3 shows an apparatus used for the power feed addition method. In FIG. 3, 311 shows the first agglomerated particle dispersion liquid, 312 shows the second resin particle dispersion liquid, and 313 shows the release agent particle dispersion liquid.

The apparatus shown in FIG. 3 accommodates a first storage tank 321 in which the first agglomerated particles are dispersed and contains the first agglomerated particle dispersion liquid, and a second resin particle dispersion liquid in which the second resin particles are dispersed. It has a second storage tank 322 and a third storage tank 323 that stores the release agent particle dispersion liquid in which the release agent particles are dispersed.

The first storage tank 321 and the second storage tank 322 are connected by a first liquid feed pipe 331. A first liquid feeding pump 341 is interposed in the middle of the path of the first liquid feeding pipe 331. By driving the first liquid feeding pump 341, the dispersion liquid contained in the second storage tank 322 is sent to the dispersion liquid stored in the first storage tank 321 through the first liquid feeding pipe 331.
A first stirring device 351 is arranged in the first storage tank 321. When the dispersion liquid contained in the second storage tank 322 is sent to the dispersion liquid stored in the first storage tank 321 by the drive of the first stirring device 351, each dispersion liquid is agitated and agitated in the first storage tank 321. Be mixed.

The second storage tank 322 and the third storage tank 323 are connected by a second liquid feed pipe 332. A second liquid feed pump 342 is interposed in the middle of the path of the second liquid feed pipe 332. By driving the second liquid feeding pump 342, the dispersion liquid stored in the third storage tank 323 is sent to the dispersion liquid stored in the second storage tank 322 through the second liquid feeding pipe 332.
A second stirring device 352 is arranged in the second storage tank 322. When the dispersion liquid contained in the third storage tank 323 is sent to the dispersion liquid stored in the second storage tank 322 by driving the second stirring device 352, each dispersion liquid is agitated and agitated in the second storage tank 322. Be mixed.

In the apparatus shown in FIG. 3, first, the first agglomerated particle forming step is carried out in the first storage tank 321 to prepare the first agglomerated particle dispersion liquid, and the first agglomerated particle dispersion liquid is put into the first storage tank 321. Contain. The first agglomerated particle dispersion may be stored in the first storage tank 321 after the first agglomerated particle forming step is carried out in another tank to prepare the first agglomerated particle dispersion.

In this state, the first liquid feed pump 341 and the second liquid feed pump 342 are driven. By this drive, the second resin particle dispersion liquid contained in the second storage tank 322 is sent to the first agglomerated particle dispersion liquid housed in the first storage tank 321. Then, by driving the first stirring device 351, each dispersion liquid is stirred and mixed in the first storage tank 321.
On the other hand, the release agent particle dispersion liquid stored in the third storage tank 323 is sent to the second resin particle dispersion liquid stored in the second storage tank 322. Then, by driving the second stirring device 352, each dispersion liquid is stirred and mixed in the second storage tank 322.

At this time, the release agent particle dispersion liquid is sequentially sent to the second resin particle dispersion liquid contained in the second storage tank 322, and the concentration of the release agent particles gradually increases. Therefore, the second storage tank 322 contains the mixed dispersion liquid in which the second resin particles and the release agent particles are dispersed, and the mixed dispersion liquid is stored in the first storage tank 321. 1 The liquid is sent to the agglomerated particle dispersion liquid. Then, the liquid transfer of the mixed dispersion liquid is continuously performed while the concentration of the release agent particle dispersion liquid in the mixed dispersion liquid is increasing.

In this way, by using the power feed addition method, a mixed dispersion in which the second resin particles and the release agent particles are dispersed while gradually increasing the concentration of the release agent particles is added to the first agglomerated particle dispersion. Can be added.
Then, in the power feed addition method, the degree of uneven distribution of the release agent in the toner particles is adjusted by adjusting the liquid feeding start time and the liquid feeding speed of each dispersion liquid stored in the second storage tank 322 and the third storage tank 323. Is adjusted. Further, in the power feed addition method, the release agent is unevenly distributed in the toner particles by adjusting the liquid feeding rate during the feeding of each dispersion liquid stored in the second storage tank 322 and the third storage tank 323. The degree is adjusted.

The power feed addition method described above is not limited to the above method. For example, 1) Separately, a storage tank containing the second resin particle dispersion liquid and a storage tank containing the mixed dispersion liquid in which the second resin particles and the release agent particle dispersion liquid are dispersed are provided, and the liquid feeding rate is changed. A method of sending each dispersion liquid from each storage tank to the first storage tank 321. Separately, a storage tank containing the release agent particle dispersion liquid and a mixture in which the second resin particles and the release agent particle dispersion liquid are dispersed. Various methods may be adopted, such as providing a storage tank containing the dispersion liquid and feeding each dispersion liquid from each storage tank to the first storage tank 321 while changing the liquid feeding rate.

As described above, the second agglomerated particles are obtained in which the second resin particles and the release agent particles are agglomerated so as to adhere to the surface of the first agglomerated particles.

-Fusion / unification process-
Next, with respect to the second agglomerated particle dispersion liquid in which the second agglomerated particles are dispersed, for example, 10 than the glass transition temperature of the first and second resin particles (for example, 10 from the glass transition temperature of the first and second resin particles). The second agglomerated particles are fused and united by heating to a temperature higher than 30 ° C.
By producing the toner particles as described above, the exposure rate of the release agent on the surface can be increased. Therefore, in the present embodiment, it is preferable to manufacture the colored toner particles used for the color toner in this way.

Further, after obtaining the agglomerated particle dispersion liquid in which the second agglomerated particles are dispersed, the second agglomerated particle dispersion liquid and the third resin particle dispersion liquid in which the third resin particles to be the binding resin are dispersed are mixed. Further mixed and aggregated so that the third resin particles are further adhered to the surface of the second aggregated particles to form the third aggregated particles, and the third aggregated particle dispersion liquid in which the third aggregated particles are dispersed. The toner particles may be produced through a step of heating the particles and fusing and coalescing the second aggregated particles to form core / shell structure toner particles.
In this way, by further forming a shell layer made of a binder resin (or the content of the release agent is small even if it contains a release agent) on the surface of the second agglomerated particles, the release agent on the surface is formed. Exposure rate is reduced. Therefore, in the present embodiment, it is preferable to produce the black toner particles used for the black toner in this way.

As described above, by producing the black toner particles and the colored toner particles, the exposure rate of the release agent on the surface of the colored toner particles is larger than the exposure rate of the release agent on the surface of the black toner particles. Will be done.

Here, after the fusion / coalescence step is completed, the toner particles formed in the solution are subjected to a known washing step, solid-liquid separation step, and drying step to obtain toner particles in a dried state.
In the cleaning step, it is preferable to sufficiently perform replacement cleaning with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration and the like may be performed from the viewpoint of productivity. The drying step is also not particularly limited, but from the viewpoint of productivity, freeze-drying, air-flow drying, fluid drying, vibration-type fluid drying and the like may be performed.

Then, the toner in the present embodiment is produced, for example, by adding an external additive containing at least specific inorganic particles to the obtained dry toner particles and mixing them. The mixing may be carried out by, for example, a V blender, a Henschel mixer, a Ladyge mixer or the like. Further, if necessary, coarse particles of toner may be removed by using a vibration sieving machine, a wind sieving machine or the like.

<Static charge image developer set>
The electrostatic charge image developer set according to the present embodiment includes at least the toner set according to the present embodiment.
The electrostatic charge image developer set according to the present embodiment may be a one-component developer containing only the toner in the toner set according to the present embodiment, or a two-component developer mixed with the toner and a carrier. May be good.

The carrier is not particularly limited, and examples thereof include known carriers. As the carrier, for example, a coating carrier in which the surface of a core material made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and blended in a matrix resin; a porous magnetic powder is impregnated with resin. Resin-impregnated carrier; etc.
The magnetic powder dispersion type carrier and the resin impregnated type carrier may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

Examples of the magnetic powder include magnetic metals such as iron, nickel and cobalt, and magnetic oxides such as ferrite and magnetite.

Examples of the coating resin and matrix resin include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, and styrene-acrylic acid ester. Examples thereof include a copolymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polypropylene, a phenol resin, an epoxy resin and the like.
The coating resin and the matrix resin may contain other additives such as conductive particles.
Examples of the conductive particles include metals such as gold, silver and copper, and particles such as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate and potassium titanate.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating resin and, if necessary, a coating layer forming solution in which various additives are dissolved in an appropriate solvent can be mentioned. The solvent is not particularly limited, and may be selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include a dipping method in which the core material is immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the core material surface, and a state in which the core material is suspended by flowing air. Examples thereof include a fluidized bed method in which a solution for forming a coating layer is sprayed, a kneader coater method in which a core material of a carrier and a solution for forming a coating layer are mixed in a kneader coater, and a solvent is removed.

The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, and more preferably 3: 100 to 20: 100.

<Image forming device / Image forming method>
The image forming apparatus / image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment relates to a first image forming means for forming a black image by the black toner for static charge image development in the static charge image developing toner set according to the present embodiment, and the first image forming means according to the present embodiment. A second image forming means for forming a colored image with the colored toner for static charge image development, a transfer means for transferring the black image and the colored image onto a recording medium, and the black color in the static charge image developing toner set. A fixing means for fixing an image and the colored image on the recording medium is provided.
The image forming apparatus according to the present embodiment forms an image holder, a charging means for charging the surface of the image holder, and a static charge image on the surface of the charged image holder as the first or second image forming means. Even in the form provided with each image forming means having each of an electrostatic charge image forming means for forming a static charge image and a developing means for developing an electrostatic charge image formed on the surface of an image holder as a toner image by an electrostatic charge image developing agent. Good.
Further, the image forming apparatus according to the present embodiment includes an image holder, a charging means for charging the surface of the image holder, and a static charge image forming means for forming a static charge image on the surface of the charged image holder. Even in the form of having as the first or second image forming means, the first and second developing means for developing the electrostatic charge image formed on the surface of the image holder by the electrostatic charge image developer as a toner image. Good.

In the image forming apparatus according to the present embodiment, the first image forming step of forming a black image by the black toner for developing an electrostatic charge image among the toner sets for developing an electrostatic charge image according to the present embodiment, and the first image forming step according to the present embodiment. A second image forming step of forming a colored image with the colored toner for static charge image development, a transfer step of transferring the black image and the colored image onto a recording medium, and the black color of the static charge image developing toner set. An image forming method (image forming method according to the present embodiment) having a fixing step of fixing an image and the colored image on the recording medium is carried out.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image (black image, colored image in this embodiment) formed on the surface of the image holder to a recording medium; the surface of the image holder. An intermediate transfer type device that first transfers the toner image formed in the above to the surface of the intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium; after the transfer of the toner image. A well-known device provided with a cleaning means for cleaning the surface of the image holder before charging; a device provided with a static elimination means for irradiating the surface of the image holder with static elimination light after transfer of the toner image and before charging. An image forming apparatus is applied.
In the case of an intermediate transfer type apparatus, the transfer means is, for example, an intermediate transfer body in which a toner image is transferred to the surface and a primary transfer in which a toner image formed on the surface of an image holder is primarily transferred to the surface of the intermediate transfer body. A configuration comprising means and secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium is applied.

In the image forming apparatus according to the present embodiment, for example, the portion including the developing means may have a cartridge structure (process cartridge) that is attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge including a developing means containing the electrostatic charge image developing agent set according to the present embodiment is preferably used.

Hereinafter, an example of the image forming apparatus according to the present embodiment will be shown, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the other parts will be omitted.

FIG. 1 is a schematic configuration diagram showing an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is an electrophotographic first to output an image of each color of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. A fourth image forming unit 10Y, 10M, 10C, 10K (image forming means) is provided. These image forming units (hereinafter, may be simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged side by side at a predetermined distance from each other in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are attached to and detached from the image forming apparatus.

An intermediate transfer belt 20 as an intermediate transfer body extends through each unit above the drawings of each unit 10Y, 10M, 10C, and 10K. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 arranged apart from each other from the left to the right in the drawing and a support roll 24 in contact with the inner surface of the intermediate transfer belt 20, and the first unit 10Y to the fourth unit 10Y to the fourth. It is designed to run in the direction toward the unit 10K. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. Further, an intermediate transfer body cleaning device 30 is provided on the side surface of the image holder of the intermediate transfer belt 20 so as to face the drive roll 22.
Further, the developing devices (development means) 4Y, 4M, 4C, and 4K of each unit 10Y, 10M, 10C, and 10K each have yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. Toner containing the four colors of toner is supplied.

Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit forming a yellow image arranged on the upstream side in the traveling direction of the intermediate transfer belt. 10Y will be described as a representative. The second to fourth units are provided with reference numerals having magenta (M), cyan (C), and black (K) instead of yellow (Y) in the portion equivalent to the first unit 10Y. The description of the units 10M, 10C, and 10K of the above is omitted.

The first unit 10Y has a photoconductor 1Y that acts as an image holder. Around the photoconductor 1Y, a charging roll (an example of charging means) 2Y that charges the surface of the photoconductor 1Y to a predetermined potential, and a laser beam 3Y based on a color-separated image signal expose the charged surface. An exposure device (an example of a static charge image forming means) 3 for forming an electrostatic charge image, and a developing device (an example of a developing means) 4Y for developing a static charge image by supplying a charged toner to the static charge image. A primary transfer roll 5Y (an example of a primary transfer means) that transfers a toner image onto an intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning means) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer. Are arranged in order.
The primary transfer roll 5Y is arranged inside the intermediate transfer belt 20 and is provided at a position facing the photoconductor 1Y. Further, a bias power supply (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power supply changes the transfer bias applied to each primary transfer roll by control by a control unit (not shown).

Hereinafter, the operation of forming a yellow image in the first unit 10Y will be described.
First, prior to the operation, the surface of the photoconductor 1Y is charged to a potential of −600V to −800V by the charging roll 2Y.
The photoconductor 1Y is formed by laminating a photosensitive layer on a conductive substrate (for example, volume resistivity at 20 ° C.: 1 × 10 ^{-6 Ωcm or less).} This photosensitive layer usually has a high resistivity (resistance of a general resin), but has a property that when the laser beam 3Y is irradiated, the specific resistance of the portion irradiated with the laser beam changes. Therefore, the laser beam 3Y is output to the surface of the charged photoconductor 1Y via the exposure device 3 according to the image data for yellow sent from the control unit (not shown). The laser beam 3Y irradiates the photosensitive layer on the surface of the photoconductor 1Y, whereby an electrostatic charge image of a yellow image pattern is formed on the surface of the photoconductor 1Y.

The static charge image is an image formed on the surface of the photoconductor 1Y by charging. The laser beam 3Y reduces the specific resistance of the irradiated portion of the photosensitizer layer, and the charged charge on the surface of the photoconductor 1Y flows. On the other hand, it is a so-called negative latent image formed by the residual charge of the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoconductor 1Y is rotated to a predetermined development position as the photoconductor 1Y travels. Then, at this developing position, the electrostatic charge image on the photoconductor 1Y is converted into a visible image (developed image) as a toner image by the developing device 4Y.

In the developing apparatus 4Y, for example, a static charge image developing agent containing at least yellow toner and a carrier is housed. The yellow toner is triboelectrically charged by being agitated inside the developing apparatus 4Y, and has a charge having the same polarity (negative electrode property) as the charged charge on the photoconductor 1Y, and is a developer roll (developing agent holder). Example) It is held on. Then, as the surface of the photoconductor 1Y passes through the developing device 4Y, the yellow toner is electrostatically adhered to the statically eliminated latent image portion on the surface of the photoconductor 1Y, and the latent image is developed by the yellow toner. .. The photoconductor 1Y on which the yellow toner image is formed is continuously traveled at a predetermined speed, and the toner image developed on the photoconductor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoconductor 1Y is transferred to the primary transfer, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force from the photoconductor 1Y toward the primary transfer roll 5Y is applied to the toner image to act on the photoconductor. The toner image on 1Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity (+) opposite to the polarity (−) of the toner, and is controlled to +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoconductor 1Y is removed by the photoconductor cleaning device 6Y and recovered.

Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
In this way, the intermediate transfer belt 20 to which the yellow toner image is transferred in the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and multiple transferred. Toner.

The intermediate transfer belt 20 on which four color toner images are multiplex-transferred through the first to fourth units is arranged on the image holding surface side of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt, and the intermediate transfer belt 20. It leads to a secondary transfer unit composed of the secondary transfer roll (an example of the secondary transfer means) 26. On the other hand, the recording paper (an example of the recording medium) P is fed to the gap where the secondary transfer roll 26 and the intermediate transfer belt 20 are in contact with each other via the supply mechanism at a predetermined timing, and the secondary transfer bias is supported by the support roll. It is applied to 24. The transfer bias applied at this time is (-) polarity, which is the same polarity as the toner polarity (-), and the electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, and the transfer bias is applied on the intermediate transfer belt 20. The toner image of is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by the resistance detecting means (not shown) for detecting the resistance of the secondary transfer unit, and is voltage controlled.

After that, the recording paper P is sent to the pressure contact portion (nip portion) of the pair of fixing rolls in the fixing device (an example of the fixing means) 28, and the toner image is fixed on the recording paper P to form the fixing image.

Examples of the recording paper P for transferring the toner image include plain paper used in electrophotographic copying machines, printers, and the like. Examples of the recording medium include an OHP sheet and the like in addition to the recording paper P.
In order to further improve the smoothness of the image surface after fixing, the surface of the recording paper P is also preferably smooth, and for example, coated paper in which the surface of plain paper is coated with resin or the like, art paper for printing, or the like is preferably used. Will be done.

The recording paper P for which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.

<Process cartridge / toner cartridge set>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment includes the first developing means containing the black static charge image developer among the electrostatic charge image developing agent sets according to the present embodiment, and the electrostatic charge image developing agent set according to the present embodiment. A process cartridge including a second developing means containing the colored electrostatic charge image developing agent, which is attached to and detached from an image forming apparatus.

The process cartridge according to the present embodiment is not limited to the above configuration, and includes a developing device and other means such as an image holder, a charging means, an electrostatic charge image forming means, and a transfer means, if necessary. It may be configured to include at least one selected from.

Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. The main parts shown in the figure will be described, and the other parts will be omitted.

FIG. 2 is a schematic configuration diagram showing a process cartridge according to the present embodiment.
The process cartridge 200 shown in FIG. 2 is provided around the photoconductor 107 (an example of an image holder) and the photoconductor 107 by, for example, a housing 117 provided with a mounting rail 116 and an opening 118 for exposure. The charged roll 108 (an example of the charging means), the developing device 111 (an example of the developing means), and the photoconductor cleaning device 113 (an example of the cleaning means) are integrally combined and held and configured to form a cartridge. There is.
In FIG. 2, 109 is an exposure device (an example of an electrostatic charge image forming means), 112 is a transfer device (an example of a transfer means), 115 is a fixing device (an example of a fixing means), and 300 is a recording paper (an example of a recording medium). An example) is shown.

Next, the toner cartridge set according to this embodiment will be described.
The toner cartridge set according to the present embodiment contains a black toner contained in the toner set according to the present embodiment and is attached to and detached from an image forming apparatus, and a color toner contained in the toner set according to the present embodiment. It is a toner cartridge set including a colored toner cartridge that houses and is attached to and detached from an image forming apparatus. The toner cartridge set contains replenishment toner for supplying to the developing means provided in the image forming apparatus.

The image forming apparatus shown in FIG. 1 is an image forming apparatus having a structure in which the toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and the developing apparatus 4Y, 4M, 4C, and 4K are each developing apparatus (color). ) Is connected to a toner cartridge (not shown). Further, when the amount of toner contained in the toner cartridge is low, the toner cartridge is replaced.

Hereinafter, the present embodiment will be described in more detail with reference to Examples and Comparative Examples, but the present embodiment is not limited to these Examples. The term "part" means "part by mass" unless otherwise specified.

<Preparation of resin particle dispersion>
[Preparation of resin particle dispersion (1)]
・ Terephthalic acid: 30 mol parts ・ Fumaric acid: 70 mol parts ・ Bisphenol A ethylene oxide adduct: 5 mol parts ・ Bisphenol A propylene oxide adduct: 95 mol parts Stirrer, nitrogen introduction pipe, temperature sensor, and rectification tower The above-mentioned material was charged into a flask provided with the above material, the temperature was raised to 210 ° C. over 1 hour, and 1 part of titanium tetraethoxydo was added to 100 parts of the above-mentioned material. The temperature was raised to 230 ° C. over 0.5 hours while distilling off the generated water, and the dehydration condensation reaction was continued at this temperature for 1 hour, and then the reaction product was cooled. In this way, a polyester resin (1) having a weight average molecular weight of 18,500, an acid value of 14 mgKOH / g, and a glass transition temperature of 59 ° C. was synthesized.

40 parts of ethyl acetate and 25 parts of 2-butanol were added to a container equipped with a temperature control means and a nitrogen substitution means to prepare a mixed solvent, and then 100 parts of the polyester resin (1) was gradually added to dissolve the resin. A 10 mass% aqueous ammonia solution (equivalent to 3 times the molar ratio of the acid value of the resin) was added and stirred for 30 minutes.
Next, the inside of the container was replaced with dry nitrogen, the temperature was maintained at 40 ° C., and 400 parts of ion-exchanged water was added dropwise at a rate of 2 parts / minute while stirring the mixed solution to emulsify. After completion of the dropping, the emulsion was returned to room temperature (20 ° C to 25 ° C), and bubbling was performed with dry nitrogen for 48 hours with stirring to reduce ethyl acetate and 2-butanol to 1,000 ppm or less, and the volume average particles were obtained. A resin particle dispersion liquid in which resin particles having a diameter of 200 nm were dispersed was obtained. Ion-exchanged water was added to the resin particle dispersion liquid to adjust the solid content to 20% by mass to obtain a resin particle dispersion liquid (1).

<Preparation of colorant particle dispersion>
[Preparation of cyan colorant dispersion (C1)]
-Cyan pigment Pigment Blue 15: 3 (manufactured by DIC Co., Ltd.): 70 parts-Anionic surfactant (Neogen RK manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 1 part-Ion-exchanged water: 200 parts Mix the above materials Then, the mixture was dispersed for 10 minutes using a homogenizer (Ultratarax T50 manufactured by IKA). Ion-exchanged water was added so that the solid content in the dispersion was 20% by mass to obtain a colorant dispersion (C1) in which colorant particles having a volume average particle diameter of 190 nm were dispersed.

[Preparation of black colorant dispersion (K1)]
-Black pigment carbon black (manufactured by Orion engineered carbon, NIPEX): 70 parts-Anionic surfactant (Neogen RK manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 1 part-Ion-exchanged water: 200 parts Mixing the above materials Then, the mixture was dispersed for 10 minutes using a homogenizer (Ultratalax T50 manufactured by IKA). Ion-exchanged water was added so that the solid content in the dispersion was 20% by mass to obtain a colorant dispersion (K1) in which colorant particles having a volume average particle diameter of 190 nm were dispersed.

<Preparation of mold release agent particle dispersion>
[Preparation of release agent particle dispersion (1)]
・ Paraffin wax (manufactured by Nippon Seiwa Co., Ltd., HNP-9): 100 parts ・ Anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1 part ・ Ion exchange water: 350 parts Was mixed and heated to 100 ° C., dispersed using a homogenizer (Ultratarax T50 manufactured by IKA), and then dispersed with a Manton Gorin high-pressure homogenizer (manufactured by Gorin), and a release agent having a volume average particle size of 200 nm. A release agent particle dispersion liquid (1) (solid content 20% by mass) in which particles were dispersed was obtained.

<Preparation of developer>
[Preparation of cyan toner particles (C1)]
The round stainless steel flask and the container A are connected by a tube pump A, the contained liquid contained in the container A is sent to the flask by driving the tube pump A, and the container A and the container B are connected by the tube pump B. Then, a device (see FIG. 3) was prepared to send the contained liquid contained in the container B to the container A by driving the tube pump B. Then, the following operations were carried out using this device.

-Resin particle dispersion (1): 500 parts-Cyan colorant dispersion (C1): 40 parts-Anionic surfactant (TaycaPower): 2 parts Put the above material in a round stainless steel flask and add 0.1N. After adjusting the pH to 3.5 by adding nitric acid, 30 parts of a nitric acid aqueous solution having a polyaluminum chloride concentration of 10% by mass was added. Subsequently, after dispersing at 30 ° C. using a homogenizer (Ultratarax T50 manufactured by IKA), the particle size of the agglomerated particles was grown while raising the temperature at a pace of 1 ° C./30 minutes in a heating oil bath. It was.
On the other hand, 150 parts of the resin particle dispersion liquid (1) was put in the container A of the polyester bottle, and 25 parts of the release agent particle dispersion liquid (1) was also put in the container B. Next, the liquid feeding speed of the tube pump A was set to 0.70 parts / minute, and the liquid feeding speed of the tube pump B was set to 0.14 parts / minute, and the inside of the round stainless flask during the formation of aggregated particles When the temperature reached 37.0 ° C., the tube pump A and the tube pump B were driven, and the delivery of each dispersion was started. As a result, while gradually increasing the concentration of the release agent particles, the mixed dispersion liquid in which the resin particles and the release agent particles were dispersed was sent from the container A to the round stainless steel flask in which the agglomerated particles were being formed.
Then, when the transfer of each dispersion liquid to the flask was completed and the temperature in the flask reached 48 ° C., the temperature was maintained for 30 minutes to form second agglomerated particles.
Then, 40 parts of the resin particle dispersion liquid (1) was gently added and held for 1 hour to form third agglomerated particles. A 0.1 N aqueous sodium hydroxide solution was added to the dispersion in which the third aggregated particles were dispersed to adjust the pH to 8.5, and then the mixture was heated to 85 ° C. while continuing stirring and held for 5 hours. Then, the particles were cooled to 20 ° C. at a rate of 20 ° C./min, filtered, thoroughly washed with ion-exchanged water, and dried to obtain cyantoner particles (C1).

[Preparation of black toner particles (K1)]
-Resin particle dispersion (1): 500 parts-Black colorant dispersion (K1): 40 parts-Anionic surfactant (TaycaPower): 2 parts The same equipment as the equipment used to prepare the cyan toner particles (C1). Prepared. The above material was placed in a round stainless steel flask, 0.1 N nitric acid was added to adjust the pH to 3.5, and then 30 parts of a nitric acid aqueous solution having a polyaluminum chloride concentration of 10% by mass was added. Subsequently, after dispersing at 30 ° C. using a homogenizer (Ultratarax T50 manufactured by IKA), the particle size of the agglomerated particles was grown while raising the temperature at a pace of 1 ° C./30 minutes in a heating oil bath. It was.
On the other hand, 150 parts of the resin particle dispersion liquid (1) was put in the container A of the polyester bottle, and 25 parts of the release agent particle dispersion liquid (1) was also put in the container B. Next, the liquid feeding speed of the tube pump A was set to 0.70 parts / minute, and the liquid feeding speed of the tube pump B was set to 0.14 parts / minute, and the inside of the round stainless flask during the formation of aggregated particles was set. When the temperature reached 37.0 ° C., the tube pump A and the tube pump B were driven, and the delivery of each dispersion was started. As a result, while gradually increasing the concentration of the release agent particles, the mixed dispersion liquid in which the resin particles and the release agent particles were dispersed was sent from the container A to the round stainless steel flask in which the agglomerated particles were being formed.
Then, when the transfer of each dispersion liquid to the flask was completed and the temperature in the flask reached 48 ° C., the temperature was maintained for 30 minutes to form second agglomerated particles.

Then, 50 parts of the resin particle dispersion liquid (1) was gently added and held for 1 hour to form third agglomerated particles. A 0.1 N aqueous sodium hydroxide solution was added to the dispersion in which the third aggregated particles were dispersed to adjust the pH to 8.5, and then the mixture was heated to 85 ° C. while continuing stirring and held for 5 hours. Then, the particles were cooled to 20 ° C. at a rate of 20 ° C./min, filtered, thoroughly washed with ion-exchanged water, and dried to obtain black toner particles (K1).

[Toner preparation]
100 parts of cyan toner particles (C1) or black toner particles (K1) and inorganic particles 1 as an external additive (titania particles, volume resistance 1 × 10 ¹³ Ωcm, average primary particle size 15 nm, manufactured by Teika Co., Ltd., 1.2 parts of trade name JMT-2000) and 1.2 parts were mixed using a Henshell mixer (peripheral speed 30 m / sec, 3 minutes) to obtain cyan toner (C1) and black toner (K1), respectively.

[Preparation of developer]
-Ferrite particles (average particle size 50 μm): 100 parts-Toluene: 14 parts-Styline / methyl methacrylate copolymer (copolymerization ratio 15/85): 3 parts-Carbon black: 0.2 parts The above components excluding ferrite particles Was dispersed in a sand mill to prepare a dispersion, and the dispersion was placed in a vacuum degassing kneader together with ferrite particles, and the pressure was reduced while stirring to dry the mixture to obtain a carrier.
Then, 8 parts of cyan toner (C1) or black toner (K1) was mixed with 100 parts of the carrier to obtain a cyan developer (C1) and a black developer (K1), respectively.

[Cyan toner particles (C2)]
In the preparation of the cyan toner particles (C1), the cyan toner particles (C2) were prepared in the same manner except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 15 parts.

[Cyan toner particles (C3)]
In the preparation of the cyan toner particles (C1), the cyan toner particles (C3) were prepared in the same manner except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 30 parts.

[Cyan toner particles (C4)]
In the preparation of the cyan toner particles (C1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 10 parts and the temperature rise temperature after pH adjustment was changed to 95 ° C. Cyan toner particles (C4) were prepared.

[Cyan toner particles (C5)]
In the preparation of the cyan toner particles (C1), the cyan toner particles (C5) were prepared in the same manner except that the temperature rise temperature after adjusting the pH was changed to 75 ° C. at the time of producing the third aggregated particles.

[Cyan toner particles (C6)]
In the preparation of the cyan toner particles (C1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 5 parts and the temperature rise temperature after pH adjustment was changed to 95 ° C. Cyan toner particles (C6) were prepared.

[Cyan toner particles (C7)]
In the preparation of the cyan toner particles (C1), the cyan toner particles (C7) were prepared in the same manner except that the temperature rising temperature after adjusting the pH was changed to 80 ° C. at the time of preparing the third aggregated particles.

[Cyan toner particles (C8)]
In the preparation of the cyan toner particles (C1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 15 parts and the temperature rise temperature after pH adjustment was changed to 80 ° C. Cyan toner particles (C8) were prepared.

[Cyan toner particles (C9)]
In the preparation of the cyan toner particles (C1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 30 parts and the temperature rise temperature after pH adjustment was changed to 90 ° C. Cyan toner particles (C9) were prepared.

[Yellow toner particles (Y1)]
In the preparation of the cyan toner particles (C1), the yellow toner particles (Y1) were prepared in the same manner except that the pigment used in the preparation of the colorant particle dispersion was changed to Pigment Yellow 180 (manufactured by Clariant).

[Magenta toner particles (Y1)]
In the preparation of the cyan toner particles (C1), the yellow toner particles (Y1) were prepared in the same manner except that the pigment used in the preparation of the colorant particle dispersion was changed to Pigment Red (manufactured by Clariant).

[Black toner particles (K2)]
In the preparation of the black toner particles (K1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 15 parts and the temperature rising temperature after pH adjustment was changed to 80 ° C. Black toner particles (K2) were prepared.

[Black toner particles (K3)]
In the preparation of the black toner particles (K1), the black toner particles (K3) were prepared in the same manner except that the temperature rising temperature after adjusting the pH was changed to 80 ° C. at the time of producing the third aggregated particles.

[Black toner particles (K4)]
In the preparation of the black toner particles (K1), the same applies except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 15 parts and the temperature rise temperature after pH adjustment was changed to 85 ° C. Black toner particles (K4) were prepared.

[Black toner particles (K5)]
In the preparation of the black toner particles (K1), the black toner particles (K5) were prepared in the same manner except that the amount of the resin particle dispersion liquid (1) added at the time of producing the third aggregated particles was changed to 30 parts.

<Examples 1 to 11 and Comparative Examples 1 to 9>
Black toner particles, cyan toner particles, and inorganic particles shown in Table 1 below were combined to prepare a black developer and a cyan developer.

<Various measurements>
The "surface release agent exposure rate" of the black toner particles and the cyan toner particles obtained in each example and the "concealment rate of the exposed portion of the release agent on the surface of the colored toner particles by the inorganic particles" are measured by the above-mentioned methods. did.
In addition, the ratio of the exposure rate of the release agent on the surface of the colored toner particles to the exposure rate of the release agent on the surface of the black toner particles was calculated.

<Evaluation>
-Releasability-
The releasability was evaluated as follows.
The image quality of the metal roll and the developer was evaluated using an image forming apparatus (DocuCenter 450CP remodeling machine: manufactured by Fuji Xerox Co., Ltd.). After adjusting the toner loading amount to 4.5 g / m ² and drawing out, the toner was fixed at a process speed of 280 mm / sec. PAL4 (manufactured by Fuji Xerox Co., Ltd.) was used as the paper used for image formation.

This was evaluated based on the following evaluation criteria. If it is A or B, it is within a practically acceptable range.
-Evaluation criteria-
A: The peeling at the time of fixing is smooth, and when the image is lightly rubbed with a nail, no image loss occurs.
B: The probability of image loss when the image is lightly rubbed with a nail is 1 or more and 2 or less out of 10.
C: The probability of image loss occurring when the image is lightly rubbed with a nail is 3 out of 10 images, which is a level that poses a problem in actual use.

-Toner splatter-
The evaluation of toner splattering was performed as follows.
As an intermediate transfer type image forming apparatus, "700 Digital Color Press" manufactured by Fuji Xerox Co., Ltd. was prepared, and the developer was filled with the black developer and the cyan developer obtained in each Example and Comparative Example. The image forming apparatus includes a cleaning blade arranged by a doctor method as a cleaning apparatus for an intermediate transfer belt.
Evaluation was started after leaving for 1 day in a high temperature and high humidity environment (30 ° C., 85% RH) and a low temperature and low humidity environment (10 ° C., 10% RH).
After 100,000 consecutive output of 100,000 color images having an area coverage (image density) of 20% not including black, 10 color images having an area coverage of 20% including a black band image are printed, and the obtained image is black. The scattering of the boundary line between the band part and the color image part was evaluated. A loupe was used for observation.
This was evaluated based on the following evaluation criteria. If it is A or B, it is within a practically acceptable range.
-Evaluation criteria-
A: The slight scattering of black toner or color toner is 2 or less, or there is no scattering.
B: The slight scattering of black toner or color toner is 3 or more and 5 or less.
C: The slight scattering of the black toner or the color toner is 6 or more, or the slightly conspicuous scattering is 1 or more and 2 or less.
D: There are three or more pieces of black toner or color toner that are slightly conspicuous, or there are splatters so that the boundary line cannot be confirmed.

-Toner fluidity-
The toner fluidity was evaluated by measuring the total amount of energy using a powder rheometer (FT4 manufactured by freeman technology). The evaluation was started after being left for one day in an environment of a temperature of 22 ° C. and a humidity of 50% RH. First, the toner to be measured is filled in a 160 mL container having an inner diameter of 50 mm and a height of 88 mm, and the rotor is rotated while the rotor blades are inserted into the toner. The rotational torque and vertical load when the rotary blade rotates at the tip speed of 100 mm / s of the rotary blade while moving in the particles filled in the container at an approach angle of −5 ° are measured. The average value of the total energy amount (mJ) when this operation was performed 5 times was taken as the total energy amount (mJ).
This was evaluated based on the following evaluation criteria. If it is A or B, it is within a practically acceptable range.
-Evaluation criteria-
A: The total amount of energy is 450 mJ or more and 700 mJ or less.
B: The total amount of energy is 250 mJ or more and less than 450 mJ.
C: The total amount of energy is 250 mJ or less, or more than 700 mJ.

The details of the inorganic particles shown in Table 1 are as follows.
-Inorganic particles 2 (Titania particles, volume resistivity 1 x 10 ¹¹ Ωcm, average primary particle size 20 nm, manufactured by Titan Kogyo, Ltd., trade name STT100H)
-Inorganic particles 3 (silica particles, volume resistivity 1 x 10 ¹⁷ Ωcm, average primary particle size 20 nm, manufactured by Nippon Aerodil Co., Ltd., trade name RY50L)
-Inorganic particles 4 (Titania particles, volume resistivity 1 × 10 ¹³ Ωcm, average primary particle size 70 nm, manufactured by TAYCA CORPORATION, trade name SF-015)

From the above results, it can be seen that in this example, the scattering of toner on the recording medium is suppressed as compared with the comparative example.

1Y, 1M, 1C, 1K photoconductor (example of image holder)
2Y, 2M, 2C, 2K charging roll (example of charging means)
3 Exposure device (an example of static charge image forming means)
3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing device (example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (example of primary transfer means)
6Y, 6M, 6C, 6K Photoreceptor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner Cartridge 10Y, 10M, 10C, 10K Image Forming Unit 20 Intermediate Transfer Belt (Example of Intermediate Transfer)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
30 Intermediate transfer member cleaning device 107 Photoreceptor (example of image holder)
108 Charging roll (an example of charging means)
109 Exposure device (an example of static charge image forming means)
111 Developing equipment (an example of developing means)
112 Transfer device (an example of transfer means)
113 Photoreceptor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening for exposure 200 Process cartridge 300 Recording paper (an example of recording medium)
311 1st agglomerated particle dispersion liquid 312 2nd resin particle dispersion liquid 313 Release agent particle dispersion liquid 321 1st storage tank 322 2nd storage tank 323 3rd storage tank 331 1st liquid supply pipe 332 2nd liquid supply pipe 341 1st 1 Liquid feed pump 342 2nd liquid feed pump 351 1st stirring device 352 2nd stirring device P Recording paper (example of recording medium)

Claims (9)

Black toner particles containing a black colorant, a binder resin and a mold release agent, the content is 1% by mass or more and 5% by mass or less with respect to the black toner particles, and the volume resistance is 1 × 10 ⁹ Ωcm or more 1 ×. 10 Black toner for electrostatic charge image development containing inorganic particles having an average primary particle size of 10 nm or more and 30 nm or ^{less, which is 14 Ω cm or less, and black toner for developing an electrostatic charge image, and}
Colored toner particles containing a colored colorant, a binder resin and a mold release agent, the content is 1% by mass or more and 5% by mass or less with respect to the colored toner particles, and the volume resistance is 1 × 10 ⁹ Ωcm or more 1 × 10 It has a colored toner for static charge image development containing inorganic particles having an average primary particle size of 10 nm or more and 30 nm or ^{less, which is 14 Ω cm or less.}
The exposure ratio of the release agent on the surface of the colored toner particles, to exposure rate of the release agent on the surface of the black toner particles state, and are 1.2 times more than 10 times or less,
The exposure rate of the release agent on the surface of the black toner particles is 0.1% or more and 3.2% or less.
A toner set for developing an electrostatic charge image in which the exposure rate of the release agent on the surface of the colored toner particles is 0.12% or more and 10.0% or less. The toner set for static charge image development according to claim 1, which has cyan toner as the colored toner for static charge image development. The toner set for static charge image development according to claim 1 or 2 , wherein the hiding rate of the exposed portion of the release agent on the surface of the colored toner particles by the inorganic particles is 30% or more and 90% or less. The toner set for developing an electrostatic charge image according to any one of claims 1 to 3 , wherein the inorganic particles are titania particles. A black static charge image developer containing the black toner for static charge image development contained in the toner set for static charge image development according to any one of claims 1 to 4.
A colored electrostatic charge image developer containing the colored toner for electrostatic charge image development contained in the toner set for developing an electrostatic charge image according to any one of claims 1 to 4.
Static charge image developer set including. A black toner cartridge that houses the black toner for electrostatic charge image development contained in the toner set for developing an electrostatic charge image according to any one of claims 1 to 4 and is attached to and detached from an image forming apparatus.
A colored toner cartridge that accommodates the colored toner for electrostatic charge image development contained in the toner set for developing an electrostatic charge image according to any one of claims 1 to 4, and is attached to and detached from an image forming apparatus.
Toner cartridge set including. The first developing means containing the black electrostatic charge image developing agent in the electrostatic charge image developing agent set according to claim 5.
A second developing means containing the colored electrostatic charge image developing agent in the electrostatic charge image developing agent set according to claim 5.
With
A process cartridge that is attached to and detached from the image forming device. The first image forming means for forming a black image by the black toner for developing an electrostatic charge image among the toner sets for developing an electrostatic charge image according to any one of claims 1 to 4.
The second image forming means for forming a colored image by the colored toner for developing an electrostatic charge image among the toner sets for developing an electrostatic charge image according to any one of claims 1 to 4.
A transfer means for transferring the black image and the colored image onto a recording medium, and
A fixing means for fixing the black image and the colored image on the recording medium, and
An image forming apparatus comprising. The first image forming step of forming a black image by the black toner for developing an electrostatic charge image among the toner sets for developing an electrostatic charge image according to any one of claims 1 to 4.
The second image forming step of forming a colored image by the colored toner for developing an electrostatic charge image among the toner sets for developing an electrostatic charge image according to any one of claims 1 to 4.
A transfer step of transferring the black image and the colored image onto a recording medium, and
A fixing step of fixing the black image and the colored image on the recording medium, and
An image forming method having.