JP7263870B2 - Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, image forming apparatus and image forming method - Google Patents

Description

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

Patent Document 1 discloses a toner for electrostatic charge image development to which silica particles surface-treated with cyclic siloxane and having a carbon content of 5% or more and 10% or less are externally added.
Patent Document 2 discloses an electrophotographic toner externally added with inorganic particles surface-treated with silicone oil.
Patent Document 3 discloses a toner containing silica treated with a titanate coupling agent.

JP 2016-167029 A JP 2007-248867 A JP-A-11-038685

The present disclosure is a toner for electrostatic image development in which the total content of low-molecular-weight siloxanes having a molecular weight of 200 to 600 is greater than 5 ppm, or a low-molecular-weight siloxane having a molecular weight of 200 to 600, which has a molecular weight of less than 200 or a molecular weight of more than 600. An object of the present invention is to provide a toner for developing an electrostatic charge image, which quickly reaches an expected charge amount by stirring in a developing device as compared with a toner for developing an electrostatic charge image containing a low-molecular-weight siloxane.

Specific means for solving the above problems include the following aspects.

<1> Toner particles, inorganic particles externally added to the toner particles, and low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less composed only of siloxane bonds and alkyl groups, and the total content of the low-molecular-weight siloxane An electrostatic charge image developing toner having an amount of 0.01 ppm or more and 5 ppm or less on a mass basis.
<2> The toner for developing an electrostatic charge image according to <1>, wherein the total content of the low-molecular-weight siloxane is 10 ppm or more and 1000 ppm or less based on the total content of the inorganic particles.
<3> The electrostatic image developing toner according to <1> or <2>, wherein the inorganic particles include sol-gel silica particles having an average primary particle size of 20 nm or more and 90 nm or less.
<4> The inorganic particles contain sol-gel silica particles having a mass reduction rate of 1% by mass or more and 10% by mass or less when heated from 30° C. to 250° C. at a heating rate of 30° C./min. The toner for electrostatic image development according to any one of <3>.
<5> The electrostatic charge according to any one of <1> to <4>, wherein the low-molecular-weight siloxane contains at least one selected from the group consisting of low-molecular-weight linear siloxane and low-molecular-weight branched siloxane. Toner for image development.
<6> The electrostatic charge image developing toner according to any one of <1> to <5>, wherein the low-molecular-weight siloxane contains a low-molecular-weight siloxane having a tetrakis structure.
<7> The electrostatic image developing toner according to any one of <1> to <6>, wherein the low-molecular-weight siloxane contains tetrakis(trimethylsiloxy)silane.
<8> An electrostatic charge image developer containing the electrostatic charge image developing toner according to any one of <1> to <7>.
<9> A toner cartridge that contains the toner for developing an electrostatic charge image according to any one of <1> to <7> and is attachable to and detachable from an image forming apparatus.
<10> Developing means for accommodating the electrostatic charge image developer according to <8> and developing the electrostatic charge image formed on the surface of the image carrier by the electrostatic charge image developer as a toner image; A process cartridge that is attached to and detached from a forming apparatus.
<11> an image carrier; charging means for charging the surface of the image carrier; electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier; developing means for accommodating a charge image developer and developing the electrostatic charge image formed on the surface of the image carrier by the electrostatic charge image developer into a toner image; and the toner formed on the surface of the image carrier. An image forming apparatus comprising: transfer means for transferring an image onto the surface of a recording medium; and fixing means for fixing the toner image transferred onto the surface of the recording medium.
<12> A charging step of 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, and the electrostatic charge image developer according to <8>, a developing step of developing an electrostatic charge image formed on the surface of the image carrier into a toner image; a transfer step of transferring the toner image formed on the surface of the image carrier onto a surface of a recording medium; and a fixing step of fixing the toner image transferred to the surface of the image forming method.

According to the invention according to <1>, the toner for electrostatic image development in which the total content of low-molecular siloxane having a molecular weight of 200 or more and 600 or less is more than 5 ppm, or the low-molecular weight siloxane having a molecular weight of 200 or more and 600 or less Provided is a toner for developing an electrostatic image, which quickly reaches an expected charge amount by stirring in a developing device, as compared with a toner for developing an electrostatic image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600.
According to the invention according to <2>, the total content of low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is more than 1000 ppm with respect to the total content of inorganic particles, and the toner for developing an electrostatic charge image has Provided is a toner for developing an electrostatic charge image that quickly reaches an expected charge amount by agitation at .
According to the invention relating to <3>, the toner for electrostatic charge image development quickly reaches the charge amount expected by stirring in the developing device compared to the case where the average primary particle diameter of the sol-gel silica particles is 100 nm. is provided.
According to the invention according to <4>, the charge amount expected by stirring in the developing device is rapidly reached compared to the case where the mass reduction rate of the sol-gel silica particles is less than 1% by mass or more than 10% by mass. An electrostatic charge image developing toner is provided.
According to the invention according to <5>, compared to the case where the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is a low-molecular-weight cyclic siloxane, the electrostatic charge quickly reaches the expected charge amount by stirring in the developing device. An image developing toner is provided.
According to the invention according to <6> or <7>, compared to the case where the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is decamethyltetrasiloxane, the charging amount can be quickly achieved by stirring in the developing device. Toners for developing electrostatic charge images are provided.

According to the invention according to <8>, the toner for electrostatic image development in which the total content of low-molecular siloxane having a molecular weight of 200 or more and 600 or less is more than 5 ppm, or the low-molecular weight siloxane having a molecular weight of 200 or more and 600 or less An electrostatic charge image containing a toner for developing an electrostatic charge image that quickly reaches the charge amount expected by stirring in a developing device compared to a toner for developing an electrostatic charge image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600. A developer is provided.
According to the invention according to <9>, the toner for electrostatic image development in which the total content of low-molecular-weight siloxane having a molecular weight of 200 to 600 is more than 5 ppm, or the low-molecular-weight siloxane having a molecular weight of 200 to 600 A toner cartridge containing a toner for developing an electrostatic charge image that quickly reaches the charge amount expected by stirring in a developing device compared to the toner for developing an electrostatic charge image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600. is provided.
According to the invention according to <10>, the toner for electrostatic image development in which the total content of low-molecular siloxane having a molecular weight of 200 or more and 600 or less is more than 5 ppm, or the low-molecular weight siloxane having a molecular weight of 200 or more and 600 or less An electrostatic charge image containing a toner for developing an electrostatic charge image that quickly reaches the charge amount expected by stirring in a developing device compared to a toner for developing an electrostatic charge image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600. A process cartridge with applied developer is provided.
According to the invention according to <11>, the toner for electrostatic image development in which the total content of low-molecular siloxane having a molecular weight of 200 or more and 600 or less is more than 5 ppm, or the low-molecular weight siloxane having a molecular weight of 200 or more and 600 or less An electrostatic charge image containing a toner for developing an electrostatic charge image that quickly reaches the charge amount expected by stirring in a developing device compared to a toner for developing an electrostatic charge image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600. An image forming apparatus applying a developer is provided.
According to the invention according to <12>, the toner for electrostatic image development in which the total content of low-molecular siloxane having a molecular weight of 200 or more and 600 or less is more than 5 ppm, or the low-molecular weight siloxane having a molecular weight of 200 or more and 600 or less An electrostatic charge image containing a toner for developing an electrostatic charge image that quickly reaches the charge amount expected by stirring in a developing device compared to a toner for developing an electrostatic charge image containing a low-molecular-weight siloxane having a molecular weight of less than 200 or more than 600. A method of forming an image using a developer is provided.

1 is a schematic configuration diagram showing an example of an image forming apparatus according to an embodiment; FIG. 1 is a schematic configuration diagram showing an example of a process cartridge detachable from an image forming apparatus according to an exemplary embodiment; FIG.

Embodiments of the present disclosure will be described below. These descriptions and examples are illustrative of embodiments and do not limit the scope of embodiments.

In the present disclosure, a numerical range indicated using "to" indicates a range including the numerical values before and after "to" as the minimum and maximum values, respectively.

In the numerical ranges described step by step in the present disclosure, the upper limit or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described step by step. . Moreover, in the numerical ranges described in the present disclosure, the upper or lower limits of the numerical ranges may be replaced with the values shown in the examples.

In the present disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

When embodiments are described in the present disclosure with reference to drawings, the configurations of the embodiments are not limited to the configurations shown in the drawings. In addition, the sizes of the members in each drawing are conceptual, and the relative relationship between the sizes of the members is not limited to this.

In the present disclosure, each component may contain multiple types of applicable substances. When referring to the amount of each component in the composition in the present disclosure, when there are multiple types of substances corresponding to each component in the composition, unless otherwise specified, the multiple types of substances present in the composition It means the total amount of substance.

Particles corresponding to each component in the present disclosure may include a plurality of types. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means a value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

In the present disclosure, "toner for developing an electrostatic charge image" may be simply referred to as "toner", and "electrostatic charge image developer" may simply be referred to as "developer".

<Toner for electrostatic charge image development>
The toner according to the exemplary embodiment includes toner particles, inorganic particles externally added to the toner particles, and low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less composed only of siloxane bonds and alkyl groups. The total content of molecular siloxane is 0.01 ppm or more and 5 ppm or less based on mass. ppm is an abbreviation for parts per million.

In the present disclosure, siloxane refers to siloxane composed only of siloxane bonds and alkyl groups, unless otherwise specified. For purposes of this disclosure, siloxanes with a molecular weight of less than 1000 fall under the category of low molecular weight siloxanes, and siloxanes with a molecular weight of 1000 or greater fall under the category of silicone oils.

The toner according to the present embodiment quickly reaches an expected charge amount by being agitated in the developing device. Therefore, with the toner according to the present embodiment, the occurrence of fogging is suppressed immediately after operation. In the present disclosure, "fogging" refers to a phenomenon in which toner adheres to a portion of an image carrier having no electrostatic charge image, and an unintended image appears on a recording medium.

In the toner according to the present embodiment, part or all of the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less adheres to the surfaces of the inorganic particles as the external additive, and the molecular weight of 200 that adheres to the surfaces of the inorganic particles It is presumed that the low-molecular-weight siloxane having a molecular weight of 600 or less increases the frictional force acting between the inorganic particles, so that the toner quickly reaches the expected charge amount by stirring in the developing device.
If the total content of low-molecular-weight siloxanes having a molecular weight of 200 or more and 600 or less is less than 0.01 ppm with respect to the mass of the toner, the above effects of the low-molecular-weight siloxanes are difficult to obtain.
If the total content of low-molecular-weight siloxanes having a molecular weight of 200 or more and 600 or less is more than 5 ppm with respect to the mass of the toner, the dielectric constant of the toner becomes relatively low, and the amount of charge is less than expected due to stirring in the developing device. assumed to be difficult to reach.
Therefore, the total content of low-molecular-weight siloxanes having a molecular weight of 200 to 600 is 0.01 ppm to 5 ppm with respect to the mass of the toner. It is presumed that the amount of charge reached quickly.

In the toner according to the exemplary embodiment, part or all of the low-molecular-weight siloxane having a molecular weight of 200 to 600 is attached to the surface of the inorganic particles as the external additive.
In a toner in which a low-molecular-weight siloxane having a molecular weight of less than 200 is attached to the surfaces of inorganic particles instead of a low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less, the kinematic viscosity of the low-molecular-weight siloxane is relatively low. It is presumed that, compared to the toner according to the present embodiment, it is difficult to reach the expected amount of charge due to agitation in the developing device because it lacks the effect of increasing the working frictional force.
A toner in which a low-molecular-weight siloxane having a molecular weight of more than 600 is attached to the surfaces of inorganic particles instead of a low-molecular-weight siloxane having a molecular weight of 200 to 600 has a low dielectric constant because the low-molecular-weight siloxane has relatively low conductivity. Compared to the toner according to the present embodiment, it is presumed that the expected amount of charge is less likely to be reached due to the agitation in the developing device.

The toner according to the present embodiment is selected from low-molecular-weight siloxane having a molecular weight of less than 200, low-molecular-weight siloxane having a molecular weight of more than 600 and less than 1,000, and silicone oil having a molecular weight of 1,000 or more, as long as the effects of the toner of the present embodiment are not impaired. may contain at least one of

Details of the toner according to the exemplary embodiment will be described below.

[Toner particles]
The toner particles contain, for example, a binder resin, and if necessary, a colorant, a release agent, and other additives.

- Binder resin -
Examples of binder resins 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 (e.g. acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), olefins (e.g., ethylene, propylene, butadiene, etc.) or a copolymer of two or more of these monomers in combination.
Examples of the binder resin include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, modified rosin, mixtures of these with the vinyl resins, or A graft polymer obtained by polymerizing a vinyl-based monomer in the coexistence thereof may also be used.
These binder resins may be used singly or in combination of two or more.

A polyester resin is suitable as the binder resin.
Examples of polyester resins include known amorphous polyester resins. A polyester resin may be used in combination with a crystalline polyester resin together with an amorphous polyester resin. However, the content of the crystalline polyester resin is preferably in the range of 2 mass % to 40 mass % (preferably 2 mass % to 20 mass %) based on the total binder resin.

The “crystallinity” of the resin means that in differential scanning calorimetry (DSC), it has a clear endothermic peak instead of a stepwise endothermic change. ) means that the half width of the endothermic peak is within 10°C.
On the other hand, the “amorphous” resin means that the half width exceeds 10° C., shows a stepwise change in endothermic amount, or shows no clear endothermic peak.

- Amorphous Polyester Resin Examples of amorphous polyester resins include condensation polymers of polyhydric carboxylic acids and polyhydric alcohols. A commercially available product or a synthesized product may be used as the amorphous polyester resin.

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

Polyhydric alcohols include, for example, aliphatic diols (eg, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (eg, cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (eg, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, as the polyhydric alcohol, for example, aromatic diols and alicyclic diols are preferred, and aromatic diols are more preferred.
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 trihydric or higher polyhydric alcohols 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 amorphous polyester resin is preferably 50°C or higher and 80°C or lower, more preferably 50°C or higher and 65°C or lower.
The glass transition temperature is obtained from a DSC curve obtained by differential scanning calorimetry (DSC). outer glass transition start temperature".

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

An amorphous polyester resin is obtained by a known production method. Specifically, for example, the polymerization temperature is set to 180° C. or higher and 230° C. or lower, and the pressure in the reaction system is reduced as necessary to remove water and alcohol generated during condensation while the reaction is performed.
If the raw material monomers do not dissolve or are not compatible with each other at the reaction temperature, a solvent with a high boiling point may be added as a dissolution aid to dissolve them. In this case, the polycondensation reaction is carried out while distilling off the solubilizing agent. If a monomer with poor compatibility is present in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance, and then the main component is polymerized. It is good to condense.

-Crystalline polyester resin Examples of crystalline polyester resins include polycondensates of polyhydric carboxylic acids and polyhydric alcohols. As the crystalline polyester resin, a commercially available product or a synthesized product may be used.
Here, the crystalline polyester resin is preferably a polycondensate using a straight-chain aliphatic polymerizable monomer rather than an aromatic ring-containing polymerizable monomer, in order to easily form a crystal structure.

Examples of polyvalent carboxylic acids include aliphatic dicarboxylic acids (eg, oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g. phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,6-dicarboxylic acid dibasic acids such as acids), anhydrides thereof, or lower alkyl esters thereof (for example, having 1 or more and 5 or less carbon atoms).
The polyvalent carboxylic acid may be used in combination with a dicarboxylic acid and a trivalent or higher carboxylic acid having a crosslinked or branched structure. Trivalent carboxylic acids include, for example, aromatic carboxylic acids (eg, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.), Anhydrides or lower alkyl esters thereof (for example, having 1 or more and 5 or less carbon atoms) can be mentioned.
As the polyvalent carboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used together with these dicarboxylic acids.
Polyvalent carboxylic acid may be used individually by 1 type, and may use 2 or more types together.

Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols having a main chain portion having 7 or more and 20 or less carbon atoms). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18- octadecanediol, 1,14-eicosandecanediol, and the like. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable as aliphatic diols.
Polyhydric alcohols may be used in combination with diols and trihydric or higher alcohols having a crosslinked or branched structure. Examples of trihydric or higher alcohol include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.
A polyhydric alcohol may be used individually by 1 type, and may use 2 or more types together.

Here, the polyhydric alcohol preferably has an aliphatic diol content of 80 mol % or more, preferably 90 mol % or more.

The melting temperature of the crystalline polyester resin is preferably 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 90° C. or lower, and even more preferably 60° C. or higher and 85° C. or lower.
The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), according to the "melting peak temperature" described in JIS K7121:1987 "Method for measuring transition temperature of plastics".

The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 6,000 or more and 35,000 or less.

A crystalline polyester resin can be obtained, for example, by a known production method in the same manner as amorphous polyester.

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

-coloring agent-
Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, thren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliant carmine 3B, brilliant Carmine 6B, Dupont Oil Red, Pyrazolone Red, Lithol 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, Pigments such as malachite green oxalate; acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine , triphenylmethane-based, diphenylmethane-based, and thiazole-based dyes;
The colorants may be used singly or in combination of two or more.

As for the coloring agent, a surface-treated coloring agent may be used as necessary, and a dispersing agent may be used in combination. Also, a plurality of types of colorants may be used in combination.

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

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

The melting temperature of the releasing agent is preferably 50° C. or higher and 110° C. or lower, more preferably 60° C. or higher and 100° C. or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), according to the "melting peak temperature" described in JIS K7121:1987 "Method for measuring transition temperature of plastics".

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

-Other additives-
Other additives include, for example, known additives such as magnetic substances, charge control agents, and inorganic powders. These additives are contained in the toner particles as internal additives.

-Characteristics of Toner Particles-
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 portion (core particle) and a coating layer (shell layer) covering the core portion. may The toner particles having a core-shell structure are composed of, for example, a core portion containing a binder resin and other additives such as a colorant and a release agent as necessary, and a binder resin. and a coating layer.

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

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

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

The average circularity of toner particles is obtained by (equivalent circle perimeter)/(perimeter) [(perimeter of circle having the same projected area as the particle image)/(perimeter of projected particle image)]. Specifically, it is a value measured by the following method.
First, a flow-type particle image analyzer (Sysmex) picks up the toner particles to be measured by suction, forms a flat flow, captures the particle image as a static image by instantaneous strobe light emission, and analyzes the image of the particle image. FPIA-3000 manufactured by Co., Ltd.). Then, the number of samples for obtaining the average circularity is 3500.
When the toner contains 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 is removed.

[External Additive]
The toner according to the exemplary embodiment contains inorganic particles as an external additive. Examples of the inorganic particles include 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. _SiO2 , _K2O .( _TiO2 )n _{, Al2O3.2SiO2} , _{CaCO3 , MgCO3} , _BaSO4 , _MgSO4 and the like.

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

In this embodiment, it is preferable that low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less adheres to some or all of the externally added inorganic particles.

When the inorganic particles are hydrophobic inorganic particles that have been subjected to a hydrophobic surface treatment, the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is preferably attached to the surface of the inorganic particles after the hydrophobic treatment.

The toner according to the exemplary embodiment may contain particles other than inorganic particles as an external additive. External additives other than inorganic particles include resin particles (resin particles such as polystyrene, polymethyl methacrylate, melamine resin, etc.), cleaning active agents (for example, metal salts of higher fatty acids represented by zinc stearate, fluorine-based high molecular weight body particles) and the like.

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

[Sol-gel silica particles]
As the external additive, sol-gel silica particles are preferred. Since the sol-gel silica particles contain an appropriate amount of water, the toner to which the sol-gel silica particles are externally added easily reaches the expected charge amount by agitation in the developing device.

The amount of water contained in the sol-gel silica particles can be evaluated by the rate of weight loss when heated. The sol-gel silica particles preferably have a mass reduction rate of 1% by mass or more and 10% by mass or less when heated from 30° C. to 250° C. at a heating rate of 30° C./min.
When the mass reduction rate is 1% by mass or more, the flow of the sol-gel silica particles on the toner particle surfaces is suppressed, and the sol-gel silica particles maintain a highly uniform dispersion state on the toner particle surfaces. It is easy to reach the expected amount of charge by stirring inside. From this point of view, the mass reduction rate is more preferably 2% by mass or more, and even more preferably 3% by mass or more.
If the weight reduction rate is 10% by weight or less, charge leakage through the sol-gel silica particles is suppressed, so that the toner easily reaches an expected charge amount by agitation in the developing device. From this point of view, the mass reduction rate is more preferably 9% by mass or less, and even more preferably 8% by mass or less.

In this embodiment, the mass reduction rate when the sol-gel silica particles are heated is obtained by the following measuring method.
Approximately 30 mg of sol-gel silica particles are placed in the sample chamber of a thermogravimetry device (manufactured by Shimadzu Corporation, model number DTG-60AH), heated from 30 ° C. to 250 ° C. at a temperature increase rate of 30 ° C./min, and the initial mass Calculate the mass reduction rate from the difference between.
The sample to be subjected to the thermogravimetry is sol-gel silica particles that are the material of the toner, or sol-gel silica particles that are separated from the toner. The method for separating the sol-gel silica particles from the toner is not limited. For example, after applying ultrasonic waves to a dispersion liquid in which the toner is dispersed in water containing a surfactant, the dispersion liquid is centrifuged at high speed, and the supernatant liquid is cooled to room temperature ( 23° C.±2° C.) to obtain sol-gel silica particles.
When the sol-gel silica particles that have been subjected to the hydrophobizing treatment are used as the external additive, the sol-gel silica particles that have been subjected to the hydrophobizing treatment are used as samples, and the above measurements are performed.

The average primary particle size of the sol-gel silica particles is preferably 20 nm or more and 90 nm or less.
When the average primary particle size of the sol-gel silica particles is 20 nm or more, they are less likely to be embedded in the toner particles. From this point of view, the average primary particle size of the sol-gel silica particles is more preferably 25 nm or more, and even more preferably 30 nm or more.
When the average primary particle size of the sol-gel silica particles is 90 nm or less, they tend to stay on the surface of the toner particles. From this point of view, the average primary particle size of the sol-gel silica particles is more preferably 85 nm or less, and even more preferably 80 nm or less.

In the present embodiment, the primary particle size of the sol-gel silica particles is the diameter of a circle having the same area as the primary particle image (so-called equivalent circle diameter). , is determined by image analysis of at least 300 sol-gel silica particles on the toner particles. The average primary particle size of the sol-gel silica particles is the particle size that is cumulatively 50% from the small size side in the number-based distribution of the primary particle sizes.

Sol-gel silica particles are obtained, for example, as follows.
Tetraalkoxysilane is added dropwise to an alkaline catalyst solution containing an alcohol compound and aqueous ammonia to hydrolyze and condense the tetraalkoxysilane to obtain a suspension containing sol-gel silica particles. The solvent is then removed from the suspension to obtain granules. The sol-gel silica particles are then obtained by drying the granules. The average primary particle size of the sol-gel silica particles can be controlled by the amount of tetraalkoxysilane added relative to the amount of the alkaline catalyst solution. The amount of water contained in the sol-gel silica particles, that is, the mass reduction rate when heated from 30° C. to 250° C. at a heating rate of 30° C./min can be controlled by the drying conditions for drying the granular material. .

The sol-gel silica particles may be hydrophobic sol-gel silica particles that have undergone a hydrophobizing surface treatment. The hydrophobizing agent is not particularly limited, but silicon-containing organic compounds are preferred. Silicon-containing organic compounds include alkoxysilane compounds, silazane compounds, and silicone oils. These may be used individually by 1 type, and may use 2 or more types together.

Silazane compounds (e.g., dimethyldisilazane, trimethyldisilazane, tetramethyldisilazane, pentamethyldisilazane, hexamethyldisilazane, etc.) are preferred as hydrophobizing agents for sol-gel silica particles. ,3,3-hexamethyldisilazane (HMDS) is particularly preferred.

Even when the sol-gel silica particles are hydrophobic sol-gel silica particles subjected to a hydrophobizing surface treatment, the mass reduction rate upon heating is preferably within the aforementioned range, and the average primary particle diameter is preferably within the aforementioned range.

When the sol-gel silica particles are hydrophobic sol-gel silica particles that have been subjected to a hydrophobizing surface treatment, the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is attached to the surface of the sol-gel silica particles after the hydrophobization treatment. is preferred.

The sol-gel silica particles and the hydrophobic sol-gel silica particles subjected to hydrophobizing surface treatment preferably have a BET specific surface area of 100 m ² /g or more and 240 m ² /g or less, and 120 m ² /g or more and 220 m ² /g or less. and more preferably 150 m ² /g or more and 200 m ² /g or less.

The BET specific surface area of sol-gel silica particles (including hydrophobic sol-gel silica particles subjected to hydrophobizing surface treatment) is measured by the BET multipoint method using nitrogen gas.
Samples to be measured are sol-gel silica particles that are the material of the toner, or sol-gel silica particles that are separated from the toner. The method for separating the sol-gel silica particles from the toner is not limited. For example, after applying ultrasonic waves to a dispersion liquid in which the toner is dispersed in water containing a surfactant, the dispersion liquid is centrifuged at high speed, and the supernatant liquid is cooled to room temperature ( 23° C.±2° C.) to obtain sol-gel silica particles.

The amount of the sol-gel silica particles externally added is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.05% by mass or more and 5% by mass or less, and 0.1% by mass or more, relative to the mass of the toner particles. 1% by mass or less is more preferable.

[Low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less]
It is preferable that part or all of the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less adheres to part or all of the inorganic particles as the external additive.

The molecular weight of the low-molecular-weight siloxane is 200 or more, preferably 250 or more, from the viewpoint of relatively increasing the kinematic viscosity of the low-molecular-weight siloxane and, as a result, increasing the frictional force acting between the inorganic particles. It is more preferably 300 or more, and even more preferably 300 or more.
The molecular weight of the low-molecular-weight siloxane is 600 or less, preferably 550 or less, and 500 or less from the viewpoint of relatively increasing the conductivity of the low-molecular-weight siloxane and, as a result, relatively increasing the dielectric constant of the toner. is more preferable, and 450 or less is even more preferable.

A low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less has at least two Si atoms in one molecule.
A low-molecular-weight siloxane having a molecular weight of 200 to 600 relatively increases the kinematic viscosity of the low-molecular-weight siloxane, and as a result, from the viewpoint of increasing the frictional force acting between inorganic particles, the number of Si atoms in one molecule is The number is preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more.
A low-molecular-weight siloxane having a molecular weight of 200 to 600 relatively increases the conductivity of the low-molecular-weight siloxane and, as a result, relatively increases the dielectric constant of the toner. The number is preferably 1 or less, more preferably 6 or less, and even more preferably 5 or less.
It is particularly preferable that the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less has 5 Si atoms per molecule from the above viewpoints.

The kinematic viscosity at 25° C. of the low-molecular-weight siloxane having a molecular weight of 200 to 600 is preferably 2 mm ² /s to 5 mm ² /s from the viewpoint of moderately increasing the frictional force acting between the inorganic particles.

In the present embodiment, the kinematic viscosity (mm ² /s) of siloxane is the value obtained by dividing the viscosity at 25° C. measured using an Ostwald viscometer, which is a type of capillary viscometer, by the density.

An example of the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is linear siloxane in which the siloxane bond is not branched.
Examples of low-molecular linear siloxanes having a molecular weight of 200 or more and 600 or less include hexaalkyldisiloxane, octaalkyltrisiloxane, decaalkyltetrasiloxane, dodecaalkylpentasiloxane, tetradecaalkylhexasiloxane, and hexadecaalkylheptasiloxane. (However, the molecular weight is 200 or more and 600 or less.).
The alkyl group of these low-molecular linear siloxanes has, for example, 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, still more preferably 1 or 2 carbon atoms) ), a branched alkyl group having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), 3 to 10 carbon atoms (preferably A cyclic alkyl group having 3 or more and 6 or less, more preferably 3 or 4) carbon atoms can be mentioned. Among them, an alkyl group having 1 to 3 carbon atoms is preferable, at least one of a methyl group and an ethyl group is preferable, and a methyl group is more preferable. A plurality of alkyl groups in one low-molecular-weight linear siloxane molecule may be the same or different.

Specific examples of low molecular weight linear siloxanes having a molecular weight of 200 to 600 include octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane, and hexadecamethylheptasiloxane.

An example of the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is a branched siloxane in which siloxane bonds are branched.
Low-molecular-weight branched siloxanes having a molecular weight of 200 to 600 include, for example, 1,1,1,3,5,5,5-heptaalkyl-3-(trialkylsiloxy)trisiloxane, tetrakis(trialkylsiloxy)silane , 1,1,1,3,5,5,7,7,7-nonaalkyl-3-(trialkylsiloxy)tetrasiloxane (provided that the molecular weight is 200 or more and 600 or less). be done.
The alkyl group possessed by these low-molecular-weight branched siloxanes has, for example, 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms). , a branched alkyl group having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), 3 to 10 carbon atoms (preferably 3 carbon atoms A cyclic alkyl group having 6 or less carbon atoms, more preferably 3 or 4 carbon atoms, can be mentioned. Among them, an alkyl group having 1 to 3 carbon atoms is preferable, at least one of a methyl group and an ethyl group is preferable, and a methyl group is more preferable. A plurality of alkyl groups present in one molecule of the low-molecular-weight branched siloxane may be the same or different.

Specific examples _of low molecular _weight branched siloxanes having _a molecular weight of 200 or more and 600 or less include methyltris(trimethylsiloxy)silane (molecular formula _C10H30O3Si4 ), tetrakis( _{trimethylsiloxy} )silane (molecular _{formula C12H36O4Si 5} ) and 1,1,1,3,5,5,7,7,7-nonamethyl-3-(trimethylsiloxy)tetrasiloxane (molecular formula C ₁₂ H ₃₆ O ₄ Si ₅ ).

An example of the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is a cyclic siloxane having a cyclic structure composed only of siloxane bonds.
Low-molecular-weight cyclic siloxanes having a molecular weight of 200 to 600 include, for example, hexaalkylcyclotrisiloxane, octaalkylcyclotetrasiloxane, decaalkylcyclopentasiloxane, dodecaalkylcyclohexasiloxane, tetradecaalkylcycloheptasiloxane, and hexadecaalkylcyclosiloxane. Octasiloxane may be mentioned (provided that the molecular weight is 200 or more and 600 or less).
Examples of alkyl groups possessed by these low-molecular-weight cyclic siloxanes include those having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, still more preferably 1 or 2 carbon atoms). Linear alkyl group, branched alkyl group having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms), 3 to 10 carbon atoms (preferably 3 or more carbon atoms) A cyclic alkyl group having 6 or less carbon atoms, more preferably 3 or 4 carbon atoms, can be mentioned. Among them, an alkyl group having 1 to 3 carbon atoms is preferable, at least one of a methyl group and an ethyl group is preferable, and a methyl group is more preferable. A plurality of alkyl groups present in one molecule of low-molecular-weight cyclic siloxane may be the same or different.

Specific examples of low-molecular-weight cyclic siloxanes having a molecular weight of 200 to 600 include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane, and hexadecamethyl Cyclooctasiloxane may be mentioned.

Low-molecular-weight linear siloxanes and low-molecular-weight branched siloxanes are used as low-molecular-weight siloxanes having a molecular weight of 200 or more and 600 or less, from the viewpoint that the toner containing low-molecular-weight siloxanes easily reaches the expected amount of charge when stirred in a developing device. At least one selected from the group consisting of is preferred, low-molecular-weight branched siloxanes are more preferred, and low-molecular-weight siloxanes having a tetrakis structure are even more preferred. A siloxane having a tetrakis structure refers to a siloxane having at least one of the following structures (that is, a tetrakissiloxysilane structure) in the molecule.

Examples of the low-molecular-weight siloxane having a tetrakis structure and a molecular weight of 200 or more and 600 or less include tetrakis(trialkylsiloxy)silane, where the alkyl group has, for example, 1 or more and 10 or less carbon atoms (preferably 1 or more and 6 carbon atoms). hereinafter, more preferably 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms), 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 carbon atoms) or 4) branched alkyl groups, and cyclic alkyl groups having 3 to 10 carbon atoms (preferably 3 to 6 carbon atoms, more preferably 3 or 4 carbon atoms). Among them, an alkyl group having 1 to 3 carbon atoms is preferable, at least one of a methyl group and an ethyl group is preferable, and a methyl group is more preferable. The alkyl groups in one molecule of low-molecular-weight siloxane having a tetrakis structure may be the same or different.

Tetrakis(trimethylsiloxy)silane is particularly preferable as the low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less, from the viewpoint that the toner containing the low-molecular-weight siloxane easily reaches the expected charge amount by stirring in the developing device.

The total content of low-molecular-weight siloxanes with a molecular weight of 200 to 600 contained in the toner is 0.01 ppm or more and 0.05 ppm or more based on the mass of the toner, from the viewpoint of increasing the frictional force acting between inorganic particles. and more preferably 0.1 ppm or more.
The total content of low-molecular-weight siloxanes having a molecular weight of 200 or more and 600 or less contained in the toner is 5 ppm or less, preferably 1 ppm or less, relative to the mass of the toner, from the viewpoint of not lowering the dielectric constant of the toner. 0.5 ppm or less is more preferable.

The total content of low-molecular-weight siloxanes with a molecular weight of 200 or more and 600 or less contained in the toner was measured using a gas chromatograph mass spectrometer (manufactured by Shimadzu Corporation, GCMS-QP2020) and a non-polar column (manufactured by Restek, Rtx-1, 10157 , film thickness 1.00 μm, length 60 m, inner diameter 0.32 mm), and measured by the headspace method. A specific identification method is as follows.
The toner is weighed into a vial, the vial is capped and sealed, and heated to 190° C. for a heating time of 3 minutes. Next, the volatile components in the vial are introduced into the column, and low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is detected under the following conditions.
・Carrier gas type: helium ・Carrier gas pressure: 120 kPa (constant pressure)
・Oven temperature: 40 ° C (5 minutes) → (15 ° C / min) → 250 ° C (6 minutes) (total 25 minutes)
・Ion source temperature: 260°C
・Interface temperature: 260℃
A calibration curve is created using a standard solution in which the standard substance (Tetrakis(trimethylsiloxy)silane 1) is diluted with ethanol and the concentration is varied. The amount of the low-molecular-weight siloxane is determined from the peak area of the low-molecular-weight siloxane having a molecular weight of 200 to 600 appearing in the chromatograph of the sample and the calibration curve of the reference substance. If the chromatograph of the sample has multiple peaks corresponding to low-molecular-weight siloxanes with a molecular weight of 200 to 600, the total amount of the low-molecular-weight siloxanes is obtained from the total area of these peak areas and the calibration curve of the reference substance. Further, the total content (ppm) of low-molecular-weight siloxane having a molecular weight of 200 to 600 is calculated with respect to the total amount of toner.

The total content of low-molecular-weight siloxane having a molecular weight of 200 to 600 contained in the toner is 1 ppm or more relative to the total content of inorganic particles contained in the toner, from the viewpoint of increasing the frictional force acting between the inorganic particles. more preferably 5 ppm or more, still more preferably 10 ppm or more, even more preferably 15 ppm or more, and even more preferably 20 ppm or more.
The total content of low-molecular-weight siloxanes with a molecular weight of 200 to 600 contained in the toner is preferably 1000 ppm or less with respect to the total content of inorganic particles contained in the toner, from the viewpoint of not lowering the dielectric constant of the toner. , is more preferably 500 ppm or less, still more preferably 200 ppm or less, even more preferably 100 ppm or less, and even more preferably 50 ppm or less.
The above mass ratio is a value obtained by converting {total content of low-molecular-weight siloxane having a molecular weight of 200 to 600 contained in the toner/total content of inorganic particles contained in the toner} into parts per million.
When the inorganic particles are hydrophobized inorganic particles, the mass of the inorganic particles refers to the mass of the inorganic particles after the hydrophobization treatment, and is the mass including the component derived from the hydrophobizing agent.

The total content of inorganic particles contained in the toner is determined by the following measuring method.
After applying ultrasonic waves to a dispersion of toner in water containing a surfactant, the dispersion is centrifuged at high speed, and the supernatant is dried at room temperature (23° C.±2° C.) to obtain inorganic particles. Weigh the inorganic particles obtained from the supernatant. Here, although low-molecular-weight siloxane may adhere to the surface of the inorganic particles obtained from the supernatant liquid, the mass of the adhered low-molecular-weight siloxane is very small compared to the mass of the inorganic particles, so it is ignored. .

The low-molecular-weight siloxane having a molecular weight of 200 or more and 600 or less is incorporated into the toner by, for example, externally adding it to toner particles; using it as a surface treatment agent for inorganic particles (especially sol-gel silica particles) as an external additive; obtain.

[Toner manufacturing method]
The toner according to the exemplary embodiment is obtained by externally adding an external additive to the toner particles after manufacturing the toner particles.

The toner particles may be produced by either a dry method (eg, kneading pulverization method, etc.) or a wet method (eg, aggregation coalescence method, suspension polymerization method, dissolution suspension method, etc.). These manufacturing methods are not particularly limited, and known manufacturing methods are employed. Among these, it is preferable to obtain toner particles by the aggregation coalescence method.

Specifically, for example, when toner particles are produced by an aggregation coalescence method, a step of preparing a resin particle dispersion in which resin particles to be a binder resin are dispersed (resin particle dispersion preparation step); A step of aggregating resin particles (other particles, if necessary) in a dispersion liquid (in a dispersion liquid after mixing other particle dispersion liquids, if necessary) to form aggregated particles (aggregated particle formation step), and a step of heating the aggregated particle dispersion in which the aggregated particles are dispersed to fuse and coalesce the aggregated particles to form toner particles (fusion/coalescing step) to produce toner particles. do.

Details of each step will be described below. In the following description, a method for obtaining toner particles containing a colorant and a release agent is described, and the colorant and release agent are used as necessary. Needless to say, additives other than colorants and release agents may be used.

-Resin particle dispersion preparation step-
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 together with a resin particle dispersion in which resin particles that serve as a binder resin are dispersed.

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-exchanged water, and alcohols. These may be used individually by 1 type, and may use 2 or more types together.

Examples of surfactants include anionic surfactants such as sulfate-based, sulfonate-based, phosphate-based, and soap-based surfactants; cationic surfactants such as amine salt-type and quaternary ammonium salt-type; polyethylene glycol. nonionic surfactants such as surfactants, alkylphenol ethylene oxide adducts, and polyhydric alcohols. Among these, anionic surfactants and cationic surfactants are particularly exemplified. Nonionic surfactants may be used in combination with anionic surfactants or cationic surfactants. Surfactants may be used singly or in combination of two or more.

As a method for dispersing the resin particles in the dispersion medium in the resin particle dispersion, for example, general dispersing methods such as a rotary shearing homogenizer, a ball mill having media, a sand mill, and a dyno mill can be used. Moreover, depending on the type of resin particles, the resin particles may be dispersed in the dispersion medium by a phase inversion emulsification method. In the phase inversion emulsification method, the resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and after neutralization by adding a base to the organic continuous phase (O phase), an aqueous medium (W phase ) to effect a phase inversion from W/O to O/W and disperse the resin in the form of particles in the aqueous medium.

The volume average particle diameter of the resin particles dispersed in the resin particle dispersion liquid is, for example, preferably 0.01 μm or more and 1 μm or less, more preferably 0.08 μm or more and 0.8 μm or less, and further preferably 0.1 μm or more and 0.6 μm or less. preferable.
The volume-average particle diameter of the resin particles is determined using a particle size distribution obtained by measurement with a laser diffraction particle size distribution analyzer (for example, LA-700 manufactured by Horiba, Ltd.). The cumulative distribution is drawn from the small particle size side, and the particle size at which the cumulative distribution is 50% of all particles is measured as the volume average particle size D50v. The volume average particle size of particles in other dispersion liquids is also measured in the same manner.

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

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 size, dispersion medium, dispersion method, and content of particles in the resin particle dispersion, the colorant particles dispersed in the colorant particle dispersion and the release agent particle dispersion The same applies to dispersed release agent particles.

-Agglomerated particle formation step-
Next, the resin particle dispersion, the colorant particle dispersion, and the releasing agent particle dispersion are mixed.
Then, in the mixed dispersion, the resin particles, the colorant particles, and the release agent particles are heteroaggregated to form resin particles, colorant particles, and release agent particles having a diameter close to the diameter of the target toner particles. form agglomerated particles containing

Specifically, for example, a flocculant is added to the mixed dispersion, the pH of the mixed dispersion is adjusted to be acidic (for example, pH 2 or more and 5 or less), a dispersion stabilizer is added as necessary, and then the resin particles are mixed. (Specifically, for example, the glass transition temperature of the resin particles -30 ° C. or more and the glass transition temperature of -10 ° C. or less) is heated to agglomerate the particles dispersed in the mixed dispersion, form agglomerated particles.
In the aggregated particle forming step, for example, the mixed dispersion is stirred with a rotary shear homogenizer, and a flocculant is added at room temperature (for example, 25° C.) to adjust the pH of the mixed dispersion to acidic (for example, pH 2 or more and 5 or less). Then, heating may be performed after adding a dispersion stabilizer as necessary.

Examples of the aggregating agent include a surfactant having a polarity opposite to that of the surfactant contained in the mixed dispersion, an inorganic metal salt, and a bivalent or higher metal complex. When a metal complex is used as the aggregating agent, the amount of surfactant used is reduced, and charging characteristics are improved.
Additives that form complexes or similar bonds with the metal ions of the flocculant may optionally be used together with the flocculant. A chelating agent is preferably used as this additive.

Examples of inorganic metal salts include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; inorganic metal salts such as polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. polymer; and the like.
A water-soluble chelating agent may be used as the chelating agent. Examples of chelating agents include oxycarboxylic acids such as tartaric acid, citric acid, and gluconic acid; aminocarboxylic acids such as iminodiacetic acid (IDA), nitrilotriacetic acid (NTA), and ethylenediaminetetraacetic acid (EDTA); be done.
The amount of the chelating agent to be added is preferably 0.01 parts by mass or more and 5.0 parts by mass or less, more preferably 0.1 parts by mass or more and less than 3.0 parts by mass, based on 100 parts by mass of the resin particles.

－Fusion/union process－
Next, the aggregated particle dispersion in which the aggregated particles are dispersed is heated, for example, to a temperature higher than the glass transition temperature of the resin particles (for example, a temperature higher than the glass transition temperature of the resin particles by 10°C to 30°C) to remove the aggregated particles. They fuse and coalesce to form toner particles.

Toner particles are obtained through the above steps.
After obtaining the aggregated particle dispersion in which the aggregated particles are dispersed, the aggregated particle dispersion and the resin particle dispersion in which the resin particles are dispersed are further mixed to further add the resin particles to the surfaces of the aggregated particles. a step of forming second aggregated particles by aggregating them so as to adhere; heating the second aggregated particle dispersion in which the second aggregated particles are dispersed to fuse and coalesce the second aggregated particles; , and a step of forming toner particles having a core-shell structure.

After the fusion/unification step, the toner particles formed in the solution are subjected to a known washing step, solid-liquid separation step, and drying step to obtain dry toner particles. In the washing step, from the viewpoint of electrification, it is preferable to sufficiently perform displacement washing with ion-exchanged water. From the viewpoint of productivity, the solid-liquid separation step may be performed by suction filtration, pressure filtration, or the like. From the viewpoint of productivity, the drying step may be freeze drying, flash drying, fluidized drying, vibrating fluidized drying, or the like.

Then, the toner according to the exemplary embodiment is produced, for example, by adding an external additive to the obtained dry toner particles and mixing them. Mixing may be carried out using, for example, a V blender, a Henschel mixer, a Loedige mixer, or the like. Further, if necessary, a vibration sieving machine, an air sieving machine, or the like may be used to remove coarse toner particles.

<Electrostatic charge image developer>
The electrostatic charge image developer according to the exemplary embodiment contains at least the toner according to the exemplary embodiment.
The electrostatic image developer according to this embodiment may be a one-component developer containing only the toner according to this embodiment, or may be a two-component developer in which the toner and carrier are mixed.

The carrier is not particularly limited and includes known carriers. Examples of carriers include coated carriers in which the surface of a core material made of magnetic powder is coated with a resin; magnetic powder-dispersed carriers in which magnetic powder is dispersed in a matrix resin; and porous magnetic powder impregnated with resin. resin-impregnated carrier;
The magnetic powder-dispersed carrier and the resin-impregnated carrier may be a carrier in which constituent particles of the carrier are used as a core material and the surface thereof is coated with a resin.

Magnetic powders include, for example, magnetic metals such as iron, nickel and cobalt; magnetic oxides such as ferrite and magnetite; and the like.

Coating resins and matrix resins include, for example, polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid. Ester copolymers, straight silicone resins containing organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenolic resins, epoxy resins and the like can be mentioned. The coating resin and matrix resin may contain other additives such as conductive particles. Examples of conductive particles include particles of metals such as gold, silver, and copper, and particles of carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, potassium titanate, and the like.

In order to coat the surface of the core material with a resin, a method of coating with a coating layer forming solution in which a coating resin and various additives (used as necessary) are dissolved in an appropriate solvent can be used. The solvent is not particularly limited, and may be selected in consideration of the type of resin to be used, coating suitability, and the like.
Specific resin coating methods include an immersion method in which the core material is immersed in the solution for forming the coating layer; a spray method in which the solution for forming the coating layer is sprayed onto the surface of the core material; A fluidized bed method in which a coating layer forming solution is sprayed; a kneader coater method in which a core material of a carrier and a coating layer forming solution are mixed in a kneader coater and then the solvent is removed;

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

<Image forming apparatus, image forming method>
An image forming apparatus and an image forming method according to this embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, charging means for charging the surface of the image carrier, electrostatic image forming means for forming an electrostatic charge image on the surface of the charged image carrier, and electrostatic charging. developing means for storing an image developer and developing an electrostatic charge image formed on the surface of the image carrier with the electrostatic charge image developer as a toner image; and a recording medium for transferring the toner image formed on the surface of the image carrier. and a fixing means for fixing the toner image transferred to the surface of the recording medium. As the electrostatic charge image developer, the electrostatic charge image developer according to the exemplary embodiment is applied.

In the image forming apparatus according to the present embodiment, the charging process of charging the surface of the image carrier, the electrostatic charge image forming process of forming an electrostatic charge image on the surface of the charged image carrier, and the electrostatic charging process according to the present 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 a recording medium; and a fixing step of fixing the toner image transferred onto the surface of the recording medium (image forming method according to the present embodiment).

The image forming apparatus according to the present embodiment is a direct transfer type apparatus for directly transferring a toner image formed on the surface of an image carrier onto a recording medium; An intermediate transfer type device that primarily transfers the toner image transferred onto the surface of the intermediate transfer body and then secondarily transfers the toner image onto the surface of the recording medium; after the toner image is transferred, the surface of the image carrier before charging is cleaned. A known image forming apparatus such as an apparatus equipped with a cleaning means; an apparatus equipped with a static elimination means for irradiating the surface of the image carrier with static elimination light to eliminate static before charging after the transfer of the toner image;
When the image forming apparatus according to the present embodiment is an intermediate transfer type apparatus, the transfer means includes, for example, an intermediate transfer body on which a toner image is transferred and a toner image formed on the surface of the image carrier. A configuration having primary transfer means for primary transfer onto the surface of the body and secondary transfer means for secondary transfer of the toner image transferred onto the surface of the intermediate transfer body onto the surface of the recording medium is applied.

In the image forming apparatus according to the present embodiment, for example, the portion including the developing means may be a cartridge structure (process cartridge) detachable from the image forming apparatus. As the process cartridge, for example, a process cartridge containing the electrostatic charge image developer according to the present embodiment and having developing means is preferably used.

An example of the image forming apparatus according to the present embodiment will be shown below, but the present invention is not limited to this. In the following description, the main parts shown in the drawings will be described, and the description of the other parts will be omitted.

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

Above each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt (an example of an intermediate transfer member) 20 extends through each unit. The intermediate transfer belt 20 is wound around a drive roll 22 and a support roll 24, and runs in the direction from the first unit 10Y to the fourth unit 10K. A force is applied to the support roll 24 in a direction away from the drive roll 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both. An intermediate transfer member cleaning device 30 is provided on the image carrier side of the intermediate transfer belt 20 so as to face the drive roll 22 .
Developing devices (an example of developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K each contain yellow, magenta, cyan, and black toner cartridges 8Y, 8M, 8C, and 8K. are supplied.

Since the first to fourth units 10Y, 10M, 10C, and 10K have the same configuration and operation, here the first unit for forming a yellow image arranged on the upstream side in the running direction of the intermediate transfer belt is used. The unit 10Y will be described as a representative.

The first unit 10Y has a photoreceptor 1Y acting as an image carrier. Around the photoreceptor 1Y, there is 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 to a laser beam 3Y based on color-separated image signals. An exposure device (an example of an electrostatic charge image forming means) 3 for forming an electrostatic charge image by applying toner, a developing device (an example of a developing means) 4Y for supplying charged toner to the electrostatic charge image to develop the electrostatic charge image, and a developing device 4Y for developing the electrostatic charge image. A primary transfer roll 5Y (an example of primary transfer means) that transfers the toner image onto the intermediate transfer belt 20, and a photoreceptor cleaning device (an example of cleaning means) 6Y that removes toner remaining on the surface of the photoreceptor 1Y after the primary transfer. are arranged in order.
The primary transfer roll 5Y is arranged inside the intermediate transfer belt 20 and provided at a position facing the photoreceptor 1Y. A bias power source (not shown) that applies a primary transfer bias is connected to the primary transfer rolls 5Y, 5M, 5C, and 5K of each unit. Each bias power supply changes the value of the transfer bias applied to each primary transfer roll under the control of a controller (not shown).

The operation of forming a yellow image in the first unit 10Y will be described below.
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 stacking a photoreceptor layer on a conductive substrate (for example, a volume resistivity of 1×10 ⁻⁶ Ωcm or less at 20° C.). This photosensitive layer normally has a high resistance (resistivity of general resin), but has the property of changing the specific resistance of the portion irradiated with the laser beam when irradiated with the laser beam. Therefore, the surface of the charged photoreceptor 1Y is irradiated with the laser beam 3Y from the exposure device 3 according to the image data for yellow sent from the controller (not shown). Thereby, an electrostatic charge image of a yellow image pattern is formed on the surface of the photoreceptor 1Y.

An electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging. The laser beam 3Y lowers the resistivity of the irradiated portion of the photosensitive layer, causing the charged charges on the surface of the photoreceptor 1Y to flow. , on the other hand, a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic image formed on the photoreceptor 1Y rotates to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is developed as a toner image by the developing device 4Y and visualized.

The developing device 4Y contains, for example, an electrostatic charge image developer containing at least yellow toner and carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y. One example) is held above. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically adhered to the static-eliminated latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. be. 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 position, the primary transfer bias is applied to the primary transfer roll 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roll 5Y acts on the toner image, resulting in a photoreceptor. The toner image on body 1 Y is transferred onto 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, for example, by a controller (not shown) in the first unit 10Y.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the photoreceptor cleaning device 6Y.

The primary transfer biases applied to the primary transfer rolls 5M, 5C, and 5K after the second unit 10M are also controlled according to the first unit.
In this way, 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 for multiple transfer. be done.

The intermediate transfer belt 20, on which the four-color toner images are multiple-transferred through the first to fourth units, consists of the intermediate transfer belt 20, the support roll 24 in contact with the inner surface of the intermediate transfer belt, and the image holding surface of the intermediate transfer belt 20. A secondary transfer portion is formed by a secondary transfer roll (an example of a secondary transfer means) 26 arranged on the side. On the other hand, a recording paper (an example of a recording medium) P is fed through a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and the secondary transfer bias is applied to the support roll. 24. The transfer bias applied at this time has the same (-) polarity as the polarity (-) of the toner. is transferred onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

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

Examples of the recording paper P onto which the toner image is transferred include plain paper used in electrophotographic copiers, printers, and the like. In addition to the recording paper P, an OHP sheet or the like can also be used as the recording medium.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper P is also smooth. preferably used.

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

<Process Cartridge, Toner Cartridge>
A process cartridge according to this embodiment will be described.
The process cartridge according to the present embodiment contains the electrostatic charge image developer according to the present embodiment, and develops the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer. and is detachable from the image forming apparatus.

The process cartridge according to the present embodiment is not limited to the configuration described above, and can be selected from developing means and other means, such as an image carrier, charging means, electrostatic image forming means, and transfer means, as required. and at least one to be provided.

An example of the process cartridge according to the present embodiment will be shown below, but the present invention is not limited to this. In the following description, the main parts shown in the drawings will be described, and the description of the other parts will be omitted.

FIG. 2 is a schematic diagram showing the process cartridge according to this embodiment.
The process cartridge 200 shown in FIG. 2 includes, for example, a photoreceptor 107 (an example of an image carrier) and a periphery of the photoreceptor 107 by means of a housing 117 having mounting rails 116 and an opening 118 for exposure. A charging roll 108 (an example of charging means), a developing device 111 (an example of developing means), and a photoreceptor cleaning device 113 (an example of cleaning means) are integrally combined and held, and formed into a cartridge. there is
In FIG. 2, 109 is an exposure device (an example of electrostatic charge image forming means), 112 is a transfer device (an example of transfer means), 115 is a fixing device (an example of fixing means), and 300 is recording paper (an example of a recording medium). is shown.

Next, the toner cartridge according to this embodiment will be described.
A toner cartridge according to the present embodiment is a toner cartridge that accommodates the toner according to the present embodiment and is detachable from an image forming apparatus. The toner cartridge accommodates replenishment toner to be supplied to 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 detachable. It is connected to the corresponding toner cartridge through a toner supply pipe (not shown). When the toner contained in the toner cartridge runs out, the toner cartridge is replaced.

The embodiments of the invention will be described in detail below with reference to examples, but the embodiments of the invention are not limited to these examples. In the following description, "parts" are based on mass unless otherwise specified.

[Preparation of Toner Particles (1)]
-Preparation of polyester resin particle dispersion (1)-
Ethylene glycol (manufactured by Wako Pure Chemical Industries, Ltd.): 37 parts Neopentyl glycol (manufactured by Wako Pure Chemical Industries, Ltd.): 65 parts 1,9-nonanediol (manufactured by Wako Pure Chemical Industries, Ltd.): 32 parts Terephthalic acid (manufactured by Wako Pure Chemical Industries, Ltd.): 96 parts

The above materials were placed in a flask, the temperature was raised to 200° C. over 1 hour, and after confirming that the reaction system was being stirred, 1.2 parts of dibutyltin oxide was added. The temperature was raised from the same temperature to 240°C over 6 hours while distilling off the generated water, and the dehydration condensation reaction was continued at 240°C for 4 hours. A polyester resin (1) having a glass transition temperature of 62° C. was obtained.

The polyester resin (1) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech) at a rate of 100 parts per minute. Separately prepared diluted ammonia water with a concentration of 0.37% was transferred to Cavitron CD1010 together with the polyester resin (1) at a rate of 0.1 liter per minute while being heated to 120° C. with a heat exchanger. Cavitron CD1010 was operated at a rotor speed of 60 Hz and a pressure of 5 kg/cm ² to obtain a polyester resin particle dispersion (1) having a solid content of 30% by mass. The volume average particle diameter of the resin particles contained in the polyester resin particle dispersion (1) was 160 nm.

-Preparation of colorant particle dispersion (1)-
・ Cyan pigment (copper phthalocyanine, CI Pigment blue 15:3, manufactured by Dainichiseika Co., Ltd.): 10 parts ・ Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 2 parts ・ Ion-exchanged water: 80 copies

The above materials were mixed and subjected to dispersion treatment for 1 hour using a high-pressure impact disperser Ultimizer (HJP30006, manufactured by Sugino Machine Co., Ltd.) to obtain a colorant particle dispersion (1) having a solid content of 20% by mass. The volume average particle size of the colorant particles contained in the colorant particle dispersion (1) was 180 nm.

-Preparation of Release Agent Particle Dispersion (1)-
・ Carnauba wax (RC-160, melting temperature 84 ° C., manufactured by Toa Kasei Co., Ltd.): 50 parts ・ Anionic surfactant (Neogen SC, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 2 parts ・ Ion-exchanged water: 200 parts

The above material is heated to 120° C., subjected to dispersion treatment with an IKA Ultra Turrax T50, and then subjected to dispersion treatment with a pressure ejection Gaulin homogenizer to obtain a release agent particle dispersion (1) having a solid content of 20% by mass. got The volume average particle diameter of the release agent particles contained in the release agent particle dispersion (1) was 200 nm.

- Preparation of toner particles -
・Polyester resin particle dispersion (1): 200 parts ・Colorant particle dispersion (1): 25 parts ・Releasing agent particle dispersion (1): 30 parts ・Polyaluminum chloride: 0.4 parts ・Ion-exchanged water : 100 copies

The above materials were placed in a stainless steel flask, subjected to dispersion treatment by Ultra Turrax manufactured by IKA, and heated to 48° C. while stirring the stainless steel flask in a heating oil bath. After holding at 48° C. for 30 minutes, 70 parts of polyester resin particle dispersion (1) was added.

Next, after adjusting the pH in the system to 8.0 using an aqueous sodium hydroxide solution with a concentration of 0.5 mol/L, the stainless steel flask was sealed, and the stirring shaft was magnetically sealed to continue stirring. Heated to 90° C. and held for 3 hours. Then, the mixture was cooled at a cooling rate of 2° C./min, filtered, washed with deionized water, and solid-liquid separated by Nutsche suction filtration. The solid content was re-dispersed in ion-exchanged water at 30° C. and washed by stirring at a rotation speed of 300 rpm for 15 minutes. This washing operation was repeated six more times, and when the pH of the filtrate reached 7.54 and the electric conductivity reached 6.5 μS/cm, solid-liquid separation was performed using filter paper by Nutsche suction filtration. The solid content was vacuum-dried to obtain toner particles (1). The volume average particle diameter of toner particles (1) was 5.8 μm.

[Preparation of hydrophobic silica particles (1)]
- Granulation process of silica particles -
300 parts of methanol and 70 parts of 10% aqueous ammonia were mixed in a glass reactor equipped with a stirrer, a dropping nozzle and a thermometer to obtain an alkaline catalyst solution. After adjusting the alkali catalyst solution to 30° C., 60 parts of tetramethoxysilane (TMOS) and 1.7 parts of 10% aqueous ammonia were added dropwise while stirring the alkali catalyst solution to obtain a silica particle dispersion. Dropping of TMOS and 10% aqueous ammonia was started at the same time, and the total amount of each was dropped over 3 minutes. Then, the silica particle dispersion was concentrated to a solid concentration of 40% by mass using a rotary filter (R-Fine manufactured by Kotobuki Kogyo Co., Ltd.). The concentrated silica particle dispersion was designated as silica particle dispersion (1).

- Surface treatment process of silica particles -
To 250 parts of the silica particle dispersion (1), 100 parts of hexamethyldisilazane (HMDS) was added as a hydrophobizing agent, heated to 130°C and reacted for 2 hours, and then dried under the drying conditions shown in Table 1. After drying, hydrophobic silica particles (S1) were obtained. Next, prepare 0.020% by mass of tetrakis(trimethylsiloxy)silane with respect to the amount of the silica particle dispersion (1), dilute it 5 times with methanol, and then add it to the hydrophobic silica particles (S1). The mixture was dried while stirring the inside of the reaction system at ℃ to obtain hydrophobic silica particles (1).

[Preparation of hydrophobic silica particles (2) to (8) and hydrophobic silica particles (C1) to (C2)]
Hydrophobic silica particles were produced in the same manner as the silica particles (1), except that the type of low-molecular-weight siloxane used in the surface treatment step of the silica particles was changed as shown in Table 1.

[Preparation of hydrophobic silica particles (9) to (12) and hydrophobic silica particles (C3) to (C4)]
Hydrophobic silica particles were prepared in the same manner as the silica particles (1) except that the addition amount of the low-molecular-weight siloxane used in the surface treatment step of the silica particles was changed as shown in Table 1.

[Preparation of hydrophobic silica particles (13) to (16)]
Hydrophobic silica particles were prepared in the same manner as the preparation of silica particles (1), except that the silica particle granulation process was changed as shown in Table 1.

[Preparation of hydrophobic silica particles (17) to (20)]
Hydrophobic silica particles were prepared in the same manner as the preparation of silica particles (1), except that the drying conditions in the surface treatment step of the silica particles were changed as shown in Table 1.

[Preparation of carrier]
・Ferrite particles (volume average particle diameter 36 μm): 100 parts ・Toluene: 14 parts ・Styrene-methyl methacrylate copolymer: 2 parts (polymerization mass ratio 90:10, weight average molecular weight 80,000)
・ Carbon black (R330 manufactured by Cabot Corporation): 0.2 parts

Toluene, a styrene-methyl methacrylate copolymer and carbon black were mixed and stirred with a stirrer for 10 minutes to prepare a dispersion. Next, the dispersion liquid and the ferrite particles were placed in a vacuum degassing kneader, stirred at 60° C. for 30 minutes, degassed under heating and dried to obtain a carrier.

[Example 1]
Toner particles (1) and hydrophobic silica particles (1) were placed in a Henschel mixer at a ratio of toner particles (1):hydrophobic silica particles (1)=99:1 (mass ratio), and stirred at a peripheral speed of 30 m/s. The mixture was stirred at sec for 15 minutes to obtain an externally added toner.
The externally added toner and the carrier were placed in a V blender at a ratio of externally added toner:carrier=10:100 (mass ratio) and stirred for 20 minutes to obtain a developer.

[Examples 2 to 20, Comparative Examples 1 to 4]
Externally added toner and developer were prepared in the same manner as in Example 1, except that the type of hydrophobic silica particles was changed as shown in Table 2.

[Performance evaluation]
-Electrification rise-
The developer was placed in an environment of 28° C. and 85% relative humidity for 24 hours to control the temperature and humidity. Next, under the same environment, 7.5 g of the developer was put into a Turbula mixer and stirred. charge amount. Further, the developer was stirred for 10 minutes, and the charge amount (μC/g) of the developer after stirring for 10 minutes was measured with a blow-off charge amount measuring device, and this value was taken as the saturated charge amount. The ratio (%) of the initial charge amount to the saturated charge amount={initial charge amount/saturated charge amount×100} was calculated and classified into A to E below. A to C are acceptable. Table 2 shows the evaluation results.

A: 95% or more B: 90% or more and less than 95% C: 85% or more and less than 90% D: 80% or more and less than 85% E: Less than 80%

-Fogging-
The developer was placed in an image forming apparatus (modified from DocuCenter Color 400) manufactured by Fuji Xerox Co., Ltd. and placed in an environment of 28° C. and 85% relative humidity for 24 hours to control the temperature and humidity. Next, under the same environment, A4 size plain paper (C2 paper manufactured by Fuji Xerox Co., Ltd.) was used, and test chart No. 2 of the Imaging Society of Japan was used. 1 was formed on 10 sheets. The background portion of the third image was observed with the naked eye and with a magnifying glass of 20 times magnification, and classified into A to E below. A to C are acceptable. Table 2 shows the evaluation results.

A: The fog cannot be confirmed with the naked eye, and cannot be confirmed even with a magnifying glass.
B: No fogging was observed with the naked eye, and 1 to 9 toner particles were observed within 1 mm ² with a magnifying glass.
C: No fogging was observed with the naked eye, and 10 or more toner grains were observed within 1 mm ² with a magnifying glass.
D: Fog is slightly visible with the naked eye.
E: Fogging can be clearly confirmed with the naked eye.

1Y, 1M, 1C, 1K photoreceptors (examples of image carriers)
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 photoreceptor cleaning device (an example of cleaning means)
8Y, 8M, 8C, 8K toner cartridges 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)
28 fixing device (an example of fixing means)
30 Intermediate transfer body cleaning device P Recording paper (an example of recording medium)
107 photoreceptor (an example of an image carrier)
108 charging roll (an example of charging means)
109 exposure device (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 photoreceptor cleaning device (an example of cleaning means)
115 fixing device (an example of fixing means)
116 mounting rail 117 housing 118 opening 200 for exposure process cartridge 300 recording paper (an example of a recording medium)

Claims (12)

toner particles;
inorganic particles externally added to the toner particles;
A low-molecular-weight siloxane with a molecular weight of 200 or more and 600 or less, which is composed only of siloxane bonds and alkyl groups,
The inorganic particles include sol-gel silica particles having an average primary particle size of 20 nm or more and 90 nm or less,
A toner for electrostatic charge image development, wherein the total content of the low-molecular-weight siloxane is 0.01 ppm or more and 5 ppm or less on a mass basis. toner particles;
inorganic particles externally added to the toner particles;
A low-molecular-weight siloxane with a molecular weight of 200 or more and 600 or less, which is composed only of siloxane bonds and alkyl groups,
The low-molecular-weight siloxane contains at least one selected from the group consisting of low-molecular-weight linear siloxane and low-molecular-weight branched siloxane,
A toner for electrostatic charge image development, wherein the total content of the low-molecular-weight siloxane is 0.01 ppm or more and 5 ppm or less on a mass basis. 3. The toner for electrostatic charge image development according to claim 2 , wherein the inorganic particles contain sol-gel silica particles having an average primary particle size of 20 nm or more and 90 nm or less. 4. The electrostatic charge image developing device according to claim 1, wherein the total content of said low-molecular-weight siloxane is 10 ppm or more and 1000 ppm or less on a mass basis with respect to the total content of said inorganic particles. toner. Claims 1 to 4 , wherein the inorganic particles include sol-gel silica particles having a mass reduction rate of 1% by mass or more and 10% by mass or less when heated from 30°C to 250°C at a heating rate of 30°C/min. The toner for developing an electrostatic charge image according to any one of . 6. The electrostatic charge image developing toner according to claim 1, wherein the low-molecular-weight siloxane contains a low-molecular-weight siloxane having a tetrakis structure. The toner for electrostatic charge image development according to any one of claims 1 to 6, wherein the low-molecular-weight siloxane contains tetrakis(trimethylsiloxy)silane. An electrostatic charge image developer containing the electrostatic charge image developing toner according to any one of claims 1 to 7. containing the electrostatic charge image developing toner according to any one of claims 1 to 7,
A toner cartridge that is attached to and detached from an image forming apparatus. 9. A developing means for accommodating the electrostatic charge image developer according to claim 8 and developing the electrostatic charge image formed on the surface of the image carrier by the electrostatic charge image developer as a toner image,
A process cartridge that is attached to and detached from an image forming apparatus. an image carrier;
charging means for charging the surface of the image carrier;
electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Developing means for accommodating the electrostatic charge image developer according to claim 8 and developing the electrostatic charge image formed on the surface of the image carrier with the electrostatic charge image developer as a toner image;
a transfer means for transferring the toner image formed on the surface of the image carrier onto the surface of a recording medium;
fixing means for fixing the toner image transferred onto the surface of the recording medium;
An image forming apparatus comprising: a charging step of 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 the electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 8;
a transfer step of transferring the toner image formed on the surface of the image carrier onto the surface of a recording medium;
a fixing step of fixing the toner image transferred onto the surface of the recording medium;
An image forming method comprising:

Images