JP6171839B2 - Electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

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

  For the purpose of forming an image having a brightness such as a metallic luster, glittering toner is used.

For example, in Patent Document 1, a) an organic layer selected from a fatty acid, an amide of at least one acid, a salt of at least one acid, an olefinic material, a natural wax, a synthetic wax, a polymer, and combinations thereof; And b) optionally, a toner comprising a metallic pigment comprising a silicate, titanate or aluminate coating;
In addition, for example, Patent Document 2 discloses a toner that defines a ratio of a glitter pigment having a specific circularity as a glitter toner excellent in transfer efficiency. For example, Patent Document 3 discloses a long axis of a toner. For example, Patent Document 4 discloses a toner that defines a ratio of a toner that does not contain a luster pigment.

Special table 2007-519982 gazette JP 2013-156343 A JP 2013-134314 A JP 2013-073017 A

  An object of the present invention is to provide a toner for developing an electrostatic charge image that can suppress a decrease in transferability under high temperature and high humidity and can form an image excellent in glitter.

Specific means for solving the above problems are as follows.
That is, the invention according to claim 1
A first coating layer formed of at least one metal oxide selected from the group consisting of silica, alumina, and titania, coated on the surface of the metal pigment; and the first coating layer A coating pigment having a second coating layer containing a resin, the surface of which is coated without a covalent bond ,
An electrostatic charge image in which the element ratio Mb / Ma measured using a fluorescent X-ray analyzer between the metal Ma in the metal pigment and the metal Mb in the first coating layer is 0.08 or more and 0.20 or less. Development toner.

The invention according to claim 2
2. The electrostatic image developing toner according to claim 1, wherein the coating amount of the second coating layer in the coating pigment is 5% by mass or more and 30% by mass or less with respect to the mass of the metal pigment.

The invention according to claim 3
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

The invention according to claim 4
Containing the toner for developing an electrostatic image according to claim 1;
The toner cartridge is detachable from the image forming apparatus.

The invention according to claim 5
A developing unit that contains the electrostatic charge image developer according to claim 3 and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer.
It is a process cartridge that can be attached to and detached from the image forming apparatus.

The invention according to claim 6
An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
A developing means for containing the electrostatic charge image developer according to claim 3 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus.

The invention according to claim 7 provides:
A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 3;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
Is an image forming method.

According to the invention of claim 1, the coated pigment is provided with the first coating layer and the second coating layer, but compared with a case where the ratio of the element ratio Mb / Ma is out of the range, at a high temperature and high humidity. Provided is a toner for developing an electrostatic charge image that can suppress a decrease in transferability and can form an image excellent in glitter.
According to the invention of claim 2, compared with the case where the coating pigment is out of the range of the coating amount of the second coating layer, an image having excellent glitter even after the physical load is applied. An electrostatic image developing toner that can be formed is provided.

According to the invention of claim 3, the coated pigment is provided with the first coating layer and the second coating layer, but compared with the case where the element ratio Mb / Ma is out of the range, the temperature is high under high humidity. There is provided an electrostatic charge image developer capable of suppressing transferability deterioration and capable of forming an image excellent in glitter.
According to the invention which concerns on Claim 4, compared with the case where a coating pigment is provided with the 1st coating layer and the 2nd coating layer, and remove | deviated from the range of element ratio Mb / Ma, it is in high temperature and high humidity. Provided is a toner cartridge containing a toner for developing an electrostatic charge image capable of suppressing transferability deterioration and capable of forming an image excellent in glitter.
According to the invention which concerns on Claim 5, compared with the case where a coating pigment is provided with the 1st coating layer and the 2nd coating layer, and remove | deviated from the range of element ratio Mb / Ma, it is in high temperature, high humidity. Provided is a process cartridge that contains toner for developing an electrostatic charge image that can suppress transferability deterioration and can form an image excellent in glitter.
According to the invention which concerns on Claim 6, compared with the case where a coating pigment is provided with the 1st coating layer and the 2nd coating layer, and remove | deviated from the range of element ratio Mb / Ma, it is in high temperature and high humidity. Provided is an image forming apparatus using a toner for developing an electrostatic charge image, which can suppress transferability deterioration and can form an image excellent in glitter.
According to the invention which concerns on Claim 7, compared with the case where a coating pigment is provided with the 1st coating layer and the 2nd coating layer, and remove | deviated from the range of element ratio Mb / Ma, it is in high temperature, high humidity. Provided is an image forming method using an electrostatic charge image developing toner capable of suppressing transferability deterioration and capable of forming an image excellent in glitter.

FIG. 3 is a cross-sectional view schematically illustrating a toner for developing an electrostatic charge image according to the exemplary embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

  Hereinafter, embodiments of an electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method of the present invention will be described in detail.

≪Toner for electrostatic image development≫
The toner for developing an electrostatic charge image according to the present embodiment (hereinafter sometimes referred to as the toner according to the present embodiment) includes a metal pigment and silica, alumina, and titania coated on the surface of the metal pigment. A coating pigment comprising: a first coating layer containing at least one metal oxide selected from the group; and a second coating layer containing a resin coating the surface of the first coating layer. ,
The electrostatic image developing toner has an element ratio Mb / Ma between the metal Ma in the metal pigment and the metal Mb in the first coating layer of 0.08 or more and 0.20 or less.

The toner for developing an electrostatic charge image according to the exemplary embodiment can suppress a decrease in transferability under high temperature and high humidity (for example, an air temperature of 30 ° C. and a humidity of 80%) and can form an image having excellent glitter.
The reason is not clear, but is presumed as follows.
In the present embodiment, “brightness” indicates that the image formed by the electrostatic image developing toner according to the present embodiment has a brightness such as a metallic luster when visually recognized.

When a color glittering image is output, a multiple toner layer is formed by overlaying a color toner on a toner using a metal pigment, and when this is used, the toner using the metal pigment is imaged. It is known that an image having sufficient glitter can be obtained by arranging the metal pigment in the toner so that the longitudinal direction of the metal pigment is opposed to the surface of the recording medium. .
In order to form the multiple toner layers as described above, for example, a multiple transfer system using an intermediate transfer belt is adopted. However, a conventional toner containing a metal pigment is used for primary transfer and secondary transfer. Charges are injected by a transfer voltage or the like, and the charge amount of the toner is lowered, resulting in a phenomenon that transferability is lowered. In addition, due to this phenomenon, the arrangement of metal pigments on the recording medium may be disturbed, and an image having sufficient glitter may not be obtained.
The phenomenon as described above was performed in a high-temperature and high-humidity environment using a toner that includes a metal pigment that is exposed from the surface of the toner particles or that has a metal oxide layer that contains moisture on the surface. It has been found that this is likely to occur.

The toner according to the present embodiment is characterized by using a coated pigment having first and second coating layers on the surface of a metal pigment.
By providing the first coating layer of a specific metal oxide, this coating pigment can suppress exposure of the metal pigment exhibiting conductivity to the toner particle surface. In addition, the element ratio Mb / Ma between the metal Ma in the metal pigment and the metal Mb in the first coating layer is in the range of 0.08 to 0.20, and the amount of the metal oxide on the surface is defined. As a result, even if the first coating layer is made of a metal oxide containing moisture, it is assumed that charge injection is less likely to occur, and the transferability can be effectively suppressed.
In addition, the coated pigment further includes a second coating layer made of resin, and this layer shows good adhesion to the binder resin constituting the toner particles, so that it is almost uniform on the surface of the coated pigment. In this case, the binder resin adheres, and it is presumed that the deterioration of transferability can be suppressed in order to prevent the metal pigment from being exposed from the surface of the toner particles. Furthermore, since the binder resin adheres to the surface of the coated pigment in a state that is nearly uniform, it becomes easy to align the longitudinal direction of the metal pigment in the toner so as to face the surface of the recording medium, and the image has excellent glitter. Will be obtained.

[Configuration of toner]
The toner according to this embodiment has a configuration including toner particles including the above-described coating pigment.
In addition to the toner particles described above, the toner according to the exemplary embodiment may include an external additive as necessary.
Hereinafter, toner particles will be described first.

(Toner particles)
The toner particles according to the exemplary embodiment preferably include other additives such as a release agent, if necessary, in addition to the above-described coating pigment having two coating layers and the binder resin.
Hereinafter, each component constituting the toner particles will be described.

-Coated pigment-
The coated pigment in the present embodiment is a metal pigment, and a first coating layer containing at least one metal oxide selected from the group consisting of silica, alumina, and titania that coats the surface of the metal pigment; And a second coating layer containing a resin coating the surface of the first coating layer.

Examples of the metal pigment constituting the coating pigment include metal powders such as aluminum, brass, bronze, nickel, stainless steel, zinc, copper, silver, gold, and platinum.
Of these, aluminum is preferably used because of its excellent metallic luster and its low specific gravity and ease of handling.

The first coating layer constituting the coating pigment includes one selected from the group of metal oxides consisting of silica, alumina, and titania, and these may be used alone or in combination of two or more. You may mix and use.
Among these, silica is preferable because it is excellent in chemical resistance when producing toner particles and can coat the pigment surface in a more uniform state.
The first coating layer may be formed only from the above metal oxide, but may contain impurities contained in the production.

In this embodiment, the element ratio Mb / Ma between the metal Ma in the metal pigment and the metal Mb in the first coating layer is 0.08 or more and 0.20 or less. The element ratio Mb / Ma is preferably 0.1 or more and 0.18 or less, and more preferably 0.12 or more and 0.16 or less.
When the element ratio Mb / Ma exceeds 0.2, the light reflectance by the first coating layer is lowered, so that it is difficult to form an image having excellent glitter. Further, when the element ratio Mb / Ma is less than 0.08, the coating on the surface of the metal pigment becomes non-uniform, so that the transferability under high temperature and high humidity is lowered.

The amount of element when obtaining the element ratio Mb / Ma is measured using a fluorescent X-ray analyzer (XRF).
Specifically, using a pressure molding machine, a disk having a diameter of 5 cm was produced by applying a compression pressure of 10 tons to 5 g of toner particles, and this was used as a measurement sample. Using this with a fluorescent X-ray analyzer (XRF-1500) manufactured by Shimadzu Corporation, the measurement conditions are tube voltage 40 KV, tube current 90 mA, measurement time 30 minutes, and the metal pigment and the first coating layer The amount of the metal element in it was measured.

As a method for coating the surface with a metal oxide, for example, a method of forming a coating layer of a metal oxide on the surface of the metal pigment by a sol-gel method, a metal hydroxide is deposited on the surface of the metal pigment, and crystallized at a low temperature And a method of forming a metal oxide coating layer.
In the present embodiment, an organometallic compound is added so that the element ratio Mb / Ma is in the range of 0.08 to 0.20, and a hydrolysis catalyst is added to the dispersion containing the metal pigment. It is preferable to deposit on the surface of the metal pigment by adjusting the pH of the dispersion.

The coating amount of the first coating layer is preferably 10% by mass to 40% by mass and more preferably 20% by mass to 30% by mass with respect to the mass of the metal pigment.
The coating amount of the first coating layer is measured by a calibration curve obtained by measuring a mixture of an aluminum pigment and silica particles in advance with a fluorescent X-ray analyzer (XRF).

The second coating layer constituting the coating pigment is a resin coating layer.
As the resin used here, a known resin is used as a binder resin for toner particles, as will be described later, such as an acrylic resin or a polyester resin.
Among these, an acrylic resin is preferable because the pigment surface can be uniformly coated.
Further, from the viewpoint of excellent chemical resistance when producing toner particles and impact resistance, the second coating layer is preferably a layer made of a crosslinked resin.
The second coating layer may be formed only from the above resin, but may contain impurities and the like that are included during manufacturing.

The coating amount of the second coating layer is preferably 5% by mass or more and 30% by mass or less, more preferably 10% by mass or more and 25% by mass or less, and more preferably 15% by mass or more with respect to the mass of the metal pigment. More preferably, it is 20 mass% or less.
When the coating amount of the second coating layer is 5% by mass or more, the coating property of the coating pigment by the binder resin is maintained, and a decrease in transferability under high temperature and high humidity is suppressed. In addition, since the coating amount of the second coating layer is 20% by mass or less, the regular reflectance is prevented from being lowered by the resin constituting the second coating layer, and an image excellent in glitter is obtained. It is formed.
Further, the coating amount of the second coating layer is a decrease in mass when the temperature is increased from 30 ° C. to 600 ° C. at a temperature increase rate of 30 ° C./min in a nitrogen stream using a calorimeter measuring device (TGA). Measured by rate.

When measuring the coating amount of the second coating layer of the coating pigment in the toner particles, the components such as the binder resin (and the release agent and other components) are dissolved and burned from the toner particles. After removing by such a method, the above method may be applied.
Further, since the release resin and other components are mixed in the binder resin in the toner particles, it is possible to distinguish the mixed region from the second coating layer in the coating pigment by using the second resin layer. You may measure the coating amount of a coating layer.

The second coating layer is formed as follows.
That is, the coated pigment on which the first coating layer is formed is solid-liquid separated, washed as necessary, dispersed in a solvent, a polymerizable monomer and a polymerization initiator are added with stirring, and heat treatment is performed. To deposit a resin on the surface of the metal pigment.
In this way, the second coating layer is formed.

  The content of the coating pigment in the toner of the exemplary embodiment is preferably 1 part by mass or more and 70 parts by mass or less, and more preferably 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin described later.

-Binder resin-
Examples of the binder resin include styrenes (eg, styrene, parachlorostyrene, α-methylstyrene, etc.), (meth) acrylic acid esters (eg, 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 (for example, acrylonitrile, Methacrylonitrile, 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, etc.) Emissions, a homopolymer of a monomer such as butadiene) and the like, or a vinyl-based resin composed of these monomers with two or more combinations copolymer.
As the binder resin, for example, epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, polyether resin, non-vinyl resin such as modified rosin, a mixture of these with the vinyl resin, or these Examples also include a graft polymer obtained by polymerizing a vinyl monomer in the coexistence.
These binder resins may be used alone or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of the polyester resin include known polyester resins.

  As a polyester resin, the condensation polymer of polyhydric carboxylic acid and polyhydric alcohol is mentioned, for example. In addition, as a polyester resin, a commercial item may be used and what was synthesize | combined may be used.

Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids (eg, 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 acids (for example, cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or lower (for example, having 1 or more carbon atoms) 5 or less) alkyl esters. Among these, as polyvalent carboxylic acid, aromatic dicarboxylic acid is preferable, for example.
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid or a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (for example, having 1 to 5 carbon atoms) alkyl esters.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

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, Hydrogenated bisphenol A, etc.) and aromatic diols (for example, ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.
As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked structure or a branched structure may be used together with the diol. Examples of the trihydric or higher polyhydric alcohol include glycerin, trimethylolpropane, and pentaerythritol.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

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 determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, described in the method for determining the glass transition temperature in JIS K7121-1987 “Method for Measuring Transition Temperature of Plastic”. It is determined by “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the polyester resin is preferably from 5,000 to 1,000,000, more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the polyester resin is preferably from 2,000 to 100,000.
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 with a THF solvent using a Tosoh GPC / HLC-8120GPC as a measuring device and a Tosoh column / TSKgel SuperHM-M (15 cm). The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

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 in the reaction system is reduced as necessary, and the reaction is performed while removing water and alcohol generated during the condensation.
In addition, when the monomer of the raw material is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added and dissolved as a solubilizing agent. In this case, the polycondensation reaction is performed while distilling off the solubilizer. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polymerized together with the main component. It is good to condense.

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

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 “melting peak temperature” described in the method for determining the melting temperature of JIS K7121-1987 “Method for measuring the transition temperature of plastic” from the DSC curve obtained by differential scanning calorimetry (DSC).

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

-Other additives-
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner particles as internal additives.

[Preferred embodiment of toner]
(About ratio (A / B))
In the toner according to the present embodiment, when a solid image is formed, the reflectance A at a light receiving angle of + 30 ° measured when the image is irradiated with incident light having an incident angle of −45 ° by a goniophotometer. And the ratio (A / B) of the reflectance B at a light receiving angle of −30 ° is preferably 2 or more and 100 or less.

A ratio (A / B) of 2 or more indicates that there is more reflection on the side opposite to the incident side (angle + side) than on the side on which incident light enters (angle-side). That is, the irregular reflection of the incident light is suppressed. When irregular reflection occurs in which incident light is reflected in various directions, the color looks dull when the reflected light is visually confirmed. Therefore, when the ratio (A / B) is less than 2, gloss may not be confirmed even when the reflected light is visually recognized, and the glitter may be inferior.
On the other hand, when the ratio (A / B) exceeds 100, the viewing angle at which the reflected light can be visually recognized becomes too narrow, and the specularly reflected light component is large, so that it may appear black depending on the viewing angle. Further, a toner having a ratio (A / B) exceeding 100 is difficult to manufacture.

  The ratio (A / B) is more preferably 50 or more and 100 or less, still more preferably 60 or more and 90 or less, and particularly preferably 70 or more and 80 or less.

(Measurement of ratio (A / B) with goniophotometer)
Here, the incident angle and the light receiving angle will be described first. In this embodiment, when measuring with a goniophotometer, the incident angle is set to −45 ° because the measurement sensitivity is high for an image in a wide range of glossiness.
The reason why the light receiving angles are set to −30 ° and + 30 ° is that the measurement sensitivity is highest in evaluating an image having a glitter feeling and an image having no glitter feeling.

Next, a method for measuring the ratio (A / B) will be described.
In this embodiment, when measuring the ratio (A / B), a “solid image” is first formed by the following method. An electrostatic charge image developer as a sample is filled in a developing device of DocuCentre-III C7600 manufactured by Fuji Xerox Co., Ltd., and fixed on a recording paper (OK topcoat + paper, manufactured by Oji Paper Co., Ltd.). A solid image with a toner loading of 4.5 g / m ² is formed at 190 ° C. and a fixing pressure of 4.0 kg / cm ² . The “solid image” refers to an image with a printing rate of 100%.
Using a spectral variable angle color difference meter GC5000L manufactured by Nippon Denshoku Industries Co., Ltd. as a variable angle photometer, incident light having an incident angle of −45 ° is incident on the solid image. The reflectance A at an angle of + 30 ° and the reflectance B at a light receiving angle of −30 ° are measured. Note that the reflectance A and the reflectance B were measured at intervals of 20 nm for light having a wavelength in the range of 400 nm to 700 nm, and the average value of the reflectance at each wavelength was used. The ratio (A / B) is calculated from these measurement results.

(About the requirements of (1) to (2))
The toner according to the exemplary embodiment desirably includes toner particles that satisfy the following requirements (1) to (2) from the viewpoint of satisfying the above-described ratio (A / B).
(1) The toner particles are flat, that is, the average equivalent circle diameter D is longer than the average maximum thickness C of the toner particles. (2) When the cross section in the thickness direction of the toner particles is observed, The number of pigment particles in which the angle between the major axis direction in the cross section and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is 60% or more of all the observed pigment particles.

Here, FIG. 1 is a sectional view schematically showing toner particles satisfying the requirements (1) to (2). The schematic diagram shown in FIG. 1 is a cross-sectional view of the toner particles in the thickness direction.
A toner particle 2 shown in FIG. 1 is a flat toner particle having a circle-equivalent diameter longer than a thickness L, and contains scale-like pigment particles 4 (corresponding to a coated pigment).

As shown in FIG. 1, when the toner particles 2 have a flat shape having a circle-equivalent diameter longer than the thickness L, the toner is transferred to an image carrier, an intermediate transfer member, a recording medium, or the like in an image forming development process or transfer process. Since the toner particles tend to move so as to cancel the charge of the toner particles as much as possible, it is considered that the toner particles are arranged so as to maximize the area of adhesion. That is, on the recording medium to which the toner particles are finally transferred, it is considered that the flat toner particles are arranged so that the flat surface side faces the recording medium surface. Also in the fixing step of image formation, it is considered that the flat toner particles are arranged so that the flat surface side faces the recording medium surface due to the pressure during fixing.
For this reason, among the scale-like pigment particles contained in the toner particles, “the angle between the major axis direction of the cross section of the toner and the major axis direction of the pigment particles is −30 ° to + 30 ° shown in the above (2). It is considered that the pigment particles satisfying the requirement “in the above range” are arranged so that the surface side having the maximum area faces the recording medium surface. When the image thus formed is irradiated with light, the ratio of the pigment particles that diffusely reflect the incident light is suppressed, so that the above range (A / B) can be achieved. . In addition, when the ratio of pigment particles that diffusely reflect incident light is suppressed, the reflected light intensity varies greatly depending on the viewing angle, so that more ideal glitter can be obtained.

-Average maximum thickness C and average equivalent circle diameter D-
As shown in (1) above, in the toner according to the exemplary embodiment, it is desirable that the average equivalent circle diameter D is longer than the average maximum thickness C of the toner particles.
Further, the ratio (C / D) of the average maximum thickness C and the average equivalent circle diameter D is preferably in the range of 0.001 to 0.500, more preferably in the range of 0.010 to 0.200. Desirably, the range from 0.050 to 0.100 is particularly desirable.
When the ratio (C / D) is 0.001 or more, the strength of the toner particles is ensured, the breakage due to the stress during image formation is suppressed, and the charging is reduced due to the exposure of the pigment, resulting in occurrence. Fog is suppressed. On the other hand, when it is 0.500 or less, excellent glitter can be obtained.

The average maximum thickness C and the average equivalent circle diameter D are measured by the following methods.
The toner particles are placed on a smooth surface and shaken to disperse the toner particles without unevenness. About 1000 toner particles, the maximum thickness C and the equivalent circle diameter D of the surface viewed from above are measured with a color laser microscope “VK-9700” (manufactured by Keyence Corporation) 1000 times, and their arithmetic is performed. Calculate by calculating the average value.

-An angle between the major axis direction of the cross section of the toner particles and the major axis direction of the pigment particles-
As shown in (2) above, when a cross section in the thickness direction of the toner particles is observed, the angle between the major axis direction of the toner particles and the major axis direction of the pigment particles is −30 ° to + 30 °. The number of pigment particles in the range is desirably 60% or more of all the observed pigment particles. Furthermore, the number is more preferably 70% or more and 95% or less, and particularly preferably 80% or more and 90% or less.
When the number is 60% or more, excellent glitter can be obtained.

Here, a method for observing the cross section of the toner particles will be described.
After embedding the toner particles with a bisphenol A liquid epoxy resin and a curing agent, a cutting sample is prepared. Next, the cutting sample is cut at −100 ° C. using a cutting machine using a diamond knife (in this embodiment, a LEICA ultramicrotome (manufactured by Hitachi Technologies)) to prepare an observation sample. A cross section of the toner particles is observed with a transmission electron microscope (TEM) at a magnification of about 5000 times. For the 1000 toner particles observed, the number of pigment particles in which the angle between the major axis direction of the toner particle cross section and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° is calculated using image analysis software. And calculate the ratio.

  The “major axis direction in the cross section of the toner particles” means a direction perpendicular to the thickness direction of the toner particles having an average equivalent circle diameter D longer than the average maximum thickness C described above. “Axial direction” represents the length direction of the pigment particles.

(Volume average particle size)
In the toner according to the exemplary embodiment, the toner particles preferably have a volume average particle diameter of 1 μm to 30 μm, and more preferably 3 μm to 20 μm.

The volume average particle size D _50v is _smaller than the particle size range (channel) divided based on the particle size distribution measured by a measuring instrument such as Multisizer II (manufactured by Coulter Inc.). Drawing the cumulative distribution from the side, the particle diameter to be accumulated 16% is the volume D _16v , the number D _16p , the particle diameter to be accumulated 50% is the volume D _50v , the number D _50p , the particle diameter to be accumulated 84% is the volume D _84v , number D _84p . Using these, the volume average particle size distribution index (GSDv) is calculated as ( _D84v / _D16v ) ^1/2 .

[Toner Production Method]
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner particles as necessary after manufacturing the toner particles.
The method for producing the toner particles is not particularly limited, but it is preferably produced by a wet method such as an emulsion aggregation method or a dissolution suspension method from the viewpoint of preventing exposure of the metal pigment to the toner surface.

(Emulsion aggregation method)
In the present embodiment, an emulsion aggregation method may be used in which the shape of the toner particles and the particle diameter of the toner particles can be easily controlled and the control range of the toner particle structure such as a core-shell structure is wide.
Hereinafter, a method for producing toner particles by the emulsion aggregation method will be described in detail.

The emulsion aggregation method includes an emulsification step of emulsifying a raw material constituting toner particles to form various dispersions such as resin particle (emulsion particle) dispersion, an aggregation step of forming an aggregate of the resin particles, and an aggregate. And fusing step.
Each step of this emulsion aggregation method will be described below.

-Emulsification process-
The resin particle dispersion is prepared by a method of preparing a dispersion of resin particles by a general polymerization method, for example, a method using an emulsion polymerization method, a suspension polymerization method, a dispersion polymerization method, etc. A method of emulsifying the solution obtained by mixing the adhering resin by applying a shearing force with a disperser is applied. At that time, particles may be formed by heating to lower the viscosity of the resin component. A dispersant may be used for stabilizing the dispersed resin particles. Furthermore, if the resin is oily and dissolves in a solvent having a relatively low solubility in water, the resin is dissolved in those solvents and dispersed in water together with a dispersant and a polymer electrolyte, and then heated or decompressed. Then, the solvent is evaporated to prepare a resin particle dispersion.

Examples of the aqueous medium include water such as distilled water and ion-exchanged water; alcohols; and the like. Water is preferable.
Examples of the dispersant used in the emulsification step include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate, Anionic surfactants such as sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, amphoteric such as lauryldimethylamine oxide Ionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Surfactants such as nonionic surfactants such as alkyl amines; and the like are; tricalcium phosphate, aluminum hydroxide, calcium sulfate, calcium carbonate, inorganic salts such as barium carbonate.

Examples of the disperser used in the emulsification step include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser.
As the size of the resin particles in the dispersion, the average particle size (volume average particle size) is preferably 1.0 μm or less, more preferably in the range of 60 nm to 300 nm, and even more preferably 150 nm to 250 nm. Range.
When the thickness is 60 nm or more, the resin particles tend to be unstable particles in the dispersion, and thus the resin particles may be easily aggregated. If the particle size is 1.0 μm or less, the particle size distribution of the toner may be narrowed.

In preparing the release agent dispersion, the release agent is dispersed in water together with an ionic surfactant, a polymer electrolyte such as a polymer acid or a polymer base, and then heated to a temperature equal to or higher than the melting temperature of the release agent. Dispersion treatment is performed using a homogenizer or a pressure discharge type disperser to which a strong shearing force is applied while heating. By undergoing such treatment, a release agent dispersion is obtained. During the dispersion treatment, an inorganic compound such as polyaluminum chloride may be added to the dispersion. Examples of desirable inorganic compounds include polyaluminum chloride, aluminum sulfate, highly basic polyaluminum chloride (BAC), polyaluminum hydroxide, and aluminum chloride. Among these, polyaluminum chloride and aluminum sulfate are desirable.
The release agent dispersion is used in the emulsion aggregation method, but the release agent dispersion may also be used when the toner particles are produced by the suspension polymerization method.

By the dispersion treatment, a release agent dispersion liquid containing release agent particles having a volume average particle diameter of 1 μm or less is obtained. In addition, the more preferable volume average particle diameter of the release agent particles is 100 nm or more and 500 nm or less.
When the volume average particle diameter is 100 nm or more, the properties of the binder resin used are affected, but the release agent component is generally easily taken into the toner particles. In the case of 500 nm or less, the dispersion state of the release agent in the toner particles is good.

For the preparation of the coating pigment dispersion, a known dispersion method can be used.For example, a general dispersion means such as a rotary shear type homogenizer, a ball mill having a medium, a sand mill, a dyno mill, or an optimizer can be employed. It is not limited.
The coated pigment is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base. The volume average particle diameter of the dispersed coated pigment may be 20 μm or less, but if it is in the range of 3 μm or more and 16 μm or less, the dispersion of the coated pigment in the toner is favorable without impairing the cohesiveness.
In addition, a dispersion of the coated pigment coated with the binder resin is prepared by dispersing and dissolving the coated pigment and the binder resin in a solvent, mixing, and dispersing in water by phase inversion emulsification or shear emulsification. Also good.

-Aggregation process-
In the agglomeration step, the resin particle dispersion, the coating pigment dispersion, the release agent dispersion, etc. are mixed to form a mixed solution, which is heated to agglomerate at a temperature lower than the glass transition temperature of the resin particles to form aggregated particles. . Aggregated particles are often formed by making the pH of the mixed solution acidic under stirring. At this time, the ratio (C / D) can be set within a preferable range depending on the stirring conditions. More specifically, the ratio (C / D) can be reduced by heating at a high speed and heating at the stage of forming aggregated particles, and by heating at a lower speed and at a lower temperature by stirring. The ratio (C / D) can be increased. In addition, as pH, the range of 2-7 is desirable, and it is also effective in this case to use a flocculant.
In the aggregation step, the release agent dispersion may be added and mixed at once with various dispersions such as a resin particle dispersion, or may be added in a plurality of divided portions.

  As the aggregating agent, a surfactant having an opposite polarity to the surfactant used for the dispersant, an inorganic metal salt, and a divalent or higher metal complex are preferably used. In particular, the use of a metal complex is particularly desirable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

As the inorganic metal salt as the flocculant, an aluminum salt and a polymer thereof are particularly suitable. In order to obtain a narrower particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. Inorganic metal salt polymers are more suitable.
In this embodiment, it is desirable to use a polymer of a tetravalent inorganic metal salt containing aluminum in order to obtain a narrow particle size distribution.

  Alternatively, a toner having a structure in which the surface of the core aggregated particles is coated with a resin may be prepared by additionally adding a resin particle dispersion when the aggregated particles have reached a desired particle size (coating step). In this case, the release agent and the coating pigment are difficult to be exposed on the toner surface, which is desirable from the viewpoint of chargeability and developability. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

-Fusion process-
In the fusing step, the agglomeration is stopped by raising the pH of the suspension of the agglomerated particles to a range of 3 to 9 under stirring conditions in accordance with the agglomeration step described above. The aggregated particles are fused by heating at a temperature.
Further, when the surface of the core aggregated particles is coated with a resin in the aggregation process, the resin is also fused to coat the core aggregated particles. The heating time may be performed to the extent that fusion is performed, and may be performed for about 0.5 hour to 10 hours.

After the fusion as described above, cooling is performed to obtain fused particles. Further, in the cooling step, crystallization may be promoted by lowering the cooling rate in the vicinity of the glass transition temperature of the resin (range of glass transition temperature ± 10 ° C.), so-called slow cooling.
The fused particles obtained by fusing are made into toner particles through a solid-liquid separation process such as filtration and, if necessary, a washing process and a drying process.

  As described below, an external additive may be added to the toner particles obtained through the respective steps relating to the emulsion aggregation method as described above.

(Dissolution suspension method)
Next, a method for producing toner particles by the dissolution suspension method will be described in detail.
The dissolution suspension method is a solution in which a material containing other components such as a binder resin, a coating pigment, and a release agent used as necessary is dissolved or dispersed in a solvent in which the binder resin can be dissolved. In this method, the toner particles are obtained by adding in an aqueous medium containing an inorganic dispersant, granulating by dispersing and suspending, and then removing the solvent.
Other components used in the dissolution suspension method include various components such as a charge control agent and organic particles in addition to a release agent.

In the present embodiment, these binder resin, coating pigment, and other components used as necessary are dissolved or dispersed in a solvent in which the binder resin can be dissolved.
Whether or not the binder resin can be dissolved depends on the components of the binder resin, the molecular chain length, the degree of three-dimensionalization, etc., so it cannot be generally stated, but in general, toluene, xylene, hexane, etc. Halogenated hydrocarbons such as hydrocarbon, methylene chloride, chloroform, dichloroethane, dichloroethylene, alcohols or ethers such as ethanol, butanol, benzyl alcohol ethyl ether, benzyl alcohol isopropyl ether, tetrahydrofuran, tetrahydropyran, methyl acetate, ethyl acetate, butyl acetate Esters such as isopropyl acetate, acetone, methyl ethyl ketone, diisobutyl ketone, dimethyl oxide, diacetone alcohol, cyclohexanone, methylcyclohexanone, and other ketones or acetals are used.

These solvents dissolve the binder resin and do not need to dissolve the coating pigment and other components. The coating pigment and other components may be dispersed in the binder resin solution.
Although there is no restriction | limiting in the usage-amount of a solvent, What is necessary is just a viscosity which can be granulated in an aqueous medium. 10/90 to 50/50 (mass ratio of the former / the latter) is easy to granulate in the ratio of the material (the former) and the solvent (the latter) containing the binder resin, the coating pigment, and other components. From the viewpoint of typical toner particle yield.

The binder resin, coating pigment, and other component liquid (toner mother liquor) dissolved or dispersed in a solvent are granulated to have a predetermined particle size in an aqueous medium containing an inorganic dispersant. Is done. Water is mainly used as the aqueous medium. The mixing ratio of the aqueous medium and the toner mother liquid is preferably aqueous medium / toner mother liquid = 90/10 to 50/50 (mass ratio).
The inorganic dispersant is preferably selected from tricalcium phosphate, hydroxyapatite, calcium carbonate, titanium oxide and silica powder.
The amount of the inorganic dispersant used is determined according to the particle size of the granulated particles, but generally it is preferably used in the range of 0.1% by mass to 15% by mass with respect to the toner mother liquor. . If the content is 0.1% by mass or more, granulation is easily performed, and if the content is 15% by mass or less, unnecessary fine particles are hardly generated and target particles are easily obtained in a high yield.

In order to improve granulation from the toner mother liquor, an auxiliary agent may be further added to the aqueous medium containing the inorganic dispersant.
As the auxiliary agent, there are known cationic type, anionic type and nonionic type surfactants, and those of the anionic type are particularly preferable. For example, there are sodium alkylbenzene sulfonate, sodium α-olefin sulfonate, sodium alkyl sulfonate, etc., and these are used in the range of 1 × 10 ⁻⁴ mass% to 0.1 mass% with respect to the toner mother liquor. preferable.

Granulation from the toner mother liquor in an aqueous medium containing an inorganic dispersant is preferably performed under shear.
At this time, it is desirable to granulate the average particle size to 20 μm or less, and it is particularly desirable to granulate to 3 μm or more and 15 μm or less.
There are various dispersers as the apparatus provided with the shearing mechanism, and among them, a homogenizer is preferable. By using a homogenizer, a substance that is incompatible with each other (in this embodiment, an aqueous medium containing an inorganic dispersant and a toner mother liquor) is passed through a gap between the casing and the rotating rotor so that the liquid is contained in a liquid. And incompatible substances can be dispersed in the form of particles.
Specific examples of the homogenizer include a TK homomixer, a line flow homomixer, an auto homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), a Silverson homogenizer (manufactured by Silverson), and a polytron homogenizer (KINEMATICA AG). Etc.).
The stirring condition using the homogenizer is preferably 2 m / sec or more in terms of the peripheral speed of the rotor blades. If the peripheral speed is 2 m / sec or more, the particle formation tends to be good.

After granulation as described above, the solvent is removed.
The removal of the solvent may be performed at room temperature (25 ° C.) and normal pressure, but since it takes a long time to remove, the temperature condition is lower than the boiling point of the solvent and the difference from the boiling point is 80 ° C. or less. It is preferable to carry out. The pressure may be normal pressure or reduced pressure, but when reducing the pressure, it is preferably 20 mmHg or more and 150 mmHg or less.

In addition, it is preferable to wash the toner particles with hydrochloric acid or the like after removing the solvent. As a result, the inorganic dispersant remaining on the surface of the toner particles can be removed to obtain the original composition of the toner particles and improve the characteristics.
Subsequently, powder toner particles are obtained by dehydration and drying.

  As described below, an external additive may be added to the toner particles obtained through the steps relating to the dissolution suspension method as described above.

(Granting external additives)
-External addition process-
To the toner particles obtained by the above method, inorganic oxides such as silica, titania, and aluminum oxide are added and adhered as external additives for the purpose of charge adjustment, fluidity provision, charge exchangeability, etc. May be.
These can be performed by, for example, a V-type blender, a Henschel mixer, a Redige mixer, or the like, and may be attached in stages.
The addition amount of the external additive is desirably in the range of 0.1 part or more and 5 parts or less, and more desirably in the range of 0.3 part or more and 2 parts or less with respect to 100 parts of the toner particles.

  In addition to the inorganic oxides described above, other components (particles) such as a charge control agent, organic particles, a lubricant, and an abrasive may be added as external additives.

  Although there is no restriction | limiting in particular as a charge control agent, A colorless or light-colored thing is desirable and used. For example, quaternary ammonium salt compounds, nigrosine compounds, complexes of aluminum, iron, chromium, and triphenylmethane pigments can be used.

Examples of the organic particles include particles usually used as an external additive on the toner surface, such as vinyl resins, polyester resins, and silicone resins. These inorganic particles and organic particles are used as fluidity aids, cleaning aids, and the like.
Examples of the lubricant include fatty acid amides such as ethylene bis stearic acid amide and oleic acid amide, and fatty acid metal salts such as zinc stearate and calcium stearate.
As an abrasive | polishing agent, the above-mentioned silica, alumina, cerium oxide etc. are mentioned, for example.

-Sieving process-
Moreover, you may provide a sieving process as needed after the external addition process. Specific examples of the sieving method include a gyro shifter, a vibration sieving machine, and a wind sieving machine.
By sieving, coarse particles of the external additive and the like are removed, and generation of streaks on the photosensitive member and scumming in the apparatus are suppressed.

  As described above, the toner according to the exemplary embodiment is obtained.

<Electrostatic image developer>
The electrostatic charge image developer according to the exemplary embodiment includes at least the toner according to the exemplary embodiment.
The electrostatic image developer according to this embodiment may be a one-component developer including only the toner according to this embodiment, or may be a two-component developer mixed with the toner and a carrier.

There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. As a carrier, for example, a coated carrier in which the surface of a core made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; a porous magnetic powder is impregnated with a resin Resin impregnated type carriers; and the like.
Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier 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 conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

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, styrene-acrylic acid copolymer. Examples thereof include a polymer, a straight silicone resin containing an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.
Note that the coating resin and the matrix resin may contain other additives such as a conductive material.

Here, in order to coat the surface of the core material with the coating resin, a method of coating with a coating layer forming solution obtained by dissolving the coating resin and, if necessary, various additives in an appropriate solvent may 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 the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the core material, and a state in which the core material is suspended by flowing air. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed, a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater, and the 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.

<< Toner Cartridge, Process Cartridge, Image Forming Apparatus, and Image Forming Method >>
Next, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method according to the present embodiment will be described together.

The image forming apparatus / image forming method according to the present embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, and an electrostatic charge. Development means for containing an image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer, and the toner image formed on the surface of the image carrier as a recording medium Transfer means for transferring to the surface of the recording medium, and fixing means for fixing the toner image transferred to the surface of the recording medium. The electrostatic charge image developer according to this embodiment is applied as the electrostatic charge image developer.

  In the image forming apparatus according to this embodiment, a charging process for charging the surface of the image carrier, an electrostatic charge image forming process for forming an electrostatic image on the surface of the charged image carrier, and an electrostatic charge according to this embodiment. A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with an image developer; a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium; An image forming method (an image forming method according to the present embodiment) including a fixing step of fixing the toner image transferred onto the surface of the recording medium is performed.

The image forming apparatus according to the present embodiment is a direct transfer type apparatus that directly transfers a toner image formed on the surface of an image carrier to a recording medium; the toner image formed on the surface of the image carrier is transferred to an intermediate transfer member An intermediate transfer type apparatus that primarily transfers the toner image transferred to the surface of the intermediate transfer body and then secondary transfer the toner image to the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. An apparatus provided with a cleaning unit; a known image forming apparatus such as an apparatus provided with a charge removing unit that discharges the surface of an image holding member by irradiating a discharge light after charging a toner image and before charging is applied.
In the case of an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred to the surface, and a primary transfer that primarily transfers the toner image formed on the surface of the image holding body to the surface of the intermediate transfer body. And a secondary transfer unit that secondarily transfers the toner image transferred onto the surface of the intermediate transfer member onto the surface of the recording medium.

In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus.
As such a process cartridge, for example, a developing unit that contains the electrostatic charge image developer according to the present embodiment and develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer. A process cartridge according to this embodiment that is provided and is detachably attached to the image forming apparatus is preferably used.
Further, the process cartridge according to the present embodiment is not limited to the above-described configuration, and other means such as a developing device and other units such as an image holding member, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one selected from the above.

Further, the image forming apparatus according to the present embodiment has a cartridge structure (toner cartridge) in which a portion for storing the toner according to the present embodiment is attached to and detached from the image forming apparatus as replenishment toner supplied to the developing unit. May be.
As such a process cartridge, for example, the toner cartridge according to the present embodiment that accommodates the toner according to the present embodiment and is detachably attached to the image forming apparatus is preferably used.

The image forming apparatus according to the present embodiment will be described below with reference to the drawings.
FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus according to the present embodiment has a tandem configuration in which a plurality of photoconductors as image holding members, that is, a plurality of image forming units (image forming units) are provided.

As shown in FIG. 2, the image forming apparatus according to the present embodiment includes four image forming units 50Y, 50M, 50C, and 50K that form toner images of yellow, magenta, cyan, and black, respectively, and a glitter image. Are formed in parallel (tandem) at intervals. The image forming units are arranged in the order of the image forming units 50Y, 50M, 50C, 50K, and 50B from the upstream side in the rotation direction of the intermediate transfer belt 33.
Here, each of the image forming units 50Y, 50M, 50C, 50K, and 50B has the same configuration except for the color of the toner in the stored developer. The unit 50Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), black (K), and silver (B) are attached to the same parts as the image forming unit 50Y in place of yellow (Y). Description of the image forming units 50M, 50C, 50K, and 50B is omitted.

  The yellow image forming unit 50Y includes a photoconductor 21Y as an image carrier, and the photoconductor 21Y is rotationally driven at a predetermined process speed by a driving unit (not shown) along the direction of an arrow A shown in the drawing. It has become so. As the photoreceptor 21Y, for example, an organic photoreceptor having sensitivity in the infrared region is used.

  A charging roll (charging means) 28Y is provided above the photoconductor 21Y. A predetermined voltage is applied to the charging roll 28Y by a power source (not shown), and the surface of the photoconductor 21Y is predetermined. Charged to a certain potential.

  Around the photoreceptor 21Y, an exposure device (electrostatic image forming means) 19Y that exposes the surface of the photoreceptor 21Y to form an electrostatic image is disposed downstream of the charging roll 28Y in the rotation direction of the photoreceptor 21Y. Has been. Here, as the exposure device 19Y, an LED array that can be miniaturized is used in terms of space, but the present invention is not limited to this, and an electrostatic charge image forming unit using another laser beam or the like is used. Of course there is no problem.

  Further, a developing device (developing means) 20Y that contains a yellow developer is disposed around the photosensitive member 21Y on the downstream side in the rotation direction of the photosensitive member 21Y with respect to the exposure device 19Y. The electrostatic charge image formed in FIG. 4 is visualized with yellow toner, and a toner image is formed on the surface of the photoreceptor 21Y.

  Below the photoconductor 21Y, an intermediate transfer belt (primary transfer means) 33 that primarily transfers a toner image formed on the surface of the photoconductor 21Y extends below the five photoconductors 21Y, 21M, 21C, 21K, and 21B. Are arranged as follows. The intermediate transfer belt 33 is pressed against the surface of the photoreceptor 21Y by the primary transfer roll 17Y. The intermediate transfer belt 33 is supported by three rolls of a drive roll 22, a support roll 23, and a bias roll 24, and is rotated in the direction of arrow B at a moving speed equal to the process speed of the photoreceptor 21Y. ing. A yellow toner image is primarily transferred onto the surface of the intermediate transfer belt 33, and toner images of each color of magenta, cyan, black, and silver (brightness) are sequentially primary transferred and stacked.

  Further, around the photoreceptor 21Y, the toner remaining on the surface of the photoreceptor 21Y or the retransferred toner is cleaned downstream of the primary transfer roll 17Y in the rotation direction (arrow A direction) of the photoreceptor 21Y. A cleaning device 15Y is arranged. The cleaning blade in the cleaning device 15Y is attached so as to be in pressure contact with the surface of the photoreceptor 21Y in the counter direction.

  A secondary transfer roll (secondary transfer unit) 34 is pressed against the bias roll 24 that supports the intermediate transfer belt 33 via the intermediate transfer belt 33. The toner image primarily transferred and laminated on the surface of the intermediate transfer belt 33 is recorded on the surface of the recording paper (recording medium) P fed from a paper cassette (not shown) at the pressure contact portion between the bias roll 24 and the secondary transfer roll 34. Electrostatically transferred. At this time, since the toner image transferred and laminated on the intermediate transfer belt 33 is the top (uppermost layer) silver toner image, the toner image transferred to the surface of the recording paper P has a silver toner image. It becomes the lowest (lowermost layer).

  Also, downstream of the secondary transfer roll 34, a fixing device (fixing means) for fixing the toner image transferred on the recording paper P onto the surface of the recording paper P by heat and pressure to form a permanent image. 35 is arranged.

  As the fixing device 35, for example, a low-surface energy material typified by a fluororesin component or a silicone resin is used on the surface, and a fixing belt having a belt shape is represented by a fluororesin component or a silicone resin on the surface. And a cylindrical fixing roll is used.

  Next, the operation of each of the image forming units 50Y, 50M, 50C, 50K, and 50B that forms images of each color of yellow, magenta, cyan, black, and silver (brightness) will be described. Since the operations of the image forming units 50Y, 50M, 50C, 50K, and 50B are the same, the operation of the yellow image forming unit 50Y will be described as a representative example.

  In the yellow developing unit 50Y, the photoreceptor 21Y rotates in the direction of arrow A at a predetermined process speed. The surface of the photoreceptor 21Y is negatively charged to a predetermined potential by the charging roll 28Y. Thereafter, the surface of the photoreceptor 21Y is exposed by the exposure device 19Y, and an electrostatic charge image corresponding to the image information is formed. Subsequently, the negatively charged toner is reversely developed by the developing device 20Y, and the electrostatic charge image formed on the surface of the photoreceptor 21Y is visualized on the surface of the photoreceptor 21Y to form a toner image. Thereafter, the toner image on the surface of the photoreceptor 21Y is primarily transferred onto the surface of the intermediate transfer belt 33 by the primary transfer roll 17Y. After the primary transfer, the transfer residual component such as toner remaining on the surface of the photoreceptor 21Y is scraped off and cleaned by the cleaning blade of the cleaning device 15Y, and is prepared for the next image forming process.

  The above operations are performed by the image forming units 50Y, 50M, 50C, 50K, and 50B, and the toner images visualized on the surfaces of the photoreceptors 21Y, 21M, 21C, 21K, and 21B are successively transferred to the intermediate transfer belt. 33 is transferred onto the surface. In the color mode, toner images of each color are transferred in the order of yellow, magenta, cyan, black, and silver (brightness). Only the toner image is single-transferred or multiple-transferred. Thereafter, the toner image singly or multiply transferred onto the surface of the intermediate transfer belt 33 is secondarily transferred onto the surface of the recording paper P conveyed from a paper cassette (not shown) by the secondary transfer roll 34, and then the fixing device 35. It is fixed by heating and pressurizing. The toner remaining on the surface of the intermediate transfer belt 33 after the secondary transfer is cleaned by a belt cleaner 26 constituted by a cleaning blade for the intermediate transfer belt 33.

  The yellow image forming unit 50Y is configured as a process cartridge in which a developing device 20Y containing a yellow developer, a photosensitive member 21Y, a charging roll 28Y, and a cleaning device 15Y are integrally attached to and detached from the image forming apparatus main body. Has been. The image forming units 50B, 50K, 50C, and 50M are also configured as process cartridges in the same manner as the image forming unit 50Y.

  The toner cartridges 40Y, 40M, 40C, 40K, and 40B are cartridges that store toner of each color and are attached to and detached from the image forming apparatus, and are connected to a developing device corresponding to each color by a toner supply pipe (not shown). Has been. When the toner stored in each toner cartridge becomes low, the toner cartridge is replaced.

  Hereinafter, although an example and a comparative example are given and this embodiment is described more concretely, this embodiment is not limited to the following examples. Unless otherwise specified, “part” and “%” are based on mass.

<Preparation of coated pigment (1)>
(Formation of the first coating layer)
To 500 parts of methanol, 154 parts (100 parts as aluminum content) of an aluminum pigment (Showa Aluminum Co., Ltd. product number 2173, solid content 65%) was added and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 15 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110 ° C. for 3 hours to obtain an aluminum pigment 1 coated with silica.

(Formation of second coating layer)
To the aluminum pigment 1 coated with silica, 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.5 parts acrylic acid, 9.8 parts epoxidized polybutadiene, 12.2 parts trimethylolpropane triacrylate, 4.4 parts divinylbenzene, and 1.8 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (1) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (2)>
(Formation of second coating layer)
To the aluminum pigment 1 coated with silica obtained with the coated pigment (1), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.1 parts acrylic acid, 2.1 parts epoxidized polybutadiene, 2.6 parts trimethylolpropane triacrylate, 0.9 parts divinylbenzene, and 0.4 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (2) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (3)>
(Formation of the first coating layer)
To 500 parts of methanol, 154 parts (100 parts as aluminum content) of an aluminum pigment (Showa Aluminum Co., Ltd. product number 2173, solid content 65%) was added and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 25 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110 ° C. for 3 hours to obtain an aluminum pigment 2 coated with silica.

(Formation of second coating layer)
To the aluminum pigment 2 coated with silica, 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.3 parts acrylic acid, 6.4 parts epoxidized polybutadiene, 7.9 parts trimethylolpropane triacrylate, 2.9 parts divinylbenzene, and 1.2 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (3) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (4)>
(Formation of the first coating layer)
To 500 parts of methanol, 154 parts (100 parts as aluminum content) of an aluminum pigment (Showa Aluminum Co., Ltd. product number 2173, solid content 65%) was added and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 35 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110 ° C. for 3 hours to obtain an aluminum pigment 3 coated with silica.

(Formation of second coating layer)
To the aluminum pigment 3 coated with silica, 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.6 parts acrylic acid, 11.3 parts epoxidized polybutadiene, 14.1 parts trimethylolpropane triacrylate, 5.1 parts divinylbenzene, and 2.1 parts azobisisobutyronitrile are added, 80 Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (4) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (5)>
(Formation of second coating layer)
500 parts of mineral spirits were added to the aluminum pigment 3 coated with silica obtained with the coated pigment (4) and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.1 part of acrylic acid, 2.4 parts of epoxidized polybutadiene, 3.0 parts of trimethylolpropane triacrylate, 1.1 parts of divinylbenzene, and 0.4 parts of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (5) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (6)>
(Formation of second coating layer)
To the aluminum pigment 1 coated with silica obtained with the coated pigment (1), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.7 parts of acrylic acid, 13 parts of epoxidized polybutadiene, 16.3 parts of trimethylolpropane triacrylate, 5.9 parts of divinylbenzene, and 2.4 parts of azobisisobutyronitrile are added at 80 ° C. Polymerized for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (6) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (7)>
(Formation of second coating layer)
To the aluminum pigment 1 coated with silica obtained with the coated pigment (1), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.1 part of acrylic acid, 1.2 parts of epoxidized polybutadiene, 1.5 parts of trimethylolpropane triacrylate, 0.5 part of divinylbenzene, and 0.2 part of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (7) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (8)>
(Formation of second coating layer)
500 parts of mineral spirits were added to the aluminum pigment 3 coated with silica obtained with the coated pigment (4) and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.8 parts acrylic acid, 15.1 parts epoxidized polybutadiene, 18.9 parts trimethylolpropane triacrylate, 6.8 parts divinylbenzene, and 2.8 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (8) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (9)>
(Formation of second coating layer)
500 parts of mineral spirits were added to the aluminum pigment 3 coated with silica obtained with the coated pigment (4) and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.1 part of acrylic acid, 1.4 parts of epoxidized polybutadiene, 1.8 parts of trimethylolpropane triacrylate, 0.6 part of divinylbenzene, and 0.3 part of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (9) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (10)>
(Formation of second coating layer)
To the aluminum pigment 1 coated with silica obtained with the coated pigment (1), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.3 parts acrylic acid, 5.8 parts epoxidized polybutadiene, 7.3 parts trimethylolpropane triacrylate, 2.6 parts divinylbenzene, and 1.1 parts azobisisobutyronitrile are added, Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (10) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (11)>
(Formation of second coating layer)
500 parts of mineral spirits were added to the aluminum pigment 3 coated with silica obtained with the coated pigment (4) and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.3 parts of acrylic acid, 6.8 parts of epoxidized polybutadiene, 8.5 parts of trimethylolpropane triacrylate, 3.0 parts of divinylbenzene, and 1.3 parts of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
Thus, a coated pigment (11) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (a)>
(Formation of the first coating layer)
To 500 parts of methanol, 154 parts (100 parts as aluminum content) of an aluminum pigment (Showa Aluminum Co., Ltd. product number 2173, solid content 65%) was added and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 10 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110 ° C. for 3 hours to obtain an aluminum pigment 4 coated with silica.

(Formation of second coating layer)
To the aluminum pigment 4 coated with silica, 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.5 parts acrylic acid, 9.4 parts epoxidized polybutadiene, 11.7 parts trimethylolpropane triacrylate, 4.2 parts divinylbenzene, and 1.8 parts azobisisobutyronitrile are added, 80 Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (a) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (b)>
(Formation of second coating layer)
To the aluminum pigment 4 coated with silica obtained with the coated pigment (a), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.1 part of acrylic acid, 2.0 parts of epoxidized polybutadiene, 2.5 parts of trimethylolpropane triacrylate, 0.9 part of divinylbenzene, and 0.4 part of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (b) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (c)>
(Formation of the first coating layer)
To 500 parts of methanol, 154 parts (100 parts as aluminum content) of an aluminum pigment (Showa Aluminum Co., Ltd. product number 2173, solid content 65%) was added and stirred at 60 ° C. for 1.5 hours. Thereafter, ammonia was added to the slurry to adjust the pH value of the slurry to 8.0. Next, 40 parts of tetraethoxysilane was added to the pH-adjusted slurry, and the mixture was further stirred at 60 ° C. for 5 hours. Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 110 ° C. for 3 hours to obtain an aluminum pigment 5 coated with silica.

(Formation of second coating layer)
To the aluminum pigment 5 coated with silica, 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Then 0.6 parts acrylic acid, 11.9 parts epoxidized polybutadiene, 14.9 parts trimethylolpropane triacrylate, 5.4 parts divinylbenzene, and 2.2 parts azobisisobutyronitrile are added, 80 Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (c) having a first coating layer and a second coating layer was obtained.

<Preparation of coated pigment (d)>
(Formation of second coating layer)
To the aluminum pigment 5 coated with silica obtained with the coated pigment (c), 500 parts of mineral spirit was added and stirred, and the temperature was raised to 80 ° C. while flowing nitrogen gas. Next, 0.1 part of acrylic acid, 2.5 parts of epoxidized polybutadiene, 3.1 parts of trimethylolpropane triacrylate, 1.1 parts of divinylbenzene, and 0.5 parts of azobisisobutyronitrile are added. Polymerization was carried out at 5 ° C. for 5 hours.
Thereafter, the slurry was filtered, and the resulting slurry containing the coated aluminum pigment was dried at 150 ° C. for 3 hours.
In this way, a coated pigment (d) having a first coating layer and a second coating layer was obtained.

[Example 1]
<Synthesis of binder resin>
Dimethyl adipate: 74 parts Dimethyl terephthalate: 192 parts Bisphenol A ethylene oxide adduct: 216 parts Ethylene glycol: 38 parts Tetrabutoxy titanate (catalyst): 0.037 parts
The above components are placed in a heat-dried two-necked flask, and nitrogen gas is introduced into the container and heated while stirring in an inert atmosphere, and then subjected to a copolycondensation reaction at 160 ° C. for 7 hours, and then gradually up to 10 Torr. The temperature was raised to 220 ° C. while reducing the pressure to 4 hours. Once the pressure was returned to normal pressure, 9 parts of trimellitic anhydride was added, the pressure was gradually reduced to 10 Torr, and maintained at 220 ° C. for 1 hour to synthesize a binder resin.
The glass transition temperature (Tg) of the binder resin is 10 ° C. from a room temperature (25 ° C.) to 150 ° C. using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-50) in accordance with ASTM D3418-8. It was determined by measuring under the conditions of / min. The glass transition temperature was the temperature at the intersection of the extended line of the base line and the rising line in the endothermic part. The glass transition temperature of the binder resin was 63.5 ° C.

<Preparation of resin particle dispersion>
・ Binder resin: 160 parts ・ Ethyl acetate: 233 parts ・ Sodium hydroxide aqueous solution (0.3N): 0.1 part The above ingredients were placed in a 1000 ml separable flask and heated at 70 ° C. A resin mixed solution was prepared by stirring with Science Co., Ltd. While this resin mixture was further stirred at 90 rpm, 373 parts of ion-exchanged water was gradually added to effect phase inversion emulsification and solvent removal to obtain a resin particle dispersion (solid content concentration: 30%).

<Preparation of release agent dispersion>
Carnauba wax (Toa Kasei Co., Ltd., RC-160): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 1.0 parts Ion-exchanged water: 200 parts The above mixture was mixed and heated to 95 ° C. and dispersed using a homogenizer (Ultra Tarax T50, manufactured by IKA), and then subjected to a dispersion treatment for 360 minutes with a Manton Gorin high-pressure homogenizer (Gorin), followed by a release agent. A release agent dispersion liquid (solid content concentration: 20%) prepared by dispersing particles was prepared.

<Preparation of coating pigment dispersion>
・ Coating pigment (1): 100 parts ・ Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R): 1.5 parts ・ Ion-exchanged water: 900 parts Coated pigment dispersion (solid content concentration: 10%) prepared by dispersing a metal pigment (aluminum pigment) by dispersing for 1 hour using CR1010).

<Production of toner>
-Coated pigment dispersion: 400 parts-Resin particle dispersion: 375 parts-Release agent dispersion: 50 parts The above components are placed in a 2 L cylindrical stainless steel container, and 4000 rpm by a homogenizer (IKA, Ultra Lalux T50). The mixture was dispersed and mixed for 10 minutes while applying a shearing force. Next, 1.75 parts of a 10% nitric acid aqueous solution of polyaluminum chloride as a flocculant was gradually added dropwise, and the homogenizer was rotated at 5000 rpm for 15 minutes and mixed to obtain a raw material dispersion.

Thereafter, the raw material dispersion was transferred to a polymerization vessel equipped with a stirring device using two paddle stirring blades for forming a laminar flow, and a thermometer, and started to be heated with a mantle heater at a stirring speed of 1000 rpm. The growth of aggregated particles was promoted at 54 ° C. At this time, the pH of the raw material dispersion was controlled in the range of 2.2 to 3.5 with 0.3N nitric acid or 1N sodium hydroxide aqueous solution. The agglomerated particles were formed by maintaining the above pH range for 2 hours. At this time, the volume average particle diameter of the aggregated particles measured using Multisizer II (aperture diameter: 50 μm, manufactured by Coulter) was 10.4 μm.
Next, 125 parts of a resin particle dispersion was additionally added, and the resin particles of the binder resin were adhered to the surface of the aggregated particles. The temperature was further raised to 56 ° C., and aggregated particles were prepared while confirming the size and form of the particles with an optical microscope and Multisizer II. Thereafter, the pH was raised to 8.0 in order to fuse the aggregated particles, and then the temperature was raised to 67.5 ° C. After confirming that the aggregated particles were fused with an optical microscope, the pH was lowered to 6.0 while maintaining at 67 ° C., and the heating was stopped after 1 hour, followed by cooling at a rate of temperature decrease of 1.0 ° C./min. Thereafter, it was sieved with a 40 μm mesh, washed repeatedly with water, and then dried with a vacuum dryer to obtain toner particles. The obtained toner particles had a volume average particle diameter of 12.2 μm.

  Using a sample mill, 100 parts of toner particles are mixed with 1.5 parts of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., RY50) and 1.0 part of hydrophobic titanium oxide (manufactured by Nippon Aerosil Co., Ltd., T805) at 10,000 rpm. And blended for 30 seconds. Thereafter, the toner was prepared by sieving with a vibrating sieve having an opening of 45 μm.

  About the obtained toner, “ratio (A / B)”, “ratio of average maximum thickness C of toner particles to average equivalent circle diameter D (C / D)”, and “thickness direction of toner particles” The number of pigment particles in which the angle between the major axis direction of the toner particles and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° among all the pigment particles observed when the cross section is observed. (Hereinafter referred to as “the number of pigment particles in the range of ± 30 °”) was measured by the method described above.

<Creation of carrier>
Ferrite particles (volume average particle diameter: 35 μm): 100 parts Toluene: 14 parts Perfluoroacrylate copolymer (critical surface tension: 24 dyn / cm): 1.6 parts Carbon black (trade name: VXC-72 Manufactured by Cabot Corporation, volume resistivity: 100 Ωcm or less): 0.12 parts Cross-linked melamine resin particles (average particle size: 0.3 μm, toluene insoluble): 0.3 parts

  First, carbon black was diluted in toluene and added to a perfluoroacrylate copolymer and dispersed with a sand mill. Next, each of the above components other than the ferrite particles was dispersed for 10 minutes with a stirrer to prepare a coating layer forming solution. Next, this coating layer forming solution and ferrite particles are put in a vacuum degassing type kneader and stirred at a temperature of 60 ° C. for 30 minutes, and then the pressure is reduced to distill off toluene to form a resin coating layer to obtain a carrier. It was.

<Production of developer>
36 parts of the toner and 414 parts of the carrier were put in a 2 liter V blender, stirred for 20 minutes, and then sieved at 212 μm to prepare a developer.

[Examples 2 to 9, Comparative Examples 1 to 4]
A toner and a developer were prepared in the same manner as in Example 1 except that the coated pigment (1) in the coated pigment dispersion in Example 1 was replaced with the coated pigment described in Table 1 below.
Further, for the obtained toner, “ratio (A / B)”, “ratio of average maximum thickness C of toner particles to average equivalent circle diameter D (C / D)”, and “thickness direction of toner particles” Of all the observed pigment particles, the angle between the major axis direction of the toner particles and the major axis direction of the pigment particles is in the range of -30 ° to + 30 °. (Hereinafter referred to as “the number of pigment particles in the range of ± 30 °”) ”was measured by the method described above.

[Evaluation Test 1: Evaluation of Transferability]
Transferability of the obtained developer was evaluated using a modified DocuCentre-III C7600 manufactured by Fuji Xerox Co., Ltd. The remodeling machine forcibly stops the machine before toner transfer so that the amount of toner on the photoconductor, intermediate transfer body, and paper (unfixed) can be measured. Further, the surface temperature of the fixing roll is 130 ° C.
For evaluation of transferability, a 5 cm × 5 cm patch was drawn using C2 paper manufactured by Fuji Xerox Co., Ltd. in an environment of 30 ° C. and 80% RH, and each toner weight after 10,000 sheets was measured. Efficiency and secondary transfer efficiency were calculated. In addition, an acceptable level was obtained by multiplying the primary transfer efficiency and the secondary transfer efficiency by 85% or more.

Primary transfer efficiency = (toner weight on intermediate transfer member) / (toner weight on photoreceptor)
Secondary transfer efficiency = (weight of unfixed toner on paper) / (weight of toner on intermediate transfer member)
Transferability (transfer efficiency) = (primary transfer efficiency) × (secondary transfer efficiency) × 100

Evaluation criteria for transferability (transfer efficiency) are as follows. The results are shown in Table 1.
G4: Transfer efficiency 95% or more G3: Transfer efficiency 90% or more and less than 95% G2: Transfer efficiency 85% or more and less than 90% G1: Transfer efficiency 85% or less

[Evaluation Test 2: Evaluation of Image Brightness]
An evaluation image was formed by the following method.
The obtained developer was filled in a developing unit of Docu Center Color 400 manufactured by Fuji Xerox Co., Ltd., and left for 24 hours in an environment of 30 ° C. temperature and 80% humidity. Thereafter, a solid image (toner applied amount 4.5 g / m ² ) of 1 cm × 10 cm was produced on recording paper (OK top coat + paper, manufactured by Oji Paper Co., Ltd.), fixing temperature 190 ° C., fixing pressure 10,000 images were continuously formed at 4.0 kg / cm ² and a process speed of 308 mm / s.
The brightness of the obtained 10,000th image was visually confirmed based on the following criteria. The evaluation results are shown in Table 1.
G4: No problem with the glitter is confirmed.
G3: Slightly inferior in glitter. Or a slight darkening can be confirmed.
G2: The glitter is inferior. Or darkening can be confirmed, but it is within the allowable range.
G1: Inferior luster or darkening is unacceptable.

As apparent from Table 1 above, the developer of the example containing the toner having an element ratio Mb / Ma in the range of 0.02 to 0.80 has a lower transferability than the developer of the comparative example. It can be seen that the brightness of the image is excellent and the brightness of the image is excellent.
In particular, it can be seen that when the coating amount of the second coating layer is 5% by mass or more and 20% by mass or less, deterioration of transferability is suppressed and both the brightness of the image is excellent.

2 toner particles 4 coated pigment particles 15 cleaning device 17 primary transfer roll (an example of (primary) transfer means)
19 Exposure apparatus (an example of electrostatic charge image forming means)
20 Developing device (an example of developing means)
21 photoconductor (an example of an image carrier)
22 Driving roll 23 Support roll 24 Bias roll 26 Belt cleaner 28 Charging roll (an example of charging means)
33 Intermediate transfer belt 34 Secondary transfer roll (an example of (secondary) transfer means)
35 Fixing device (an example of fixing means)
40 toner cartridge 50 image forming unit

Claims (7)

A first coating layer formed of at least one metal oxide selected from the group consisting of silica, alumina, and titania, coated on the surface of the metal pigment; and the first coating layer A coating pigment having a second coating layer containing a resin, the surface of which is coated without a covalent bond ,
An electrostatic charge image in which the element ratio Mb / Ma measured using a fluorescent X-ray analyzer between the metal Ma in the metal pigment and the metal Mb in the first coating layer is 0.08 or more and 0.20 or less. Developing toner.   2. The electrostatic image developing toner according to claim 1, wherein in the coating pigment, the coating amount of the second coating layer is 5% by mass or more and 30% by mass or less with respect to the mass of the metal pigment.   An electrostatic charge image developer comprising the toner for developing an electrostatic charge image according to claim 1. Containing the toner for developing an electrostatic image according to claim 1;
A toner cartridge to be attached to and detached from the image forming apparatus. A developing unit that contains the electrostatic charge image developer according to claim 3 and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer.
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
A developing means for containing the electrostatic charge image developer according to claim 3 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 3;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: