JP2017062402A - 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 suppresses a change in hue of a red image after being exposed to the sunlight for a long period.SOLUTION: There is provided a toner for electrostatic charge image development comprising toner particles including a binder resin and Pigment Yellow 74, where the maximum absorption wavelength λmax is in a range of 400 nm or more and 440 nm or less; when the absorbance of the maximum absorption wavelength λmax is standardized as 1, the absorbance at a wavelength of 510 nm is 0.20 or less and the absorbance at a wavelength of 550 nm is 0.10 or less.SELECTED DRAWING: None

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.

  In recent years, in the field of electrophotographic commercial printing, the demand for high-quality output images such as catalogs and pamphlets has increased rapidly. In particular, red has high human discrimination ability, and high saturation and excellent color reproducibility are required.

  For example, Patent Document 1 discloses that a toner image formed with only yellow toner has a specific wavelength for the purpose of obtaining high saturation and excellent color reproducibility for a “red” toner image formed as a secondary color. A full-color image forming method is disclosed in which the reflectance satisfies a specific relational expression.

JP 2008-146039 A

  An object of the present invention is a toner having toner particles containing a binder resin and Pigment Yellow 74, wherein the maximum absorption wavelength λmax exceeds 440 nm, or the absorbance at the maximum absorption wavelength λmax is normalized to 1. To provide a toner for developing an electrostatic charge image in which a change in color tone in a red image is suppressed when exposed to sunlight for a long period of time as compared with a toner whose absorbance at a wavelength of 510 nm or absorbance at a wavelength of 550 nm does not fall within the scope of the present application. It is.

  The above problem is solved by the following means.

The invention according to claim 1
Having toner particles including a binder resin and Pigment Yellow 74;
When the maximum absorption wavelength λmax is in the range of 400 nm to 440 nm and the absorbance at the maximum absorption wavelength λmax is normalized to 1, the absorbance at a wavelength of 510 nm is 0.20 or less and the absorbance at a wavelength of 550 nm is 0.10 or less. Toner for charge image development.

The invention according to claim 2
The electrostatic image developing toner according to claim 1, wherein the full width at half maximum of the absorption peak at the maximum absorption wavelength λmax is 50 nm or less.

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

The invention according to claim 4
Containing the toner for developing an electrostatic image according to claim 1;
A toner cartridge to be attached to and detached from the image forming apparatus.

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

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

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

  According to the first aspect of the present invention, a toner having toner particles containing a binder resin and Pigment Yellow 74, wherein the toner has a maximum absorption wavelength λmax exceeding 440 nm, or the absorbance at the maximum absorption wavelength λmax is specified as 1. Provides an electrostatic charge image developing toner that suppresses a change in color tone in a red image when exposed to sunlight for a long period of time, compared to a toner whose absorbance at a wavelength of 510 nm or absorbance at a wavelength of 550 nm does not fall within the scope of the present application. Is done.

  According to the invention of claim 2, the color tone in the red image when exposed to sunlight for a long period of time compared to the case where the maximum absorption wavelength λmax is in the range of 400 nm to 440 nm and the full width at half maximum exceeds 50 nm. There is provided a toner for developing an electrostatic image in which the change of the toner is suppressed.

  According to the invention of claim 3, 4, 5, 6, or 7, the toner having toner particles containing a binder resin and Pigment Yellow 74, wherein the toner has a maximum absorption wavelength λmax exceeding 440 nm, or a maximum Compared to the application of a toner whose absorbance at wavelength 510 nm when the absorbance at the absorption wavelength λmax is normalized to 1 or the absorbance at a wavelength of 550 nm is not within the scope of the present application, the color tone in the red image when exposed to sunlight for a long time is applied. An electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, or an image forming method in which changes are suppressed are provided.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

  Hereinafter, an embodiment which is an example of the present invention will be described in detail.

<Toner for electrostatic image development>
The electrostatic image developing toner according to the present exemplary embodiment (hereinafter referred to as “toner”) has toner particles including a binder resin and Pigment Yellow 74. Further, the toner of this embodiment has a maximum absorption wavelength λmax in the range of 400 nm to 440 nm, and when the absorbance at the maximum absorption wavelength λmax is normalized to 1, the absorbance at a wavelength of 510 nm is 0.20 or less. The absorbance at a wavelength of 550 nm is 0.10 or less. Hereinafter, the absorbance when the absorbance at the maximum absorption wavelength λmax is normalized to 1 may be referred to as “normalized absorbance”.
The toner according to the present exemplary embodiment suppresses a change in color tone in a red image when exposed to sunlight for a long period (for example, 500 hours). Specifically, when the toner according to the present embodiment is used as a yellow toner and combined with magenta toner to form a red image, a change in color tone in the red image when exposed to sunlight for a long time is suppressed. . The reason is not clear, but is presumed to be due to the following reasons.

  As described above, as a method of forming a red image, there is a method of superposing yellow toner and magenta toner. However, since magenta pigments often have higher light resistance than yellow pigments, if a red image formed using yellow toner and magenta toner is exposed to sunlight, it will be yellower than magenta pigments. The pigment is quickly deteriorated. As a result, the amount of light absorption by the yellow pigment is reduced, and the color of the red image may change.

  Here, it is considered that the color of the red image is easily influenced by the absorbance at a wavelength of 450 nm to 600 nm. Many of the yellow pigments have a maximum absorption wavelength in the range of 400 nm to 500 nm and also absorb light in a wavelength region of 500 nm to 600 nm. Therefore, if the yellow pigment has a high absorbance at a wavelength of 450 nm or more and 600 nm or less, the absorbance of the red image at a wavelength of 450 nm or more and 600 nm or less decreases with the deterioration of the yellow pigment, and the color of the image is likely to change. Conceivable.

In contrast, in this embodiment, Pigment Yellow 74 is used as the yellow pigment, the maximum absorption wavelength λmax of the toner is 400 nm to 440 nm, the normalized absorbance at a wavelength of 510 nm is 0.20 or less, and the normalized absorbance at a wavelength of 550 nm. Is 0.10 or less. That is, in the toner of the present embodiment, the maximum absorption wavelength of Pigment Yellow 74 itself included as a yellow pigment is 400 nm or more and 440 nm or less, and the normalized absorbance at a wavelength of 510 nm and the normalized absorbance at a wavelength of 550 nm are also in the above range.
As described above, in the present embodiment, the absorbance of the yellow pigment on the long wavelength side is suppressed as much as possible while ensuring yellow coloration. Therefore, the red image formed by using the toner of the present embodiment and the magenta toner together has a light absorption amount of 450 nm or more and 600 nm or less due to the yellow toner, as compared with the case where the conventional yellow toner is used. Therefore, even if the yellow pigment is deteriorated by sunlight, it is presumed that the change in color is suppressed because the rate of decrease in absorbance at a wavelength of 450 nm to 600 nm is small.
For the reasons described above, it is presumed that the toner according to the present embodiment suppresses a change in color when a red image is formed and exposed to sunlight for a long time.

  Further, as described above, the toner of the present embodiment has a maximum absorption wavelength λmax in the range of 400 nm to 440 nm and has a small normalized absorbance at wavelengths of 510 nm and 550 nm, and therefore is used in combination with other color toners. As a result, an image having a wide color gamut is obtained, and the color reproducibility is improved.

  In the present embodiment, in the absorption spectrum in which the absorbance at the maximum absorption wavelength λmax is normalized to 1, the full width at half maximum of the absorption peak at the maximum absorption wavelength λmax (hereinafter sometimes simply referred to as “full width at half maximum”) is 50 nm or less. It is desirable to be. The maximum absorption wavelength λmax of the toner is in the range of 400 nm or more and 440 nm or less, and the full width at half maximum is 50 nm or less, thereby further suppressing the change in color tone when a red image is formed and exposed to sunlight for a long time. Is done. The reason is not clear, but is presumed as follows.

When the maximum absorption wavelength λmax of the toner is in the range of 400 nm to 440 nm and the full width at half maximum is 50 nm or less, the maximum absorption wavelength of the pigment yellow 74 included in the toner is also from 400 nm to 440 nm and the full width at half maximum is 50 nm. It is as follows. Therefore, compared with the case where the full width at half maximum exceeds 50 nm, the absorbance of Pigment Yellow 74 is particularly small on the side close to 450 nm among wavelengths of 450 nm to 600 nm. Therefore, it is estimated that the influence on the color tone of the red image due to the deterioration of the pigment yellow 74 is further reduced.
Further, when the full width at half maximum of the toner is 50 nm or less, the color gamut of the image obtained by combining with the toner of other colors is further widened, and the color reproducibility is further improved.

The maximum absorption wavelength λmax of the toner is preferably 400 nm or more and 440 nm or less, more preferably 410 nm or more and 420 nm or less, and the normalized absorbance at 510 nm is preferably 0.20 or less, more preferably 0.10 or less, and the specification at 550 nm. The total absorbance is preferably 0.10 or less, and more preferably 0.05 or less.
Further, the full width at half maximum of the toner is preferably 10 or more and 50 or less, and more preferably 15 or more and 40 or less.
Further, the normalized absorbance at 490 nm of the toner is preferably 0.40 or less, more preferably 0.35 or less, and the normalized absorbance at 500 nm of the toner is preferably 0.30 or less, more preferably 0.25 or less.

Here, the maximum absorption wavelength λmax of the toner, the normalized absorbance at a specific wavelength, and the full width at half maximum are measured as follows. Specifically, for example, using a coated paper (OS coated paper W manufactured by Fuji Xerox Co., Ltd.) as a recording medium, an absorption spectrum is measured for a solid image (5 cm × 5 cm) formed to have an image density of 100%. The maximum absorption wavelength of the obtained absorption spectrum is defined as the maximum absorption wavelength λmax of the toner, and the absorbance and full width at half maximum of the absorption spectrum obtained by standardizing the absorbance of the maximum absorption wavelength to 1, respectively, at the specific wavelength of the toner Normalized absorbance and full width at half maximum.
In addition, the measurement of the absorption spectrum measured 360 nm-730 nm 10 nm at a time using the spectrophotometer (Ultra scan Pro, hunterlab).

  Hereinafter, details of the toner according to the exemplary embodiment will be described.

  The toner according to the exemplary embodiment includes toner particles and, if necessary, external additives.

(Toner particles)
The toner particles include, for example, a binder resin, pigment yellow 74 which is a yellow pigment as a colorant, and a release agent and other additives as necessary.

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

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

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

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

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

The glass transition temperature (Tg) of the polyester resin is preferably 50 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 65 ° C. or lower.
The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically described in the method for determining the glass transition temperature in JIS K 7121-1987 “Method for Measuring Plastic Transition Temperature”. Of “extrapolated glass transition start temperature”.

The weight average molecular weight (Mw) of the polyester resin is preferably from 5,000 to 1,000,000, and more preferably from 7,000 to 500,000.
The number average molecular weight (Mn) of the polyester resin is preferably from 2,000 to 100,000.
The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less.
The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC). The molecular weight measurement by GPC is performed with a THF solvent using a Tosoh GPC / HLC-8120GPC as a measuring device and a Tosoh column / TSKgel SuperHM-M (15 cm). The weight average molecular weight and the number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from this measurement result.

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

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

-Colorant-
As a colorant, as described above, Pigment Yellow 74 is used.
In the toner of the present exemplary embodiment, if the maximum absorption wavelength λmax of the toner, the normalized absorbance at a wavelength of 510 nm, and the normalized absorbance at a wavelength of 550 nm are within the above-described ranges, other colorants other than Pigment Yellow 74 are added. May be included. However, the content of the other colorant is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably no other colorant is used with respect to the entire colorant.

Examples of the pigment yellow 74 having the maximum absorption wavelength, the normalized absorbance at a wavelength of 510 nm, and the normalized absorbance at a wavelength of 550 nm in the above-described range include those obtained by treating a commercially available pigment yellow 74 by a specific processing method described later. Can be mentioned.
Specific treatment methods include, for example, a method in which Pigment Yellow 74 is dispersed in an aqueous dispersion medium containing a surfactant, separated by a centrifuge, and the supernatant is taken. From the supernatant, the maximum absorption wavelength is exemplified. Pigment Yellow 74 having a normalized absorbance at a wavelength of 510 nm and a normalized absorbance at a wavelength of 550 nm in the above ranges is obtained.

The aqueous dispersion medium and the surfactant used in the specific treatment method may be the same as those used in the production of a general colorant particle dispersion.
Examples of the aqueous dispersion medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.
Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an anionic surfactant and a cationic surfactant are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
Surfactant may be used individually by 1 type and may use 2 or more types together.
As an addition amount of surfactant, the range of 1 mass part or more and 80 mass parts or less is mentioned with respect to 100 mass parts of pigment yellow 74, for example, 5 mass parts or more and 50 mass parts or less are preferable, and 10 mass parts or more are preferable. 30 parts by mass or less is more preferable.

Examples of a method for dispersing Pigment Yellow 74 in an aqueous dispersion medium in a specific treatment method include a dispersion method using a rotary shearing homogenizer, a high-pressure impact disperser, a ball mill having a medium, a sand mill, a dyno mill, and the like. You may use together.
However, from the viewpoint of setting the maximum absorption wavelength λmax in the toner within the above range, after dispersing Pigment Yellow 74 in an aqueous dispersion medium in the same manner as in the production of a general colorant particle dispersion, a high-pressure impact disperser is further added. It is desirable to process by. Examples of the pressure in the treatment using the high-pressure impact disperser include a range of 200 MPa to 300 MPa, and examples of the number of passes include a range of 5 to 50.
In addition, examples of the conditions for separation by the centrifuge include a gravitational acceleration range of 3 × 10 ⁴ G to 5 × 10 ⁶ G and a centrifuge time range of 10 minutes to 600 minutes.

Examples of the volume average particle size of Pigment Yellow 74 processed by a specific processing method include 70 nm to 300 nm, preferably 80 nm to 200 nm, and more preferably 100 nm to 150 nm.
In addition, the volume average particle size of the pigment yellow 74 is a particle size range (channel) divided by using a particle size distribution obtained by measurement with a laser diffraction particle size distribution measuring apparatus (for example, LA-700 manufactured by Horiba, Ltd.). On the other hand, the cumulative distribution is drawn from the small particle size side with respect to the volume, and the particle size that becomes 50% cumulative with respect to all particles is measured as the volume average particle size D50v. As a measurement sample, a dispersion liquid in which Pigment Yellow 74 is dispersed in the aqueous dispersion medium is used, the input value of the refractive index of the dispersion medium is 1.333, and the input value of the refractive index of the particles (Pigment Yellow 74) is 1. As 590, the particle size distribution is calculated.

As specific gravity of the pigment yellow 74 processed by the specific processing method, 1.00 or more and 1.30 or less are mentioned, for example, 1.00 or more and 1.20 or less are preferable, and 1.00 or more and 1.10 or less are mentioned. More preferred.
The specific gravity was measured using an AD1653 specific gravity measurement kit manufactured by A & D.

As D84v / D50v of the pigment yellow 74 processed by the specific processing method, 1.00 or more and 2.00 or less are mentioned, for example, 1.00 or more and 1.70 or less are more preferable.
In addition, said D84v / D50v is calculated | required from the value obtained by the measurement of the volume average particle diameter of the above-mentioned pigment yellow 74. FIG. Specifically, with respect to the divided particle size range (channel), the cumulative distribution is drawn from the small particle size side with respect to the volume, and the particle size that is 84% cumulative with respect to all the particles is “D84v”. The particle diameter which becomes 50% cumulative is set to “D50v”, and the value of “D84v / D50v” is obtained.

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

-Release agent-
Examples of 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; and ester waxes such as fatty acid esters and montanic acid esters. And so on. 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.
Note that the melting temperature is obtained from the DSC curve obtained by differential scanning calorimetry (DSC) according to “melting peak temperature” described in JIS K 7121-1987 “Method for measuring the melting temperature of plastics”. .

  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.

-Toner particle characteristics-
The toner particles may be toner particles having a single layer structure, or toner particles having a so-called core / shell structure composed of a core (core particle) and a coating layer (shell layer) covering the core. May be.
Here, the core / shell structure toner particles include, for example, a core portion including a binder resin and, if necessary, other additives such as a colorant and a release agent, and a binder resin. It is good to be comprised with the comprised coating layer.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less.

In addition, various average particle diameters and various particle size distribution indexes of toner particles are measured using Coulter Multisizer II (manufactured by Beckman Coulter, Inc.), and an electrolytic solution is measured using ISOTON-II (manufactured by Beckman Coulter, Inc.). The
In the measurement, 0.5 mg to 50 mg of a measurement sample is added as a dispersant to 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate). This is added to 100 ml or more and 150 ml or less of the electrolytic solution.
The electrolyte in which the sample is suspended is dispersed for 1 minute with an ultrasonic disperser, and the particle size distribution of particles having a particle size in the range of 2 μm to 60 μm is measured using a 100 μm aperture with a Coulter Multisizer II. taking measurement. The number of particles to be sampled is 50,000.
For the particle size range (channel) divided based on the measured particle size distribution, the cumulative distribution is drawn from the smaller diameter side to the volume and number, respectively, and the particle size to be 16% is the volume particle size D16v, the number particle size D16p, a particle size that is 50% cumulative is defined as a volume average particle size D50v, a cumulative number average particle size D50p, and a particle size that is 84% cumulative is defined as a volume particle size D84v and a number particle size D84p.
Using these, the volume average particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

  The shape factor SF1 of the toner particles is preferably 110 or more and 150 or less, and more preferably 120 or more and 140 or less.

The shape factor SF1 is obtained by the following formula.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner, and A represents the projected area of the toner.
Specifically, the shape factor SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and is calculated as follows. That is, by capturing an optical microscope image of particles dispersed on the surface of a slide glass into a Luzex image analyzer using a video camera, obtaining the maximum length and projected area of 100 particles, calculating by the above formula, and obtaining the average value can get.

(External additive)
Examples of the external additive include inorganic particles. As the inorganic particles, SiO ₂ , TiO ₂ , Al ₂ O ₃ , CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , MgO, BaO, CaO, K ₂ O, Na ₂ O, ZrO ₂ , CaO. _{SiO 2, K 2 O · (} TiO 2) n, Al 2 O 3 · 2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 , and the like.

The surface of the inorganic particles as an external additive is preferably subjected to a hydrophobic treatment. The hydrophobic treatment is performed, for example, by immersing inorganic particles in a hydrophobic treatment agent. The hydrophobizing agent is not particularly limited, and examples thereof include silane coupling agents, silicone oils, titanate coupling agents, aluminum coupling agents and the like. These may be used individually by 1 type and may use 2 or more types together.
The amount of the hydrophobizing agent is usually 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles, for example.

  Examples of external additives include resin particles (resin particles such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, fluorine-based high molecular weight substances). Particle) and the like.

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

(Toner production method)
Next, a toner manufacturing method according to this embodiment will be described.
The toner according to the exemplary embodiment can be obtained by externally adding an external additive to the toner particles after the toner particles are manufactured.

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

Specifically, for example, when toner particles are produced by an aggregation coalescence method,
Preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparing step), and preparing a colorant particle dispersion in which colorant particles as pigment yellow 74 particles are dispersed In the mixed dispersion after mixing the step (colorant particle dispersion preparation step), the resin particle dispersion and the colorant particle dispersion (and other particle dispersions as necessary) Aggregating the colorant particles (and other particles as necessary) to form aggregated particles (aggregated particle forming step), and heating the aggregated particle dispersion in which the aggregated particles are dispersed to form aggregated particles The toner particles are manufactured through a step of fusing and coalescing to form toner particles (fusion and coalescence step).

Details of each step will be described below.
In the following description, a method for obtaining toner particles containing a release agent in addition to the binder resin and the colorant that is Pigment Yellow 74 will be described. However, the release agent is used as necessary. Of course, you may use other additives other than a mold release agent.

-Preparation step of resin particle dispersion-
First, together with a resin particle dispersion in which resin particles serving as a binder resin are dispersed, for example, a colorant particle dispersion in which colorant particles are dispersed and a release agent particle dispersion in which release agent particles are dispersed are prepared. To do.

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

Examples of the dispersion medium used for the resin particle dispersion include an aqueous medium.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together.

Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol And nonionic surfactants such as polyphenols, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, an anionic surfactant and a cationic surfactant are particularly mentioned. The nonionic surfactant may be used in combination with an anionic surfactant or a cationic surfactant.
Surfactant may be used individually by 1 type and may use 2 or more types together.

Examples of the method for dispersing the resin particles in the dispersion medium in the resin particle dispersion include a general dispersion method such as a rotary shear homogenizer, a ball mill having media, a sand mill, and a dyno mill. Depending on the type of resin particles, the resin particles may be dispersed in the resin particle dispersion using, for example, a phase inversion emulsification method.
The phase inversion emulsification method is a method in which a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and a base is added to the organic continuous phase (O phase) to neutralize the aqueous medium. (W phase) is added to convert the resin from W / O to O / W (so-called phase inversion) to form a discontinuous phase and disperse the resin in an aqueous medium in the form of particles. It is.

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

  As content of the resin particle contained in a resin particle dispersion liquid, 5 to 50 mass% is preferable, for example, and 10 to 40 mass% is more preferable.

In addition, when using the pigment yellow 74 processed by the above-mentioned specific processing method as a coloring agent, you may use the supernatant liquid isolate | separated with the centrifuge as a coloring agent particle dispersion liquid as it is, for example.
The release agent particle dispersion may be prepared in the same manner as the resin particle dispersion, for example. That is, the volume average particle diameter of the particles in the resin particle dispersion, the dispersion medium, the dispersion method, and the content of the particles are the same for the release agent particles dispersed in the release agent particle dispersion.

-Aggregated particle formation process-
Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion.
Then, in the mixed dispersion, resin particles, colorant particles, and release agent particles are hetero-aggregated to have resin particles, colorant particles, and release agent particles having a diameter close to the diameter of the target toner particles. Aggregated particles are formed.

Specifically, for example, the flocculant is added to the mixed dispersion, and the pH of the mixed dispersion is adjusted to acidic (for example, the pH is 2 or more and 5 or less), and a dispersion stabilizer is added as necessary. The resin particles are heated to a glass transition temperature (specifically, for example, the glass transition temperature of the resin particles −30 ° C. or more and the glass transition temperature −10 ° C. or less), and the particles dispersed in the mixed dispersion liquid are aggregated. , Forming aggregated particles.
In the agglomerated particle forming step, for example, the aggregating agent is added at room temperature (for example, 25 ° C.) while stirring the mixed dispersion with a rotary shearing homogenizer, and the pH of the mixed dispersion is acidic (for example, the pH is 2 or more and 5 or less). ), And after adding a dispersion stabilizer as necessary, the heating may be performed.

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

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic substances such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include metal salt polymers.
A water-soluble chelating agent may be used as the chelating agent. Examples of the chelating agent include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid, iminodiacid (IDA), nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), and the like.
As addition amount of a chelating agent, 0.01 mass part or more and 5.0 mass part or less are preferable with respect to 100 mass parts of resin particles, for example, and 0.1 mass part or more and less than 3.0 mass parts are more preferable.

-Fusion / unification process-
Next, the aggregated particle dispersion in which the aggregated particles are dispersed is heated to, for example, a glass transition temperature or higher of the resin particles (for example, a temperature of 10 to 30 ° C. higher than the glass transition temperature of the resin particles). Are fused and united to form toner particles.

Through the above steps, toner particles are obtained.
In addition, after obtaining the aggregated particle dispersion liquid in which the aggregated particles are dispersed, the aggregated particle dispersion liquid and the resin particle dispersion liquid in which the resin particles are dispersed are further mixed, and the resin particles are further added to the surface of the aggregated particles. A process of aggregating to adhere to form second aggregated particles, and heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles. The toner particles may be manufactured through a step of forming toner particles having a core / shell structure.

Here, after completion of the fusion / unification process, toner particles formed in the solution are dried through a known washing process, solid-liquid separation process, and drying process to obtain toner particles.
In the washing step, it is preferable to sufficiently carry out substitution washing with ion-exchanged water from the viewpoint of chargeability. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, etc. are preferably performed from the viewpoint of productivity. Also, the drying process is not particularly limited, but from the viewpoint of productivity, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying, or the like is preferably performed.

  The toner according to the exemplary embodiment is manufactured, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing may be performed by, for example, a V blender, a Henschel mixer, a Laedige mixer, or the like. Further, if necessary, coarse toner particles may be removed using a vibration sieving machine, a wind sieving machine, or the like.

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

There is no restriction | limiting in particular as a carrier, A well-known carrier is mentioned. As a carrier, for example, a coated carrier in which the surface of a core made of magnetic powder is coated with a coating resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; a porous magnetic powder is impregnated with a resin Resin impregnated type carriers; and the like.
Note that the magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

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

Examples of the 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.
The coating resin and matrix resin may contain other additives such as conductive particles.
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.

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.

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

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

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

  In the image forming apparatus according to the present embodiment, for example, the part including the developing unit may have a cartridge structure (process cartridge) that is detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge including a developing unit containing the electrostatic charge image developer according to the present embodiment is preferably used.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the present embodiment.
The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter sometimes simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel at a predetermined distance from each other in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a drive roll 22 and a support roll 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other in the left to right direction in the drawing. The vehicle travels in the direction toward the unit 10K. The support roll 24 is applied with a force in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around the support roll 24. An intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the drive roll 22.
Further, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K has yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The toner including the four color toners is supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. It should be noted that reference numerals with magenta (M), cyan (C), and black (K) are attached to the same parts as those of the first unit 10Y instead of yellow (Y). Description of the units 10M, 10C, and 10K will be omitted.

The first unit 10Y includes a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, a charging roll (an example of a charging unit) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on the color-separated image signal. Then, an exposure device (an example of an electrostatic image forming unit) 3 that forms an electrostatic image, and a developing device (an example of a developing unit) 4Y that develops the electrostatic image by supplying toner charged to the electrostatic image, developed A primary transfer roll 5Y (an example of a primary transfer unit) that transfers a toner image onto the intermediate transfer belt 20, and a photoconductor cleaning device (an example of a cleaning unit) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer. Are arranged in order.
The primary transfer roll 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rolls 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roll under the control of a control unit (not shown).

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

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is visualized (developed image) as a toner image by the developing device 4Y.

  In the developing device 4Y, for example, an electrostatic charge image developer containing at least yellow toner and a carrier is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged electric charge on the photoreceptor 1Y, and has a developer roll (a developer holding member). Example) is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

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

Further, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M is also controlled in accordance with the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner. The

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

  Thereafter, the recording paper P is fed into the pressure contact portions (nip portions) of a pair of fixing rolls in a fixing device (an example of a fixing unit) 28, and the toner image is fixed on the recording paper P to form a fixed image.

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

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

<Process cartridge / toner cartridge>
The process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment accommodates the electrostatic image developer according to the present embodiment, and develops the electrostatic image formed on the surface of the image carrier as a toner image by the electrostatic image developer. And a process cartridge that can be attached to and detached from the image forming apparatus.

  Note that 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 carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one selected from the above.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

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

Next, the toner cartridge according to this embodiment will be described.
The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.

  The image forming apparatus shown in FIG. 1 is an image forming apparatus having a configuration in which toner cartridges 8Y, 8M, 8C, and 8K are attached and detached, and the developing devices 4Y, 4M, 4C, and 4K are each developing devices (colors). And a toner supply pipe (not shown). Further, when the amount of toner stored in the toner cartridge becomes low, the toner cartridge is replaced.

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to these Examples at all. The “part” means “part by mass” unless otherwise specified.

<Adjustment of colorant particle dispersion (treatment of pigment yellow 74)>
[Preparation of Colorant Particle Dispersion (1)]
C. I. 20 parts by mass of Pigment Yellow 74 (manufactured by Clariant), 2 parts by mass of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC), and 78 parts by mass of ion-exchanged water were mixed, and a homogenizer (manufactured by IKA, Ultra Dispersion was carried out at 6000 rpm for 5 minutes using Tarax T50). This is designated as a pre-colorant particle dispersion.
Thereafter, the mixture was stirred for one day with a stirrer to defoam, and then the dispersion was dispersed at a pressure of 240 MPa using a high-pressure impact disperser ultimateizer (HJP30006, manufactured by Sugino Machine Co., Ltd.). Dispersion was performed for 20 passes. Then, using a centrifuge (Himac CR22G manufactured by Hitachi Koki Co., Ltd.), separated at a gravitational acceleration of 5.5 × 10 ⁴ G for 35 minutes, allowed to stand for 25 minutes, and then collected 30% by volume of the supernatant. Colorant particle dispersion (1) was obtained.

The volume average particle diameter of the colorant particles in the colorant particle dispersion (1) was 170 nm, the specific gravity was 1.07, and D84v / D50v = 1.83.
In addition, ion-exchanged water was added so that the pigment concentration was 0.04 g / L, and the absorption spectrum of the colorant particle dispersion (1) was measured using a spectrophotometer (Ultra scan Pro, Hunterlab). As a result, the maximum absorption wavelength was 456 nm, the full width at half maximum was 40 nm, the normalized absorbance at a wavelength of 510 nm was 0.09, and the normalized absorbance at a wavelength of 550 nm was 0.03.

[Preparation of Colorant Particle Dispersion (2)]
Colorant particles as in the preparation of the colorant particle dispersion (1) except that the high-pressure impact disperser optimizer for the preparation of the colorant particle dispersion (1) is equivalent to 25 passes and the centrifugation time is 25 minutes. Dispersion liquid (2) was prepared. The volume average particle diameter was 124 nm and D84v / D50v = 1.47. The maximum absorption wavelength was 435 nm, the full width at half maximum was 41 nm, the normalized absorbance at a wavelength of 510 nm was 0.19, and the normalized absorbance at a wavelength of 550 nm was 0.06.

[Preparation of Colorant Particle Dispersion (3)]
A colorant particle dispersion (3) was prepared in the same manner as the colorant particle dispersion (2) except that the centrifugation time for preparing the colorant particle dispersion (2) was 30 minutes. The volume average particle diameter was 125 nm and D84v / D50v = 1.46. The maximum absorption wavelength was 436 nm, the full width at half maximum was 41 nm, the normalized absorbance at a wavelength of 510 nm was 0.13, and the normalized absorbance at a wavelength of 550 nm was 0.04.

[Preparation of Colorant Particle Dispersion (4)]
A colorant particle dispersion (4) was prepared in the same manner as the colorant particle dispersion (2) except that the centrifugation time for preparing the colorant particle dispersion (2) was 35 minutes. The volume average particle diameter was 126 nm, D84v / D50v = 1.44. The maximum absorption wavelength was 437 nm, the full width at half maximum was 43 nm, the normalized absorbance at a wavelength of 510 nm was 0.09, and the normalized absorbance at a wavelength of 550 nm was 0.03.

[Preparation of Colorant Particle Dispersion (5)]
Colorant particles as in the preparation of the colorant particle dispersion (1) except that the high-pressure impact disperser optimizer for the preparation of the colorant particle dispersion (1) is equivalent to 30 passes and the centrifugation time is 25 minutes. A dispersion (5) was prepared. The volume average particle diameter was 100 nm and D84v / D50v = 1.30. The maximum absorption wavelength was 418 nm, the full width at half maximum was 44 nm, the normalized absorbance at a wavelength of 510 nm was 0.18, and the normalized absorbance at a wavelength of 550 nm was 0.06.

[Preparation of Colorant Particle Dispersion (6)]
A colorant particle dispersion (6) was prepared in the same manner as the colorant particle dispersion (5) except that the centrifugation time for preparing the colorant particle dispersion (5) was 30 minutes. The volume average particle diameter was 98 nm and D84v / D50v = 1.31. The maximum absorption wavelength was 416 nm, the full width at half maximum was 46 nm, the normalized absorbance at a wavelength of 510 nm was 0.13, and the normalized absorbance at a wavelength of 550 nm was 0.03.

[Preparation of Colorant Particle Dispersion (7)]
A colorant particle dispersion (7) was prepared in the same manner as the colorant particle dispersion (5) except that the centrifugation time for preparing the colorant particle dispersion (5) was 35 minutes. The volume average particle diameter was 96 nm, and D84v / D50v = 1.32. The maximum absorption wavelength was 420 nm, the full width at half maximum was 45 nm, the normalized absorbance at a wavelength of 510 nm was 0.09, and the normalized absorbance at a wavelength of 550 nm was 0.03.

[Preparation of Colorant Particle Dispersion (8)]
Colorant particles as in the preparation of the colorant particle dispersion (1) except that the high-pressure impact disperser optimizer for the preparation of the colorant particle dispersion (1) is equivalent to 35 passes and the centrifugation time is 35 minutes. Dispersion (8) was prepared. The volume average particle diameter was 81 nm and D84v / D50v = 1.34. The maximum absorption wavelength was 396 nm, the full width at half maximum was 46 nm, the normalized absorbance at a wavelength of 510 nm was 0.09, and the normalized absorbance at a wavelength of 550 nm was 0.03.

<Preparation of resin particle dispersion>
[Preparation of resin particle dispersion (1)]
・ Terephthalic acid: 30 mol part ・ Fumaric acid: 70 mol part ・ Bisphenol A ethylene oxide adduct: 5 mol part ・ Bisphenol A propylene oxide adduct: 95 mol part Stirrer, nitrogen introduction tube, temperature sensor, and rectifying column The above material was charged into a 5 liter flask equipped with the above, the temperature was raised to 220 ° C. over 1 hour, and 1 part of titanium tetraethoxide was added to 100 parts of the material. The temperature was raised to 230 ° C. over 0.5 hours while distilling off the produced water, and the dehydration condensation reaction was continued at that temperature for 1 hour, and then the reaction product was cooled. Thus, a polyester resin (1) having a weight average molecular weight of 18,000, an acid value of 15 mgKOH / g, and a glass transition temperature of 60 ° C. was synthesized.

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

<Preparation of release agent particle dispersion>
[Preparation of release agent particle dispersion (1)]
-Paraffin wax (Nippon Seiwa Co., Ltd. HNP-9) 100 parts-Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK) 1 part-Ion-exchanged water 350 parts After heating to 100 ° C. and dispersing using a homogenizer (Ultra Turrax T50 manufactured by IKA), dispersion treatment is performed using a Menton Gorin high-pressure homogenizer (manufactured by Gorin), and release agent particles having a volume average particle diameter of 200 nm are dispersed. A release agent particle dispersion (1) (solid content 20% by mass) was obtained.

<Preparation of yellow toner>
[Preparation of Yellow Toner (1)]
Resin particle dispersion (1): 402.5 parts Colorant particle dispersion (1): 22.5 parts Release agent particle dispersion (1): 50 parts Anionic surfactant (TaycaPower): 2 parts The above materials were placed in a round stainless steel flask, and 0.1N nitric acid was added to adjust the pH to 3.5, followed by addition of 30 parts of a nitric acid aqueous solution having a polyaluminum chloride concentration of 10% by mass. Subsequently, the mixture was dispersed at 30 ° C. using a homogenizer (Ultra Turrax T50 manufactured by IKA), then heated to 45 ° C. in a heating oil bath and held for 30 minutes. Thereafter, 100 parts of the resin particle dispersion (1) was slowly added and held for 1 hour, and the pH was adjusted to 8.5 by adding a 0.1N sodium hydroxide aqueous solution. And heated for 5 hours. Thereafter, the mixture was cooled to 20 ° C. at a rate of 20 ° C./min, filtered, sufficiently washed with ion exchange water, and dried to obtain yellow toner particles (1) having a volume average particle diameter of 7.5 μm.
100 parts of yellow toner particles (1) and 0.7 parts of dimethyl silicone oil-treated silica particles (RY200 manufactured by Nippon Aerosil Co., Ltd.) were mixed using a Henschel mixer to obtain yellow toner (1).

[Preparation of Yellow Toner (2) to (8)]
In the same manner as the yellow toner particles (1) and the yellow toner (1) except that the colorant particle dispersions (2) to (8) are used instead of the colorant particle dispersion (1), a yellow toner is used. Particles (2) to (8) and yellow toners (2) to (8) were obtained.

<Preparation of magenta toner>
[Preparation of magenta toner (MA)]
Mixing 20 parts by mass of PR238 (naphthol) (manufactured by Sanyo Dye), 2 parts by mass of an anionic surfactant (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Neogen SC) and 78 parts by mass of ion-exchanged water as a colorant Then, it was dispersed for 5 minutes at 6000 rpm using a homogenizer (manufactured by IKA, Ultra Tarrax T50). Thereafter, the mixture was stirred for one day with a stirrer to defoam, and then the dispersion was dispersed at a pressure of 240 MPa using a high-pressure impact disperser ultimateizer (HJP30006, manufactured by Sugino Machine Co., Ltd.). Dispersion was performed for 25 passes to obtain a colorant particle dispersion (MA).
A magenta toner (MA) was obtained in the same manner as the yellow toner (1) except that the colorant particle dispersion (MA) was used instead of the colorant particle dispersion (1).

<Production of developer>
・ Ferrite particles (average particle size 50 μm) 100 parts ・ Toluene 14 parts ・ Styrene / methyl methacrylate copolymer (copolymerization ratio 15/85) 2 parts ・ Carbon black 0.2 parts A carrier was obtained by dispersing to prepare a dispersion, putting the dispersion together with ferrite particles in a vacuum degassing kneader, and drying under reduced pressure while stirring.
Then, 5 parts of each toner was mixed with 100 parts of the carrier to obtain a developer.

<Evaluation of toner>
The following operations, image formation, and measurement were performed in an environment of a temperature of 25 ° C. and a humidity of 60% RH.
A DocuCenter Color 400 manufactured by Fuji Xerox Co., Ltd. was prepared as an image forming apparatus for forming an evaluation image, and the developer (developer containing toner of the corresponding color) was put in the developing device. During image formation, the fixing temperature was 190 ° C. and the fixing pressure was 4.0 kg / cm ² . As the recording medium, coated paper (OS coated paper W manufactured by Fuji Xerox Co., Ltd.) was used.

[Measurement of absorption spectrum of yellow toner]
Yellow toner images (5 cm × 5 cm) were formed on the coated paper so that the absorption spectra of the yellow toners (1) to (8) were 100%, and each yellow toner image (solid image) obtained was formed. ) Was measured by the method described above. Maximum absorption wavelength λmax (“λmax” in the table) of each yellow toner, normalized absorbance at wavelength 510 nm (“A ₅₁₀ ” in table), normalized absorbance at wavelength 550 nm (“A ₅₅₀ ” in table), and The full width at half maximum (“FWHM” in the table) is shown in Table 1.

[Evaluation of color change by light irradiation]
A developer containing each yellow toner (any one of yellow toners (1) to (8)) and a developer containing magenta toner (magenta toner (MA)) are placed in the image forming apparatus, and 1 inch square (2. A red solid image of 54 cm × 2.54 cm) was formed. Specifically, adjustment is made so that the toner adhesion amount (toner application amount on the recording medium) when a red solid image (density 100%) is formed is 5.5 g / m ² (adjustment of development bias) Then, image formation was performed. The order of toner lamination on the coated paper was magenta toner and yellow toner from the coated paper side.
And the coordinate value of CIE1976L ^* a ^* b ^* color system of the obtained red solid image was measured at 10 locations using X-Rite 939 (aperture diameter: 4 mm) manufactured by X-Rite, L ^* value, The average value of a ^* value and b ^* value was calculated.

Next, on the obtained red solid image, Suntest CPS + (manufactured by ATLAS Co., Ltd .; light source: 1500 W xenon air-cooled lamp, irradiance 100 klx, black standard temperature 42 ° C., lamp filter: B (outdoor direct light)) Light irradiation was performed for 960 hours.
Also for the red solid image after light irradiation, the coordinate values of the CIE 1976 L ^* a ^* b ^* color system are measured using X-Rite 939 (aperture diameter: 4 mm) as in the case of the red solid image before light irradiation. Ten points were measured and the average value of L ^* value, a ^* value and b ^* value was calculated.

  Based on the following formula, the color difference ΔE between the red solid image before light irradiation and the red solid image after light irradiation was calculated, and the color change (color difference ΔE) of the red solid image due to light irradiation was evaluated according to the following criteria. . The results are shown in Table 1.

In the above formula, L ₁ , a ₁ , and b ₁ are respectively the L ^* value, a ^* value, and b ^* value in the red solid image before light irradiation, and L ₂ , a ₂ , and b ₂ are L ^* value, a ^* value, and b ^* value in the red solid image after light irradiation, respectively.

-Evaluation criteria-
G0: Color difference ΔE is 15 or less G1: Color difference ΔE exceeds 15 and 40 or less G2: Color difference ΔE exceeds 40 G0 and G1 are at a level where there is no problem.

[Evaluation of color reproducibility]
CIE1976L ^* a ^* b ^* color system coordinate values (L ^* value, a ^* value and b ^* value) in the “red solid image before light irradiation” obtained in the above “evaluation of color change by light irradiation” The saturation C of the red solid image was obtained from the following formula, and the color reproducibility of the red solid image was evaluated according to the following criteria. The results are shown in Table 1.
Formula: C = ((a ^* ) ² + (b ^* ) ² ) ^1/2

-Evaluation criteria-
G0: Saturation C is 85 or more G1: Saturation C is 80 or more and less than 85 G2: Saturation C is less than 80 Note that G0 and G1 are at a level where there is no problem.

  As shown in the above results, it can be seen that in this example, the change in color due to light irradiation in the red solid image is suppressed as compared with Comparative Example 1.

1Y, 1M, 1C, 1K photoconductor (an example of an image carrier)
2Y, 2M, 2C, 2K charging roll (an example of charging means)
3. Exposure device (an example of electrostatic charge image forming means)
3Y, 3M, 3C, 3K Laser beams 4Y, 4M, 4C, 4K Developing device (an example of developing means)
5Y, 5M, 5C, 5K primary transfer roll (an example of primary transfer means)
6Y, 6M, 6C, 6K Photoconductor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt (an example of an intermediate transfer member)
22 Drive roll 24 Support roll 26 Secondary transfer roll (an example of secondary transfer means)
30 Intermediate transfer member cleaning device 107 Photosensitive member (an example of an image holding member)
108 Charging roll (an example of charging means)
109 Exposure apparatus (an example of electrostatic charge image forming means)
111 Developing device (an example of developing means)
112 Transfer device (an example of transfer means)
113 photoconductor cleaning device (an example of cleaning means)
115 Fixing device (an example of fixing means)
116 Mounting rail 117 Housing 118 Opening 200 for exposure Process cartridge 300 Recording paper (an example of a recording medium)
P Recording paper (an example of a recording medium)

Claims (7)

Having toner particles including a binder resin and Pigment Yellow 74;
When the maximum absorption wavelength λmax is in the range of 400 nm to 440 nm and the absorbance at the maximum absorption wavelength λmax is normalized to 1, the absorbance at wavelength 510 nm is 0.20 or less, and the absorbance at wavelength 550 nm is 0.10. The toner for developing an electrostatic charge image is as follows.   The electrostatic image developing toner according to claim 1, wherein the full width at half maximum of the absorption peak at the maximum absorption wavelength λmax is 50 nm or less.   An electrostatic charge image developer comprising the toner for developing an electrostatic charge image according to claim 1. Containing the toner for developing an electrostatic image according to claim 1;
A toner cartridge to be attached to and detached from the image forming apparatus. A developing unit that contains the electrostatic charge image developer according to claim 3 and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer.
A process cartridge attached to and detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
A developing means for containing the electrostatic charge image developer according to claim 3 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the surface of the recording medium;
An image forming apparatus comprising: A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 3;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred to the surface of the recording medium;
An image forming method comprising: