JP2018049151A - 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 reduction in image density occurring when the toner is stored for a long period in a high-temperature and high-humidity environment, an image with a low image density is repeatedly formed, and subsequently a solid image is formed.SOLUTION: A toner for electrostatic charge image development includes toner particles each containing a binder resin and a metal that can take an ionic valence of divalent or more, where the density Mx of the metal measured by X-ray fluorescence analysis (XRF) is 0.02 mass% or more and 0.10 mass% or less; when the volume average particle diameter of the toner particles is D, the relationship between the density Mes (unit: %) of the metal measured by energy dispersive X-ray spectroscopy (EDX) in a condition: acceleration voltage=0.6×D+0.9(kV) and the density Met (unit: %) of the metal measured by energy dispersive X-ray spectroscopy (EDX) in a condition: acceleration voltage=1.8×D+4.9(kV) satisfies the following formula (1): 0.3≤Mes/Met≤0.5.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.

  A method for visualizing image information through an electrostatic charge image by electrophotography or the like is currently used in various fields. In electrophotography, image information is formed as an electrostatic charge image on the surface of an image carrier (for example, a photoreceptor), and a toner image is developed on the surface of the image carrier using a developer containing toner. The image is visualized as an image through a transfer process for transferring the image to a recording medium such as paper and a fixing process for fixing the toner image on the surface of the recording medium.

For example, Patent Document 1 discloses a toner having toner particles containing at least a polyester resin, a colorant, a layered double hydroxide salt and a wax, wherein the layered double hydroxide salt includes an organic anion, and A toner containing at least Mg ²⁺ and Al ³⁺ .

Patent Document 2 states that “in a negatively chargeable toner containing at least a binder resin and a colorant, the general formula (1): Al ₁ (OH) _m (SO ₄ ) _n · xH ₂ O [wherein l, m, and n each represents an integer of 1 or more, and x represents 0 or an integer of 1 or more.] is a negatively chargeable toner containing a basic aluminum sulfate compound.

  Further, Patent Document 3 has “toner particles produced by polymerizing a monomer composition containing at least a polymerizable monomer, a colorant, a crystalline polyester, and a crystal nucleating agent in an aqueous medium. Toner "is disclosed. Furthermore, Patent Document 3 discloses the use of an aluminum benzoate compound or the like as a crystal nucleating agent.

JP 2012-133193 A JP 2004-101859 A JP 2008-015232 A

  An object of the present invention is to provide an electrostatic charge image developing toner having a binder resin and a toner particle containing a metal capable of taking an ionic valence of 2 or more, and the amount of metal measured by fluorescent X-ray analysis (XRF). The concentration Mx is less than 0.02 mass% or more than 0.10 mass%, or the metal concentration Mes and the metal concentration Met measured by energy dispersive X-ray spectroscopy (EDX) do not satisfy the formula (1). Compared to the case, the toner is stored for a long time in a high-humidity environment, and the toner for developing an electrostatic charge image that suppresses a decrease in image density that occurs when a solid image is formed after repeatedly forming an image with a low image density. Is to provide.

  The above problem is solved by the following means. That is,

The invention according to claim 1
The metal concentration Mx is 0.02% by mass or more and 0.10% by mass or less as measured by fluorescent X-ray analysis (XRF), including a binder resin and a metal capable of taking an ionic valence of 2 or more. Have certain toner particles,
When the volume average particle diameter of the toner particles is D, the metal concentration Mes (measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 0.6 × D + 0.9 (kV) (Unit:%) and the metal concentration Met (unit:%) measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 1.8 × D + 4.9 (kV) An electrostatic charge image developing toner satisfying the following formula (1).
Formula (1): 0.30 ≦ Mes / Met ≦ 0.50

The invention according to claim 2
The relation between the acid value AV (KOHmg / g) of the binder resin, the concentration Mx (mass%) of the metal, and the ionic valence IV of the metal satisfies the following formula (2). Toner for developing electrostatic images.
Formula (2): 0.003 ≦ (Mx × IV) /AV≦0.030

The invention according to claim 3
The electrostatic image developing toner according to claim 1, wherein the metal is aluminum.

The invention according to claim 4
An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.

The invention according to claim 5
An electrostatic charge image developing toner according to any one of claims 1 to 3 is accommodated,
A toner cartridge to be attached to and detached from the image forming apparatus.

The invention according to claim 6
A developing means for containing the electrostatic charge image developer according to claim 4 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.

The invention according to claim 7 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;
Development means for containing the electrostatic charge image developer according to claim 4 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 8 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 4;
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, an electrostatic image developing toner having toner particles containing a binder resin and a metal capable of taking an ionic valence of 2 or more is measured by fluorescent X-ray analysis (XRF). The metal concentration Mx is less than 0.02 mass% or more than 0.10 mass%, or the metal concentration Mes and the metal concentration Met measured by energy dispersive X-ray spectroscopy (EDX) are expressed by the formula (1) The electrostatic charge that suppresses the decrease in image density that occurs when a solid image is formed after repeatedly forming a low-image-density image after storing the toner in a high-humidity environment for a long time. An image developing toner is provided.
According to the second aspect of the present invention, compared with the case where the relationship between the acid value AV of the binder resin, the metal concentration Mx, and the ionic valence of the metal does not satisfy the formula (2), the toner can be used in a high humidity environment. Provided is a toner for developing an electrostatic charge image, which is stored for a long period of time and repeatedly suppresses a decrease in image density which occurs when a solid image is formed after repeatedly forming an image having a low image density.
According to the third aspect of the present invention, when the solid image is formed after the toner is stored for a long time in a high-humidity environment and an image having a low image density is repeatedly formed as compared with the case where the metal is barium. Provided is a toner for developing an electrostatic image that suppresses a reduction in image density that occurs.
According to the invention of claim 4, 5, 6, 7, or 8, an electrostatic charge image developing toner comprising toner particles containing a binder resin and a metal capable of taking an ionic valence of 2 or more. The metal concentration Mx measured by X-ray fluorescence analysis (XRF) is less than 0.02% by mass or more than 0.10% by mass, or the metal concentration measured by energy dispersive X-ray spectroscopy (EDX) Compared to the case where an electrostatic charge image developing toner in which the density Mes and the metal density Met do not satisfy the formula (1) is applied, the toner is stored for a long time in a high humidity environment, and an image having a low image density is repeatedly formed. Thereafter, there are provided an electrostatic charge image developer, a toner cartridge, a process cartridge, an image forming apparatus, and an image forming method that suppress a decrease in image density that occurs when a solid image is formed.

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 of this embodiment.

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

(Static image developing toner)
An electrostatic charge image developing toner according to the exemplary embodiment (hereinafter referred to as “toner”) includes a binder resin and a metal capable of taking an ionic valence of 2 or more (hereinafter also simply referred to as “metal”). The toner particles have a metal concentration Mx of 0.02% by mass or more and 0.10% by mass or less as measured by X-ray fluorescence analysis (XRF).
When the volume average particle diameter of the toner particles is D, the metal concentration Mes measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 0.6 × D + 0.9 (kV). (Unit:%) and the metal concentration Met (unit:%) measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 1.8 × D + 4.9 (kV) Satisfies the following formula (1).
Formula (1): 0.30 ≦ Mes / Met ≦ 0.50

  The toner according to the present embodiment has the above-described configuration, after the toner is stored for a long time in a high humidity environment, and an image having a low image density is repeatedly formed (for example, after being stored for 1 week in an environment of 85% RH or higher). , After outputting 20000 images with an image density of 15% or less on A4 paper), suppressing the decrease in image density that occurs when a solid image (image with 100% image density (Cin), image density 100%) is formed To do. The reason is estimated as follows.

  For example, when a solid image is formed after repeatedly forming a low image density image using a toner cartridge stored for a long time in a high humidity environment, the image density decreases. This is because the toner absorbs moisture when stored in a high-humidity environment, and the toner consumption is small in repeated low-image density image formation, and the same toner continues to be subjected to a mechanical load in the developing means. This is presumably because the toner is easily embedded in the toner particles, so that the toner transportability is lowered. That is, if a solid image with a large amount of toner consumption is formed in a state where the toner transportability is lowered, it is considered that the supply of toner cannot catch up and the image density of the solid image is lowered.

  In contrast, in the toner according to the present exemplary embodiment, the metal concentration Mx is set in the above range, and the relationship between the metal concentration Mes and the metal concentration Met satisfies the formula (1).

Here, since the metal concentration Mx is a metal concentration measured by X-ray fluorescence analysis (XRF), it indicates the ratio (mass ratio) of the metal to the entire toner particles.
The metal concentration Mes is determined by energy dispersive X-ray spectroscopy (EDX) under a low acceleration voltage condition of acceleration voltage = 0.6 × D + 0.9 (kV), where D is the volume average particle diameter of toner particles. Since the measured metal concentration, the ratio of metal in the toner particle surface layer (for example, a depth region within 15% of the volume average particle diameter of the toner particles from the surface of the toner particles) on the side irradiated with the electron beam (Mass ratio) is shown.
The metal concentration Met is a metal concentration measured by energy dispersive X-ray spectroscopy (EDX) under the condition of high acceleration voltage such as acceleration voltage = 1.8 × D + 4.9 (kV). Ratio of metal (mass ratio) in the entire toner particles in the irradiated area (the entire area from the surface of the toner particle irradiated with the electron beam to the back surface on the opposite side). ).

  That is, “Mes / Met” in the formula (1) indicates the ratio of the metal concentration Mes in the toner particle surface layer on the side irradiated with the electron beam to the metal concentration Met in the entire toner particles. The expression (1): satisfying 0.30 ≦ Mes / Met ≦ 0.50 indicates that the metal contained in the toner particles is unevenly distributed in the toner particle surface layer.

  On the other hand, it can be considered that the metal contained in the toner particles exists as metal ions. The metal ions are considered to form ionic crosslinks with the functional group (for example, carboxyl group, hydroxyl group, etc.) of the binder resin.

  Then, by suppressing the metal concentration Mx with respect to the entire toner particles to the above range and by making the metal ions unevenly distributed on the surface of the toner particles, the metal ions cause the moisture absorption of the toner particles in the surface layer compared to the central portion of the toner particles. Therefore, even when the toner is stored in a high-humidity environment, moisture absorption of the toner is suppressed. In addition, when the surface layer has more ionic crosslinks due to metal ions than in the central part of the toner particles, the hardness of the surface of the toner particles increases, and even if images with low image density are repeatedly formed, the external additive is It becomes difficult to be embedded in toner particles. As a result, a decrease in toner transportability is suppressed, and even when a solid image with a large amount of toner consumption is formed, toner supply follows and a decrease in the image density of the solid image is suppressed.

  As described above, the toner according to the exemplary embodiment is a solid image (image density (Cin) 100% and image density 100) after the toner is stored for a long time in a high humidity environment and an image with a low image density is repeatedly formed. % Image) is presumed to suppress a decrease in image density.

If the metal concentration of the entire toner particles is increased and ionic cross-linking by metal ions is formed on the entire toner particles, the dielectric constant of the toner particles increases excessively, resulting in a decrease in toner charging ability and poor transfer. It tends to occur. In addition, since the whole toner particles are hardened, fixing defects are likely to occur.
Therefore, the metal concentration Mx with respect to the entire toner particles is suppressed to the above range, and the metal is unevenly distributed on the surface layer of the toner particles so as to satisfy the formula (1), thereby suppressing the decrease in the image density of the solid image. Is also effective from the viewpoint of toner transferability and fixability.

In the toner according to the present exemplary embodiment, the higher the acid value AV of the binder resin, the easier it is to crosslink with metal ions. If the acid value AV of the binder resin is too high, the hygroscopicity of the toner increases. Therefore, from the viewpoint of suppressing a decrease in the image density of a solid image, the relationship between the acid value AV (KOH mg / g) of the binder resin, the metal concentration Mx (mass%), and the metal ionic valence IV is expressed by the following equation: It is preferable to satisfy (2), and it is more preferable to satisfy the following formula (2A).
Formula (2): 0.003 ≦ (Mx × IV) /AV≦0.030
Formula (2A): 0.006 ≦ (Mx × IV) /AV≦0.02

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

  The toner according to this embodiment has toner particles. The toner may have an external additive attached to the surface of the toner particles as necessary.

(Toner particles)
The toner particles include, for example, a binder resin and a metal. The toner particles may contain a colorant, 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 there is a monomer with poor compatibility, it is recommended to condense the monomer with poor compatibility with the monomer and the acid or alcohol to be polycondensed in advance before polycondensing with the main component. .

A styrene (meth) acrylic resin is also suitable as the binder resin.
Examples of the styrene (meth) acrylic resin include known styrene (meth) acrylic resins.

Styrene (meth) acrylic resin is composed of styrene polymerizable monomer (polymerizable monomer having styrene skeleton) and (meth) acrylic polymerizable monomer (polymerizable monomer having (meth) acryloyl skeleton). ) At least a copolymer.
“(Meth) acryl” is an expression including both “acryl” and “methacryl”.

Examples of the styrenic polymerizable monomer include styrene and alkyl-substituted styrene (for example, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrene (for example, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), vinylnaphthalene and the like. A styrene-type polymerizable monomer may be used individually by 1 type, and may use 2 or more types together.
Among these, as the styrene monomer, styrene is preferable in terms of easy reaction, easy control of reaction, and availability.

  Examples of the (meth) acrylic polymerizable monomer include (meth) acrylic acid and (meth) acrylic acid ester. Examples of (meth) acrylic acid esters include (meth) acrylic acid alkyl esters (for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, n-pentyl (meth) acrylate, n-hexyl acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid n-dodecyl, n-lauryl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-octadecyl (meth) acrylate, isopropyl (meth) acrylate, (meth) Isobutyl acrylate, t-butyl (meth) acrylate, isopentyl (meth) acrylate, (meth) acrylic acid Mill, neopentyl (meth) acrylate, isohexyl (meth) acrylate, isoheptyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl Acid t-butylcyclohexyl, etc.), (meth) acrylic acid aryl esters (for example, phenyl (meth) acrylate, biphenyl (meth) acrylate, diphenylethyl (meth) acrylate, t-butylphenyl (meth) acrylate), (Meth) acrylic acid terphenyl etc.), (meth) acrylic acid dimethylaminoethyl, (meth) acrylic acid diethylaminoethyl, (meth) acrylic acid methoxyethyl, (meth) acrylic acid 2-hydroxyethyl, (meth) acrylic acid β-carboxyethyl, (meta ) Acrylamide and the like. The (meth) acrylic acid-based polymerizable monomer may be used alone or in combination of two or more.

  The copolymerization ratio (mass basis, styrene polymerizable monomer / (meth) acrylic polymerizable monomer) between the styrene polymerizable monomer and the (meth) acrylic polymerizable monomer is, for example, 85. / 15 to 70/30 is preferable.

  The styrene (meth) acrylic resin may have a crosslinked structure. The styrene (meth) acrylic resin having a cross-linked structure is, for example, a cross-linked cross-link by at least copolymerizing a styrene polymerizable monomer, a (meth) acrylic acid polymerizable monomer, and a cross-linkable monomer. Things.

Examples of the crosslinkable monomer include bifunctional or higher functional crosslinking agents.
Examples of the bifunctional crosslinking agent include divinylbenzene, divinylnaphthalene, and di (meth) acrylate compounds (for example, diethylene glycol di (meth) acrylate, methylenebis (meth) acrylamide, decanediol diacrylate, glycidyl (meth) acrylate, etc.) , Polyester type di (meth) acrylate, 2-([1′-methylpropylideneamino] carboxyamino) ethyl methacrylate, and the like.
Examples of the polyfunctional crosslinking agent include tri (meth) acrylate compounds (for example, pentaerythritol tri (meth) acrylate, trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, etc.), tetra (meth) acrylate Compound (for example, tetramethylolmethane tetra (meth) acrylate, oligoester (meth) acrylate, etc.), 2,2-bis (4-methacryloxy, polyethoxyphenyl) propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate , Triallyl trimellitate, diaryl chlorendate and the like.

  The copolymerization ratio of the crosslinkable monomer to the total monomer (mass basis, crosslinkable monomer / total monomer) is preferably, for example, 2/1000 to 30/1000.

The glass transition temperature (Tg) of the styrene (meth) acrylic resin is, for example, 50 ° C. or higher and 75 ° C. or lower, preferably 55 ° C. or higher and 65 ° C. or lower, more preferably 57 ° C. or higher and 60 ° C. or lower. It is.
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 of the styrene (meth) acrylic resin is, for example, from 30,000 to 200,000, preferably from 40,000 to 100,000, and more preferably from 50,000 to 80,000 in terms of storage stability.
The weight average molecular weight is 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 is calculated from the measurement result using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

  Here, the acid value AV (mg number of KOH necessary for neutralizing 1 g of resin) of the binder resin is the acid value of the binder resin (1 g of resin is medium) from the viewpoint of suppressing a decrease in the image density of the solid image. 10.5 mgKOH / g or more and 14.5 mgKOH / g or less is preferable, and 11 mgKOH / g or more and 13 mgKOH / g or less is more preferable. The acid value is measured by neutralization titration according to JIS K-0070 (1992).

  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.

-Metal-
As a metal, it is a metal which can take the ion valence more than bivalence. However, as the metal, for example, a metal having an ionic valence of 2 or more (preferably 2 to 4) is preferable.
Specifically, the metal is preferably a metal other than chromium, zirconium, or lead. Suitable examples of the metal include at least one metal ion selected from the group consisting of aluminum, magnesium, zinc, calcium, iron, and copper.

Examples of the metal supply source (compound to be included in the toner particles as an additive) include metal salts, inorganic metal salt polymers, metal complexes, and the like. The metal salt, inorganic metal salt polymer, and metal complex are added to the toner particles as an aggregating agent, for example, when the toner particles are produced by an aggregation coalescence method.
Examples of the metal salt include aluminum sulfate, aluminum chloride, magnesium chloride, magnesium sulfate, iron (II) chloride, zinc chloride, calcium chloride, calcium sulfate and the like.
Examples of the inorganic metal salt polymer include polyaluminum chloride, polyaluminum hydroxide, polyiron sulfate (II), and calcium polysulfide.
Examples of the metal complex include a metal salt of aminocarboxylic acid. Specific examples of the metal complex include metal salts based on known chelates such as ethylenediaminetetraacetic acid, propanediaminetetraacetic acid, nitriletriacetic acid, triethylenetetraminehexaacetic acid, diethylenetriaminepentaacetic acid (for example, calcium salts, Magnesium salt, iron salt, aluminum salt, etc.).

  In addition, you may add these metal supply sources as a mere additive instead of a coagulant | flocculant use.

The higher the ionic valence of the metal, the easier it is to form a network ion bridge, and the metal element having a smaller atomic number has a smaller metal (the metal ion) and a smaller network structure of the bridge. From the viewpoint of reducing the hygroscopicity of the toner due to ionic crosslinking of metal ions, improving the surface hardness of the toner particles, and suppressing the decrease in the image density of the solid image.
For this reason, as a metal, a trivalent metal (especially Al ion) is preferable. That is, the metal supply source is preferably an aluminum salt (for example, aluminum sulfate, aluminum chloride, etc.) or an aluminum salt polymer (for example, polyaluminum chloride, polyaluminum hydroxide). Further, from the viewpoint of suppressing a decrease in the image density of a solid image, an inorganic metal salt polymer is preferable to a metal salt even if the metal ions have the same valence among the metal ion supply sources.

  The metal concentration Mx (concentration of the metal measured by X-ray fluorescence analysis (XRF)) is 0.02% by mass or more and 0.10% by mass or less. From the viewpoint of toner transferability and fixability, it is preferably 0.03% by mass or more and 0.08% by mass or less, and more preferably 0.04% by mass or more and 0.07% by mass or less.

Here, the metal concentration Mx is measured as follows using a fluorescent X-ray analysis method (XRF).
First, a resin and a metal supply source are mixed to obtain a resin mixture having a known metal concentration. A pellet sample is obtained from 200 mg of this resin mixture using a tableting machine having a diameter of 13 mm. The mass of the pellet sample is precisely weighed, and the fluorescent X-ray intensity of the pellet sample is measured to determine the peak intensity. Similarly, measurement is also performed on a pellet sample in which the addition amount of the metal supply source is changed, and a calibration curve is created from these results. Then, using this calibration curve, the metal concentration Mx in the toner particles to be measured is quantitatively analyzed.

When the volume average particle diameter of the toner particles is D, the metal concentration measured by energy dispersive X-ray spectroscopy (EDX) under the condition of metal concentration Mes (acceleration voltage = 0.6 × D + 0.9 (kV)). Concentration) and metal concentration Met (concentration of metal measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 1.8 × D + 4.9 (kV)) Although satisfy | filling Formula (1), it is preferable to satisfy | fill following formula (1A) from a viewpoint of the density fall suppression of a solid image, and it is more preferable to satisfy | fill following formula (1B).
Formula (1): 0.30 ≦ Mes / Met ≦ 0.50
Formula (1A): 0.35 ≦ Mes / Met ≦ 0.50
Formula (1B): 0.40 ≦ Mes / Met ≦ 0.50

Here, the metal concentration Mes and the metal concentration Met are measured as follows using energy dispersive X-ray spectroscopy (EDX).
A pellet sample is obtained from 120 mg of toner particles using a tablet molding machine having a diameter of 13 mm. The pellet sample is measured using an SEM (scanning electron microscope) with an energy dispersive X-ray spectrometer (EDX apparatus) (manufactured by Horiba: Xmax) with an acceleration voltage set. In addition, the content rate of the metal element in the range obtained by observation magnification 1000 times is measured.

  Note that the measurement of metal concentration by X-ray fluorescence analysis (XRF) and energy dispersive X-ray spectroscopy (EDX) is carried out when the external additive is externally added to the toner particles. The toner particles that have been subjected to sonication (cooling water temperature of 20 ° C. or less, treatment strength (amplitude) 180 μm, 30 minutes) to remove external additives adhering to the surface of the toner particles (free) are washed, dried, and recovered. Perform on samples. This operation is repeated until the external additive can be removed.

-Colorant-
Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliant carmine 3B, and brilliant. Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Pigment Blue, Phthalocyanine Green, Various pigments such as malachite green oxalate, or acridine, xanthene, , Benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazole, and other dyes Etc.
A colorant may be used individually by 1 type and may use 2 or more types together.

  As the colorant, a surface-treated colorant may be used as necessary, or it may be used in combination with a dispersant. A plurality of colorants may be used in combination.

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

-Release agent-
Examples of 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.
In addition, a metal is contained in a coating | coated part. Moreover, although the metal may be contained in any of the core part and the coating layer, it is contained in the coating part higher than the core part.

  The volume average particle diameter (D50v) of the toner particles is preferably 2 μm or more and 15 μm or less, and more preferably 3 μm or more and 9 μm or less.

In addition, various average particle diameters and various particle size distribution indexes of the toner particles are measured using Coulter Multisizer II (manufactured by Beckman-Coulter), and the electrolyte is measured using ISOTON-II (manufactured by Beckman-Coulter). 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 particle size distribution index (GSDv) is calculated as (D84v / D16v) ^1/2 and the number particle size distribution index (GSDp) is calculated as (D84p / D16p) ^1/2 .

  The average circularity of the toner particles is preferably from 0.94 to 1.00, more preferably from 0.95 to 0.98.

The average circularity of the toner particles is obtained by (circle equivalent perimeter) / (perimeter) [(perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projected image)]. Specifically, it is a value measured by the following method.
First, the toner particles to be measured are collected by suction, a flat flow is formed, a flash image is instantaneously emitted, a particle image is captured as a still image, and the particle image is analyzed (Sysmex). FPIA-2100) manufactured by the company. The number of samplings for obtaining the average circularity is 3500.
When the toner has an external additive, the toner (developer) to be measured is dispersed in water containing a surfactant and then subjected to ultrasonic treatment to obtain toner particles from which the external additive has been removed. .

(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, and aluminum coupling agents. 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, PMMA, and melamine resin), cleaning activators (for example, metal salts of higher fatty acids typified by zinc stearate, particles of a fluorine-based high molecular weight substance), and the like. Can be mentioned.

  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, from the viewpoint of obtaining toner particles satisfying the metal concentration Mx and the formula (1), it is preferable to obtain toner particles by an aggregation coalescence method.

Specifically, for example, when toner particles are produced by an aggregation coalescence method,
In the first resin particle dispersion liquid in which the first resin particles to be the binder resin are dispersed (in the dispersion liquid after mixing other particle dispersion liquid if necessary), the first resin particles (if necessary) Other particles) to form first aggregated particles (first aggregated particle formation step);
Heating the first agglomerated particle dispersion in which the first agglomerated particles are dispersed, fusing and coalescing the first agglomerated particles to form core particles (first fusing and coalescing step);
The core particle dispersion liquid in which the core particles are dispersed and the second resin particle dispersion liquid in which the second resin particles serving as the binder resin are dispersed are mixed so that the second resin particles adhere to the surface of the core particles. And forming a second aggregated particle (second aggregated particle forming process);
Heating the second agglomerated particle dispersion in which the second agglomerated particles are dispersed, and fusing and coalescing the second agglomerated particles to form core particles (second fusing and coalescing step);
Then, toner particles are manufactured.

Details of each step will be described below.
In the following description, a method of obtaining toner particles containing a colorant and a release agent will be described. However, the colorant and the release agent are used as necessary. Of course, you may use other additives other than a coloring agent and a mold release agent.

-Preparation step of resin particle dispersion-
First, first and second resin particle dispersions (hereinafter collectively referred to as “resin particle dispersions”) in which first and second resin particles (hereinafter collectively referred to as “resin particles”) serving as a binder resin are dispersed. In addition, 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.

  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 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.

  For example, a colorant particle dispersion and a release agent particle dispersion are also prepared in the same manner as the resin particle dispersion. In other words, regarding 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, the colorant particles dispersed in the colorant particle dispersion and the release agent particle dispersion The same applies to the release agent particles to be dispersed.

-First aggregated particle forming step-
Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the first resin particle dispersion.
Then, in the mixed dispersion liquid, the first resin particles, the colorant particles, and the release agent particles are heteroaggregated, and the aggregate includes the first resin particles, the colorant particles, and the release agent particles having a target diameter. Form particles.

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 first resin particles are heated to a glass transition temperature (specifically, for example, the glass transition temperature of the resin particles −30 ° C. or higher and the glass transition temperature −10 ° C. or lower), and the particles dispersed in the mixed dispersion are aggregated. To form 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.

As the flocculant, for example, a surfactant having a reverse polarity to the surfactant used as a dispersant added to the mixed dispersion, an inorganic metal salt, a divalent or higher valent metal complex, and the like are used. 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.
And when using an inorganic metal salt, a bivalent or more metal complex, etc. as an aggregating agent, the additive which forms a complex or a similar bond with the metal (metal ion) of an aggregating agent is added after completion | finish of aggregation. As this additive, a chelating agent is preferably used. By adding this chelating agent, the flocculant is removed from the core particles to be formed, and the metal concentration in the core particles is reduced or no metal is contained in the core particles.

  Here, the metal salt, metal salt polymer, and metal complex as the flocculant are used as a metal supply source. These examples are as described above.

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.

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

  In addition, after completion | finish of a 1st fusion | combination and uniting process, a solid-liquid separation process, a well-known washing | cleaning process, etc. are implemented for the core particle formed in the solution, and a core particle is obtained. Moreover, after passing through the washing process, the solid-liquid separation process and the drying process may be performed to obtain the dried core particles.

-Second aggregated particle forming step-
Next, the core particle dispersion in which the core particles are dispersed and the second resin particle dispersion are mixed.
Then, in the mixed dispersion, the second resin particles adhere to the surface of the core particles having a diameter close to the target toner particle diameter by heteroaggregating so that the second resin particles adhere to the surface of the core particles. 2 Form aggregated particles.

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. Particles heated to a temperature of the glass transition temperature of the second resin particles (specifically, for example, the glass transition temperature of the second resin particles −30 ° C. or more and the glass transition temperature −10 ° C. or less) and dispersed in the mixed dispersion liquid Are aggregated to form second aggregated particles.
In the second agglomerated particle forming step, for example, the agglomerating 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). 5 or less) and, if necessary, after adding a dispersion stabilizer, the heating may be performed.

As the aggregating agent, an inorganic metal salt or a metal complex capable of taking a valence of 2 or more is used.
And after completion | finish of aggregation, the additive which forms a complex or a similar bond with the metal (metal ion) of an aggregating agent is added. As this additive, a chelating agent is preferably used. Adjustment of the metal concentration of the surface layer of the toner particles to be formed is realized by the addition amount of the chelating agent.

Here, the metal salt, metal salt polymer, and metal complex as the flocculant are used as a metal supply source. These examples are as described above.
Examples of chelating agents are as described above.
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.

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

  Through the above-described steps, the toner particles satisfying the above-mentioned range and the relationship between the metal concentration Mes and the metal concentration Met satisfying the formula (1) can be obtained.

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. In addition, the drying process is not particularly limited, but from the viewpoint of productivity, freeze drying, airflow 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. Furthermore, if necessary, coarse particles of toner may be removed using a vibration sieving machine, a wind power classifier, 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 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, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

Examples of the coating resin and the 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 ester. Examples thereof include a straight silicone resin comprising a copolymer, 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, a 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 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 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. 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 embodiment explains this embodiment in detail, this embodiment is not limited to these examples at all. In the following description, “part” and “%” are all based on mass unless otherwise specified.

<Preparation of resin particle dispersion>
(Preparation of resin particle dispersion (P1))
・ Terephthalic acid: 20 mol parts ・ Fumaric acid: 50 mol parts ・ Bisphenol A ethylene oxide adduct: 20 mol parts ・ Bisphenol A propylene oxide adduct: 80 mol parts Stirrer, nitrogen introduction tube, temperature sensor, and rectification tower 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 having a weight average molecular weight of 22,000, a glass transition temperature of 58 ° C., and an acid value of 12 KOH mg / g was synthesized.

40 parts of ethyl acetate and 25 parts of 2-butanol are put into a container equipped with a temperature control means and a nitrogen replacement means to make a mixed solvent, and then 100 parts of a polyester resin is gradually added and dissolved therein. % 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 solution. After completion of the dropping, the temperature is returned to room temperature (20 ° C. to 25 ° C.), and bubbling with dry nitrogen is performed for 48 hours while stirring to reduce ethyl acetate and 2-butanol to 1000 ppm or less to disperse the resin particles. Got. Ion exchange water was added to the resin particle dispersion to adjust the solid content to 20% by mass.
Through the above operation, a resin particle dispersion (P1) was obtained.

(Preparation of resin particle dispersion (P2))
Resin particles except that 15 mol parts of terephthalic acid, 50 mol parts of fumaric acid, 5 mol parts of trimellitic acid, 70 mol parts of bisphenol A ethylene oxide adduct and 25 mol parts of bisphenol A propylene oxide adduct Similarly to the dispersion liquid (P1), a resin particle dispersion liquid (P2) in which polyester resin particles having a weight average molecular weight of 40000, a glass transition temperature of 62 ° C., and an acid value of 10.8 KOH mg / g were dispersed was obtained.

(Preparation of resin particle dispersion (P3))
The resin particle dispersion (P1) was the same as the resin particle dispersion (P1) except that 30 mol parts of terephthalic acid, 70 mol parts of fumaric acid, 5 mol parts of bisphenol A ethylene oxide adduct, and 95 mol parts of bisphenol A propylene oxide adduct were used. Thus, a resin particle dispersion (P3) in which polyester resin particles having a weight average molecular weight of 18000, a glass transition temperature of 60 ° C., and an acid value of 15 KOH mg / g were dispersed was obtained.

(Preparation of resin particle dispersion (P4))
Except for 45 parts by mole of terephthalic acid, 5 parts by mole of fumaric acid, 45 parts by mole of bisphenol A ethylene oxide adduct and 55 parts by mole of bisphenol A propylene oxide adduct, the same as the resin particle dispersion (P1). Thus, a resin particle dispersion (P4) in which polyester resin particles having a weight average molecular weight of 28000, a glass transition temperature of 59 ° C., and an acid value of 10 KOH mg / g were dispersed was obtained.

(Preparation of resin particle dispersion (S1))
-Styrene: 320 parts by mass-n-butyl acrylate: 80 parts by mass-Acrylic acid: 12 parts by mass-10-dodecanethiol: 2 parts by mass A mixture of the above components dissolved therein is dissolved in a nonionic surfactant ( Nonipol 400 (manufactured by Sanyo Chemical Co., Ltd.) 6 parts by mass and anionic surfactant (Neogen SC, Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts by mass in ion-exchanged water 550 parts by mass in a flask While emulsifying and dispersing, slowly mixing for 10 minutes, 50 parts by mass of ion-exchanged water having 4 parts by mass of ammonium persulfate dissolved therein was added thereto. After carrying out nitrogen substitution, while stirring the inside of the flask, the contents were heated in an oil bath until the temperature reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin dispersion was obtained in which styrene acrylic resin particles having a volume average particle diameter D50v = 210 nm, a weight average molecular weight of 38000, a glass transition temperature of 50 ° C., and an acid value of 13.5 KOHmg / g were dispersed.

<Preparation of colorant particle dispersion>
(Preparation of colorant particle dispersion (1))
Cyan pigment: 10 parts by mass [Pigment Blue 15: 3, manufactured by Dainichi Seika Kogyo Co., Ltd.]
Anionic surfactant: 2 parts by mass [Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.]
-Ion-exchanged water: 80 parts by mass The above components are mixed and dispersed for 1 hour by a high-pressure impact disperser optimizer [HJP30006, manufactured by Sugino Machine Co., Ltd.], with a volume average particle size of 180 nm and a solid content of 20% by mass. A colorant particle dispersion (1) was obtained.

<Preparation of release agent particle dispersion>
(Releasing agent particle dispersion (1))
Carnauba wax: 50 parts by mass [RC-160, melting temperature 84 ° C., manufactured by Toa Kasei Co., Ltd.]
Anionic surfactant: 2 parts by mass [Neogen SC, manufactured by Daiichi Kogyo Seiyaku]
・ Ion-exchanged water: 200 parts by mass The above components were heated to 120 ° C., mixed and dispersed with IKA's Ultra Turrax T50, and then dispersed with a pressure discharge type homogenizer. A release agent particle dispersion (1) having a content of 20% by mass was obtained.

<Example 1>
(Production of Toner (1))
-Core particle formation process-
Polyester resin particle dispersion (P1): 400 parts by weight Colorant particle dispersion (1): 15 parts by weight Release agent particle dispersion (1): 25 parts by weight Ion exchange water: 1000 parts by weight The components were dispersed in a round stainless steel flask with a homogenizer (IKA, Ultra Turrax T50) so that the components were sufficiently mixed. Thereafter, 5 parts by mass of a 10% polyaluminum chloride aqueous solution as a flocculant was added to the dispersion, and the contents in the flask were stirred using a water bath. After confirming that it was dispersed, using a three-one motor (BLh300 manufactured by Shinto Kagaku Co., Ltd.), stirring at a stirring rotation speed of 150 rpm, heating and stirring to 45 ° C. at a heating rate of 0.5 ° C./min, Hold at 45 ° C. for 60 minutes. When the obtained contents were observed with an optical microscope, it was confirmed that aggregated particles having a particle diameter of 4.0 μm were generated. Next, after adding 1 part by mass of 30% EDTA aqueous solution as a chelating agent, the pH was adjusted to 7.5 with 0.8 M sodium hydroxide aqueous solution. Thereafter, the temperature was raised and the aggregated particles were fused and united at 95 ° C. for 5 hours, then cooled, filtered, sufficiently washed with ion-exchanged water, and dried to obtain core particles.

-Toner particle formation process-
Next, 15 parts by mass of the obtained core particles were again mixed with 100 parts of ion-exchanged water to prepare a core particle dispersion.
80 parts by mass of the core particle dispersion and 10 parts by mass of the polyester resin particle dispersion (P1) are mixed in a round stainless steel flask with a homogenizer (IKA, Ultra Turrax T50). To disperse. Thereafter, 5 parts by mass of a 10% polyaluminum chloride aqueous solution as a flocculant was added to the dispersion, and the contents in the flask were stirred using a water bath. After confirming that it was dispersed, using a three-one motor (BLh300 manufactured by Shinto Kagaku Co., Ltd.), stirring at a stirring rotation speed of 150 rpm, heating and stirring to 45 ° C. at a heating rate of 0.5 ° C./min, Hold at 45 ° C. for 60 minutes. Next, after adding 0.5 mass part of 30% EDTA aqueous solution as a chelating agent, pH was adjusted to 7.5 with 0.8 M sodium hydroxide aqueous solution. Thereafter, the temperature is raised and the aggregated particles are fused and united at 95 ° C. for 5 hours, and then cooled, filtered, sufficiently washed with ion-exchanged water, and dried to a toner having a volume average particle diameter of 5.1 μm. Particles (1) were obtained.

-Toner preparation process-
Thereafter, 3.3 parts by mass of hydrophobic silica particles (produced by Nippon Aerosil Co., Ltd., RY50) were added as an external additive to 100 parts by mass of the toner particles (1). Next, the mixture was mixed for 3 minutes at a peripheral speed of 30 m / s using a Henschel mixer. Thereafter, the toner (1) was obtained by sieving with a vibration sieve having an opening of 45 μm.

<Examples 2 to 15 and Comparative Examples 1 to 5>
According to Table 1, except that the type of resin particle dispersion, the type and amount of the flocculant and chelating agent in the core particle preparation step, and the type and amount of the flocculant and chelating agent in the toner particle preparation step were changed. In the same manner as in Example 1, toner particles were prepared, and toner was obtained using the toner particles.

<Measurement / Evaluation>

(Various measurements)
For each toner (toner particle), the metal concentration Mx, the metal concentration Mes, and the metal concentration Met were measured according to the method described above.
Further, the relationship between the acid value AV (KOH mg / g) of the binder resin, the metal concentration Mx (mass%), and the ionic valence IV of the metal was also examined.
These results are shown in Table 1. Table 1 also shows the volume average particle diameter D (expressed as “particle diameter D” in the table) of the toner particles.

(Development of developer)
8 parts by mass of the toner prepared in each example and 92 parts by mass of the following carrier (A) were placed in a V blender and stirred for 20 minutes, and then sieved with a 105 μm mesh to prepare a developer.

-Production of carrier (A)-
Ferrite particles (volume average particle size 50 μm): 100 parts by mass Toluene: 100 parts by mass Styrene-methyl methacrylate copolymer (component molar ratio: 90/10): 2 parts by mass Carbon black (R330, manufactured by Cabot Corporation) ): 0.25 parts by mass First, the above components excluding ferrite particles were stirred with a stirrer for 10 minutes to prepare a dispersed coating solution, and then this coating solution and ferrite particles were put in a vacuum degassing type kneader. After stirring at 25 ° C. for 25 minutes, carrier A was prepared by further depressurizing while heating and degassing and drying. This carrier (A) had a shape factor = 120, a true specific gravity = 4.4, a saturation magnetization = 63 emu / g, and a volume resistivity value of 1000 Ω · cm at an applied electric field of 1000 V / cm.

(Image density evaluation)
The obtained developer was filled in a developing device of an image forming apparatus (“Versant ^™ 2100 Press” manufactured by Fuji Xerox Co., Ltd.). Further, the toner of each example was filled in a toner cartridge. The image forming apparatus and the toner cartridge were stored in a high temperature and high humidity environment (28 ° C. and 85% RH environment). Thereafter, the toner cartridge was attached to the image forming apparatus.

Using this image forming apparatus, after outputting 20000 images with an image density of 15% on A4 paper, 20 solid images with 100% image density (images with 100% image density (Cin)) are printed on A4 paper. Output. The image density of the output fifth solid image was measured.
On the other hand, the image density of a solid image when a solid image similar to the above was formed using an image forming apparatus and a toner cartridge that were not stored under a high temperature and high humidity environment (28 ° C. and 85% RH environment) was also measured.
Then, an image density difference (ΔSAD: absolute value) between solid images when stored in a high temperature and high humidity environment and when not stored was evaluated according to the following evaluation criteria. The results are shown in Table 1.
-Evaluation criteria-
A (◎): ΔSAD ≦ 0.1
B (◯): 0.1 <ΔSAD ≦ 0.2
C (Δ): 0.2 <ΔSAD ≦ 0.3
D (x): 0.3 <ΔSAD

  From the above results, in this embodiment, compared with the comparative example, the image density generated when a solid image is formed after repeatedly storing a toner in a high humidity environment for a long time and repeatedly forming a low image density image. It turns out that a fall is suppressed.

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 Attachment rail 118 Opening 117 for exposure 117 Case 200 Process cartridge 300 Recording paper (an example of recording medium)
P Recording paper (an example of a recording medium)

Claims (8)

The metal concentration Mx is 0.02% by mass or more and 0.10% by mass or less as measured by fluorescent X-ray analysis (XRF), including a binder resin and a metal capable of taking an ionic valence of 2 or more. Have certain toner particles,
When the volume average particle diameter of the toner particles is D, the metal concentration Mes (measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 0.6 × D + 0.9 (kV) (Unit:%) and the metal concentration Met (unit:%) measured by energy dispersive X-ray spectroscopy (EDX) under the condition of acceleration voltage = 1.8 × D + 4.9 (kV) An electrostatic charge image developing toner satisfying the following formula (1).
Formula (1): 0.30 ≦ Mes / Met ≦ 0.50 The relation between the acid value AV (KOHmg / g) of the binder resin, the concentration Mx (mass%) of the metal, and the ionic valence IV of the metal satisfies the following formula (2). Toner for developing electrostatic images.
Formula (2): 0.003 ≦ (Mx × IV) /AV≦0.030   The electrostatic image developing toner according to claim 1, wherein the metal is aluminum.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1. An electrostatic charge image developing toner according to any one of claims 1 to 3 is accommodated,
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 4 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;
Development means for containing the electrostatic charge image developer according to claim 4 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 4;
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: