JP2015052740A - Toner for electrostatic charge image development, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development that can form images with excellent brightness even after the provision of a physical load.SOLUTION: A toner for electrostatic charge image development includes toner particles and wet method silica. When a solid image is formed with the toner, a ratio between a reflectance A at an incident angle of +30° and a reflectance B at an incident angle of -30° (A/B) is 2 or more and 100 or less, which is measured in the case where the image is irradiated with incident light at an incident angle of -45° by a goniophotometer.

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 Documents 1 to 7, when a solid image is formed, which has an effect that an image having excellent glitter can be formed, an incident angle of −45 ° is incident on the image by a goniophotometer. A toner having a ratio (A / B) of a reflectance A at a light receiving angle of + 30 ° and a reflectance B at a light receiving angle of −30 ° (A / B) measured when irradiated with light of 2 to 100 is disclosed. .
Further, Patent Document 8 discloses a toner that indicates the ratio of toner particles that do not contain a luster pigment in the toner that exhibits luster as a whole.
Further, Patent Document 9 discloses a toner that uses a flat pigment and indicates the number of pigments contained in the toner particles and the ratio thereof.

JP 2012-032765 A JP 2013-117597 A JP 2013-113995 A JP 2012-068522 A JP 2012-042624 A JP 2012-032764 A JP 2012-022156 A JP 2013-073017 A JP 2010-256613 A

  An object of the present invention is to provide a toner for developing an electrostatic image that can form an image having excellent glitter even after a physical load is applied.

Specific means for solving the above problems are as follows.
That is, the invention according to claim 1
Toner particles and wet process silica,
When a solid image is formed, the reflectance A at a light receiving angle of + 30 ° and a light receiving angle at −30 ° are measured when the image is irradiated with incident light having an incident angle of −45 ° by a goniophotometer. The toner for developing an electrostatic charge image has a ratio (A / B) with a reflectance B of 2 or more and 100 or less.

The invention according to claim 2
2. The electrostatic image developing toner according to claim 1, wherein the wet method silica is sol-gel method silica.

The invention according to claim 3
The electrostatic image developing toner according to claim 1, wherein the wet-process silica is monodispersed and spherical.

The invention according to claim 4
The electrostatic image development according to any one of claims 1 to 3, wherein in the wet process silica, a ratio of particles having a particle diameter exceeding 100 nm to all particles is 50% by number or more and 100% by number or less. Toner.

The invention according to claim 5
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

The invention according to claim 6
Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 4,
The toner cartridge is detachable from the image forming apparatus.

The invention according to claim 7 provides:
A developing means for containing the electrostatic charge image developer according to claim 5 and developing 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 8 provides:
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;
Developing means for containing the electrostatic charge image developer according to claim 5 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 9 is:
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 image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
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 according to claim 1, after satisfying the value of the ratio (A / B), after applying a physical load as compared with the case where dry process silica is contained or no external additive is used. Even so, an electrostatic charge image developing toner capable of forming an image excellent in glitter is provided.
According to the second aspect of the invention, compared to the case where the wet process silica is not the sol-gel process silica, the electrostatic image development capable of forming an image having excellent glitter even after the physical load is applied. Toner is provided.
According to the third aspect of the present invention, compared to the case where the wet process silica is polydispersed or deformed, a static image capable of forming an image excellent in glitter even after a physical load is applied. A charge image developing toner is provided.
According to the invention according to claim 4, it is possible to form an image excellent in glitter even after the physical load is applied, compared with the case where the particle size distribution of the wet process silica is out of the above range. An electrostatic charge image developing toner is provided.

According to the invention of claim 5, the physical load is satisfied as compared with the case of using a toner containing dry process silica or not using an external additive while satisfying the value of the ratio (A / B). There is provided an electrostatic charge image developer capable of forming an image having excellent glitter even after the application of.
According to the invention of claim 6, after satisfying the value of the ratio (A / B), after applying a physical load as compared with the case where dry process silica is contained or no external additive is used. Even so, a toner cartridge containing an electrostatic charge image developing toner capable of forming an image excellent in glitter is provided.
According to the invention of claim 7, after satisfying the value of the ratio (A / B), after applying a physical load as compared with the case where dry process silica is included or no external additive is used. Even so, there is provided a process cartridge that accommodates toner for developing an electrostatic image capable of forming an image excellent in glitter.
According to the invention according to claim 8, after satisfying the value of the ratio (A / B), after applying a physical load as compared with the case where dry process silica is included or no external additive is used. Even so, an image forming apparatus using an electrostatic image developing toner capable of forming an image excellent in glitter is provided.
According to the invention according to claim 9, after satisfying the value of the ratio (A / B), after applying a physical load as compared with the case where dry process silica is included or no external additive is used. Even so, an image forming method using an electrostatic image developing toner capable of forming an image excellent in glitter is provided.

FIG. 3 is a cross-sectional view schematically illustrating a toner for developing an electrostatic charge image according to the exemplary embodiment. It is a figure explaining the state of a screw about an example of a screw extruder used for manufacture of toner for electrostatic image development concerning this 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 toner particles and wet method silica, and forms a solid image when the solid image is formed. Ratio of reflectance A at a light receiving angle of + 30 ° and reflectance B 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 (A / B) is a toner for developing electrostatic images having a value of 2 or more and 100 or less.

The toner for developing an electrostatic charge image according to the exemplary embodiment can form an image having excellent glitter even after a physical load is applied.
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.

In the case of using a toner containing a glitter pigment as a colorant, it is desirable to efficiently arrange the glitter pigment on the recording medium in order to obtain an image exhibiting sufficient glitter.
From such a viewpoint, the particle diameter is large and the shape is flat and includes a flat luster pigment. Using flat toner particles, the size of the contact area depending on the shape of the particles is used to determine the longitudinal direction of the toner particles. A technique has been adopted in which an image having sufficient glitter is obtained by arranging the recording medium so as to face the surface of the recording medium.
However, in the case of toner particles containing bright pigments, one end in the longitudinal direction of the toner particles selectively adheres to the surface of the recording medium in spite of a small contact area in an environment where the physical load from the outside is strong. However, it has been found that if the toner particles come out so that the longitudinal direction of the toner particles intersects the surface of the recording medium, the brightness of the image may be lowered.

The following may be considered as a mechanism in which the above phenomenon occurs.
Generally, the surface state of the toner particles is an important factor that determines the contact state of the toner particles with other members such as the surface of the recording medium. For example, when the external additive is present on the surface of the toner particle, the toner particle comes into contact with the other member through the external additive, so that the contact area of the toner particle with respect to the other member is reduced. Accordingly, both the non-electrostatic adhesion force and the electrostatic adhesion force of the toner particles are reduced.
In the case of flat toner particles containing a bright pigment, when a physical load is applied from the outside, a large load is applied to the end portion in the longitudinal direction due to the shape. At this time, the external additive existing at the end of the toner particle in the longitudinal direction progresses to be buried, and the contact area between the toner particle and the other member at the end increases compared to that before the external additive is buried. Therefore, both the non-electrostatic adhesion force and the electrostatic adhesion force increase. As a result, one end in the longitudinal direction of the toner particles having increased adhesion force selectively adheres to the surface of the recording medium, so that the arrangement in which the longitudinal direction of the toner particles faces the surface of the recording medium is disturbed and glossy. It is considered that the arrangement of the pigment itself is disturbed, and the brightness of the image is lowered.

The wet process silica as an external additive in the toner for developing an electrostatic charge image according to the present embodiment is a silica having a relatively high water content and easily leaks charges due to low resistance, and is derived from a material such as silica. The adhesive force on the toner particle surface is relatively low and the toner particle surface is easy to flow. For this reason, in the case of an electrostatic charge image developing toner containing wet method silica as an external additive, like the toner according to the present embodiment, some wet method silica is applied after an external physical load is applied. Even after non-electrostatic adhesion and increase in electrostatic adhesion occur after being buried, wet-process silica flows selectively from other parts of the surface of the toner particles selectively to the part where the adhesion is increased. I think it will come. In the place where the wet-process silica that has flowed is present, the contact area with respect to other members becomes small, the electric charge leaks, and the local increase in electric charge can be suppressed. Therefore, even when one end in the longitudinal direction of the toner particles is selectively attached to the surface of the recording medium, the wet process silica flows to the one end, so that the attached state is eliminated, It is considered that an arrangement state in which the longitudinal direction of the toner particles and the surface of the recording medium are arranged to face each other using the size of the contact area depending on the shape of the toner particles is considered.
As a result, in the case of the toner according to the exemplary embodiment, even after a physical load from the outside is applied, the wet process silica effectively functions as an external additive and has sufficient glitter. It is considered that an image can be obtained.

[Configuration of toner]
The toner according to this embodiment has a configuration including toner particles and wet silica.
Hereinafter, the wet process silica will be described first.

(Wet process silica)
In this embodiment, “wet process silica” is distinguished from gas phase process silica by the method of producing synthetic silica, and neutralizes sodium silicate with mineral acid or hydrolyzes alkoxysilane. Amorphous silica obtained by decomposing.
It is well known that wet-process silica is water-containing silica, that is, water-containing silica, because it undergoes the manufacturing process as described above.
The wet method silica is classified into precipitation method silica, gel method silica, and sol-gel method silica according to the production method.
In addition, the wet process silica used in the present embodiment preferably has a surface subjected to a hydrophobic treatment.

-Manufacture of wet process silica-
Hereinafter, the method for producing the wet process silica used in the present embodiment will be described by taking the sol-gel method as an example.
The sol-gel method, which is a wet method, is preferable because monodispersed and spherical silica particles (hereinafter referred to as “monodispersed spherical silica particles”) are produced. Note that the method for producing monodispersed spherical silica particles is not limited to this sol-gel method.
The particle diameter of the monodispersed spherical silica particles can be freely controlled by the weight ratio of alkoxysilane, ammonia, alcohol, water in the sol-gel method, condensation polymerization step, reaction temperature, stirring rate, and supply rate.

Hereinafter, a method for producing monodispersed spherical silica particles by the sol-gel method will be specifically described.
That is, tetramethoxysilane is dropped and stirred while applying temperature using ammonia water as a catalyst in the presence of water and alcohol. Next, the desired monodispersed spherical silica particles are obtained by removing the solvent from the silica sol suspension obtained by the reaction and drying.
Thereafter, the obtained monodispersed spherical silica particles are subjected to a hydrophobic treatment as necessary.

In addition, when producing monodispersed spherical silica particles by the sol-gel method, the surface of the silica particles may be hydrophobized at the same time.
In this case, as described above, the silica sol suspension obtained by the reaction is centrifuged and separated into wet silica gel, alcohol and aqueous ammonia, and then the solvent is added to the wet silica gel to form a silica sol again. A hydrophobizing agent is added to hydrophobize the surface of the silica particles. Next, the target monodispersed spherical silica particles are obtained by removing the solvent from the hydrophobized silica sol and drying it.
In addition, the monodispersed spherical silica particles thus obtained may be subjected to a hydrophobic treatment again.

Examples of the hydrophobizing agent used for the hydrophobizing treatment on the silica particle surface as described above include general organosilicon compounds.
Specific examples include known organosilicon compounds having an alkyl group (for example, a methyl group, an ethyl group, a propyl group, a butyl group, etc.), and specific examples include, for example, a silane compound (for example, a methyltrimethyl group). Methoxysilane, dimethyldimethoxysilane, trimethylchlorosilane, trimethylmethoxysilane, etc.) and silazane compounds (for example, hexamethyldisilazane, tetramethyldisilazane, etc.).
Among these hydrophobizing agents, hexamethyldisilazane is preferable because it is excellent in reactivity with the hydroxyl group on the surface of the silica particles.
The hydrophobizing agent may be used alone or in combination.

Hydrophobizing treatment on the surface of silica particles includes a dry method such as a spray drying method in which a silica particle suspended in a gas phase is sprayed with a hydrophobizing agent or a solution containing a hydrophobizing agent, or a hydrophobizing treatment. A wet method in which silica particles are immersed in a solution containing an agent and drying, or a mixing method in which a hydrophobizing agent and silica particles are mixed with a mixer may be employed.
In addition, after the hydrophobization treatment on the surface of the silica particles, a step of washing the silica particles with a solvent to remove the remaining hydrophobizing agent and low-boiling residue may be added.

When hydrophobizing the surface of the silica particles, the number of hydroxyl groups present on the surface of the silica particles is reduced as much as possible, and a nearly uniform surface treatment layer is formed to suppress aggregation of the silica particles due to hydrogen bonding between the hydroxyl groups. Dispersed silica particles are easily obtained. From this viewpoint, it is preferable to improve the reactivity between the surface of the silica particles and the hydrophobizing agent.
In order to improve the reactivity between the surface of the silica particles and the hydrophobizing agent, for example, (1) a method of adjusting the pH of the hydroxyl groups on the silica particles to increase the reactivity of the hydroxyl groups can be mentioned. By adjusting the pH by this method, contamination (foreign matter, impurities) on the surface of the silica particles can be removed, so that the reaction between the hydroxyl group and the hydrophobizing agent can be further improved.
In addition, when hydrophobizing the silica particle surface, (2) lowering the temperature during hydrophobing, reducing the concentration of the hydrophobizing agent, adding a low-boiling alcohol solvent, reducing the stirring speed, etc. It is also effective in reducing the reactivity of the hydrophobizing agent to increase the reaction uniformity between the silica particle surface and the hydrophobizing agent, in order to obtain a nearly uniform surface treatment layer.

  As described above, according to the hydrophobization treatment in which the surface of the silica particles is reacted with the hydroxyl group and the hydrophobizing agent, the aggregation of the silica particles due to the hydroxyl group is suppressed and a physical load from the outside is applied. Occasionally, the hydrophobic treatment layer can be prevented from peeling off (that is, the hydrophobic treatment layer is a layer having excellent resistance to rubbing stress). As a result, even when a physical load is applied from the outside, the function of the hydrophobized layer is maintained, and the monodispersed state continues, and the wet process silica is used as an external additive. The effects described above will be sufficiently exhibited.

In this embodiment, the wet process silica is preferably sol-gel process silica from the viewpoint that silica having a relatively high water content is obtained and charge leakage is easy.
As described above, the sol-gel silica is preferable because it can be easily granulated into a spherical shape due to the production method.

In this embodiment, monodispersed and spherical silica is preferable as the wet process silica from the viewpoint that the adhesion force of the toner particles to the surface is low and the fluidity of the surface is high.
As described above, the sol-gel silica is preferable because it can be easily monodispersed and spherically granulated due to the production method.

Here, “monodisperse” in the present embodiment can be discussed as a standard deviation with respect to the average particle diameter including aggregates, and the standard deviation is preferably number average particle diameter × 0.22 or less.
In addition, the “spherical shape” in the present embodiment refers to an average circularity shown below that is 0.81 or more (preferably 0.9 or more).

Measurement of average circularity The circularity of the wet process silica, which is an external additive, is obtained by observing primary particles of the external additive after adding the external additive to the toner particles with a SEM apparatus at a magnification of 40000 times. It is obtained as “100 / SF2” calculated by the following formula from image analysis using the obtained primary particle image processing analysis software WinRof (Mitani Corporation).
Circularity (100 / SF2) = 4π × (A / I ² )
[In the formula, I represents the perimeter of the primary particles of the external additive on the image, and A represents the projected area of the primary particles of the external additive. SF2 represents a shape factor. ]
The average circularity of the external additive (wet process silica) is obtained as 50% circularity in the cumulative frequency of the equivalent circle diameter of 100 primary particles obtained by the image analysis.

In this embodiment, the particle diameter of the wet process silica is preferably 30 nm to 300 nm (desirably 50 nm to 200 nm, more desirably 80 nm to 150 nm) in terms of number average particle diameter.
In the present embodiment, the wet-process silica has a ratio of particles having a particle diameter of more than 100 nm to 50% by number or more and 100% by number or less (more preferably 70% by number or more and 100% by number or less, more preferably, of all particles. 80% by number or more and 100% by number or less) is desirable. That is, in this embodiment, it is preferable that many wet process silicas with a diameter exceeding 100 nm are contained. This is because particles having a larger diameter have lower adhesion to the surface of the toner particles and higher fluidity on the surface.
In the case of the sol-gel method, the particle diameter of the wet process silica is freely controlled by the weight ratio of alkoxysilane, ammonia, alcohol, water in the hydrolysis and condensation polymerization processes, the reaction temperature, the stirring speed, and the supply speed as described above. be able to.
The particle size and particle size distribution of the wet process silica were measured as follows.

・ Measurement of particle size and particle size distribution The particle size of the wet method silica, which is an external additive, was measured by observing the primary particles of the external additive after adding the external additive to the toner particles at a magnification of 40000 with a SEM apparatus. Obtained from image analysis using the obtained primary particle image processing analysis software WinRoof (Mitani Corporation).
In addition, the ratio of particles having a particle diameter exceeding 100 nm in the total particles is obtained by calculating the equivalent circle diameter from the analyzed image, and in the cumulative frequency of the equivalent circle diameter, the ratio (number%) of particles having a diameter of 100 nm or more. Is calculated.
In addition, the standard deviation with respect to the average particle diameter including the aggregates, which defines “monodisperse”, is also calculated using the above particle size distribution.

The addition amount of the wet process silica as described above is preferably in the range of 0.1 to 5 parts by mass, and in the range of 0.3 to 2 parts by mass with respect to 100 parts by mass of the toner particles. More desirably, the range of 1 part by mass or more and 2 parts by mass or less is further desirable.
In the toner according to the exemplary embodiment, in addition to the wet process silica, other particles such as an inorganic oxide, a charge control agent, an organic particle, a lubricant, and an abrasive may be added as an external additive.

(Toner particles)
Next, toner particles will be described.
The toner particles in the present embodiment preferably include other additives such as a release agent, if necessary, in addition to the bright pigment and the binder resin.

-Bright pigment-
As the bright pigment used in the present embodiment, for example, metal powder such as aluminum, brass, bronze, nickel, stainless steel, and zinc is used.
The surface of the metal powder may be coated with silica, acrylic resin, polyester resin or the like.

  The content of the glitter pigment in the toner particles 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 an amorphous 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 can be produced by a known production 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.

[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 required to be 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, and further preferably 60 or more and 90 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 top coat + paper, manufactured by Oji Paper Co., Ltd.). 190 ° C., at fusing pressure 4.0 kg / cm ^2, the amount of applied toner to form a solid image of 4.0 g / 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.

[Preferred embodiment of toner]
(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 the thickness L, and contains scale-like pigment particles 4 (corresponding to a bright 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 a 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.
Therefore, among the scale-like pigment particles contained in the toner particles, “the angle between the major axis direction in the cross section of the toner particles and the major axis direction of the pigment particles is −30 ° to +30” shown in (2) above. It is considered that the pigment particles satisfying the requirement “in the range of °” 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 more, 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 wet silica as an external additive to the toner particles after the toner particles are manufactured.
The method for producing the toner particles is not particularly limited, and the toner particles are produced by a known dry method such as a kneading / pulverizing method or a wet method such as an emulsion aggregation method or a dissolution suspension method.

(Kneading and grinding method)
The kneading and pulverization method involves mixing each material such as a luster pigment, then melt-kneading the above materials using a kneader, an extruder, etc., roughly pulverizing the obtained melt-kneaded material, a jet mill, etc. And obtaining toner particles having a target particle size with an air classifier.
More specifically, the kneading and pulverizing method is divided into a kneading step for kneading a toner forming material containing a glitter pigment and a binder resin, and a pulverizing step for pulverizing the kneaded product. You may have other processes, such as a cooling process which cools the kneaded material formed by the kneading process as needed.
Below, each process which concerns on the kneading | mixing and the grinding | pulverization method is demonstrated in detail.

-Kneading process-
In the kneading step, a toner forming material containing a luster pigment, a binder resin, and a release agent, if necessary, is kneaded.
In the kneading process, 0.5 to 5 parts by mass of an aqueous medium (for example, water such as distilled water or ion-exchanged water, alcohols, or the like) may be added to 100 parts by mass of the toner forming material. desirable.

  Examples of the kneader used in the kneading process include a single screw extruder, a twin screw extruder, and the like. Hereinafter, as an example of a kneading machine, a kneading machine having a feed screw part and two kneading parts will be described with reference to the drawings, but the invention is not limited thereto.

FIG. 2 is a diagram for explaining a screw state of an example of a screw extruder used in a kneading process in the toner manufacturing method according to the present embodiment.
The screw extruder 11 includes a barrel 12 having a screw (not shown), an inlet 14 for injecting a toner forming material as a raw material of the toner into the barrel 12, and an aqueous medium added to the toner forming material in the barrel 12. A liquid addition port 16 for discharging the toner, and a discharge port 18 for discharging the kneaded material formed by kneading the toner forming material in the barrel 12.

  The barrel 12 has a feed screw portion SA for transporting the toner forming material injected from the injection port 14 to the kneading portion NA in order from the side closer to the injection port 14, and the toner forming material is melt-kneaded by the first kneading process. A kneading part NA, a feed screw part SB for transporting the toner forming material melted and kneaded in the kneading part NA to the kneading part NB, and the toner forming material is melted and kneaded in a second kneading process. It is divided into a kneading part NB that forms the smelted product and a feed screw part SC that transports the formed kneaded product to the discharge port 18.

  The barrel 12 is provided with temperature control means (not shown) that is different for each block. That is, the temperature may be controlled at different temperatures from the block 12A to the block 12J. FIG. 2 shows a state in which the temperature of the block 12A and the block 12B is controlled to t0 ° C., the temperature of the block 12C to the block 12E is controlled to t1 ° C., and the temperature of the block 12F to the block 12J is controlled to t2 ° C. Yes. Therefore, the toner forming material of the kneading part NA is heated to t1 ° C., and the toner forming material of the kneading part NB is heated to t2 ° C.

  When a toner forming material including a binder resin, a bright pigment, and a release agent as necessary is supplied from the injection port 14 to the barrel 12, the toner forming material is sent to the kneading portion NA by the feed screw portion SA. . At this time, since the temperature of the block 12C is set to t1 ° C., the toner forming material is fed into the kneading portion NA in a state of being heated and changed into a molten state. Since the temperatures of the block 12D and the block 12E are also set to t1 ° C., the toner forming material is melted and kneaded at the temperature of t1 ° C. in the kneading portion NA. The binder resin and the release agent are in a molten state at the kneading portion NA and are subjected to shearing by the screw.

Next, the toner forming material that has been kneaded in the kneading part NA is sent to the kneading part NB by the feed screw part SB.
Then, in the feed screw portion SB, the aqueous medium is added to the toner forming material by injecting the aqueous medium into the barrel 12 from the liquid addition port 16.
Further, FIG. 2 shows a mode in which the aqueous medium is injected in the feed screw part SB, but the present invention is not limited to this, and the aqueous medium may be injected in the kneading part NB, and the feed screw part SB and the kneading part. An aqueous medium may be injected in both NBs. That is, the position and the injection location for injecting the aqueous medium are selected as necessary.

As described above, when the aqueous medium is injected into the barrel 12 from the liquid addition port 16, the toner forming material and the aqueous medium in the barrel 12 are mixed, and the toner forming material is cooled by the latent heat of vaporization of the aqueous medium. The temperature of the toner forming material is maintained.
Finally, the kneaded material formed by being melted and kneaded by the kneading part NB is transported to the discharge port 18 by the feed screw part SC and discharged from the discharge port 18.
As described above, the kneading process using the screw extruder 11 shown in FIG. 2 is performed.

-Cooling process-
The cooling step is a step of cooling the kneaded product formed in the kneading step. In the cooling step, the cooling temperature is 40 ° C. at an average temperature decrease rate of 4 ° C./sec or more from the temperature of the kneaded product at the end of the kneading step. It is preferable to cool to below. When the cooling rate of the kneaded product is slow, the mixture finely dispersed in the binder resin in the kneading step (inner additives such as a bright pigment and a release agent that is internally added to the toner particles as necessary) May be recrystallized and the dispersion diameter may increase. On the other hand, quenching at the above average cooling rate is preferable because the dispersed state immediately after the end of the kneading process is maintained. In addition, the said average temperature-fall rate means the average value of the speed | rate to temperature-fall from the temperature of the kneaded material at the time of the completion | finish of a kneading process (for example, t2 degreeC when using the screw extruder 11 of FIG. 2) to 40 degreeC. .
Specific examples of the cooling method in the cooling step include a method using a rolling roll in which cold water or brine is circulated, a sandwiching cooling belt, and the like. When cooling is performed by the above method, the cooling rate is determined by the speed of the rolling roll, the flow rate of brine, the supply amount of the kneaded material, the slab thickness at the time of rolling the kneaded material, and the like. The slab thickness is preferably 1 mm or more and 3 mm or less.

-Crushing process-
The kneaded material cooled by the cooling process is pulverized by the pulverization process, and particles are formed. In the pulverization step, for example, a mechanical pulverizer or a jet pulverizer is used.

-Classification process-
The particles obtained by the pulverization step may be classified by a classification step in order to obtain toner particles having a volume average particle diameter in a target range, if necessary.
In the classification process, conventionally used centrifugal classifiers, inertia classifiers, etc. are used, and fine powder (particles smaller than the target range of particle diameter) and coarse powder (target range of particle diameter). Larger particles) are removed.

  The toner according to the exemplary embodiment can be obtained by externally adding a wet method silica to the toner particles obtained through the steps related to the kneading and pulverization method as described above by an external addition step described later.

(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 glitter 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 media, a sand mill, a dyno mill, an optimizer, etc. can be employed. There are no restrictions.
The glitter pigment is dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base. The dispersed pigment may have a volume average particle diameter of 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 glitter pigment in the toner is preferable without impairing the cohesiveness.
Also, a dispersion of the glitter pigment coated with the binder resin is prepared by dispersing and dissolving the glitter pigment and the binder resin in a solvent, mixing, and dispersing in water by phase inversion emulsification or shear emulsification. May be.

-Aggregation process-
In the agglomeration step, resin particle dispersion, glitter pigment dispersion, release agent dispersion, etc. are mixed to form a mixture, which is heated to agglomerate at a temperature below the glass transition temperature of the resin particles to form aggregated particles. To do. 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 glitter 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.

  The toner according to the exemplary embodiment can be obtained by externally adding wet silica to the toner particles obtained through the steps related to the emulsion aggregation method as described above by an external addition step described later.

(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 bright pigment, and a release agent used as necessary is dissolved or dispersed in a solvent in which the binder resin can be dissolved. Is added to an aqueous medium containing an inorganic dispersant, and the mixture is dispersed and suspended for granulation, and then the solvent is removed to obtain toner particles.
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, glitter 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 glitter pigment and other components. The glitter 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 easily granulated by the ratio of the binder resin, the luster pigment, and the other component-containing material (the former) to the solvent (the latter) This is preferable in terms of the final toner particle yield.

The binder resin, glitter pigment, and other component liquid (toner mother liquor) dissolved or dispersed in a solvent are prepared so as to have a predetermined particle size in an aqueous medium containing an inorganic dispersant. Grained. 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 can be obtained by dehydration and drying.

  The toner according to the exemplary embodiment can be obtained by externally adding wet silica to the toner particles obtained through the steps related to the dissolution suspension method as described above by an external addition step described later.

(External addition of wet method silica)
-External addition process-
External additives such as wet silica are externally added by, for example, a V-type blender, a Henschel mixer, a Redige mixer, or the like, and may be attached in stages.

-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 And a resin-dispersed carrier in which conductive particles are dispersed and blended in a matrix resin.
The magnetic powder dispersion type carrier, the resin impregnated type carrier, and the conductive particle dispersion type 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 oxide, 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 unit 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. 3 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. 3, the image forming apparatus according to this embodiment includes four image forming units 50Y, 50M, 50C, and 50K that form glittering images of yellow, magenta, cyan, and black, respectively, and a toner image. Image forming units 50B that form (brilliant images) are arranged 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. Further, the intermediate transfer belt 33 is held by three rolls of a drive roll 22, a support roll 23, and a bias roll 24, and is moved 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 and the retransferred toner are 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 means) 34 is pressed against the bias roll 24 that holds 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 silica particles 1)
Put 300 parts by mass of methanol and 49.6 parts by mass of 10% ammonia water in a 3 L glass reaction vessel with a metal stir bar, dripping nozzle (Teflon (registered trademark) micro tube pump), and thermometer. The mixture was stirred and mixed to obtain an alkali catalyst solution.
Next, the temperature of the alkali catalyst solution was adjusted to 28 ° C., and the alkali catalyst solution was purged with nitrogen. Thereafter, while stirring the alkali catalyst solution, 440 parts by mass of tetramethoxysilane (TMOS), 10 parts by mass of tetraethoxysilane, and 270 parts by mass of ammonia water having a catalyst (NH ₃ ) concentration of 4.44% are supplied as follows. An amount of silica particles was dropped simultaneously to obtain a suspension of silica particles (silica particle suspension).
Here, while stirring at 30 rpm, the supply amount of silanes was 2.60 parts by mass / min, and the supply amount of 4.44% ammonia water was 1.56 parts by mass / min. The temperature control at this time was performed at 27 ° C to 30 ° C.
Next, the obtained suspension of hydrophilic silica particles (hydrophilic silica particle dispersion) was dried by spray drying to remove the solvent to obtain hydrophilic silica particle powder.

Subsequently, 100 parts of the above powder was charged into a glass reaction vessel, 200 parts of distilled water was added and the pH was adjusted to 3.5 using sodium hydroxide and acetic acid, and then distilled off under reduced pressure using an evaporator. Thereto, 200 parts of toluene was added and stirred at 50 rpm, and 30 parts by mass of hexamethyldisilazane (HMDS) was added dropwise over 2 hours to the powder of hydrophilic silica particles, and 50 parts of ethanol was added to 1 part. After dropwise addition over time, the mixture was further stirred for 2 hours to be reacted. In addition, the liquid temperature at this time was 21 degreeC-25 degreeC. Then, after freeze-drying for about 60 hours with a centrifugal settling machine, a hydrophobic silica particle powder having a hydrophobic surface was obtained.
Thereby, the silica particle 1 was obtained.

(Preparation of silica particles 2)
In the production of the silica particles 1, the amount of silica 1 (TMOS) is 7.56 parts by mass / min, except that the amount of 4.44% ammonia water is 4.53 parts by mass / min. In the same manner as in the preparation, silica particles 2 were obtained.

(Preparation of silica particles 3)
In the production of the silica particles 1, the amount of 10% ammonia water used is 49.1 parts by mass, and the amount of silanes (TMOS) supplied is 2.60 parts by mass / min, and 4.44% ammonia water is supplied. Silica particles 3 were obtained in the same manner as in the preparation of silica particles 1 except that the amount was 1.56 parts by mass / min.

(Preparation of silica particles 4)
In the production of the silica particles 1, the amount of 10% ammonia water used is 48.4 parts by mass, and the amount of silanes (TMOS) supplied is 2.83 parts by mass / min, and 4.44% ammonia water is supplied. Silica particles 4 were obtained in the same manner as the preparation of silica particles 1 except that the amount was 1.70 parts by mass / min.

(Preparation of silica particles 5)
Using vapor-phase method silica (UFP-30, manufactured by Denki Kagaku Kogyo) with a number average particle diameter of 150 nm, the surface of this vapor-phase method silica was subjected to a hydrophobizing treatment with HMDS in the same manner as in the preparation of silica particles 1 to obtain silica particles 5 Got.

For the silica particles 1 to 5 obtained as described above, the number average particle size, monodispersity (standard deviation), average circularity, and the proportion of particles with a particle size exceeding 100 nm in all particles (100 nm or more particles) The ratio was expressed by the method described above.
The results are shown in Table 1.

[Production of Toner Particles (1)]
<Synthesis of binder resin>
-Bisphenol A ethylene oxide 2-mol adduct: 216 parts-Ethylene glycol: 38 parts-Terephthalic acid: 200 parts-Tetrabutoxy titanate (catalyst): 0.037 parts Place the above ingredients in a heat-dried two-necked flask and place in a container Nitrogen gas was introduced and the temperature was raised while stirring in an inert atmosphere, followed by a copolycondensation reaction at 160 ° C. for 7 hours, and then the temperature was raised to 220 ° C. while gradually reducing the pressure to 10 Torr, and held for 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.

<Preparation of resin particle dispersion>
・ Binder resin: 160 parts ・ Ethyl acetate: 233 parts ・ Sodium hydroxide aqueous solution (0.3 N): 0.1 part The above ingredients were placed in a 1000 ml separable flask and heated at 70 ° C. A resin mixture was prepared by stirring with the use of Kagaku Co., Ltd. While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added, phase inversion emulsification was carried out, and the solvent was removed 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 After mixing the above and heating to 95 ° C. and dispersing using a homogenizer (IQA, Ultra Tarrax T50), the dispersion was treated with a Manton Gorin high-pressure homogenizer (Gorin) for 360 minutes to obtain a volume average particle. A release agent dispersion (solid content concentration: 20%) prepared by dispersing release agent particles having a diameter of 0.23 μm was prepared.

<Preparation of glitter pigment particle dispersion>
Aluminum pigment (Showa Aluminum Powder Co., Ltd., 2173EA): 100 parts Anionic surfactant (Daiichi Kogyo Seiyaku, Neogen R): 1.5 parts Ion-exchanged water: 900 parts From aluminum pigment paste After removing the solvent, the above are mixed and dispersed for 1 hour using an emulsifier-dispersing machine Cavitron (manufactured by Taiheiyo Kiko Co., Ltd., CR1010) to disperse the glitter pigment particles (aluminum pigment). A particle dispersion (solid content concentration: 10%) was prepared.

<Preparation of toner particles>
-Resin particle dispersion: 450 parts-Release agent dispersion: 50 parts-Bright pigment particle dispersion: 21.74 parts-Nonionic surfactant (IGEPAL CA897): 1.40 parts The mixture was placed in a stainless steel container and dispersed and mixed for 10 minutes while applying a shearing force at 4000 rpm with a homogenizer (manufactured by IKA, Ultra Lalux T50). 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 stirrer using a two-paddle stirring blade for forming a laminar flow and a thermometer, and started to be heated with a mantle heater at a stirring speed of 810 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 in 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 Beckman-Coulter) was 10.4 μm.
Next, 100 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 the temperature at 67.5 ° C., and the heating was stopped after 1 hour, followed by cooling at a rate of temperature decrease of 1.0 ° C./min. Thereafter, the mixture was sieved with a 20 μm mesh, washed repeatedly with water, and then dried with a vacuum dryer to obtain toner particles (1).

[Production of Toner Particles (2)]
Preparation of toner particles (1) except that the stirring rotation speed of the step of promoting the growth of the aggregated particles was changed from 810 rpm to 660 rpm, and the temperature of the step of fusing the aggregated particles was changed from 67.5 ° C. to 74 ° C. Similarly, toner particles (2) were produced.

[Preparation of Toner Particle 3]
Preparation of toner particles (1) except that the stirring rotation speed in the step of promoting the growth of the aggregated particles was changed from 810 rpm to 520 rpm and the temperature in the step of fusing the aggregated particles was changed from 67.5 ° C. to 80 ° C. Similarly, toner particles (3) were produced.

[Production of toner]
To 100 parts by weight of the toner particles shown in Table 1, the external additive shown in Table 1 is added in the amount shown in Table 1 (external addition amount), mixed by a Henschel mixer, and added. Toners T1 to T8 used in Examples 1 to 8 and toners TC1 and TC2 used in Comparative Examples 1 and 2 were obtained, respectively.
Regarding the obtained toners T1 to T8, TC1, and TC2, “the ratio of the average maximum thickness C of the toner to the average equivalent circle diameter D (C / D)” and “the cross section in the thickness direction of the toner particles are observed. In this case, among all the observed pigment particles, the number of pigment particles in which the angle between the major axis direction in the cross section of the toner particles and the major axis direction of the pigment particles is in the range of −30 ° to + 30 ° (hereinafter “ “The number of pigment particles in the range of ± 30 °” was measured by the method described above. The results are shown in Table 1 below.

<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: 0.12 parts (Product) Name: VXC-72, manufactured by Cabot, volume resistivity: 100 Ωcm or less)
Crosslinked melamine resin particles (average particle size: 0.3 μm, toluene insoluble): 0.3 part First, carbon black was diluted in toluene to a perfluoroacrylate copolymer and dispersed by a sand mill. Next, the above components other than the ferrite particles were dispersed therein with a stirrer for 10 minutes to prepare a coating layer forming solution. Next, this coating layer forming liquid and ferrite particles were put into a vacuum degassing type kneader and stirred at a temperature of 60 ° C. for 30 minutes, and then the pressure was reduced and toluene was distilled off to form a resin coating layer to obtain a carrier. .

<Production of developer>
8 parts of the toner listed in Table 1 and 100 parts of the carrier were placed in a 2 liter V blender, stirred for 20 minutes, and then sieved at 212 μm to prepare a developer.

[Evaluation test for glitter]
An evaluation image was formed by the following method.
First, a physical load was applied to the developer as a sample as follows.
That is, the developer used as a sample is filled in a developing device of DocuCentre-III C7600 manufactured by Fuji Xerox Co., Ltd., and seasoned overnight in a high-temperature, low-humidity (35 ° C., 50 RH%) environment. + paper, on Oji paper Co., Ltd.), fixing temperature 190 ° C., at fusing pressure 4.0 kg / cm ^2, a solid image of 5 cm × 5 cm of amount of applied toner is 4.0 g / cm ² 10, 000 sheets were formed continuously.
The ratio (A / B) of the tenth and 10,000th solid images was measured by the method described above.
Note that the ratio (A / B) of the tenth solid image is “initial ratio (A / B)”, and the ratio (A / B) of the 10,000th solid image is “after applying physical load”. Ratio (A / B) ". The ratio (A / B) after applying the load is preferably 2 or more and 100 or less, more preferably 50 or more and 100 or less, and still more preferably 60 or more and 90 or less.
The results are also shown in Table 1 below.

As apparent from Table 1 above, the developer of the example including the toner using the wet process silica as the external additive has a ratio (A / B) after application of the load as compared with the developer of the comparative example. It turns out that it is excellent in value. Thereby, it turns out that the developer of an Example has tolerance to the physical load from the outside.
In addition, since the developer of each example has less change in the value of the initial ratio (A / B) and the value of the ratio after application of the load (A / B) compared to the developer of the comparative example, It can be seen that the initial brightness is easily maintained even when an external physical load is applied.

2 Toner particles 4 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 (9)

Including toner particles containing a luster pigment and a binder resin, and wet process silica,
When a solid image is formed, the reflectance A at a light receiving angle of + 30 ° and a light receiving angle at −30 ° are measured when the image is irradiated with incident light having an incident angle of −45 ° by a goniophotometer. An electrostatic image developing toner having a ratio (A / B) with a reflectance B of 2 or more and 100 or less.   The electrostatic image developing toner according to claim 1, wherein the wet process silica is a sol-gel process silica.   The electrostatic image developing toner according to claim 1, wherein the wet process silica is monodispersed and spherical.   The electrostatic image development according to any one of claims 1 to 3, wherein in the wet process silica, a ratio of particles having a particle diameter exceeding 100 nm to all particles is 50% by number or more and 100% by number or less. toner.   An electrostatic charge image developer containing the electrostatic charge image developing toner according to claim 1. Containing the toner for developing an electrostatic charge image according to any one of claims 1 to 4,
A toner cartridge to be attached to and detached from the image forming apparatus. A developing means for containing the electrostatic charge image developer according to claim 5 and developing 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;
Developing means for containing the electrostatic charge image developer according to claim 5 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 image formed on the surface of the image carrier as a toner image by the electrostatic image developer according to claim 5;
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: