JP2009169150A - Electrostatic charge image developing toner, electrostatic charge image developer, toner cartridge, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic charge image developing toner which reduces fogging over a long period of time, an electrostatic charge image developer, a toner cartridge, a process cartridge, and an image forming apparatus. <P>SOLUTION: The electrostatic charge image developing toner for an amorphous silicon photoreceptor includes toner particles containing a binder resin and a colorant and inorganic particles other than silica, wherein the inorganic particles are at least one selected from selenium oxide, alumina, titania and strontium titanate, a ratio of isolation of the inorganic particles from the toner particles is ≥20%, and the inorganic particles have been surface-treated with a quaternary ammonium salt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  In electrophotography, generally, a latent image is electrically formed on the surface of a photoconductor (image carrier) using a photoconductive substance by various means, and the formed latent image is replaced with toner. After developing with a developer containing the developer, a developed image is formed, and then the developed image is transferred to a surface of a transfer medium such as paper via an intermediate transfer body as necessary, and then heated, pressurized, and heated and pressed. An image is formed through a plurality of steps of fixing by, for example. In addition, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for development.

  By the way, it has been proposed to prevent fogging by applying a quaternary ammonium salt to the photoreceptor or adding it to the overcoat layer so that the surface potential by the contact charging method is close to or higher than the developing bias. (For example, refer to Patent Document 1).

  Further, silica treated with a quaternary ammonium salt is used as an external additive of the toner for the purpose of obtaining excellent image quality without occurrence of image defects, with excellent fluidity, casing resistance, chargeability and environmental stability of the toner. It is proposed to use (see, for example, Patent Documents 2 to 4)

  For the purpose of suppressing various image defects, the surface oxide layer of the amorphous silicon photoreceptor is polished and removed, and the charge amount can be easily controlled in the same manner as the external addition of only a normal silica-based external additive. It has been proposed to use an abrasive together with a silica-based external additive in the toner (see, for example, Patent Document 5).

  In particular, amorphous silicon photoconductors have a feature that they are harder and less wearable than organic photoconductors, so they are superior in maintainability. By using amorphous silicon photoconductors, in addition to normal fog, charging ability and charge holding ability There has been a problem that fog unique to an amorphous silicon photoreceptor is caused due to a low value.

In order to suppress the occurrence of filming, it has been proposed to use a conductive powder having a high release rate for the toner (see, for example, Patent Document 6).
Japanese Patent Laid-Open No. 7-244422 Japanese Patent Laid-Open No. 5-6032 Japanese Patent Application Laid-Open No. 5-100471 Japanese Patent Laid-Open No. 5-100491 JP-A-8-190221 JP 2007-4088 A

  An object of the present invention is to provide an electrostatic image developing toner, an electrostatic image developer, a toner cartridge, a process cartridge, and an image forming apparatus in which fog is reduced over a long period of time.

The above problem is solved by the following means. That is,
The invention according to claim 1
At least toner particles containing a binder resin and a colorant, and at least inorganic particles other than silica,
A liberation ratio of the inorganic particles to the toner particles is 20% or more;
The inorganic particles are surface-treated with a quaternary ammonium salt.
An electrostatic charge developing toner.

The invention according to claim 2
2. The electrostatic charge developing toner according to claim 1, wherein the inorganic particles are at least one selected from cerium oxide, alumina, titania, and strontium titanate.

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

The invention according to claim 4
A toner cartridge, wherein the toner for developing an electrostatic charge image according to claim 1 is contained.

The invention according to claim 5
A process cartridge comprising at least a developer holder and containing the electrostatic charge image developer according to claim 3.

The invention according to claim 6
An image carrier,
Developing means for developing the electrostatic image formed on the image carrier as a toner image with a developer;
Transfer means for transferring a toner image formed on the image carrier onto the transfer target;
Fixing means for fixing the toner image transferred onto the transfer material;
Have
An image forming apparatus, wherein the developer is the electrostatic charge image developer according to claim 3.

The invention according to claim 7 provides:
The image forming apparatus according to claim 6, wherein the image carrier is an amorphous silicon photoconductor.

According to the first aspect of the present invention, the fog is reduced over a long period of time.
According to the invention of claim 2, the fog is more effectively reduced over a long period of time. According to the invention of claim 3, the fog is reduced over a long period of time.
According to the invention of claim 4, the fog is reduced over a long period of time.
According to the invention of claim 5, the fog is reduced over a long period of time.
According to the invention of claim 6, the fog is reduced over a long period of time.
According to the seventh aspect of the present invention, even if the surface of the amorphous silicon photoconductor is hard to be scraped off, not only fogging due to toner charging but also fog peculiar to the amorphous silicon photoconductor is reduced over a long period of time.

Hereinafter, embodiments of the present invention will be described in detail.
<Toner for electrostatic image development>
An electrostatic charge image developing toner according to an exemplary embodiment (hereinafter sometimes referred to as “toner”) includes at least toner particles including a binder resin and a colorant, and at least inorganic particles other than silica. The release rate of the particles from the toner particles is 20% or more, and the inorganic particles are surface-treated with a quaternary ammonium salt.

  With the toner according to the embodiment having the above-described configuration, the release rate with respect to the toner particles is equal to or higher than a predetermined value, and the inorganic particles surface-treated with the quaternary ammonium salt are stably supplied to the surface of the image carrier (photoreceptor). Since the application of grade 4 ammonium salt is performed, fogging is prevented over a long period of time. In particular, even if the surface of the image bearing member is an amorphous silicon photosensitive member whose surface is difficult to be scraped off, not only fogging due to toner charging but also fogging peculiar to the amorphous silicon photosensitive member is reduced.

  Here, conventionally, 1) a quaternary ammonium salt is applied to the surface of the image carrier (photoreceptor) or contained in the surface layer, 2) a quaternary ammonium salt is surface-treated as an external additive to silica, and 3) fill. There has been proposed a technique of adding conductive particles having a high release rate to toner in order to prevent mingling.

However, the method of applying a quaternary ammonium salt to the photoreceptor is effective at the beginning, but the suppression of fogging with time is reduced. Moreover, when it is contained in the overcoat, the surface exposure of the quaternary ammonium salt is small and the suppression of fogging is small.
Silica that has been surface-treated with a quaternary ammonium salt as an external additive is originally used to improve toner characteristics. Silica adheres to and is collected on toner particles, and friction with an image carrier (photoreceptor). Due to the strong negative chargeability due to, the adhesion to the photoreceptor is small, and the quaternary ammonium salt coating effect is not exhibited.
Conductive particles having a high release rate are used as an abrasive and are a conventionally used technique, which is effective for removing contaminants, but cannot suppress fogging.

  On the other hand, in this embodiment, it discovered that the fog reduction effect improved based on having discovered the following knowledge. 1) In order to always apply a fixed amount of a quaternary ammonium salt to an image carrier (photoreceptor) regardless of image / non-image, it is effective to treat it as an external additive to the toner. 2) The higher the release ratio of the external additive to the toner, the more uniform and stable application can be achieved. 3) The inorganic particles other than silica are effective for stable coating.

  In other words, the high liberation rate of the external additive means that it easily adheres uniformly to the image carrier (photoreceptor) regardless of the image, easily accumulates on the cleaning member, and the toner characteristics have an effect on toner development. Small and has little effect on powder characteristics. In particular, when inorganic particles other than silica are used as an external additive, they are not collected together with the toner particles because they hardly adhere to the toner particles, and exhibit positive chargeability or weak negative chargeability due to friction with the image carrier (photoconductor). As a result, the adhesion to the image carrier (photoreceptor) is increased and the coating effect of the quaternary ammonium salt is improved.

  Therefore, in this embodiment, it is considered that fogging is prevented over a long period of time.

Here, the fog specific to the amorphous silicon photoreceptor will be described.
The wavelength of the exposure light source for forming an image and the wavelength of the charge removal light are preferably short wavelengths in consideration of light fatigue of the photoreceptor and image resolution. However, in recent years, many small-sized and low-cost LEDs and LDs have been adopted as light sources, and their wavelengths have become longer than 600 nm to 800 nm. As a result, the penetration distance to the photoconductor is long, so that the generation position of carriers due to the photoelectric effect is deep, and the static elimination light used for the static elimination process for releasing the carriers trapped in the photosensitive layer is about the same as the exposure light source. It is necessary to use the wavelength. However, since the photocarrier generated by static elimination light is also generated at a deep position, it is not sufficiently removed until the next charging process, and moves inside the photoconductor during the charging to development process, reducing the dark decay of the photoconductor Cause it. In particular, when high-speed printing is performed, this phenomenon becomes prominent because the time required for the static elimination process and the charging process is shortened. In addition, this phenomenon occurs due to the behavior of the generated carrier in the photosensitive layer, so that the phenomenon appears particularly prominently when an amorphous silicon photoconductor having a small charge holding ability is used. This decrease in dark attenuation (decrease in surface charge) is a problem that causes printing defects such as fogging.
When the contact charging method is used and an amorphous silicon photoconductor is used for the photosensitive drum, the influence of the nip width between the charging roller and the photosensitive drum is large, and even a slight difference in the nip width greatly affects the surface potential. This means that the amorphous silicon photoconductor has a lower charging capability than the organic photoconductor, and the surface potential is uneven, which causes problems such as fogging.
As described above, the use of the amorphous silicon photoconductor causes a characteristic fog that cannot be seen in the organic photoconductor.
It is considered that not only the fog due to charging of the toner but also the specific fog generated by using the amorphous silicon photoconductor as described above is reduced.

  Hereinafter, a specific configuration of the toner will be described in detail.

(Toner particles)
The toner particles include a binder resin, a colorant, and other additives as necessary. The structure of the toner particles is not particularly limited, and may be a single layer structure. For example, a core layer including a binder resin and a colorant or a release agent, and a core layer including the binder resin are covered. A so-called core-shell structure having a shell layer can also be used.

-Binder resin-
As the binder resin, various resins such as an amorphous polyester resin and a crystalline polyester resin can be used as well as an amorphous resin typified by a vinyl resin.

  Examples of vinyl binder resins include vinyl styrenes such as styrene and parachlorostyrene, vinyl naphthalene, vinyl chloride, vinyl bromide, vinyl fluoride, vinyl acetate, vinyl propionate, vinyl benzoate, vinyl butyrate, etc. Esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloroethyl acrylate, phenyl acrylate, α-methyl chloroacrylate, methacryl Methylene aliphatic carboxylic acid esters such as methyl acid, ethyl methacrylate, butyl methacrylate, acrylonitrile, methacrylonitrile, acrylamide, for example vinyl such as vinyl methyl ether, vinyl ethyl ether, vinyl isobutyl ether Monomers such as N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone and the like, monomers having an N-containing polar group, methacrylic acid, acrylic acid, cinnamic acid, Homopolymers and copolymers of vinyl monomers such as vinyl carboxylic acids such as carboxyethyl acrylate and / or various polyesters, and various waxes can also be used.

  In the case of vinyl monomers, emulsion polymerization can be performed using an ionic surfactant or the like to prepare a resin particle dispersion. In the case of other resins, the resin is oily and has a relatively high solubility in water. If it is soluble in a low solvent, dissolve the resin in those solvents, disperse it in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte, and then heat or reduce the solvent. The resin particle dispersion can be obtained by evaporating.

As the crystalline resin, a crystalline polyester resin is preferable, and an aliphatic crystalline polyester resin having an appropriate melting point is more preferable. Hereinafter, a crystalline polyester resin will be described as an example.
Some crystalline aliphatic polyesters, such as polycaprolactone, progress through ring-opening polymerization, but many are synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. The “acid-derived constituent component” refers to a constituent portion that was an acid component prior to the synthesis of the polyester resin, and the “alcohol-derived constituent component” refers to a configuration that was the alcohol component prior to the synthesis of the polyester resin. Refers to the site.

When the polyester resin is not crystalline, that is, non-crystalline, it may be difficult to maintain toner blocking resistance and image storage stability while ensuring good low-temperature fixability.
In the present embodiment, “crystalline polyester resin” means that the half-value width of the endothermic peak observed in differential scanning calorimetry (DSC) is 6 ° C. or less, and other polyester resins are It means an amorphous polyester resin.
In the present embodiment, the “polyester resin” is not only a resin having a pure polyester structure, but also a polymer in which other components are copolymerized with respect to the polyester main chain. A polymer is also meant.

-Acid-derived constituent component The acid-derived constituent component is preferably an aliphatic dicarboxylic acid, and particularly preferably a linear carboxylic acid.
For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof And acid anhydrides, but are not limited thereto.

As the acid-derived constituent component, in addition to the above-mentioned aliphatic dicarboxylic acid-derived constituent component, constituent components such as a dicarboxylic acid-derived constituent component having a double bond and a dicarboxylic acid-derived constituent component having a sulfonic acid group are included. Is preferred.
The component derived from a dicarboxylic acid having a double bond is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Components are also included. The dicarboxylic acid-derived constituent component having a sulfonic acid group is derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a sulfonic acid group, in addition to a constituent component derived from a dicarboxylic acid having a sulfonic acid group. Components are also included.

The dicarboxylic acid having a double bond can be suitably used to prevent hot offset at the time of fixing since the entire resin can be crosslinked using the double bond. Examples of the dicarboxylic acid include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, fumaric acid, maleic acid and the like are preferable in terms of cost.
The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment.

  Further, when the toner base particles are prepared by emulsifying or suspending the whole resin in water, if there is a sulfonic acid group, it can be emulsified or suspended without using a surfactant as described later. . Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. Among these, 5-sulfoisophthalic acid sodium salt is preferable in terms of cost.

Content of acid-derived components other than aliphatic dicarboxylic acid-derived components (dicarboxylic acid-derived components having double bonds and / or dicarboxylic acid-derived components having sulfonic acid groups) in the acid-derived components Is preferably from 1 component mol% to 20 component mol%, more preferably from 2 component mol% to 10 component mol%.
When the content is less than 1 constituent mol%, pigment dispersion may not be good, the emulsified particle diameter may be large, and adjustment of the toner diameter by aggregation may be difficult. On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. Sometimes.

  In the present embodiment, “constituent mol%” refers to a percentage when each constituent component (acid-derived constituent component, alcohol-derived constituent component) in the polyester resin is 1 unit (mol).

-Alcohol-derived components-
The alcohol component is preferably an aliphatic dicarboxylic acid, for example, 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-dodecanediol, 1,12-undecanediol, 1,13-tridecanediol, 1,14-tetradecanediol 1,18-octadecanediol, 1,20-eicosanediol, and the like, but are not limited thereto.

  When the alcohol-derived constituent component is an aliphatic diol-derived constituent component, the content of the aliphatic diol-derived constituent component is 80 constituent mol% or more, and other components are included as necessary. Furthermore, when the alcohol-derived constituent component is an aliphatic diol-derived constituent component, the content of the aliphatic diol-derived constituent component is preferably 90 constituent mol% or more.

When the content of the aliphatic diol-derived constituent component is less than 80 constituent mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability are deteriorated. End up.
Other components included as necessary include diol-derived components having double bonds and diol-derived components having sulfonic acid groups.
Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol, and the like.
Examples of the diol having a sulfonic acid group include 1,4-dihydroxy-2-sulfonic acid benzene sodium salt, 1,3-dihydroxymethyl-5-sulfonic acid benzene sodium salt, and 2-sulfo-1,4-butanediol sodium. Examples include salts.

  When adding an alcohol-derived component other than these linear aliphatic diol-derived components, that is, when adding a diol-derived component having a double bond and / or a diol-derived component having a sulfonic acid group, The content of the diol-derived constituent component having a double bond and / or the diol-derived constituent component having a sulfonic acid group in the alcohol-derived constituent component is preferably from 1 constituent mol% to 20 constituent mol%, and preferably from 2 constituent mol% to 10 constituent mol%. It is more preferably less than mol%.

When the content of the alcohol-derived constituent component other than the aliphatic diol-derived constituent component is less than 1 constituent mol% with respect to the total alcohol-derived constituent component, the pigment dispersion is not good or the emulsion particle size is increased. In some cases, it is difficult to adjust the toner diameter by aggregation.
On the other hand, if it exceeds 20 component mol%, the crystallinity of the polyester resin is lowered, the melting point is lowered, the image storage stability is deteriorated, or the emulsion particle size is too small to dissolve in water, and no latex is produced. Sometimes.

  The melting point of the binder resin of the toner is preferably 50 ° C. or higher and 120 ° C. or lower, and more preferably 60 ° C. or higher and 110 ° C. or lower. If the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. On the other hand, if the temperature is higher than 120 ° C., sufficient low-temperature fixing may not be obtained as compared with conventional toners.

  In the present embodiment, a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001) (hereinafter abbreviated as “DSC”) is used to measure the melting point of the crystalline resin at room temperature. It can be determined as the melting peak temperature of the input compensated differential scanning calorimetry shown in JIS K-7121 when measurement is performed at a rate of temperature increase of 10 ° C. per minute (for example, 25 ° C., the same applies hereinafter) to 150 ° C. The crystalline resin may show a plurality of melting peaks, but in this embodiment, the maximum peak is regarded as the melting point.

  The method for producing the polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. For example, direct polycondensation, transesterification method, etc. Produced separately for different types. The molar ratio (acid component / alcohol component) when the acid component reacts with the alcohol component varies depending on the reaction conditions and the like, and cannot be generally stated, but is usually about 1/1.

The polyester resin can be produced at a polymerization temperature of 180 ° C. or higher and 230 ° C. or lower. If necessary, the reaction system is reduced in pressure and reacted while removing water and alcohol generated during condensation.
When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. If there is a monomer with poor compatibility in the copolymerization reaction, the monomer with poor compatibility and the monomer and the acid or alcohol to be polycondensed may be condensed in advance before polycondensation with the main component. .

  Catalysts that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium, alkaline earth metal compounds such as magnesium and calcium, and metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium. , Phosphorous acid compounds, phosphoric acid compounds, amine compounds, etc., specifically, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, stearic acid Zinc, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, trib Ruantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, triphenyl Examples of the compound include phosphite, tris (2,4-di-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, and triphenylamine.

  When a toner is prepared using an emulsion polymerization aggregation method described later, the binder resin is used as a resin particle dispersion containing resin particles obtained by emulsifying and dispersing the binder resin in an aqueous medium.

The average particle diameter of the resin particles is usually 1 μm or less, and preferably 0.01 μm or more and 1 μm or less. When the average particle size exceeds 1 μm, the particle size distribution of the finally obtained toner may be broadened, or free particles may be generated, which may easily lead to a decrease in performance and reliability.
On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toners becomes good, and the variation in performance and reliability is advantageous. The average particle size can be measured using, for example, a Coulter Multimizer.

Examples of the dispersion medium in the resin particle dispersion include an aqueous medium and an organic solvent.
Examples of the aqueous medium include water such as distilled water and ion exchange water, and alcohols. These may be used individually by 1 type and may use 2 or more types together. In the present embodiment, it is preferable to add and mix a surfactant in the aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like.
Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.
Examples of the organic solvent include ethyl acetate and toluene, which are selected according to the binder resin.

  When the resin particles are homopolymers or copolymers (vinyl resins) of vinyl monomers such as esters having the vinyl group, the vinyl nitriles, the vinyl ethers, the vinyl ketones, By subjecting the vinyl monomer to emulsion polymerization or seed polymerization in an ionic surfactant, resin particles made of a homopolymer or copolymer (vinyl resin) of the vinyl monomer are converted into an ionic interface. A dispersion is prepared by dispersing in an active agent.

  When the resin particle is a resin other than the homopolymer or copolymer of the vinyl monomer, the resin can be used as long as the resin is dissolved in an oily solvent having a relatively low solubility in water. Is dissolved in the oily solvent, and the solution is dispersed in water together with an ionic surfactant and polymer electrolyte using a disperser such as a homogenizer, and then the oily solvent is evaporated by heating or decompression. Thus, a dispersion liquid in which resin particles made of resin other than vinyl resin are dispersed in an ionic surfactant is prepared.

  On the other hand, when the resin particles are a crystalline polyester and an amorphous polyester resin, some or all of the functional groups that have self-water dispersibility and can be hydrophilic, containing functional groups that can become anionic by neutralization Is neutralized with a base and can form a stable aqueous dispersion under the action of an aqueous medium. In the crystalline polyester and the amorphous polyester resin, the functional group that can become a hydrophilic group by neutralization is an acidic group such as a carboxyl group or a sulfone group, and examples of the neutralizing agent include sodium hydroxide, potassium hydroxide, Examples thereof include inorganic bases such as lithium hydroxide, calcium hydroxide, sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

  Further, when a polyester resin that does not disperse in water, that is, does not have self-water dispersibility, is used as a binder resin, the resin solution and / or an aqueous medium mixed with the resin solution, as described later, 1 μm easily when dispersed with a polymer electrolyte such as a surfactant, polymer acid, polymer base, etc., heated above the melting point, and treated with a homogenizer or pressure discharge type disperser capable of applying a strong shear force The following particles can be made. When this ionic surfactant or polymer electrolyte is used, the concentration in the aqueous medium is suitably about 0.5% by mass or more and 5% by mass or less.

  The volume average particle size of the resin particles in the resin particle dispersion thus obtained can be measured with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

-Colorant-
As the colorant, a known colorant can be used. For example, the following colorants can be used.
Examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.
Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, hansa yellow, hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, permanent yellow NCG, and the like. be able to.

  Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange G, indanthrene brilliant orange RK, and indanthrene brilliant orange GK.

  Red pigments include Bengala, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B rake, lake red C Naphthol red such as Rose Bengal, Eoxin Red, Alizarin Lake, Pigment Red 146, 147, 184, 185, 155, 238 and 269.

  Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, indanthrene blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate.

Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.
Examples of the green pigment include chromium oxide, chromium green, pigment green, malachite green lake, final yellow green G, and the like.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.

Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.
Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

  These colorants are used alone or in combination. In the case of producing a toner by using an emulsion polymerization aggregation method described later, these colorants are used as a colorant dispersion liquid in which colorant particles are dispersed. For example, a dispersion of colorant particles can be prepared using a media-type disperser such as a rotary shearing homogenizer, a ball mill, a sand mill, or an attritor, a high-pressure opposed collision disperser, or the like. Further, these colorants can be dispersed in an aqueous system by a homogenizer using a polar surfactant.

The colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner.
The colorant can be added in the range of 4% by mass to 15% by mass with respect to the total toner constituent solid weight. When a magnetic material is used as the black colorant, it can be added in an amount of 12% by mass to 240% by mass, unlike other colorants.
The blending amount of the colorant is a necessary amount for securing the color developability at the time of fixing. Moreover, OHP transparency and color developability can be ensured by setting the center diameter (median diameter) of the colorant particles in the toner to 100 nm or more and 330 nm or less. The center diameter of the colorant particles can be measured, for example, with a laser diffraction particle size distribution measuring device (LA-700, manufactured by Horiba, Ltd.).

-Release agent-
A known release agent can be used for the toner of the exemplary embodiment as needed. Specific examples thereof include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, and silicones that exhibit a softening point when heated. , Fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, etc., plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, beeswax And mineral waxes such as animal wax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, microcrystalline wax, Fischer-Tropsch wax, etc., and modified products thereof. .
These waxes are hardly dissolved in a solvent such as toluene at room temperature or very little even if dissolved.

  These mold release agents are dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, heated above the melting point, and have strong shearing ability and pressure discharge type A release agent dispersion containing release agent particles having a volume average particle diameter of 1 μm or less can be prepared by dispersing in a particle form using a disperser (Gorin homogenizer, manufactured by Gorin).

It is desirable to add these release agents in the range of 5% by mass or more and 25% by mass or less with respect to the total weight of the toner constituting solids, in order to ensure the releasability of the fixed image in the oilless fixing system.
The particle size of the obtained release agent particle dispersion was measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.). In addition, when using a release agent, after the resin particles, colorant particles, and release agent particles are aggregated, it is possible to add resin particle dispersion to adhere the resin particles to the surface of the aggregated particles. It is desirable from the viewpoint of securing the property.

-Other (additives)-
For the toner particles, a known internal additive or external additive may be used as necessary.
For example, when used as a magnetic toner, magnetic powder may be included. Specifically, a material that is magnetized in a magnetic field is used, but a ferromagnetic powder such as iron, cobalt, or nickel, or a compound such as ferrite or magnetite is used.
When obtaining toner in the aqueous phase, it is necessary to pay attention to the aqueous phase migration of the magnetic material, and it is preferable to modify the surface of the magnetic material in advance, for example, to perform a hydrophobic treatment or the like.

Also, magnetic materials such as ferrite, magnetite, reduced iron, cobalt, nickel, manganese and other metals, alloys, and compounds containing these metals are used as internal additives, and quaternary ammonium salt compounds, nigrosine-based as charge control agents. Various commonly used charge control agents such as dyes composed of complexes of compounds, aluminum, iron, chromium and the like, and triphenylmethane pigments can be used. However, when the toner is prepared by using the emulsion polymerization aggregation method, a material that is difficult to dissolve in water is preferable from the viewpoint of controlling ionic strength that affects aggregation and temporary stability and reducing wastewater contamination.
Furthermore, it is possible to add a known lubricant or the like to improve the cleaning characteristics. It is preferable to use a fatty acid metal salt such as resin fine particles or zinc stearate in combination.

-Toner particle characteristics-
The volume average particle size of the toner particles is preferably in the range of 3 μm to 9 μm, and more preferably in the range of 3 μm to 8 μm. When the volume average particle diameter of the toner particles exceeds 9 μm, the ratio of coarse particles increases, and the reproducibility and gradation of fine lines and fine dots of the image obtained through the fixing process are lowered. On the other hand, if the volume average particle size of the toner particles is less than 3 μm, the powder fluidity, developability, or transferability of the toner deteriorates, and the cleaning properties of the toner remaining on the surface of the image carrier deteriorate. Various problems occur in other processes due to the deterioration of characteristics.

  As the particle size distribution index of the toner particles, the volume average particle size distribution index GSDv is preferably 1.30 or less, and the ratio GSDv / GSDp to the number average particle size distribution index GSDp is 0.95 or more. More preferred. When the volume distribution index GSDv exceeds 1.30, the resolution decreases, and when the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is less than 0.95, a decrease in chargeability occurs. At the same time, it may scatter and cause image defects such as fog.

The volume average particle size and the particle size distribution index were measured and calculated as follows. First, with respect to the divided particle size range (channel) of the toner particle size distribution measured using a Coulter Multisizer II (manufactured by Beckman-Coulter) as a measuring device, the volume and number of individual toner particles from the small diameter side. A cumulative distribution is drawn, and the particle size at 16% cumulative is defined as volume average particle size D16v and number average particle size D16p. The particle size at 50% cumulative is defined as volume average particle size D50v (this value is defined as volume average particle size). Defined as D50p). Similarly, particle diameters that are 84% cumulative are defined as volume average particle diameters D84v and D84p. Using these, the volume average particle size distribution index GSDv is defined as (D84v / D16v) ^1/2 and the number average particle size distribution index GSDp is defined as (D84p / D16p) ^1/2 .

Furthermore, the shape factor SF1 of the toner particles is preferably in the range of 110 to 140.
Here, the shape factor SF1 is obtained by the following equation.
SF1 = (ML ² / A) × (π / 4) × 100
In the above formula, ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, the optical microscope image of the toner spread on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, the maximum length and the projected area of 100 toner particles are obtained, and the average value is obtained by the above formula. Is obtained.

(Inorganic particles)
The inorganic particles have a liberation rate of 20% or more with respect to the toner particles, and are surface-treated with a quaternary ammonium salt.

  The inorganic particles have a liberation rate of 20% or more with respect to the toner particles, preferably 30% or more, and more preferably 40% or more. The higher the release rate, the better the fog reduction effect. However, the upper limit is 60% or less from the point of contamination in the apparatus (contamination in the developing machine) by inorganic particles.

  Here, the liberation rate is a value measured using a particle analyzer DP-1000. The particle analyzer introduces particles one by one into a high-temperature non-thermal equilibrium plasma and knows the element, the number of particles, and the particle size of the particles from the emission spectrum of the particles accompanying this excitation. Specifically, the number of light emission of the element of the inorganic particle and the number of light emission of the inorganic particle emitted simultaneously with carbon which is the constituent element of the binder resin are measured with a particle analyzer. At the time of measurement, helium gas is used, and when the emission voltage of carbon is X and the emission voltage of the element of inorganic particles is Y, the liberation rate is obtained from the number of free inorganic particles in 3000 particles.

  In addition, as a method for controlling the liberation rate within the above range, for example, a multistage blending method in which the blending conditions are weakened, the inorganic particles of this specification are externally added after treating other external additives, The method of using large inorganic particles can be mentioned.

  Inorganic particles, for example, specific examples of inorganic fine powders include, for example, cerium oxide, cerium oxide containing rare earth element oxide, aluminum, nickel, zinc oxide, titanium oxide, tin oxide, aluminum oxide, indium oxide, magnesium oxide, Among the barium oxide, molybdenum oxide, iron oxide, tungsten oxide, tungsten carbide, cadmium sulfide, strontium titanate, potassium titanate, and complex oxides thereof, inorganic particles having an aggregate of primary particles are preferable. It is done. These inorganic particles may be used alone or in combination of two or more.

  Among these, it is preferable to select from cerium oxide, alumina, titania, and strontium titanate. These inorganic particles function as an abrasive and are used as an abrasive having an abrasive effect on the surface of the image carrier, so that contaminants on the surface of the image carrier (photoreceptor) are removed and put onto the image carrier in a fresh state. Quaternary ammonium salt is applied.

  There are no particular limitations on the quaternary ammonium salt that is surface-treated on the inorganic particles, for example, the quaternary ammonium salt is not particularly limited, but includes tetraalkylammonium salt, trialkylarylammonium salt, dialkyldiarylammonium salt, alkyl Known materials such as triaryl ammonium salts, tetraaryl ammonium salts, cyclic ammonium salts, and bicyclic ammonium salts can be used. Preferred examples of the quaternary ammonium salt include those having the structures shown below.

  The amount of treatment of the quaternary ammonium salt on the surface of the inorganic particles is, for example, preferably 1 part by weight or more and 30 parts by weight or less, more preferably 3 parts by weight or more and 20 parts by weight or less, and further preferably 5 parts by weight with respect to 100 parts by weight of the inorganic particles. It is not less than 10 parts by weight.

  As a method for treating the surface of inorganic particles with quaternary ammonium salt, for example, there is a method in which quaternary ammonium salt is dissolved in an appropriate solvent, added to inorganic particles and coated with the surface, and then the solvent is dried. Examples include kneader coaters, spray dryers, thermal processors, and fluidized beds. You may grind | pulverize and classify as needed. Moreover, it is also possible to process it dry-type with Nobilta etc.

The particle size of the inorganic particles surface-treated with the quaternary ammonium salt is preferably 10 nm or more and 5000 nm or less, more preferably 50 nm or more and 3000 nm or less, and further preferably 100 nm or more and 2000 nm or less in terms of volume average particle size. .
Here, the volume average particle diameter D _50, and measuring the particle diameter of the particles in the image observation with an electron microscope (manufactured by JEOL) (maximum diameter) refers to a value calculated. That is, the standard deviation is obtained under the conditions of sampling number: 100, particle size: 0.001 μm to 1 μm, and the volume average particle size of the external additive is calculated.

  The addition amount (external addition amount) of the inorganic particles surface-treated with the quaternary ammonium salt is preferably 0.05 parts by mass or more and 3.0 parts by mass or less with respect to 100 parts by mass of the toner particles. Preferably they are 0.2 mass part or more and 1.0 mass part or less. When the addition amount (external addition amount) is in the above range, the fog suppression effect is effectively exhibited.

  In addition, you may use together a well-known external additive with the inorganic particle by which the quaternary ammonium salt was surface-treated. Known external additives are used in combination for improving powder characteristics and charging characteristics. As a known external additive, silica, titania, alumina and the like are preferable. In addition, a known external additive is preferably subjected to a hydrophobic treatment.

(Toner production method)-
The toner according to the embodiment may be produced by either a kneaded powder grinding method or a wet method, and is not particularly limited. For example, in the kneading and pulverizing method, first, the toner components are mixed, and then the above materials are melt-kneaded using a kneader, an extruder, or the like. Thereafter, the melt-kneaded product is coarsely pulverized and then finely pulverized by a jet mill or the like, and toner particles having a target particle diameter are obtained by an air classifier. Further, an external additive (quaternary ammonium salt-treated inorganic particles) is externally added to complete the final toner.

  In addition, as a wet manufacturing method, in particular, after adding one or more kinds of aggregating agent to a raw material dispersion containing one or more kinds of raw material particles, the one or more kinds of raw material particles are aggregated to form aggregated particles. A production method (so-called emulsion polymerization aggregation method) including an aggregated particle forming step and a fusion step of fusing the aggregated particles by heating is suitably employed.

  Here, as raw material particles in the wet manufacturing method, at least resin particles (constituting a binder resin) are used, and colorant particles, release agent particles, and the like are used as necessary. When a polyester resin is used as the binder resin for the toner, a resin particle containing a polyester resin is used. Therefore, when two or more types of raw material particles are used, a raw material dispersion is prepared by mixing a dispersion containing each type of raw material particles.

  Further, when preparing a toner having a so-called core-shell structure, for example, a resin particle dispersion in which resin particles are dispersed and one or more kinds of aggregating agents are added to the raw material dispersion after the aggregate particle formation step. Then, the fusion step can be performed after the coating layer forming step of forming the coating layer by attaching the resin particles to the surface of the aggregated particles.

Here, when the process involving the aggregation of the raw material particles is performed only once in the toner production (that is, when only the aggregated particle forming process is performed), an Al element is used as an aggregating agent used in the aggregated particle forming process. A coagulant containing is used.
Further, in the production of toner, when the process involving aggregation of raw material particles is performed twice or more (for example, when the aggregated particle forming process and the coating layer forming process are performed), the aggregation used in at least one of the processes As the agent, an aggregating agent containing Al element is used.

  The resin particles used in the aggregated particle forming step and the coating layer forming step are preferably resin particles containing a polyester resin. Thereby, a toner containing a polyester resin can be produced.

Further, when the resin particles used in the aggregated particle forming step and the coating layer forming step are resin particles containing a polyester resin, the raw material dispersion used in the aggregated particle forming step and the resin particle dispersion used in the coating layer forming step When the solid content concentration of these dispersions is adjusted to 30% by mass, the electrical conductivity is preferably dialyzed to be in the range of 100 μS / cm or more and 1000 μS / cm or less, and 150 μS / cm or more. It is more preferable that dialysis treatment is performed so as to be in a range of 800 μS / cm or less.
In the dialysis treatment, the dispersion is put in a dialysis membrane (for example, UC 1-7-8-50 manufactured by Sanko Junyaku Co., Ltd.) and held in ion-exchanged water until the electric conductivity falls within the above range. Can be implemented. Here, for measurement of conductivity, a CyberScan con400 manufactured by Eutech was used at 25 ° C.

When the electrical conductivity of the dispersion exceeds 1000 μS / cm, the toner mother particles are dissolved in tetrahydrofuran (THF), and then the mixture obtained by further mixing ion-exchanged water is filtered with a filter having a mesh opening of 1.0 μm. It may be difficult to control the solid content contained in the filtrate obtained by filtration within the range of 10% by mass or less in the toner base particles.
When the electrical conductivity of the dispersion is less than 100 μS / cm, the toner base particles are dissolved in tetrahydrofuran (THF) and then mixed with ion-exchanged water to obtain a mixture having an opening of 1.0 μm. It may be difficult to control the solid content contained in the filtrate obtained by filtering with a filter to a range of 0.1% by mass or more in the toner base particles. On the other hand, if the conductivity of the dispersion is too low, the dispersion stability of the raw material particles dispersed in the dispersion cannot be maintained, and as a result, the particle size distribution of the toner tends to easily spread to the small diameter side. In this case, fogging may occur when an image is formed for a long time under high temperature and high humidity due to the toner on the small diameter side of the particle size distribution.
Next, each step such as the aggregated particle forming step will be described in more detail.

-Aggregated particle formation process-
In the agglomerated particle forming step, in addition to the resin particle dispersion, a colorant dispersion is usually added, and other dispersion added as necessary (for example, a release agent dispersion in which a release agent is dispersed) Etc.) is further added to the raw material dispersion obtained by mixing, and heated to form aggregated particles in which these particles are aggregated. In the case where the resin particles are a crystalline resin such as crystalline polyester, the aggregated particles obtained by aggregating these particles by heating at a temperature near the melting point of the crystalline resin and at a temperature not higher than the melting point are used. Form.

Aggregated particles are formed by adding a flocculant at room temperature under stirring with a rotary shearing homogenizer to make the pH of the raw material dispersion acidic.
The aggregating agent used in the aggregated particle forming step is preferably a surfactant having a polarity opposite to that of the surfactant used as the dispersing agent added to the raw material dispersion, that is, an inorganic metal salt or a divalent or higher-valent metal complex. Can be used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Among these, an aluminum salt and a polymer thereof are particularly preferable. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

When the toner is manufactured in the case where the step of using the flocculant is only the step of forming the aggregated particles, the flocculant containing Al element is used as the flocculant in this step. Moreover, when the process using an aggregating agent is an agglomerated particle forming process and a coating layer forming process, an aggregating agent containing an Al element as an aggregating agent may be used in both processes or one of the processes.
Here, as the aggregating agent containing Al element, those listed above such as polyaluminum chloride can be used.

  In order to stop the agglomeration reaction in the agglomerated particle formation step and the coating layer formation step before the fusion step, in the conventional emulsion polymerization aggregation method, after adding the aggregating agent, an alkaline solution such as sodium hydroxide is added. The pH of the raw material dispersion is adjusted from the acidic side to the alkaline side (pH = 6.5 or more and 8.5 or less). Then, subsequent processes such as a fusion process are performed.

-Coating layer formation process-
After the aggregated particle forming step, the coating layer forming step may be performed if necessary. In the coating layer forming step, the coating layer is formed by attaching resin particles for forming a coating layer to the surface of the aggregated particles formed through the above-described aggregated particle forming step. Thereby, a toner having a so-called core / shell structure can be obtained.

  The coating layer can be formed by usually adding a resin particle dispersion containing amorphous resin particles to the raw material dispersion in which the aggregated particles (core particles) are formed in the aggregated particle forming step.

  A surfactant can be used for emulsion polymerization of the binder resin, pigment dispersion, resin particle dispersion, release agent dispersion, particle aggregation, and aggregation particle stabilization. Specifically, sulfate surfactants, sulfonates, phosphates, soaps and other anionic surfactants, amine salts, quaternary ammonium salts and other cationic surfactants, polyethylene glycols, It is also effective to use a nonionic surfactant such as an alkylphenol ethylene oxide adduct system or a polyhydric alcohol system. Can be used

-Fusion process-
In the agglomeration step performed after the aggregated particle forming step or the aggregated particle forming step and the coating layer forming step, the pH of the suspension containing the aggregated particles formed through these steps is 6.5 or more and 10 or less. By making it into the range, the progress of aggregation is stopped. When using the second (Al) ₁ / (Al) ₂ value control method, the pH of the suspension can be selected within the above range, but the second (Al) ₁ / (Al) ₂ When using the value control method, the pH of the suspension is adjusted within the range of 9 or more and 10 or less.
Then, after the progress of aggregation is stopped, the aggregated particles are fused by heating. When a crystalline resin is used as the binder resin, the aggregated particles are fused by heating at a temperature equal to or higher than the melting point of the binder resin.

-Cleaning, drying process, etc.-
After completing the coalesced particle fusion step, desired toner particles are obtained through an arbitrary washing step, solid-liquid separation step, and drying step. In consideration of charging properties, the washing step may be replaced with ion exchange water. desirable. Moreover, although there is no restriction | limiting in particular in a solid-liquid separation process, From the point of productivity, suction filtration, pressure filtration, etc. are suitable. Further, the drying process is not particularly limited, but freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

  The final toner is completed by externally adding the various external additives (quaternary ammonium salt-treated inorganic particles) described above to the toner particles after drying.

<Electrostatic image developer>
Next, the electrostatic charge image developer of this embodiment will be described.
The electrostatic image developer of this embodiment is not particularly limited except that it contains the toner of this embodiment, and can have a component composition according to the purpose. The developer of this embodiment becomes a one-component developer when the toner is used alone, and becomes a two-component developer when the toner and the carrier are used in combination.

Specific examples of the carrier include the following resin-coated carriers. Examples of the core material of the carrier include ordinary iron powder, ferrite, and magnetite molding, and the volume average particle size is in the range of about 30 μm to 200 μm.
The carrier core material preferably has a volume resistivity of 1 × 10 ^7.5 Ωcm or more and 1 × 10 ^9.5 Ωcm or less. When the volume resistivity is less than 1 × 10 ^7.5 Ω · cm, when the toner concentration in the developer is reduced by repeated copying, charges are injected into the carrier, and the carrier itself may be developed. is there. On the other hand, if the volume resistivity is higher than 1 × 10 ^9.5 Ω · cm, the image quality such as a prominent edge effect or pseudo contour may be adversely affected. The core material is not particularly limited as long as the above conditions are satisfied. For example, magnetic metals such as iron, steel, nickel, and cobalt, alloys of these with manganese, chromium, rare earth, and magnetic materials such as ferrite and magnetite. An oxide etc. are mentioned. Among these, ferrite, particularly an alloy with manganese, lithium, strontium, magnesium or the like is preferable from the viewpoint of core surface properties and core material resistance.

  The coating resin preferably contains at least a fluorine resin, and can be selected according to the purpose. However, a fluorine resin such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Examples of the resin known per se. These may be used individually by 1 type and may use 2 or more types together.

  Moreover, it is preferable that at least resin particles and / or conductive particles are dispersed in the resin coating layer (coating film). When the resin particles are dispersed in the coating film, they are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Surface formation similar to that at the time of use can be maintained, and good charge imparting ability for the toner can be maintained over a long period of time. Further, when conductive particles are dispersed in the coating film, since the conductive particles are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface, the carrier film is used for a long period of time. Even if it wears out, it can always maintain the same surface formation as when it is not used, and carrier deterioration can be prevented for a long time. In addition, when the resin particle and electroconductive particle are disperse | distributed to a coating film, the above-mentioned effect can be show | played simultaneously.

  Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle size of the resin particles is preferably about 0.1 μm to 2 μm, more preferably 0.2 μm to 1 μm. When the average particle diameter of the resin particles is less than 0.1 μm, the dispersibility of the resin particles in the coating film is very poor. On the other hand, when the average particle diameter exceeds 2 μm, the resin particles easily fall off from the coating film. It may not be effective. As conductive particles, metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate Examples thereof include particles whose surface such as powder is covered with tin oxide, carbon black, metal or the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable from the viewpoints of production stability, cost, conductivity, and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of about 50 ml / 100 g or more and 250 ml / 100 g or less is preferable because of excellent production stability.

  Examples of the method for forming the resin coating layer on the surface of the core material include an immersion method in which the coating film-forming liquid containing the coating resin is immersed, a spray method in which the coating film forming liquid is sprayed on the surface of the carrier core material, and a carrier. Examples thereof include a kneader coater method in which the core material is mixed with a coating film forming liquid in a state where the core material is floated by flowing air, and the solvent is removed.

  The amount of the resin coating formed by the above method is used by coating an amount of 0.5% by mass or more and 10% by mass or less with respect to the carrier core material. The mixing ratio (mass ratio) of the toner and the carrier is preferably in the range of toner: carrier = 1: 100 to 30: 100, and more preferably in the range of 3: 100 to 20: 100.

<Image forming apparatus>
Next, the image forming apparatus of this embodiment using the toner for developing an electrostatic charge image of this embodiment will be described.
The image forming apparatus according to the present embodiment includes an image carrier, a developing unit that develops an electrostatic image formed on the image carrier as a toner image with a developer, and a toner image formed on the image carrier. The image forming apparatus includes a transfer unit that transfers onto a transfer body and a fixing unit that fixes a toner image transferred onto the transfer body, and uses the electrostatic charge image developer of the present embodiment as the developer. .

In this image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus main body. As the process cartridge, a developer holding body is used. The process cartridge of the present embodiment is preferably used that includes at least the electrostatic charge image developer of the present embodiment.
Hereinafter, although an example of the image forming apparatus of this embodiment is shown, it is not necessarily limited to this. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

  FIG. 1 is a schematic diagram showing a quadruple tandem full-color image forming apparatus. The image forming apparatus shown in FIG. 1 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

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

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

The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, an electrostatic charge image is formed by exposing the surface of the photoreceptor 1Y to a predetermined potential with a charging roller 2Y and the charged surface with a laser beam 3Y based on the color-separated image signal. An exposure device 3; a developing device (developing means) 4Y for supplying the charged toner to the electrostatic image and developing the electrostatic image; a primary transfer roller 5Y (primary) for transferring the developed toner image onto the intermediate transfer belt 20; A transfer unit) and a photoconductor cleaning device (cleaning unit) 6Y for removing toner remaining on the surface of the photoconductor 1Y after the primary transfer with a cleaning blade.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

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

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

  In the developing device 4Y, for example, yellow toner having a volume average particle diameter of 7 μm including at least a yellow colorant, a crystalline resin, and an amorphous resin is accommodated. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to about +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning device 6Y.

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

  The intermediate transfer belt 20 onto which the four color toner images have been transferred through the first to fourth units is arranged on the image transfer surface side of the intermediate transfer belt 20 and the support roller 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer means) 26 is connected to a secondary transfer portion. On the other hand, the recording paper (transfer object) P is fed at a predetermined timing into a gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via a supply mechanism, and a predetermined secondary transfer bias is supported. Applied to the roller 24. The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P is applied to the toner image, and the transfer bias is applied to the intermediate transfer belt 20. The toner image is transferred onto the recording paper P. Note that the secondary transfer bias at this time is determined according to the resistance detected by a resistance detecting 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 fixing device (fixing means) 28, where the toner image is heated, and the color-superposed toner image is melted and fixed on the recording paper P. The recording paper P on which the color image has been fixed is carried out toward the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus exemplified above is configured to transfer the toner image onto the recording paper P via the intermediate transfer belt 20, but the present invention is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

<Process cartridge>
FIG. 2 is a schematic configuration diagram showing a preferred example of a process cartridge containing the electrostatic charge image developer according to the present embodiment. The process cartridge 200 includes, together with the photoconductor 107, a charging roller 108, a developing device 111, a photoconductor cleaning device (cleaning means) 113 including a cleaning blade, an opening 118 for exposure, and an opening for static elimination exposure. 117 is combined and integrated using mounting rails 116.
The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus. Reference numeral 300 denotes a recording sheet.

  The process cartridge shown in FIG. 2 includes a charging device 108, a developing device 111, a cleaning device (cleaning means) 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. Can be selectively combined. In the process cartridge according to the present embodiment, in addition to the photosensitive member 107, the charging device 108, the developing device 111, the cleaning device (cleaning means) 113, the opening 118 for exposure, and the opening 117 for static elimination exposure. At least one selected from the group consisting of:

  Next, the toner cartridge of this embodiment will be described. The toner cartridge according to this embodiment is detachably attached to the image forming apparatus, and at least the toner cartridge that stores toner to be supplied to the developing unit provided in the image forming apparatus. The toner according to the exemplary embodiment. It should be noted that at least the toner may be stored in the toner cartridge of the present embodiment, and for example, a developer may be stored depending on the mechanism of the image forming apparatus.

  Therefore, in the image forming apparatus having a configuration in which the toner cartridge can be attached and detached, the storability is maintained even in the toner cartridge having a smaller container by using the toner cartridge containing the toner of the present embodiment. Therefore, it is possible to achieve low temperature fixing while maintaining high image quality.

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

  Hereinafter, the present embodiment will be specifically described by way of examples. However, the present embodiment is not limited to these examples. In the following description, “part” and “%” all mean “part by mass” and “mass%” unless otherwise specified.

[Example 1]
Polyester resin (linear polyester obtained from terephthalic acid / bisphenol A / ethylene oxide adduct / cyclohexanedimethanol: glass transition temperature 60 ° C., number average molecular weight 3,600, weight average molecular weight 28,000, acid value 15): 84 parts, carbon black (Mitsubishi Chemical Corporation: trade name # 25): 8 parts, polyethylene wax (trade name 400P, weight average molecular weight 4000, made by Mitsui Chemicals): 3 parts, positive charge control agent (nigrosine dye: Orient Chemical Co., Ltd .: Brand name Bontron N-04): 2 parts The above composition is mixed with powder using a Henschel mixer, and this is heat-kneaded with an extruder with a set temperature of 105 ° C. Thus, toner particles having a volume average particle diameter D50 of 8.8 μm were obtained.

  100 parts of the toner particles and hydrophobic silica particles (4 parts of hexamethyldisilazane and 8 parts of aminosilane coupling agent with respect to 100 parts of silica: manufactured by Nippon Aerosil Co., Ltd .: trade name RA200H) 1.0 Part and 0.5 part of cerium oxide surface-treated with a quaternary ammonium salt were mixed with a Henschel mixer (conditions: see Table 1) to obtain a toner.

In addition, the surface treatment was performed as follows with quaternary ammonium salt to cerium oxide (CeO ₂ ) (manufactured by Mitsui Kinzoku Co., Ltd .: trade name E10). 10 parts of quaternary ammonium salt (Orient Chemical Co., Ltd. Bontron P51) was dissolved in ethyl alcohol, stirred and mixed with cerium oxide, and then oxidized by removing the solvent ethyl alcohol by vacuum drying at 50 ° C. for 2 hours. A quaternary ammonium salt was applied to the cerium surface.

[Examples 2 to 8, Comparative Examples 1 to 3]
A toner was prepared in the same manner as in Example 1 except that the inorganic particles surface-treated with a quaternary ammonium salt and the external addition conditions were changed according to Table 1.
The surface treatment amount, surface treatment method, external addition amount, and external treatment method of the quaternary ammonium salt were the same as in Example 1.

[Evaluation]
A carrier was prepared as follows. 1,000 parts of Mn—Mg ferrite (volume average particle size: 50 μm, manufactured by Powder Tech Co., Ltd., shape factor SF1: 120) were added to a kneader, and a perfluorooctylmethyl acrylate-methyl methacrylate copolymer (polymerization ratio: 20 / 80, Tg: 72 ° C., weight average molecular weight: 72,000, manufactured by Soken Chemical Co., Ltd.) 150 parts dissolved in 700 parts of toluene, mixed at room temperature for 20 minutes, then heated to 70 ° C. under reduced pressure After drying, it was taken out to obtain a coat carrier. Furthermore, the obtained coated carrier was sieved with a mesh having an opening of 75 μm, and coarse powder was removed to obtain a carrier. The shape factor SF1 of the carrier was 122.

  The above carrier and each of the obtained toners were combined in a V blender at a mass ratio of 95: 5 and stirred for 20 minutes to prepare a developer. Then, using the developer thus obtained, the non-image area gabbly toner was evaluated with a DocuPrint 1100CF remodeling machine manufactured by Fuji Xerox Co., Ltd.

  According to Table 1, the DocuPrint 1100CF remodeling machine manufactured by Fuji Xerox Co., Ltd. was evaluated by replacing it with either an amorphous silicon photoconductor or an organic photoconductor. The results are shown in Table 1.

-Fabrication of amorphous silicon photoconductor-
A charge injection layer, a photoconductive layer, a charge trapping layer, and a surface layer were formed on the surface of an Al cylindrical substrate having a thickness of 4 mm and a diameter of 84 mm by glow discharge. The charge injection layer, photoconductive layer, and charge trapping layer were formed with silane gas, hydrogen gas, and diborane gas, and the film thicknesses were about 2 μm, about 15 μm, and about 0.8 μm, respectively. The surface layer was formed with silane gas, hydrogen gas, and ammonia gas, and the film thickness was about 0.1 μm.

-Preparation of organic photoreceptor-
To 170 parts by mass of n-butyl alcohol in which 4 parts by mass of polyvinyl butyral resin (ESREC BM-S, manufactured by Sekisui Chemical Co., Ltd.) was dissolved, 30 parts by mass of an organic zirconium compound (acetylacetone zirconium butyrate) and an organic silane compound (Y -Aminopropyltrimethoxysilane) 3 parts by mass was added and mixed and stirred to obtain a coating solution for forming the undercoat layer.

  This coating solution was dip-coated on an aluminum support having an outer diameter of 40 mm and a length of 350 mm roughened by a honing treatment, and air-dried at room temperature for 5 minutes. Thereafter, the support was heated to 50 ° C. in 10 minutes, placed in a constant temperature and humidity chamber at 50 ° C. and 85% RH (dew point 47 ° C.), and subjected to a humidification hardening acceleration treatment for 20 minutes. Then, it put into the hot air dryer and dried for 10 minutes at 170 degreeC, and formed the undercoat layer.

  15 parts by mass of gallium chloride phthalocyanine as a charge generation material, 10 parts by mass of vinyl chloride-vinyl acetate copolymer resin (VMCH, manufactured by Nippon Union Carbide) and 300 parts by mass of n-butyl alcohol are mixed and mixed. A liquid was obtained. The mixing was performed by dispersing the mixture with a sand mill for 4 hours. This dispersion was dip coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Next, 40 parts by mass of N, N′-bis (3-methylphenyl) -N, N′-diphenylbenzidine, 60 parts by mass of bisphenol Z polycarbonate resin (molecular weight 40,000), and tetrohydrofuran 235 It was sufficiently dissolved and mixed in parts by mass and 100 parts by mass of monochlorobenzene to obtain a coating solution. This coating solution was dip coated on an aluminum support formed up to the charge generation layer and dried at 120 ° C. for 40 minutes to form a charge transport layer having a thickness of 20 μm.

  As a protective layer forming material, 2.5 parts of a compound represented by the following structural formula, 3 parts of Shonor BRL-204 (manufactured by Showa Polymer), hindered phenolic antioxidant (AO-80: manufactured by Asahi Denka) 0.1 part, 0.2 part of fluorine graft polymer (ZX007C: manufactured by Fuji Kasei) and 0.1 part of fluorine coupling agent (KBM-7803: manufactured by Shin-Etsu Chemical Co., Ltd.), 5 parts of isopropyl alcohol, methyl It was dissolved in 5 parts of butyl ketone to obtain a coating solution for forming a protective layer. This coating solution was applied onto the charge transport layer by a ring-type dip coating method, air-dried at room temperature for 30 minutes, and then cured by heat treatment at 150 ° C. for 1 hour to form a protective layer having a thickness of about 6 μm.

-Evaluation of fog toner-
Using a chart with an image printing rate of 5%, output was performed at A4, and the number of toner particles in the non-image area was confirmed after 1000 sheets were output. A 2 mm × 2 mm square observation is performed with a microscope, and five points are selected at random. The average value was calculated by counting the number of toner particles at five locations. The criteria for determination are shown below.
○: The average value of the number of toners is 20 or less Δ: The average value of the number of toners is 20 or more and less than 70 ×: The average value of the number of toners is 70 or more

From the above results, it can be seen that in this embodiment, the number of fog toners is reduced as compared with the comparative example.
From the results of Examples 1 to 3, it can be seen that the fog is decreased as the liberation rate is larger. Further, in Example 4, when an organic photoconductor is used, it is worn more than the amorphous silicon photoconductor, so that a lot of fog is generated, but the fog can be sufficiently suppressed. Moreover, in Examples 6-8, even if it uses inorganic particles other than cerium oxide, it turns out that fog can be suppressed.
In Comparative Example 1, since the negative chargeability of silica is strong, fogging occurs due to contamination. In Comparative Example 2, fog is generated because the quaternary ammonium salt is not applied. In Comparative Example 3, it can be seen that since the liberation rate is low, the quaternary ammonium salt is not sufficiently applied to the photoreceptor and fogging occurs.

[Example 9, Comparative Example 4]
The same toner as in Example 1 was evaluated using a DocuPrint 1100CF remodeling machine equipped with an amorphous silicon photoreceptor using the same toner as in Example 4. However, the evaluation of fog toner with time after output of 100,000 sheets was performed. This was designated Example 6.
On the other hand, amorphous silicon coated with a quaternary ammonium salt (bontron P51 manufactured by Orient Chemical Co., Ltd.) at a coating amount of 0.1 g using the same toner (toner not using quaternary ammonium salt-treated inorganic particles) as in Comparative Example 2. The fog toner was evaluated in the same manner as in Example 6 using a modified DocuPrint 1100CF equipped with a photoconductor. This was designated as Comparative Example 4. The results are shown in Table 2.

  From the above results, it can be seen that in this embodiment, the number of fog toners is reduced over time as compared with the comparative example.

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

Explanation of symbols

1Y, 1M, 1C, 1K, 107 photoconductor (image carrier)
2Y, 2M, 2C, 2K, 108 Charging roller 3Y, 3M, 3C, 3K Laser beam 3, 110 Exposure device 4Y, 4M, 4C, 4K, 111 Developing device (developing means)
5Y, 5M, 5C, 5K Primary transfer rollers 6Y, 6M, 6C, 6K, 113 Photoconductor cleaning device (cleaning means)
8Y, 8M, 8C, 8K Toner cartridge 10Y, 10M, 10C, 10K Unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller (transfer means)
28, 115 Fixing device (fixing means)
30 Intermediate transfer member cleaning device 112 Transfer device 116 Mounting rail 117 Opening portion 118 for static elimination exposure Opening portion 200 for exposure Process cartridge P, 300 Recording paper (transfer object)

Claims (7)

Toner particles containing a binder resin and a colorant, and at least inorganic particles other than silica,
A liberation ratio of the inorganic particles to the toner particles is 20% or more;
The inorganic particles are surface-treated with a quaternary ammonium salt.
An electrostatic charge developing toner.   2. The electrostatic charge developing toner according to claim 1, wherein the inorganic particles are at least one selected from cerium oxide, alumina, titania, and strontium titanate.   An electrostatic charge image developer comprising the electrostatic charge image developing toner according to claim 1.   A toner cartridge, wherein the toner for developing an electrostatic charge image according to claim 1 is contained.   A process cartridge comprising at least a developer holder and containing the electrostatic charge image developer according to claim 3. An image carrier,
Developing means for developing the electrostatic image formed on the image carrier as a toner image with a developer;
Transfer means for transferring a toner image formed on the image carrier onto the transfer target;
Fixing means for fixing the toner image transferred onto the transfer material;
Have
An image forming apparatus, wherein the developer is the electrostatic charge image developer according to claim 3.   The image forming apparatus according to claim 6, wherein the image carrier is an amorphous silicon photoconductor.