JP6477057B2 - Electrostatic image developing carrier, electrostatic image developer, toner cartridge, process cartridge, image forming apparatus, and image forming method - Google Patents

Description

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

  The electrostatic image developing carrier used for the electrostatic image developer is generally divided into a resin-coated carrier having a coating layer of a coating resin on the surface of magnetic core particles and an uncoated carrier having no coating layer on the surface. In recent years, resin-coated carriers are frequently used.

  For example, in Patent Document 1, in an electrophotographic carrier having a resin coating layer on the surface of a core material, the resin forming the coating layer includes an alicyclic methacrylate monomer and a single chain methacrylate ester. The surfactant formed in the resin coating layer is 5 to 1,000 ppm with respect to the entire coating resin, and the monomer remaining in the resin coating layer is coated. An electrophotographic carrier characterized by 10 to 2,000 ppm relative to the entire resin is described.

  In Patent Document 2, in a carrier for an electrostatic charge image developer having a coating layer containing at least a binder resin and fine particles on a carrier core material, the core material is subjected to surface oxidation treatment, and the core material surface exposure of the carrier is disclosed. An electrostatic latent image developing carrier having an area ratio of 0.1 to 5.0% is described.

Japanese Patent No. 3691085 JP 2014-170086 A

  The problem to be solved by the present invention is to provide a carrier for developing an electrostatic charge image that is excellent in halftone image quality after long-term continuous image formation and after standing, suppression of white spot generation, and fine line reproducibility.

The above-described problems of the present invention have been solved by means described in the following <1> and <4> to <8>. It is shown below with <2> and <3> which are preferable embodiments.
<1> A magnetic core material particle and a coating resin are contained, and the compound represented by the following formula (1) is contained in the coating resin in an amount of 100 to 20,000 ppm with respect to the total mass of the coating resin. A carrier for developing an electrostatic charge image,
C _n H _{2n + 1} (C ₆ H ₅ ) (1)
In formula (1), n represents an integer of 6 to 20,
<2> The electrostatic charge image developing carrier according to <1>, wherein the alkyl group in formula (1) is linear.
<3> The electrostatic charge image developing carrier according to <1> or <2>, wherein the coating resin contains a structural repeating unit derived from an alicyclic alkyl (meth) acrylate compound,
<4> an electrostatic charge image developing toner comprising: an electrostatic charge image developing toner; and the electrostatic charge image developing carrier according to any one of <1> to <3>.
<5> A toner cartridge comprising a developer holder that contains the electrostatic charge image developer according to <4> and holds and conveys the electrostatic charge image developer.
<6> A developing unit that contains the electrostatic charge image developer according to <4>, and that develops the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer. A process cartridge to be attached to and detached from the forming apparatus;
<7> An image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the charged surface of the image carrier, and the electrostatic image according to <4>. Developing means for containing a charge image developer and developing the electrostatic image formed on the surface of the image carrier as a toner image with the electrostatic image developer; and a toner formed on the surface of the image carrier An image forming apparatus comprising: transfer means for transferring an image to the surface of the recording medium; and fixing means for fixing the toner image transferred to the surface of the recording medium;
<9> A charging step of charging the surface of the image carrier, an electrostatic charge image forming step of forming an electrostatic image on the surface of the charged image carrier, and the electrostatic image developer according to <4>. A developing step of developing the electrostatic image formed on the surface of the image carrier as a toner image, a transfer step of transferring the toner image formed on the surface of the image carrier to the surface of the recording medium, and the recording medium A fixing step of fixing the toner image transferred onto the surface of the image forming method.

According to the invention described in <1> above, the magnetic core particles and the coating resin are contained, and the compound represented by the formula (1) in the coating resin is 100 to 20, based on the total mass of the coating resin. Compared to the case where the content of the compound represented by the formula (1) is outside the above range, the electrostatic charge image developing carrier containing 000 ppm has halftone image quality and white spot after long-term continuous image formation and after standing. There is provided a carrier for developing an electrostatic image excellent in suppression of generation and excellent reproducibility of fine lines.
According to the invention described in <2>, an electrostatic charge image developing carrier that is more excellent in biodegradability than the case where the alkyl group of the compound represented by the formula (1) is not linear is provided.
According to the invention described in <3>, compared to the case where the constitutional repeating unit derived from the alicyclic alkyl (meth) acrylate compound is not contained, the halftone image quality after the long-term continuous image formation and after standing, There is provided a carrier for developing an electrostatic image excellent in suppression of generation and excellent reproducibility of fine lines.
According to the invention described in <4>, compared to the case where the electrostatic charge image developing carrier having the configuration of <1> to <3> is not contained, the halftone image quality after white continuous image formation and after standing, white An electrostatic charge image developer excellent in suppression of dot generation and excellent reproducibility of fine lines is provided.
According to the invention described in <5>, halftone image quality and generation of white spots after long-term continuous image formation and after standing as compared with the case where no electrostatic charge image developer having the configuration of <4> is contained. A toner cartridge that is excellent in suppression and fine line reproducibility is provided.
According to the invention described in <6>, halftone image quality after generation of a continuous image for a long time and after standing, and generation of white spots, as compared with the case where no electrostatic charge image developer having the configuration of <4> is contained. And a process cartridge excellent in fine line reproducibility is provided.
According to the invention described in <7>, halftone image quality and white spot generation after long-term continuous image formation and after standing as compared with the case where no electrostatic charge image developer having the configuration of <4> is contained. An image forming apparatus having excellent suppression of fineness and fine line reproducibility is provided.
According to the invention described in <8>, halftone image quality and generation of white spots after long-term continuous image formation and after standing as compared with the case where no electrostatic charge image developer having the configuration of <4> is contained. And an image forming method excellent in fine line reproducibility.

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

  Hereinafter, this embodiment will be described in detail. In the present embodiment, the description “A to B” represents not only a range between A and B but also a range including A and B at both ends thereof. Moreover, in the following description, description of mass% and a mass part is synonymous with weight% and a weight part, respectively. Furthermore, in the following description, a combination of preferable embodiments is a more preferable embodiment.

(Carrier for developing electrostatic image)
The electrostatic image developing carrier of the present embodiment (hereinafter also simply referred to as “carrier”) contains magnetic core particles (hereinafter also simply referred to as “core material”) and a coating resin. It contains 100 to 20,000 ppm of the compound represented by the above formula (1) in the total mass of the coating resin.

For a carrier used as a developer for image formation by electrophotography, it is desired to suppress changes in surface composition and structure over a long period of time from the viewpoint of maintaining stable charging performance. Note that the toner surface composition such as an external additive detached from the toner in the developer may adhere to the carrier, thereby causing a change in the composition of the carrier surface.
Therefore, by softening the coating layer of the carrier to such an extent that friction due to friction with the toner additive and friction between carriers occurs, the toner additive adhered to the surface together with a part of the coating layer scraped by the abrasion A method of promoting removal of the surface and suppressing changes in the surface composition and structure can be considered.

However, if the coating layer is made too soft, the coating layer may be peeled off or scraped off due to friction with the toner additive or friction between carriers, resulting in fluctuations in the surface composition. As a result, the carrier having reduced electric resistance is developed, and the image carrier (photosensitive member), the image carrier cleaning member, and the like are contaminated or damaged, and as a result, image defects such as white spots may occur. Note that such a phenomenon becomes more prominent as the temperature is higher and the humidity is higher.
Therefore, a method of controlling the carrier coating layer so as to cause wear as described above, and controlling the wear to be moderately advanced to the extent that peeling or scraping does not occur excessively has been considered.

  However, in order to prolong the life of the developer, there is a demand for a carrier with little fluctuation in electric resistance even when the coating layer is peeled off or scraped.

  Usually, a resin that is soft enough to cause wear due to friction with the toner additive or friction between carriers is used as the coating resin for the coating layer. When the wear progresses, the surface of the magnetic core particle is gradually exposed, and the resistance of the carrier fluctuates.

  On the other hand, in the carrier according to the present embodiment, the coating layer contains a coating resin and a compound represented by the formula (1) having high electrical insulation. As a result, the compound represented by the formula (1) adheres to the magnetic core particles moderately, and fluctuations in electrical resistance are suppressed. As a result, a stable toner charge amount can be obtained over a long period of time. Presumed to be excellent in image quality and fine line reproducibility. Furthermore, it is estimated that the occurrence of image defects such as white spots is also suppressed.

  Hereinafter, the configuration of the carrier according to the present embodiment will be described.

<Magnetic core particles>
The magnetic core particles are not particularly limited, and examples thereof include magnetic metals such as iron, steel, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and resin particles in which magnetic particles are dispersed internally. It is done. Specifically, a magnetic material is used and the magnetic powder is used alone as magnetic core particles, and a magnetic powder is made into particles and dispersed in a resin.
Examples of the resin used for the magnetic core particles include a styrene resin, an acrylic resin, a styrene-acrylic copolymer resin, a polyolefin resin, and a phenol resin.

  The volume average particle diameter of the magnetic core particles is preferably 20 μm or more and 100 μm or less. When the volume average particle diameter of the magnetic core particles is 20 μm or more, development with the toner is suppressed when the carrier is used, and when the carrier is 100 μm or less, the toner is uniformly distributed when the carrier is used. Can be charged.

  The volume average particle diameter of the magnetic core particles can be measured using a laser diffraction / scattering particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by Beckman-Coulter). For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size at 50% cumulative is taken as the volume average particle size.

As for the magnetic force of the magnetic core particles, the saturation magnetization at 1,000 oersted is preferably 50 emu / g or more and 100 emu / g or less, and more preferably 60 emu / g or more and 100 emu / g or less. When the saturation magnetization is 50 emu / g or more and 100 emu / g or less, the hardness of the magnetic brush is kept moderately, so that the fine line reproducibility is improved, and the carrier is developed on the photoreceptor together with the toner. Can be suppressed.
The apparatus capable of measuring the magnetic properties is not particularly limited, but a vibration sample type magnetic measurement apparatus VSMP10-15 (manufactured by Toei Industry Co., Ltd.) is preferably used.
For example, the measurement sample is packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. The measurement applies an applied magnetic field and sweeps up to 1,000 oersted. Next, the applied magnetic field is reduced to create a hysteresis curve on the recording paper. From the curve data, saturation magnetization, residual magnetization, and coercive force can be obtained. In this embodiment, the saturation magnetization indicates the magnetization measured in a 1,000 oersted magnetic field.

The volume electrical resistance (volume resistivity) of the magnetic core particles is preferably in the range of 10 ⁵ Ω · cm to 10 ¹² Ω · cm, and in the range of 10 ⁷ Ω · cm to 10 ⁹ Ω · cm. More preferably. When the volume electrical resistance is 10 ⁵ Ω · cm or more, when the toner concentration in the developer is reduced by repeated copying, charge injection into the carrier does not occur and development of the carrier itself is suppressed. it can. On the other hand, when the volume electric resistance is 10 ¹² Ω · cm or less, the outstanding edge effect, pseudo contour, and the like can be suppressed, and the image quality is excellent.
In the present embodiment, the volume electrical resistance (Ω · cm) of the core material is measured as follows. The measurement environment is a temperature of 20 ° C. and a humidity of 50% RH.
The object to be measured is placed flat on the surface of a circular jig having a 20 cm ² electrode plate so as to have a thickness of about 1 mm to 3 mm, thereby forming a layer. A 20 cm ² electrode plate similar to the above is placed thereon, and the layers are sandwiched. In order to eliminate gaps between objects to be measured, a thickness (cm) of the layer is measured after a load of 4 kg is applied on the electrode plate placed on the layer. Both electrodes above and below the layer are connected to an electrometer and a high voltage power generator. A high voltage is applied to both electrodes so that the electric field is 10 ^3.8 V / cm, and the current value (A) flowing at this time is read to calculate the volume electrical resistance (Ω · cm) of the measurement object. The calculation formula of the volume electrical resistance (Ω · cm) of the measurement object is as shown in the following formula.
Formula: R = E × 20 / (I−I ₀ ) / L
In the above formula, R is the volume electric resistance (Ω · cm) of the measurement object, E is the applied voltage (V), I is the current value (A), I ₀ is the current value (A) at the applied voltage of 0 V, and L is Each layer thickness (cm) is expressed. A coefficient of 20 represents the area (cm ² ) of the electrode plate.

<Coating layer>
The magnetic core particles in the electrostatic image developing carrier used in this embodiment are preferably coated with a coating layer containing a coating resin described later.
As a resin coating method for forming a coating layer on the surface of magnetic core particles, there are a wet method using a solvent and a dry method using no solvent.

As a wet method, the coating resin is dissolved in a soluble solvent, and an additive such as a coating resin, a conductive material, a compound represented by the formula (1) is added to form a coating layer forming solution, and the magnetic core particles are coated. Immersion method of immersing in layer forming solution, spray method of spraying coating layer forming solution on the surface of magnetic core particles, spraying coating layer forming solution with magnetic core particles suspended by flowing air There are a fluidized bed method, a kneader coater method in which magnetic core particles and a coating layer forming solution are mixed in a kneader coater, and then the solvent is removed.
When forming a coating layer by a wet method, the compound represented by Formula (1) can be added by adding to a solvent as mentioned above.
As the compound represented by the formula (1), for example, grade alkene L manufactured by JX Nippon Oil & Energy Corporation can be used.

As a dry method, resin particles are synthesized by an emulsion polymerization method or a suspension polymerization method, or resin particles obtained by emulsifying and dispersing the synthesized resin in a pulverization classification or water are mixed with magnetic core particles. For example, there is a method in which the coating layer is formed by adhering to the surface of the magnetic core particles by a mechanical impact force and, if necessary, heating and melting above the glass transition temperature of the resin.
The dry method preferably includes a coating step of coating the surface of the magnetic core particles with a resin composition containing a coating resin, and a heating step of heat-treating the magnetic core particles coated with the resin composition.
In the coating step, it is preferable to mix the magnetic core particles and the resin particles to form a resin particle adhesion layer on the surface of the magnetic core particles. The resin particles are resin particles containing at least a coating resin, and may contain other components.
The resin composition only needs to contain at least a coating resin, and may or may not contain other components. In addition, for example, other components such as a conductive material to be described later may be added to the resin particles in advance, or may be added individually with the resin particles and adhered to the magnetic core particles in the coating step. Since it is preferable to obtain a uniform structure, mixing in advance is preferable. Moreover, as an addition method, in order to control a coating layer structure, you may change a composition ratio and may add in several times.
As a device for mixing the magnetic core particles and the resin particles, a known powder mixing device can be used, which may be a batch type or a continuous type. As the batch type, a mixing device with a stirrer such as a Henschel mixer or a Nauter mixer is preferably exemplified. Moreover, if it is a continuous type, a uniaxial type or a biaxial type paddle mixer, a ribbon mixer, an extrusion mixer etc. will be illustrated.
The mixing temperature at the time of mixing is preferably not higher than the glass transition temperature of the resin particles, more preferably 10 ° C. or more lower than the glass transition temperature of the resin particles, and 20 ° C. or higher than the glass transition temperature of the resin particles. More preferably, the temperature is low.

In the heat treatment step, the magnetic core particles coated with the resin composition are heated, and the resin composition is heated and melted to form a resin coating layer. Here, it is preferable that heating temperature is higher than the glass transition temperature of the used resin particle, and it is more preferable that it is 150-250 degreeC. When the heating temperature is within the above range, the resin can be easily melted, and thermal decomposition of the resin is suppressed.
In the heat treatment step, it is preferable to heat while stirring and mixing the magnetic core particles coated with the resin composition from the viewpoint of crushing the adhesion between the particles and suppressing the generation of coarse aggregates, From the viewpoint of productivity, it is more preferable to heat with continuous stirring and mixing. Examples of the apparatus used in the heat treatment step include, but are not limited to, a paddle mixer, a screw mixer, a turbulizer, a continuous kneader, and a twin-screw extrusion kneader equipped with heating means.
In addition to the coating step and the heat treatment step, other known steps may be included. Specifically, a classification step of classifying the obtained magnetic core particles having the resin coating layer, a sieving step of sieving the magnetic core particles having the obtained resin coating layer, and the like can be mentioned. The classification means and sieve used in the classification step and the sieving step are not particularly limited, and known ones may be used.

  In this embodiment, although not particularly limited, a dry method in which a surfactant particle having an alkylbenzene structure is polymerized by an emulsion polymerization method and dried to fix and fix the resin particles to the surface of the magnetic core particles by heating. It is preferable to be manufactured.

The average film thickness of the resin coating layer is preferably from 0.5 μm to 10 μm, more preferably from 1 μm to 5 μm, and still more preferably from 1 μm to 3 μm.
The average film thickness (μm) of the resin coating layer is ρ (dimensionless) as the true specific gravity of the magnetic core particles, d (μm) as the volume average particle size of the magnetic core particles, and ρ _{C as} the average specific gravity of the resin coating layer. When the total content of the resin coating layer with respect to 100 parts by mass of the magnetic core particles is W _C (parts by mass), it can be obtained by the following formula (A).
Formula (A): Average film thickness (μm) = {[amount of coating resin per carrier (including all additives such as conductive powder) / surface area per carrier]} / average specific gravity of resin coating layer
= {[4 / 3π · (d / 2) ³ · ρ · W _C ] / [4π · (d / 2) ² ]} / ρ _C
= (1/6) · (d · ρ · W _C / ρ _C )

  The content of the resin coating layer in the carrier of the present embodiment is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, and 1 to 5 parts by weight with respect to 100 parts by weight of the magnetic core particles. Part is more preferred. When the content of the resin coating layer is 0.1 parts by mass or more, the surface exposure of the magnetic core particles is small and injection of the development electric field can be suppressed. Further, when the content of the resin coating layer is 20 parts by mass or less, the resin powder released from the resin coating layer is small, and the resin powder peeled off in the developer can be suppressed from the initial stage.

The coverage of the surface of the magnetic core particles by the resin coating layer can be controlled as appropriate, but is preferably 80% or more, and more preferably 90% or more.
The coverage of the resin coating layer can be determined by XPS measurement. As an XPS measuring device, for example, JPS80 manufactured by JEOL Ltd. is used, and measurement is performed using MgKα ray as an X-ray source, setting an acceleration voltage to 10 kV, and an emission current to 20 mV, and coating with resin. Measure the main element constituting the layer (usually carbon) and the main element constituting the core material (for example, iron and oxygen when the core material is an iron oxide-based material such as magnetite) (hereinafter, the core material is The explanation is based on the assumption that it is based on iron oxide.) Here, the C1s spectrum is measured for carbon, the Fe2p _3/2 spectrum is measured for iron, and the O1s spectrum is measured for oxygen.
Based on the spectrum of each of these elements, the number of carbon, oxygen, and iron elements (A _C + A _O + A _Fe ) is obtained, and the following formula (B) is obtained from the obtained carbon, oxygen, and iron element number ratio. Based on this, the iron content rate after coating the core material alone and the core material with the resin coating layer (carrier) was determined, and then the coverage rate was determined by the following formula (C).
Formula (B): Iron content rate (atomic%) = A _Fe / (A _C + A _O + A _Fe ) × 100
Formula (C): Coverage rate (%) = {1- (iron content rate of carrier) / (iron content rate of core material)} × 100
When a material other than iron oxide is used as the magnetic core material particle, the spectrum of the metal element constituting the core material in addition to oxygen is measured, and conforms to the above formulas (B) and (C). If the same calculation is performed, the coverage can be obtained.

[Coating resin]
In the case of producing a carrier by a dry method in the present embodiment, it is preferable that the coating resin is a resin particle. As a method for producing the resin particle, the resin particle is synthesized by an emulsion polymerization method or a suspension polymerization method, There are methods for obtaining a resin after synthesis by pulverizing and emulsifying and dispersing in water. In the present embodiment, it is desirable to use resin particles prepared by polymerization and drying by an emulsion polymerization method using a surfactant having an alkylbenzene structure.

The volume average particle size of the resin particles is usually 3 μm or less, and preferably in the range of 10 nm to 1,000 nm.
When the volume average particle diameter of the resin particles is 3 μm or less, the thickness of the coating layer of the finally obtained carrier is precisely controlled, and various additives are well dispersed. Further, it is advantageous in that uneven distribution of the composition in the coating layer of the carrier is reduced, and variations in performance and reliability are reduced. The volume average particle diameter of the resin particles may be measured using, for example, a microtrack.

The coating resin contained in the coating layer preferably contains a constitutional repeating unit derived from a styrene monomer, a (meth) acrylic monomer, or a polyvinyl monomer.
Examples of the styrene monomer include styrene compounds.
Examples of (meth) acrylic monomers include (meth) acrylate compounds and alkyl (meth) acrylate compounds. Examples of the alkyl (meth) acrylate compounds include alicyclic alkyl (meth) acrylate compounds such as methyl (meth) acrylate compounds, ethyl (meth) acrylate compounds, and cyclohexyl (meth) acrylate compounds.
Among these, a coating resin containing a constitutional repeating unit derived from a styrene monomer or a (meth) acrylic monomer having particularly good chargeability controllability is preferable, particularly from the point of low hygroscopicity, etc. A coating resin containing a constitutional repeating unit derived from an alicyclic alkyl (meth) acrylate compound such as cyclohexyl methacrylate is more preferred.
Examples of the alicyclic (meth) acrylic ester resin include cyclohexyl methacrylate resin.

  In addition, as the coating resin, other resins may be used in combination with other resins, such as polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, Examples thereof include, but are not limited to, polyvinyl ketone, polyacrylate, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, fluororesin, polyester, and polycarbonate.

-Polymerization initiator-
There is no particular limitation on the radical polymerization initiator (hereinafter also simply referred to as “initiator”) used when emulsification polymerization is performed in the present embodiment. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, Lauroyl oxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid tert-butyl hydroperoxide, formic acid tert- Peroxides such as butyl, tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl permethoxyacetate, tert-butyl perN- (3-toluyl) carbamate; 2 , 2'-azo Bispropane, 2,2′-dichloro-2,2′-azobispropane, 1,1′-azo (methylethyl) diacetate, 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2 '-Azobis (2-amidinopropane) nitrate, 2,2'-azobisisobutane, 2,2'-azobisisobutyramide, 2,2'-azobisisobutyronitrile, 2,2'-azobis-2 -Methyl methyl propionate, 2,2'-dichloro-2,2'-azobisbutane, 2,2'-azobis-2-methylbutyronitrile, dimethyl 2,2'-azobisisobutyrate, 1,1'-azobis ( 1-methylbutyronitrile-3-sodium sulfonate), 2- (4-methylphenylazo) -2-methylmalonodinitrile, 4,4′-azobis-4-cyanovaleric acid, 3,5-dihydroxymethyl Enylazo-2-methylmalonodinitrile, 2- (4-bromophenylazo) -2-allylmalonodinitrile, 2,2'-azobis-2-methylvaleronitrile, 4,4'-azobis-4-cyano Dimethyl herbate, 2,2′-azobis-2,4-dimethylvaleronitrile, 1,1′-azobiscyclohexanenitrile, 2,2′-azobis-2-propylbutyronitrile, 1,1′-azobis-1 -Chlorophenylethane, 1,1'-azobis-1-cyclohexanecarbonitrile, 1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-phenylethane, 1,1'-azobiscumene, 4-nitrophenylazobenzylcyanoacetate ethyl, phenylazodiphenylmethane, phenylazotriphenylmethane, 4-nitrophenyla Triphenylmethane, 1,1′-azobis-1,2-diphenylethane, poly (bisphenol A-4,4′-azobis-4-cyanopentanoate), poly (tetraethylene glycol-2,2′-azo Azo compounds such as bisisobutyrate; 1,4-bis (pentaethylene) -2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and the like.

  The molecular weight of the coating resin in this embodiment may be adjusted using a chain transfer agent. The chain transfer agent is not particularly limited, and specifically has a covalent bond between a carbon atom and a sulfur atom, and more specifically, n-propyl mercaptan, n-butyl mercaptan, n-amyl. N-alkyl mercaptans such as mercaptan, n-hexyl mercaptan, n-heptyl mercaptan, n-octyl mercaptan, n-nonyl mercaptan, n-decyl mercaptan; isopropyl mercaptan, isobutyl mercaptan, s-butyl mercaptan, tert-butyl mercaptan, Chain-chain alkyl mercaptans such as cyclohexyl mercaptan, tert-hexadecyl mercaptan, tert-lauryl mercaptan, tert-nonyl mercaptan, tert-octyl mercaptan, tert-tetradecyl mercaptan S; allyl mercaptan, 3-phenylpropyl mercaptan, phenyl mercaptan, mercaptans 含芳 incense ring system such as mercapto triphenylmethane; and the like.

-Surfactant-
Although it does not specifically limit as surfactant used when implementing emulsion polymerization in this embodiment, A cationic surfactant, an anionic surfactant, and a nonionic surfactant may be used individually by 1 type, or 2 types You may use the above together.

  In this embodiment, it is necessary for the carrier coating layer to contain a compound represented by the formula (1), and as the surfactant, an alkylbenzene sulfonic acid that generates the compound represented by the formula (1) by desulfonation It is preferred to use a salt. Specific examples include sodium decylbenzenesulfonate, sodium undecylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium tridecylbenzenesulfonate, sodium tetradecylbenzenesulfonate, and the like. These alkylbenzene sulfonates may be used alone or in combination, and general dodecylbenzene sulfonate is often the above mixture.

  Examples of the cationic surfactant include amine salt type and quaternary ammonium salt type. Specific examples include laurylamine hydrochloride, stearylamine hydrochloride, oleylamine acetate, stearylamine acetate, stearylaminopropylamineacetic acid. Amine salts such as salts; lauryltrimethylammonium chloride, dilauryldimethylammonium chloride, distearylammonium chloride, distearyldimethylammonium chloride, lauryldihydroxyethylmethylammonium chloride, oleylbispolyoxyethylenemethylammonium chloride, lauroylaminopropyldimethylethylammonium Etosulphate, lauroylaminopropyldimethylhydroxyethylammonium perchlorate, alkyl Benzene dimethyl ammonium chloride, quaternary ammonium salts such as alkyl trimethyl ammonium chloride; and the like.

  Specific examples of the anionic surfactant include fatty acid soaps such as potassium laurate, sodium oleate and sodium castor oil; sulfates such as octyl sulfate, lauryl sulfate, lauryl ether sulfate and nonyl phenyl ether sulfate; lauryl sulfonate , Dodecyl sulfonate, dodecyl benzene sulfonate, triisopropyl naphthalene sulfonate, dibutyl naphthalene sulfonate, etc. Sulfonates such as lauryl phosphate, isopropyl phosphate Phosphoric acid esters such as nonyl phenyl ether phosphate; dialkyl sodium sulfosuccinates, such as sodium dioctyl sulfosuccinate, sodium lauryl sulfosuccinate 2, polyoxyethylene sulfo sulfosuccinate salts such as succinic acid lauryl disodium; and the like.

  Specific examples of the nonionic surfactant include polyoxyethylene octyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and other alkyl ethers; Alkylphenyl ethers such as oxyethylene nonylphenyl ether; alkyl esters such as polyoxyethylene laurate, polyoxyethylene stearate, polyoxyethylene oleate; polyoxyethylene lauryl amino ether, polyoxyethylene stearyl amino ether, polyoxy Alkylamines such as ethylene oleyl amino ether, polyoxyethylene soybean amino ether, polyoxyethylene beef tallow amino ether; Alkyl amides such as xylethylene lauric acid amide, polyoxyethylene stearic acid amide, polyoxyethylene oleic acid amide; vegetable oil ethers such as polyoxyethylene castor oil ether, polyoxyethylene rapeseed oil ether; lauric acid diethanolamide, stearin Alkanolamides such as acid diethanolamide and oleic acid diethanolamide; sorbitan ester ethers such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate And the like.

  In the present embodiment, the surfactant content is preferably 1,000 to 55,000 ppm, more preferably 5,000 to 20,000 ppm, based on the total mass of the coating resin. Resin particles having a required particle diameter can be obtained by increasing the amount to more than 1,000 ppm, and rapid charge reduction due to hygroscopicity can be suppressed by setting the amount to 55,000 ppm or less.

  As a method for measuring the content of the surfactant in the coating resin of the carrier of this embodiment, 5 g of carrier and 50 g of chloroform are placed in a beaker, and the coating resin is sufficiently dissolved by an ultrasonic dispersing machine, and the magnetic core material particles, conductive powder A surfactant is extracted from a coating resin extract obtained by filtering and separating insoluble matter such as, and then obtained by high performance liquid chromatography analysis.

In this embodiment, it is necessary to contain 100 to 20,000 ppm of the compound represented by the formula (1) in the coating layer with respect to the total mass of the coating resin. The compound represented by the formula (1) may be added to the coating resin, but the resin particles prepared by emulsion polymerization using an alkylbenzene sulfonate are coated on the magnetic core particles and then removed by heating. A method in which sulfonation is performed to obtain a compound represented by the formula (1) is preferable.
As a method for adding the compound represented by the formula (1) to the coating resin, a dispersion containing the compound represented by the formula (1) when the magnetic core particles and the resin particles are mixed in the dry method. The method of spraying is mentioned.
In that case, as a compound represented by Formula (1), the grade Alkene L made from JX Nippon Mining & Energy Corporation can be used, for example.
C _n H _{2n + 1} (C ₆ H ₅ ) (1)
In formula (1), n represents an integer of 6 to 20.

In formula (1), n represents an integer of 6 to 20, and n is preferably an integer of 6 to 10. When n is less than 6, the volatilization temperature is low and the inside of the apparatus may be contaminated during use. When n exceeds 20, the thermal decomposition temperature may be low and the blending ratio may not be controlled.
Moreover, it is preferable that the alkyl group contained in Formula (1) is linear from a biodegradable viewpoint.
Note that the alkyl group contained in the formula (1), bonded to the benzene ring represented by the formula (1) in the _(C 6 _{H 5),} refers to a group represented by C _{n H 2n + 1.}

  In this embodiment, content of the compound represented by Formula (1) is 100-20,000 ppm with respect to the total mass of coating resin, and it is preferable that it is 1,000-5,000 ppm. If it is less than 100 ppm, the insulating effect is insufficient, and if it exceeds 20,000 ppm, there is a possibility that adhesion of additives and the like will increase on the carrier surface.

  As a method for measuring the content of the compound represented by the formula (1) in the coating resin of the carrier of this embodiment, 5 g of carrier and 50 g of chloroform are put in a beaker, and the coating resin is sufficiently dissolved by an ultrasonic dispersing machine. The compound represented by the formula (1) is extracted from the coating resin extract obtained by filtering and separating insolubles such as magnetic core particles and conductive powder, and a gas chromatograph mass spectrometer LKB9000 (manufactured by Shimadzu Corporation) is used. Can be analyzed. The column was an SE-54 (0.3 mm × 25 m) silica capillary column, and helium was used as a carrier gas for measurement. The content rate was calculated by a calibration curve method using a standard material manufactured by Tokyo Chemical Industry Co., Ltd. as a standard material.

[Thermosetting resin particles, crosslinked resin particles]
In this embodiment, in order to increase the strength of the coating layer, the coating layer may contain thermosetting resin particles or crosslinked resin particles.

  Although it will not specifically limit if it is a thermosetting resin as a thermosetting resin particle to be used, The particle | grains containing a nitrogen element are preferable. Among them, melamine resin, urea resin, urethane resin, guanamine resin, and amide resin are preferable because they have high positive chargeability and high resin hardness, so that a decrease in charge amount due to peeling of the coating layer is suppressed.

  Examples of commercially available products include Eposta S (manufactured by Nippon Shokubai Co., Ltd., melamine / formaldehyde condensation resin), Eposta MS (manufactured by Nippon Shokubai Co., Ltd., benzoguanamine / formaldehyde condensation resin), and the like.

The crosslinked resin particles to be used are not particularly limited as long as they are polymers of polymerizable monomers. For example, a resin using at least one selected from a styrene monomer, a (meth) acrylic monomer, and a polyvinyl monomer having good chargeability controllability is preferable.
Examples of the styrene monomer include styrene monomer.
Examples of (meth) acrylic monomers include (meth) acrylic monomers and alkyl (meth) acrylate monomers. Examples of the alkyl (meth) acrylate monomer include alicyclic alkyl (meth) acrylate monomers such as methyl (meth) acrylate monomer, ethyl (meth) acrylate monomer, and cyclohexyl (meth) acrylate monomer.
Of these, alicyclic (meth) acrylic acid ester resins having low hygroscopicity are more preferred. Examples of the alicyclic (meth) acrylic ester resin include cyclohexyl methacrylate resin.

  The crosslinked resin particles may contain a nitrogen-containing monomer in order to give a charge-imparting effect, for example, dialkylaminoalkyl (meth) acrylates such as diethylaminoethyl (meth) acrylate and dimethylaminoethyl (meth) acrylate, ethyl Alkylaminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, aminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate, 1,2,2,6,6-pentamethyl Examples include -4-piperidyl methacrylate and 2,2,6,6-tetramethyl-4-piperidyl methacrylate.

  The means for forming the crosslinked structure when producing the crosslinked resin particles is not particularly limited, and there is a method using a crosslinking agent such as a crosslinking monomer.

  Specific examples of the crosslinking agent include, for example, aromatic polyvinyl compounds such as divinylbenzene and divinylnaphthalene; divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl homophthalate, divinyl trimesate / trivinyl, naphthalene dicarboxylic acid Polyvinyl esters of aromatic polyvalent carboxylic acids such as divinyl and divinyl biphenyl carboxylates; divinyl esters of nitrogen-containing aromatic compounds such as divinyl pyridine dicarboxylate; vinyl pyromutinate, vinyl furan carboxylate, pyrrole-2-carboxylic acid Vinyl esters of unsaturated heterocyclic compounds such as vinyl acetate and vinyl thiophenecarboxylate; butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate (Meth) acrylic acid esters of linear polyhydric alcohols such as dodecanediol methacrylate; branches such as neopentyl glycol dimethacrylate, 2-hydroxy-1,3-diaacryloxypropane, (meth) of substituted polyhydric alcohols Acrylic acid esters; Polyethylene glycol di (meth) acrylate, Polypropylene polyethylene glycol di (meth) acrylates; Divinyl succinate, divinyl fumarate, vinyl / divinyl maleate, divinyl diglycolate, vinyl / divinyl itaconate, acetone dicarboxylic Divinyl acid, divinyl glutarate, divinyl 3,3′-thiodipropionate, trans-aconite divinyl / trivinyl, divinyl adipate, divinyl pimelate, divinyl suberate, dibi azelate Le, sebacate, divinyl dodecanedioate divinyl, the polyvinyl esters of polycarboxylic acids such as oxalic acid, divinyl; and the like.

  In this embodiment, these crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more types. Of the above crosslinking agents, (meth) acrylic acid esters are desirable so as not to impair the chargeability of the crosslinked resin particles, such as butanediol methacrylate, hexanediol acrylate, octanediol methacrylate, decanediol acrylate, and dodecanediol methacrylate. (Meth) acrylic acid esters of linear polyhydric alcohols; branched (meth) acrylic acid esters of branched polyhydric alcohols such as neopentyl glycol dimethacrylate, 2-hydroxy-1,3-diaacryloxypropane; It is preferable to use polyethylene glycol di (meth) acrylate, polypropylene polyethylene glycol di (meth) acrylate and the like.

In the present embodiment, the volume average particle diameter of the thermosetting resin particles and the crosslinked resin particles is usually 3 μm or less, and preferably in the range of 10 nm to 1,000 nm. When the volume average particle diameter of each particle is 3 μm or less, exposure from the coating layer is suppressed, and other additives are well dispersed, thereby improving performance and reliability. In addition, the strength of the coating layer of the carrier is kept moderate, and wear during long-term use is controlled.
The particle sizes of the thermosetting resin particles and the crosslinked resin particles may be the same, or may be adjusted in consideration of dispersibility and resin strength. In addition, what is necessary is just to measure the volume average particle diameter of both particle | grains using a microtrack etc., for example.

  As a method for measuring the composition, content, and particle size of particles in the carrier coating layer of the present embodiment, 5 g of carrier and 100 g of toluene are put in a beaker, and the coating resin is sufficiently dissolved by an ultrasonic dispersing machine to form magnetic core particles. After removing the insoluble matter with a magnet, the insoluble matter was filtered and washed, separated, and then diluted again and dissolved in 10 mL of chloroform, 20 mg of the coating resin from which the conductive material, the thermosetting particles, and the crosslinked resin particles were separated by a centrifuge, After filtration, there is a method of analyzing the composition by infrared absorption spectrum analysis or the like. The content and particle size can be measured by separation in the same manner.

(Charge control agent)
In the carrier according to the present embodiment, as the charge control agent that may be contained in the coating layer, for example, nigrosine dye, benzimidazole compound, quaternary ammonium salt compound, alkoxylated amine, alkylamide, molybdate chelate pigment, Any known compounds such as a triphenylmethane compound, a salicylic acid metal salt complex, an azo chromium complex, and copper phthalocyanine may be used. Particularly preferred are quaternary ammonium salt compounds, alkoxylated amines and alkylamides.

  The addition amount of the charge control agent used in the present embodiment is preferably 0.001 part by mass or more and 5 parts by mass or less, and 0.01 part by mass or more and 0.5 part by mass with respect to 100 parts by mass of the magnetic core particles. Part or less is more preferable.

  When the addition amount of the charge control agent is 5 parts by mass or less, the strength of the coating layer is obtained, and the ease of alteration due to stress during use is suppressed. When the addition amount of the charge control agent is 0.001 part by mass or more, the function of the charge control agent is sufficiently exhibited, and the dispersibility of the additive such as a conductive material can be obtained.

  Examples of the conductive material that may be added to the coating layer in this embodiment include metals such as carbon black, gold, silver, and copper, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, potassium titanate, and oxidation. Examples thereof include tin, antimony-doped tin oxide, tin-doped indium oxide, aluminum-doped zinc oxide, and metal-coated resin particles.

The content of the conductive material is preferably 0.01 parts by mass or more and 10 parts by mass or less, and 0.05 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the coating resin in order to make the carrier volume specific resistance a desired characteristic. Is more preferable.
It is preferable that the content of the conductive material is 0.01 parts by mass or more because a resistance adjusting effect is obtained. Moreover, since it becomes difficult to detach | leave a conductive material as content is 10 mass parts or less, it is preferable.

  The average film thickness of the coating layer is, for example, 0.1 μm or more and 10 μm or less, but preferably 0.5 μm or more and 3 μm or less in order to develop a stable volume resistivity of the carrier over time.

The volume specific resistance value of the carrier according to the present embodiment is 10 ⁶ Ω · cm or more and 10 ¹⁴ Ω · cm or less at 1,000 V corresponding to the upper and lower limits of a normal development contrast potential in order to achieve high image quality. Preferably, it is 10 ⁸ Ω · cm or more and 10 ¹³ Ω · cm or less.
When the volume resistivity of the carrier is 10 ⁶ Ω · cm or more, the reproducibility of fine lines is improved, the amount of carriers transferred to the photoreceptor (image carrier) is reduced, and damage to the photoreceptor is suppressed. The On the other hand, when the volume resistivity of the carrier is 10 ¹⁴ Ω · cm or less, the reproducibility of a black solid image or a halftone image is improved.

The volume average particle size of the carrier according to this embodiment is preferably 20 μm or more and 100 μm or less.
When the volume average particle diameter of the carrier is 20 μm or more, development with the toner is suppressed, and when it is 100 μm or less, the toner can be easily charged without unevenness.

(Electrostatic image developer)
The electrostatic charge image developer according to this embodiment is configured as a two-component developer including the carrier and toner according to this embodiment.
The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner: carrier = 1: 100 to 30: 100, more preferably 3: 100 to 20: 100.
Hereinafter, the toner used for the electrostatic charge image developer according to the exemplary embodiment will be described.

The toner according to the exemplary embodiment includes toner base particles and, if necessary, an external additive.
The toner base particles preferably include a binder resin and a colorant, and more preferably include a binder resin, a colorant, and a release agent. The electrostatic image developing toner is preferably a toner in which an external additive is externally added to toner base particles (hereinafter also referred to as colored particles).

<Toner base particles>
The toner base particles include, for example, a binder resin and, if necessary, a colorant, a release agent, and other additives.

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

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

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

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

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

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

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

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

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

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

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

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

〔Release agent〕
Examples of mold release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum waxes such as montan wax; ester types such as fatty acid esters and montanic acid esters Wax; and the like. The release agent is not limited to this.

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

  The content of the release agent is, for example, preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 15% by mass or less based on the entire toner base particles.

[Other additives]
Examples of other additives include known additives such as a magnetic material, a charge control agent, and inorganic powder. These additives are contained in the toner base particles as an internal additive.

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

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

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

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

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

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

In the present embodiment, it is preferable to use an external additive having a volume average particle size of 50 nm or more and 200 nm or less from the viewpoint of obtaining long-term stable print quality. However, an external additive having this particle size range tends to cause embedding, deformation, polishing and the like on the carrier surface.
However, in this embodiment, even when a toner having an external additive in the above particle size range is used, the wear of the carrier coating layer is moderately controlled, and as a result, image defects such as white spots can be suppressed.

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

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

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

[Toner Production Method]
Next, a toner manufacturing method according to this embodiment will be described.
The toner according to the exemplary embodiment is obtained by externally adding an external additive to the toner base particles after the toner base particles are manufactured.

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

  Specifically, for example, when toner base particles are produced by an aggregation and coalescence method, a step of preparing a resin particle dispersion in which resin particles serving as a binder resin are dispersed (resin particle dispersion preparation step), a resin Step of agglomerating resin particles (other particles as necessary) to form aggregated particles in the particle dispersion (in the dispersion after mixing other particle dispersion as necessary) (aggregated particles) Forming step), heating the aggregated particle dispersion in which the aggregated particles are dispersed, and fusing and coalescing the aggregated particles to form toner base particles (fusion and coalescence process), Toner base particles are produced.

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

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

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

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

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

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

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

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

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

-Aggregated particle formation process-
Next, the colorant particle dispersion and the release agent particle dispersion are mixed together with the resin particle dispersion.
In the mixed dispersion, the resin particles, the colorant particles, and the release agent particles are hetero-aggregated, and the resin particles, the colorant particles, and the release agent particles have a diameter close to the diameter of the target toner base particles. To form agglomerated particles.

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

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

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

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

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

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

  The toner according to the exemplary embodiment is produced, for example, by adding an external additive to the obtained dry toner base particles and mixing them. Mixing may be performed, for example, with a V blender, a Henschel mixer, a Ladyge mixer, or the like. Furthermore, if necessary, coarse toner particles may be removed using a vibration classifier, a wind classifier, or the like.

(Image forming apparatus / image forming method)
The image forming apparatus / image forming method according to the present embodiment will be described.
An image forming apparatus according to the present embodiment includes an image carrier, a charging unit that charges the surface of the image carrier, an electrostatic image forming unit that forms an electrostatic image on the surface of the charged image carrier, Developing means for containing the electrostatic charge image developer of the present embodiment and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer, and the surface of the image carrier A transfer unit that transfers the toner image formed on the surface of the recording medium; and a fixing unit that fixes the toner image transferred to the surface of the recording medium.

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

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

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

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  Note that the process cartridge according to the present embodiment is not limited to the above-described configuration, and other means such as a developing device and other units such as an image carrier, a charging unit, an electrostatic charge image forming unit, and a transfer unit, if necessary. And at least one selected from the above.

  Hereinafter, an example of the process cartridge according to the present embodiment will be shown, but the present invention is not limited to this. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

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

The toner cartridge according to the present exemplary embodiment is a toner cartridge that accommodates the toner according to the present exemplary embodiment and is detachable from the image forming apparatus. The toner cartridge contains toner for replenishment to be supplied to the developing means provided in the image forming apparatus.
It can also be combined with trickle development proposed in Japanese Patent Publication No. 2-21591. By accommodating the carrier of this embodiment in the toner cartridge, stable image formation can be performed for a longer period of time.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited by the following Example. In the following description, “parts” means “parts by mass” unless otherwise specified.

(Preparation of resin particle 1 for forming coating layer)
Cyclohexyl methacrylate monomer (Asahi Kasei Chemicals Corporation): 100 parts by weight Dodecanethiol (Kao Corporation): 1 part by weight An anionic surfactant (Neogen SC: Direct) Chain dodecylbenzenesulfonate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was emulsion-polymerized in a flask in which 400 parts by mass of ion-exchanged water was dissolved, and this was mixed with an initiator (peroxide) while slowly mixing for 10 minutes. 50 parts by mass of ion-exchanged water in which 0.5 part by mass of ammonium sulfate (manufactured by ADEKA Corporation) was dissolved was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion 1 in which resin particles having a volume average particle diameter of 300 nm were dispersed was obtained. This resin particle dispersion 1 was freeze-dried to obtain resin particles 1 for forming a coating layer. The weight average molecular weight of the coating layer forming resin particles 1 was 350,000.
In addition, the weight average molecular weights of the coating layer forming resins 1 to 4 are converted by the molecular weight of standard styrene using Tosoh Corporation HLC-8120GPC, SC-8020 apparatus, using THF (tetrahydrofuran) as an eluent. It was measured.

(Preparation of resin particle 2 for coating layer formation)
Cyclohexyl methacrylate monomer (Asahi Kasei Chemicals Corporation): 100 parts by weight Dodecanethiol (Kao Corporation): 1 part by weight An anionic surfactant (Neogen SC: Direct) Chain dodecylbenzene sulfonate: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. 2 parts by mass in a flask in which 400 parts by mass of ion-exchanged water is dissolved and subjected to emulsion polymerization while slowly mixing for 10 minutes. And 50 parts by mass of ion-exchanged water in which 0.5 part by mass was dissolved. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion 2 in which resin particles having a volume average particle diameter of 100 nm were dispersed was obtained. This resin particle dispersion 2 was freeze-dried to obtain resin particles 2 for forming a coating layer. The weight average molecular weight of the coating layer forming resin particles 2 was 380,000.

(Preparation of resin particle 3 for forming coating layer)
Cyclohexyl methacrylate monomer (Asahi Kasei Chemicals Co., Ltd.): 100 parts by mass Dodecanethiol (manufactured by Kao Corporation): 1 part by mass A mixture of the above components dissolved therein is dissolved in a cationic surfactant (stearyl trimethyl ammonium chloride). Compound, Cotamin 86P Conch: manufactured by Kao Co., Ltd. 0.5 mass parts dissolved in 400 parts by mass of ion-exchanged water was emulsion polymerized and slowly mixed for 10 minutes while adding initiator (V-50: 50 parts by mass of ion-exchanged water in which 0.5 parts by mass of Wako Pure Chemical Industries, Ltd.) was dissolved was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the content reached 70 ° C., and emulsion polymerization was continued for 5 hours.
As a result, a binder resin particle dispersion 3 in which coated resin particles having a volume average particle diameter of 350 nm were dispersed was obtained. This binder resin particle dispersion 3 was freeze-dried to obtain resin particles 3 for forming a coating layer. The weight average molecular weight of the coating layer forming resin particles 3 was 340,000.

(Preparation of resin particle 4 for forming coating layer)
Methyl methacrylate monomer (Asahi Kasei Chemicals Co., Ltd.): 80 parts by mass Styrene monomer (Mitsubishi Chemical Co., Ltd.): 20 parts by mass The same as the method for producing coating layer forming resin particles 1 except that the monomer composition is changed to the above. By this method, a resin particle dispersion 4 in which resin particles having a volume average particle diameter of 320 nm are dispersed was obtained. This coating resin particle dispersion 4 was lyophilized to obtain coating layer forming resin particles 4. The weight average molecular weight of the coating layer forming resin particles 4 was 320,000.

Example 1
<Preparation of carrier 1>
Ferrite particles (Mn—Mg ferrite, true specific gravity 4.7 g / cm ³ , volume average particle size 40 μm, saturation magnetization 60 emu / g, surface roughness 1.5 μm, manufactured by Powdertech Co., Ltd.): 100 parts by mass Covering layer formation Resin particles 1: 2.0 parts by mass Charge-adjusted resin particles (Eposta S: melamine resin particles 200 nm manufactured by Nippon Shokubai Co., Ltd.): 0.5 parts by mass Carbon black (manufactured by Mitsubishi Chemical Corporation): 0.5 parts by mass Part The above material was put in a 5 L Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd.) and mixed at 2,000 rpm for 60 minutes to immobilize the coating layer forming resin particles 1 on the ferrite particles. After maintaining the Henschel mixer temperature at 210 ° C. and stirring at 2,000 rpm for 20 minutes, the mixture was cooled to 50 ° C. while rotating at 1,000 rpm to obtain a coating layer forming carrier 1. The carrier 1 was obtained by sieving the coating layer-formed carrier 1 with a mesh having an opening of 75 μm.

<Preparation of Toner 1>
Styrene-butyl acrylate copolymer (weight average molecular weight Mw = 150,000, copolymerization ratio 80:20, manufactured by Mitsubishi Chemical Corporation) 100 parts, carbon black (Mogal L: manufactured by Cabot Corporation) 5 parts, and carnauba A mixture of 6 parts of wax is kneaded with an extruder, pulverized with a jet mill, and then spheronized with warm air is carried out with Kryptron (manufactured by Kawasaki Heavy Industries, Ltd.) and classified with a wind classifier to obtain a particle size of 6 A toner base particle of 2 μm was obtained.
100 parts by mass of toner base particles and 1.2 parts by mass of silicone oil-treated silica particles (RY50: manufactured by Nippon Aerosil Co., Ltd.) having a volume average particle size of 40 nm and hexamethyldisilazane (HMDS) treated silica having a volume average particle size of 150 nm The external additive toner 1 was obtained by mixing 1.5 parts by mass of particles (manufactured by Hoechst) with a sample mill.

  External additive toner 1: 8 parts by mass and carrier 1: 100 parts by mass were stirred for 20 minutes at 40 rpm using a V blender, and sieved using a sieve of 125 μm mesh to obtain developer 1.

(Evaluation of carrier and developer)
Using the above developer 1, a copy machine manufactured by Fuji Xerox Co., Ltd. Docu Center Color 500 was used to print 100,000 sheets of a 1% print chart in a high temperature and high humidity environment of 35 ° C. and 85% RH. (10th sheet) Halftone image quality that is easily affected by chargeability after printing 10,000 sheets, 50,000 sheets, 80,000 sheets, and 100,000 sheets, and after standing for 72 hours after printing 100,000 sheets The white spots and fine line reproducibility were evaluated according to the following criteria. The obtained results are shown in Tables 2 to 4.

<Halftone image quality>
A: When halftone image quality degradation is not visually observed at all. B: When halftone image quality degradation is slightly observed visually. C: When halftone image quality degradation is clearly observed. Whether the above evaluation is A or B. For practical use, there is no problem in halftone image quality, and A is preferable.

<White spot>
At each time point, 10 halftone images were continuously printed on A3 paper, and the number of white spots was counted.
A: 3 or less B: 4 or more and 10 or less C: 11 or more If the above evaluation is A or B, there is practically no problem in the generation of white spots, and A is preferable.

<Thin wire reproducibility>
Using the modified machine, a 1 on 1 off image was output at a resolution of 2,400 dpi, and a 5 cm × 5 cm chart perpendicular to the developing direction was output to the upper left, center and lower right of A4 paper. The output samples were graded according to the following criteria from the distance at which the line interval was the narrowest due to toner scattering, etc., using a loupe with a scale of x100. The obtained results are shown in Tables 2 to 4.
A: When there is almost no increase in distance due to scattering or thinning due to splattering B: When there is a decrease or increase, but a fine line can be confirmed C: When the distance between fine lines cannot be identified or missing If it is A or B, there is no problem in the reproducibility of fine lines in practice, and A is preferable.

(Example 2)
The carrier 2 and the developer 2 shown in Table 1 were prepared and evaluated in the same manner as in Example 1 except that the coating layer forming particles 1 of Example 1 were changed to the coating layer forming particles 2. The obtained results are shown in Tables 2 to 4.

(Example 3)
The carrier 3 and the developer 3 shown in Table 1 were prepared and evaluated in the same manner as in Example 1 except that the coating layer forming resin particles 1 in Example 1 were changed to the coating layer forming resin particles 4. The obtained results are shown in Tables 2 to 4.

Example 4
<Preparation of carrier>
Ferrite particles (Mn—Mg ferrite, true specific gravity 4.7 g / cm ³ , volume average particle size 40 μm, saturation magnetization 60 emu / g, surface roughness 1.5 μm, manufactured by Powdertech Co., Ltd.): 100 parts by mass Covering layer formation Resin particles 3: 2.0 parts by mass Charge-adjusting resin particles (Eposta S: Melamine resin particles 200 nm manufactured by Nippon Shokubai Co., Ltd.): 0.5 parts by mass Carbon black (manufactured by Mitsubishi Chemical Corporation): 0.5 parts by mass Part The above material was put into a 5 L Henschel mixer (manufactured by Nippon Coke Industries Co., Ltd.) and mixed at 2,000 rpm for 60 minutes to immobilize resin particles on ferrite particles. Alkylbenzene (Grade Alkene L: manufactured by JX Nippon Oil & Energy Co., Ltd.) 0.5 parts by mass is dispersed in methanol and sprayed. The mixture is stirred at 2,000 rpm for 20 minutes while maintaining the Henschel mixer temperature at 100 ° C., then 1,000 rpm The coating layer-formed carrier 4 was obtained by cooling to 50 ° C. while being rotated. Carrier 4 was obtained by sieving the coating layer-formed carrier with a mesh having a mesh size of 75 μm.
Developer 4 was prepared using the carrier 4 and evaluated in the same manner as in Example 1. The obtained results are shown in Tables 2 to 4.

(Example 5)
The carrier 5 and the developer 5 shown in Table 1 were prepared and evaluated in the same manner as in Example 1 except that the Henschel mixer temperature of Example 1 was maintained at 210 ° C. and the holding time of 20 minutes at 2,000 rpm was changed to 1 minute. Went. The obtained results are shown in Tables 2 to 4.

(Example 6)
<Preparation of coating layer forming solution 1>
Cyclohexyl methacrylate resin (toluene solution: resin content 15%, manufactured by Soken Chemical, sodium acrylbenzene sulfonate not contained): 30 parts by mass Charge-adjusting resin particles (Eposta S: Melamine resin particles 200 nm manufactured by Nippon Shokubai Co., Ltd.): 0 Carbon black (manufactured by Mitsubishi Chemical): 0.5 part by mass Alkylbenzene (grade alkene L: manufactured by JX Nippon Oil & Energy Corporation): 0.5 part by mass The above materials are put into a container equipped with a stirrer. The solution, carbon, and crosslinked melamine resin particles that were stirred for 2 hours at a temperature were stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 6.

[Preparation of carrier]
Ferrite particles (Mn—Mg ferrite, true specific gravity 4.7 g / cm ³ , volume average particle size 40 μm, saturation magnetization 60 emu / g, surface roughness 1.5 μm, manufactured by Powdertech Co., Ltd.): 100 parts by mass Covering layer formation Solution 1: 31.5 parts by mass Ferrite particles (magnetic core material particles) and coating layer forming solution 1 were put into a kneader, heated to 60 ° C., kept at 60 ° C., stirred for 10 minutes, and then depressurized. Toluene was distilled off. The mixture was further heated to 70 ° C. and decompressed to distill off toluene. Carrier 6 was obtained by sieving the resin-coated layer-formed carrier with a mesh having an opening of 75 μm. Developer 6 was prepared using the carrier 6 and evaluated in the same manner as in Example 1. The obtained results are shown in Tables 2 to 4.

(Comparative Example 1)
A carrier 7 and a developer 7 shown in Table 1 were prepared and evaluated in the same manner as in Example 1 except that the Henschel mixer temperature in Example 1 was changed to 100 ° C. The obtained results are shown in Tables 2 to 4.

(Comparative Example 2)
The carrier 8 and the developer 8 shown in Table 1 were prepared and evaluated in the same manner as in Example 1 except that the coating layer forming resin particles 1 in Example 1 were changed to the coating layer forming resin particles 3. . The obtained results are shown in Tables 2 to 4.

(Comparative Example 3)
Ferrite particles (Mn—Mg ferrite, true specific gravity 4.7 g / cm ³ , volume average particle size 40 μm, saturation magnetization 60 emu / g, surface roughness 1.5 μm, manufactured by Powdertech Co., Ltd.): 100 parts by mass Covering layer formation Resin particles 3: 2.0 parts by mass Charge-adjusting resin particles (Eposta S: Melamine resin particles 200 nm manufactured by Nippon Shokubai Co., Ltd.): 0.5 parts by mass Carbon black (manufactured by Mitsubishi Chemical Corporation): 0.5 parts by mass Part The above material was put into a 5 L Henschel mixer (manufactured by Nippon Coke Kogyo Co., Ltd.) and mixed at 2,000 rpm for 60 minutes to immobilize the coating layer forming resin particles 3 on the ferrite particles. Alkylbenzene (Grade Alkene L: manufactured by JX Nippon Oil & Energy Corporation) 5.5 parts by mass is dispersed in methanol and sprayed. After maintaining the Henschel mixer temperature at 100 ° C. and stirring at 2,000 rpm for 20 minutes, 1,000 rpm The coating layer-formed carrier 9 was obtained by cooling to 50 ° C. while rotating. The carrier 9 was obtained by sieving the coating layer-formed carrier with a mesh having an opening of 75 μm.
Developer 9 was prepared using the carrier 9 and evaluated in the same manner as in Example 1. The obtained results are shown in Tables 2 to 4.

  As the results of Examples 1 to 6 show, the developer carrier containing the coating resin contains 100 to 20,000 ppm of the compound represented by the above formula (1) in the coating resin. Compared with the developers in Comparative Examples 1 to 3, the developer of halftone image quality is suppressed after long-term image formation under high temperature and high humidity and after standing, white spots are suppressed, and fine line reproducibility is reduced. It was good. This is presumably because the decrease in charge of the carrier was suppressed.

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

Claims (8)

Containing magnetic core particles and coating resin,
A carrier for developing an electrostatic charge image, comprising 3500 to 20,000 ppm of a compound represented by the following formula (1) in the coating resin with respect to the total mass of the coating resin.
C _n H _{2n + 1} (C ₆ H ₅ ) (1)
In formula (1), n represents an integer of 6 to 20.   The carrier for developing an electrostatic charge image according to claim 1, wherein the alkyl group in the formula (1) is linear.   The carrier for developing an electrostatic charge image according to claim 1, wherein the coating resin contains a constitutional repeating unit derived from an alicyclic alkyl (meth) acrylate compound.   An electrostatic charge image developer comprising: an electrostatic charge image developing toner; and the electrostatic charge image developing carrier according to claim 1. A toner cartridge, comprising: a developer holder that contains the electrostatic charge image developer according to claim 4 and that holds and conveys the electrostatic charge image developer. A developing means for containing the electrostatic charge image developer according to claim 4 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer,
A process cartridge attached to or detached from the image forming apparatus. An image carrier,
Charging means for charging the surface of the image carrier;
An electrostatic charge image forming means for forming an electrostatic charge image on the surface of the charged image carrier;
Development means for containing the electrostatic charge image developer according to claim 4 and developing the electrostatic charge image formed on the surface of the image carrier as a toner image by the electrostatic charge image developer;
Transfer means for transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
An image forming apparatus comprising: fixing means for fixing the toner image transferred to the surface of the recording medium. A charging step for charging the surface of the image carrier;
An electrostatic charge image forming step of forming an electrostatic charge image on the surface of the charged image carrier;
A developing step of developing an electrostatic charge image formed on the surface of the image carrier as a toner image with the electrostatic charge image developer according to claim 4;
A transfer step of transferring a toner image formed on the surface of the image carrier to the surface of a recording medium;
A fixing step of fixing the toner image transferred onto the surface of the recording medium.

Images