JP2011065092A - Carrier for electrostatic charge image development, method for producing carrier for electrostatic charge image development, developer for electrostatic charge image development, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrier having higher durability of a coating layer compared to a conventional carrier and produced in a dry process. <P>SOLUTION: The carrier 10 for electrostatic charge image development includes a core material 12 and a coating layer formed by depositing conductive particles 16 and organic resin particles 14, and is characterized in that: the coating layer has voids 18; the resin of the organic resin particles 14 exhibits, in the measurement of dynamic viscoelasticity at a shear rate of 3.14 rad/sec and a temperature change condition of 2°C/min, a storage modulus G' of not more than 1.2×10<SP>5</SP>Pa when a tanδ, which is a ratio of a loss modulus G" to a storage modulus G', becomes minimum; and the carrier for electrostatic charge image development has an electric resistance of not more than 10<SP>11</SP>Ω cm in an electric field of 500 V/cm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

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

  In electrophotography, an electrostatic latent image is formed on a latent image holding member (photoreceptor) by charging and exposure processes, developed with toner, the developed image is transferred onto a transfer member, and fixed by heating or the like to obtain an image. Developers used in such an electrophotographic method are roughly classified into a one-component developer using a toner in which a colorant is dispersed in a binder resin and a two-component developer composed of the toner and a carrier. Can do. Two-component developers are currently widely used because of their high controllability because the carrier has a charging / conveying function. The two-component developer has a feature such that the carrier has functions such as stirring, transporting, and charging of the developer, and the function as the developer is separated, so that the controllability is good.

  On the other hand, the method for producing a carrier used for a two-component developer is roughly classified into a solvent production method and a dry production method. The dry production method is basically a method in which a conductive layer or resin particles are adhered to a core material surface by a mechanical impact force without using a solvent to form a coating layer.

  Patent Document 1 describes a carrier produced by a dry process and having a coating resin layer containing at least inorganic particles and a resin on a core, and a developer for developing an electrostatic latent image comprising a toner. The weight average molecular weight (Mw) is 300,000 to 600,000, and the inorganic particles in the carrier-coated resin layer are flat having a ratio R1 / D of the major axis R1 to the thickness D of 3.0 to 100 On the other hand, it is described that the toner contains inorganic fine particles having a number average particle diameter of 80 to 300 nm as an external additive.

On the other hand, Patent Document 2 describes a carrier for an electrophotographic developer, the surface of which is coated with an insulating resin containing a white conductive agent, and the white conductive agent has a spherical to massive TiO ₂ , ZnO ₂ or SnO. ₂ and two or more kinds of powders having different average particle diameters, and the powder has a SnO ₂ conductive layer in which a Group V metal is solid-solved on the surface, and the thickness of the conductive layer is 5 to 5. It is described that it is 50cm.

  Patent Document 3 describes an electrophotographic developer carrier comprising core material particles and a coating layer covering the core material particles, the coating layer of the carrier containing white conductive fine particles, and white conductive particles. It is described that the base of the conductive fine particles is aluminum oxide, the lower layer contains tin dioxide, and the upper layer contains indium oxide as the conductive coating layer of the white conductive fine particles.

JP 2009-009000 A JP 2000-244204 A JP 2008-262155 A

  Since the present invention has a highly durable coating layer that has high impact relaxation properties and is prevented from being peeled off from the core material in response to a carrier coating layer obtained by a conventional dry manufacturing method, the fine line reproducibility of images The main objective is to provide an improved career.

  As a result of intensive studies to solve the above problems, the present inventors have completed the present invention shown below. The present invention has the following features.

(1) An electrostatic charge image developing carrier in which at least conductive particles and organic resin particles are adhered to a core material to form a coating layer. The coating layer has voids, and the organic resin particles The resin is in a molten state under a shear rate of 3.14 rad / sec and a temperature change condition of 2 ° C./min when measuring the dynamic viscoelasticity, and the loss elastic modulus G ″ and storage elastic modulus. The storage elastic modulus G ′ when the ratio tan δ of G ′ is minimized is 1.2 × 10 ⁵ Pa or less, and the electric resistance of the electrostatic charge image developing carrier is 10 ¹¹ Ω · cm at an electric field of 500 V / cm. The following electrostatic charge image developing carrier.

  (2) The electrostatic charge image developing carrier according to (1), wherein the resin of the organic resin particles is a resin polymerized using 50 mol% or more of hexyl methacrylate.

  (3) The electrostatic image developing carrier according to (1) or (2), wherein the conductive particles are white conductive powder.

  (4) The electrostatic image developing carrier coating layer according to any one of (1) to (3) above, wherein the electrostatic image developing carrier coating layer is formed by applying a mechanical impact force. It is.

  (5) An electrostatic charge image developing developer comprising the electrostatic charge image developing carrier and the toner according to any one of (1) to (3) above.

  (6) a latent image holder, charging means for charging the latent image holder, exposure means for exposing the charged latent image holder to form an electrostatic latent image on the latent image holder, Developing means for developing the electrostatic latent image with the developer for developing an electrostatic charge image described in (5) to form a toner image, and transfer for transferring the toner image from the latent image holding member to the transfer target And at least one selected from the group consisting of cleaning means for removing the toner remaining on the surface of the image carrier.

  (7) A latent image forming unit that forms a latent image on the latent image carrier, a developing unit that develops the latent image using a developer for developing an electrostatic charge image, and an intermediate transfer member for developing the developed toner image. An image forming apparatus comprising: a transfer unit that transfers the toner image on the transfer body; and a fixing unit that fixes the toner image on the transfer body. An image forming apparatus which is the developer for developing an electrostatic image according to (5).

  According to the first aspect of the present invention, compared to the case where the present structure is not provided, the coating layer of the dry-produced carrier has a high impact relaxation property, and the peeling from the core material due to the impact is suppressed, and the durability is improved. .

  According to the second aspect of the present invention, even when a resin having a relatively bulky structure that is easy to form a conductive path is used for the organic resin particles, the coating layer can be peeled off by impact compared with the case without this configuration. It is suppressed.

  According to the third aspect of the present invention, compared to the case where carbon black is used as the conductive particles, even if the coating layer of the carrier is partially peeled and as a result an image is formed with the toner, the color dullness of the image is increased. Is suppressed.

  According to invention of Claim 4, compared with a solvent manufacturing method, a solvent volatilization process becomes unnecessary, and electroconductive particle is distribute | arranged to the limited location between organic resin particles, and a conductive path is easy to be formed.

  According to the fifth aspect of the present invention, a stable and high-quality image can be obtained over time compared to the case where the present configuration is not provided.

  According to the sixth aspect of the present invention, a stable and high-quality image can be obtained over time as compared with the case without this configuration.

  According to the seventh aspect of the present invention, a stable and high-quality image can be obtained over time as compared with the case where this configuration is not provided.

1 is a schematic diagram illustrating an example of a configuration of an image forming apparatus used in an image forming method of the present invention. It is a figure explaining the viscoelastic property of resin used for the organic resin particle contained in the coating layer of the carrier in this invention. It is a cross-sectional schematic diagram explaining an example of the structure of the carrier in this invention. FIG. 4 is an enlarged schematic diagram of an X region surrounded by a broken line in FIG. 3. It is the scanning transmission electron microscope photograph which image | photographed the cross section of the coating layer of an example of the carrier in this invention.

  An electrostatic charge image developing carrier, an electrostatic charge image developing carrier manufacturing method, an electrostatic charge image developing developer, a process cartridge, and an image forming apparatus according to embodiments of the present invention will be described below.

[Electrostatic image developing carrier and method for producing the same]
In the solvent production method, since the solvent is used at the time of producing the carrier, it is necessary to finally evaporate the solvent from the carrier. On the other hand, since the solvent is not used in the dry manufacturing method, the solvent volatilization step during the production of the toner is omitted, but the carrier coating layer may be partially peeled compared to the solvent manufacturing method.

As shown in FIG. 3, the electrostatic image developing carrier (hereinafter also simply referred to as “carrier”) according to the present embodiment adheres at least conductive particles 16 and organic resin particles 14 onto a core material 12. The electrostatic charge image developing carrier 10 is formed, and the coating layer has voids 18. As shown in FIG. 2, the resin of the organic resin particles 14 is in a molten state under a shear rate of 3.14 rad / sec and a temperature change condition of 2 ° C. per minute during dynamic viscoelasticity measurement. (Ie, in a high temperature region exceeding the two-dot broken line in FIG. 2), the ratio of the loss elastic modulus G ″ (indicated by the thick broken line in FIG. 2) and the storage elastic modulus G ′ (indicated by the one-dot broken line in FIG. 2) The storage elastic modulus G ′ when tan δ (= G ″ / G ′) is minimal is 1.2 × 10 ⁵ Pa or less (that is, the thin broken line in FIG. 2 or less), and the electric charge of the electrostatic charge image developing carrier The resistance is 10 ¹¹ Ω · cm or less at an electric field of 500 V / cm.

  As a method for controlling the porosity, it is possible to control by stirring conditions (temperature, time, apparatus) and material processing (hydrophilic and hydrophobic processing) conditions at the time of carrier preparation. For example, conditions under which viscosity is appropriately reduced in a mixer If the stirring is continued for a long time, the mixing of the particles is sufficiently improved and the agglomerated particles are sufficiently crushed to reduce the amount of voids, and to improve the adhesion to magnetic powders such as ferrite, which becomes the core of the carrier. By subjecting the magnetic powder to a hydrophobizing treatment or the like, the amount of voids is reduced. On the contrary, if a carrier is prepared by suddenly applying strong stirring without treatment, the amount of voids increases.

  Dynamic viscoelasticity measurement is performed from 30 ° C to 130 ° C at a shear rate of angular velocity of 3.14 rad / sec using “Dynamic Viscoelasticity Measuring Device DMA” manufactured by TA Instruments Japan Co., Ltd. The temperature was measured at 2 ° C./min.

The resin having a storage elastic modulus G ′ of 1.2 × 10 ⁵ Pa or less when the ratio tan δ between the loss elastic modulus G ″ and the storage elastic modulus G ′ is minimized is smaller than the resin used for the conventional coating layer of the carrier. However, the carrier in the present embodiment is provided with a void in the coating layer, the impact on the coating layer is mitigated by this void, and is contained in the coating layer. Thus, the conductive particles are connected between the organic resin particles, and a significant peeling of the coating layer from the core material is suppressed.

  The presence or absence of voids in the coating layer was observed by photographing the cross section of the carrier with a scanning transmission electron microscope (STEM). Further, the porosity in the coating layer was binarized with an image processing analyzer LUZEX AP (manufactured by Nireco), and the porosity per unit area was measured as shown in FIG. The porosity in the coating layer of the carrier of this embodiment is preferably 1% or more and 50% or less.

  The electric resistance of the carrier is a resistance that is dynamically measured under developing conditions by a magnetic brush. The aluminum electrode drum having the same dimensions as the photoconductor drum is replaced with a photoconductor drum, particles are supplied onto the developing sleeve to form a magnetic brush, and the magnetic brush is slid against the electrode drum. By applying a voltage (500 V) between them and measuring the current flowing between them, the resistance of the carrier particles was determined by the following equation.

DVR (Ωcm) = (V / I) × (N × L / Dsd)
DVR: Carrier resistance (Ωcm)
V: Voltage between developing sleeve and drum (V)
I: Measurement current value (A)
N: Development nip width (cm)
L: Development sleeve length (cm)
Dsd: Distance between developing sleeve and drum (cm)
In this embodiment and the examples described later, measurement is performed at V = 500 V, N = 1 cm, L = 6 cm, and Dsd = 0.6 mm.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, the carrier must be a magnetic material. Is preferred. An example of ferrite is generally represented by the following formula.

(MO) _X (Fe ₂ O ₃ ) _Y
(In the formula, M contains at least one selected from Cu, Zn, Fe, Mg, Mn, Ca, Li, Ti, Ni, Sn, Sr, Al, Ba, Co, Mo and the like: X, Y represents a weight mol ratio and satisfies the condition X + Y = 100).

The resin used for the organic resin particles is a resin having a storage elastic modulus G ′ of 1.2 × 10 ⁵ Pa or less when the ratio tan δ between the loss elastic modulus G ″ and the storage elastic modulus G ′ is minimized, for example, , A resin comprising a homopolymer or a copolymer polymerized using 50 mol% or more of hexyl methacrylate (hereinafter sometimes abbreviated as “CHMA”). Here, other monomers used for the polyhexyl methacrylate copolymer include, for example, styrenes such as styrene, parachlorostyrene, and α-methylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, and n-acrylate. -Esters having a vinyl group such as butyl, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate; acrylonitrile, methacrylonitrile Vinyl nitriles such as vinyl ethers such as vinyl methyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl ethyl ketone and vinyl isopropenyl ketone; ethylene, propylene, butadiene, Including olefins such as isoprene and the like. These monomers may be used individually by 1 type, and may use 2 or more types together.

  The weight average molecular weight of the resin used for the organic resin particles is 100,000 or more and 1,000,000 or less, and in the case of a polyhexyl methacrylate homopolymer, it is 100,000 or more and 200,000 or less. In the case of coalescence, it is 100,000 or more and 1,000,000 or less. When the weight average molecular weight of the resin is less than 100,000, the carrier coating layer is easily peeled off when used as a developer. On the other hand, when the weight average molecular weight exceeds 1,000,000, the organic resin particles on the core during dry production are used. Is stuck.

  Although the volume average particle diameter of the organic resin particles is not limited, the volume average particle diameter of the organic fine particles is preferably 1 μm or less because additives such as conductive particles for the purpose of controlling conductivity are sufficiently dispersed and arranged. , 300 nm or less is more desirable, and smaller is more desirable.

  The conductive particles are not particularly limited, and carbon black and white conductive powder shown below are used. Examples of the white conductive powder include magnesium oxide, magnesium hydroxide, zinc oxide, tin oxide, titanium oxide, strontium titanate, calcium titanate, and composite oxides of metals such as magnesium, calcium, aluminum, and silicon. In particular, titanium oxide having a high whiteness is particularly preferable in that a color dullness is hardly generated even when a part of the coating layer of the carrier is peeled off and transferred to the toner image.

  The volume average particle diameter of the conductive particles is preferably 1 μm or less, more preferably 300 nm or less, and even more preferably 40 nm or less, in view of dispersive arrangement in the coating layer.

  In the carrier manufacturing method in the present embodiment, a coating layer is formed on a core material by a dry coating method. In the dry coating method in the present embodiment, the conductive particles and organic resin particles, and if necessary, charge control particles and low-resistance fine particles are mechanically applied to the surface of the core material to be coated under non-heating or heating. Using a high-speed agitator / mixer capable of imparting an impact force, the impact force is repeatedly applied to the mixture by high-speed stirring, and the conductive particles and organic resin particles, etc. deposited on the surface of the core material are fixed by melting or softening. A coating layer is formed. When heating, 60-125 degreeC is preferable. This is because if the heating temperature is too high, aggregation of carrier particles tends to occur.

[Toner for electrostatic image development]
Hereinafter, the toner in the present embodiment has a binder resin, and in the case of a colored toner, it further contains a flooring agent, and further contains a release agent and other components as required. The resin-resin will be described below.

  The case where the binder resin is a polyester resin will be described below.

-Crystalline polyester resin-
The crystalline polyester resin in the present embodiment will be described below. The “crystalline polyester resin” refers to a resin having a clear endothermic peak in differential scanning calorimetry (DSC). “Crystallinity” used in the toner for developing an electrostatic charge image of the present invention means that it has a clear endothermic peak in differential scanning calorimetry (DSC). Specifically, the temperature rising rate is 10 ° C./min. It means that the half-value width of the endothermic peak when measured by is within 6 ° C.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 4000 or more, and more preferably 6000 or more. If the number average molecular weight (Mn) is less than 4000, the toner may permeate into the surface of a recording medium such as paper at the time of fixing to cause uneven fixing, or the bending strength of the fixed image may be reduced.

  The crystalline polyester is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. Hereinafter, the acid (dicarboxylic acid) component and the alcohol (diol) component will be described in more detail. In the present invention, a copolymer obtained by copolymerizing other components at a ratio of 50% by mass or less with respect to the main chain of the crystalline polyester is also referred to as a crystalline polyester.

  The acid (dicarboxylic acid) component preferably contains an aliphatic dicarboxylic acid. For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,10-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof, An acid anhydride is mentioned, However, It is not limited to these.

  As said acid (dicarboxylic acid) component, the component of the dicarboxylic acid component which has a double bond other than the above-mentioned aliphatic dicarboxylic acid component may be contained. The dicarboxylic acid component having a double bond includes a component derived from a lower alkyl ester or acid anhydride of a dicarboxylic acid having a double bond, in addition to a component derived from a dicarboxylic acid having a double bond. Is also included.

  The dicarboxylic acid having a double bond can be suitably used for obtaining fixing strength in that the entire resin can be crosslinked using the double bond. Examples of such dicarboxylic acids include, but are not limited to, fumaric acid, maleic acid, 3-hexenedioic acid, and 3-octenedioic acid. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. In addition to the aliphatic dicarboxylic acid compound, the divalent carboxylic acid component which may be contained in the carboxylic acid component includes aromatic carboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; alicyclic such as cyclohexanedicarboxylic acid Carboxylic acids; and anhydrides of these acids, alkyl (C1-3) esters, and the like. Examples of the trivalent or higher polyvalent carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, and pyromellitic acid. Aromatic carboxylic acids such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) methane , Aliphatic carboxylic acids such as 1,2,7,8-octanetetracarboxylic acid, alicyclic carboxylic acids such as 1,2,4-cyclohexanetricarboxylic acid; and their acid anhydrides, alkyls (1 to 3) Derivatives such as esters are listed.

  On the other hand, the alcohol (diol) component preferably contains an aliphatic diol. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13 -Tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol and the like are exemplified, but not limited thereto.

  On the other hand, if necessary, a diol component having a double bond, such as a trihydric or higher polyhydric alcohol, may be contained.

  Examples of the diol having a double bond include 2-butene-1,4-diol, 3-butene-1,6-diol, 4-butene-1,8-diol and the like. Examples of the trihydric or higher polyhydric alcohol component include aromatic alcohols such as 1,3,5-trihydroxymethylbenzene; sorbitol, 1,2,3,6-hexanetetrol, pentaerythritol, dipentaerythritol, tripenta Such as erythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, etc. Aliphatic alcohols; alicyclic alcohols such as 1,4-sorbitan and the like.

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

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

  Catalysts usable in the production of the crystalline polyester include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compound: Phosphorous acid compound, phosphoric acid compound, amine compound and the like are mentioned, and specifically, the following compounds are mentioned.

  For example, sodium acetate, sodium carbonate, lithium acetate, calcium acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetra Butoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, zirconium naphthenate, zirconyl carbonate, zirconyl acetate, zirconyl acetate , Zirconyl octylate, germanium oxide, triphenyl phosphite, tris (2,4-di-t-butylphenyl) phosphite Ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  In addition, a monofunctional monomer may be introduced into the crystalline polyester for the purpose of blocking the polar group at the end of the crystalline polyester and improving the environmental stability of toner charging characteristics.

  Monofunctional monomers include benzoic acid, chlorobenzoic acid, bromobenzoic acid, sulfobenzoic acid monoammonium salt, sulfobenzoic acid monosodium salt, cyclohexylaminocarbonylbenzoic acid, n-dodecylaminocarbonylbenzoic acid, tertiary butyl. Benzoic acid, naphthoic acid, 4-methylbenzoic acid, 3-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenylacetic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, octanecarboxylic acid, lauric acid, stearyl acid, and lower Monocarboxylic acids such as alkyl esters; or monoalcohols such as aliphatic alcohols, aromatic alcohols, and alicyclic alcohols are used.

-Amorphous polyester resin-
A known amorphous polyester resin is used as the amorphous polyester resin used in the toner of the present embodiment.

  The range of the glass transition temperature (Tg) of the amorphous polyester resin is preferably 45 ° C. or higher and 85 ° C. or lower, and more preferably 50 ° C. or higher and 75 ° C. or lower. When the glass transition temperature (Tg) is lower than 45 ° C., it may be difficult to store the toner. When the glass transition temperature (Tg) is higher than 85 ° C., energy consumption for fixing may increase.

  The weight average molecular weight (Mw) of the amorphous polyester resin is preferably in the range of 5,000 to 100,000, but from the viewpoint of low temperature fixability and mechanical strength, the weight average molecular weight (Mw) is 8,000 to 50,000. A range is more preferable.

  The method for producing the amorphous polyester resin is not particularly limited, as with the method for producing the crystalline polyester resin described above, and is produced by a general polyester polymerization method as with the crystalline polyester.

  As the acid (dicarboxylic acid) component used for the synthesis of the amorphous polyester resin, various dicarboxylic acids mentioned for the crystalline polyester resin are similarly used. In particular, substituted with dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, dodecenyl succinic acid, octyl succinic acid and the like or alkyl groups having 1 to 20 carbon atoms or alkenyl groups having 2 to 20 carbon atoms Succinic acid, trimellitic acid, pyromellitic acid, anhydrides of these acids and alkyl (carbon number 1 to 3) esters of these acids are preferably used. As the alcohol (diol) component, various diols used for the synthesis of the amorphous polyester resin are used. In addition to the aliphatic diols mentioned for the crystalline polyester resin, polyoxypropylene (2.2) -2 , 2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and other bisphenol A alkylene (2 to 3 carbon atoms) oxide (average addition) Mole number 1-10) Adduct, hydrogenated bisphenol A, etc. are used. Further, both the acid (dicarboxylic acid) component and the alcohol component may contain a plurality of components.

  Similarly to the above-mentioned crystalline polyester resin, a monofunctional monomer is introduced into the amorphous polyester resin for the purpose of blocking the polar group at the end of the amorphous polyester resin and improving the environmental stability of the toner charging characteristics. May be. As the monofunctional monomer, various compounds mentioned for the crystalline polyester resin are used.

  In addition, examples of the binder resin used for other toners in the present embodiment include styrenes such as styrene and chlorostyrene, monoolefins such as ethylene, propylene, butylene, and isoprene, vinyl acetate, vinyl propionate, and benzoic acid. Vinyl esters such as vinyl acid and vinyl butyrate, methyl acrylate, ethyl acrylate, butyl acrylate, dodecyl acrylate, octyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, dodecyl methacrylate Α-methylene aliphatic monocarboxylic acid esters such as vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether and other vinyl ethers, vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone and other vinyl ketones, etc. Homopolymers and copolymers are exemplified, and typical binder resins include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene- Examples thereof include a butadiene copolymer, a styrene-maleic anhydride copolymer, polyethylene, and polypropylene. Further examples include polyester, polyurethane, epoxy resin, silicone resin, polyamide, modified rosin, paraffin wax and the like.

  Examples of the colorant include carbon black, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brillianthamine 3B, and brillianthamine. 6B, dapon oil red, pyrazolone red, resol red, rhodamine B rake, lake red C, rose bengal, aniline blue, ultramarine blue, chalcoil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxaleray Various pigments such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, dioxazine And various dyes such as thiazine, azomethine, indico, thioindico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, thiazine, thiazole and xanthene. These colorants may be used alone or in combination of two or more.

  Examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point when heated, fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide. , Plant wax such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil, animal wax such as beeswax, montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, fisher Examples thereof include mineral-based and petroleum-based waxes such as Tropsch wax, ester-based waxes such as fatty acid esters, montanic acid esters, and carboxylic acid esters, and modified products thereof. These release agents may be used alone or in combination of two or more.

  In addition, various components such as an internal additive, a charge control agent, and organic particles can be added as necessary. Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel and manganese, alloys, and magnetic materials such as compounds containing these metals. Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  The toner has a volume average particle diameter of 3 to 10 μm, preferably 3 to 9 μm, and more preferably 3 to 8 μm. The number average particle diameter of the toner of the present embodiment is preferably 3 to 10 μm, and more preferably 2 to 8 μm. If the particle size is too small, not only the productivity becomes unstable, but the chargeability becomes insufficient and the developability may be lowered, and if it is too large, the resolution of the image is lowered.

  The toner manufacturing method in the present embodiment includes, for example, a kneading and pulverizing method in which the binder resin described above and a release agent and a pigment having a complementary color relationship with the hue of the binder resin are kneaded, pulverized, and classified. , A method of changing the shape of the particles obtained by the kneading and pulverization method by mechanical impact force or thermal energy, emulsion polymerization of a polymerizable monomer of the binder resin, and the formed dispersion and the binder resin A pigment dispersion and a release agent dispersion that are complementary to each other in hue are mixed, agglomerated, and heat-fused to obtain toner particles. Suspension polymerization in which a solution of a pigment and a release agent that are complementary to the color of the polymer and the binder resin is suspended in an aqueous solvent to polymerize, and the complementary color relationship to the hue of the binder resin and the binder resin Suspension method, etc., in which the solution of the pigment and the release agent is suspended in an aqueous solvent and granulated It can be used. In addition, a manufacturing method may be performed in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure.

  The transparent toner prepared by the kneading and pulverization method and the dissolution suspension method is easy to localize the pigment, and it is difficult to eliminate the localization after fixing, whereas the transparent toner prepared by the emulsion aggregation method has a uniform pigment. It is easy to disperse and uniformly disperse the pigment after fixing.

  As the above kneading and pulverizing method, for example, the following method is used. First, components such as the above-described binder resin, colorant, infrared absorber and the like are mixed and then melt-kneaded. Examples of the melt kneader include a three-roll type, a single screw type, a twin screw type, and a Banbury mixer type. After roughly pulverizing the obtained kneaded material, for example, it is pulverized by a pulverizer such as a micronizer, ulmax, jet-O-mizer, jet mill, kryptron, turbo mill, etc., elbow jet, microplex, DS separator, etc. The toner is obtained by performing a classification process with the classifier.

  In the present embodiment, an emulsion polymerization aggregation method capable of intentionally controlling the shape and surface structure of the toner is more preferable, and emulsification described in Japanese Patent No. 2547016, Japanese Patent Laid-Open No. 6-250439, and the like is more preferable. The toner may be produced by a polymerization aggregation method. In the emulsion polymerization aggregation method, a toner having a small diameter is efficiently produced in principle because a starting material is a finely divided raw material that is usually 1 μm or less. In this production method, a resin dispersion is generally prepared by emulsion polymerization or the like, while a colorant dispersion in which a colorant is dispersed in the same liquid is prepared, and the resin dispersion and the colorant dispersion are mixed to prepare a toner. Aggregated particles corresponding to the particle diameter are formed, and then heated to fuse and coalesce the aggregated particles to obtain a toner.

  Further, when a polyester resin is used as the binder resin, the emulsification step shown below is performed in order to improve the compatibility between the crystalline polyester resin and the amorphous polyester resin.

-Emulsification process-
In the emulsification step of the present invention, one or more types of crystalline resins and one or more types of non-crystalline polyester resins have a melting point of the resin, a glass transition temperature that is higher than the higher temperature, and lower than the boiling point of the organic solvent to be used. After heating to a temperature and dissolving to make a uniform solution, a basic aqueous solution is added as a neutralizing agent to this, and then the phase is changed by maintaining stirring at pH 7 to 9 while adding pure water to give a stirring shear. A / W type emulsion (emulsion) is obtained. Next, the obtained emulsion is distilled under reduced pressure to remove the solvent and obtain a resin particle emulsion.

  The pH after neutralization is 7 to 9, preferably 7 to 8. As the basic aqueous solution, for example, an alkali metal hydroxide such as an aqueous ammonium solution, sodium hydroxide, or potassium hydroxide may be used. When the pH is less than 7, there is a problem that coarse particles are likely to be generated in the emulsion, and when the pH is more than 9, there is a problem that the agglomerated particle size is expanded due to aggregation in the next step.

  By using particles in which the crystalline polyester resin and the non-crystalline polyester resin are compatible as described above, the release agent particles have a lower acid value, and the resin particle portions and the agglomeration easily occur. A toner having a structure is obtained.

<Emulsified dispersion>
As an average particle diameter of the said resin particle, it is 1 micrometer or less normally, and it is preferable that it is 0.01-1 micrometer. When the average particle diameter exceeds 1 μm, the particle diameter distribution of the finally obtained electrostatic image developing toner is broadened, or free particles are generated, which tends to cause deterioration in performance and reliability. On the other hand, when the average particle size is within the above range, there are no disadvantages, and the uneven distribution among the toners is reduced, the dispersion in the toner is improved, and the performance and reliability are improved. The average particle diameter is measured using, for example, a Coulter Multisizer, a laser scattering particle size measuring apparatus, or the like.

  Examples of the dispersion medium in the dispersion include an aqueous medium and an organic solvent.

  Examples of the aqueous medium include water such as distilled water and ion exchange water, alcohols, acetate esters, ketones, and mixtures thereof. These may be used singly or in combination of two or more.

  In the present invention, a surfactant may be added to and mixed with the aqueous medium. Although it does not specifically limit as surfactant, For example, anionic surfactants, such as sulfate ester type, sulfonate type, phosphate ester type, soap type; amine salt type, quaternary ammonium salt type, etc. Nonionic surfactants such as polyethylene glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based, and the like. Among these, anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with the anionic surfactant or the cationic surfactant. The said surfactant may be used individually by 1 type, and may use 2 or more types together.

  Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable.

  As the organic solvent, for example, alcohol such as ethyl acetate, methyl ethyl ketone, acetone, toluene and isopropyl alcohol is used, which is appropriately selected according to the binder resin.

  When the resin particle is a crystalline polyester or an amorphous polyester resin, it has a self-water dispersibility containing a functional group that can become an anionic type by neutralization, and a part or all of the functional group that can become hydrophilic is a base. A stable aqueous dispersion can be formed under the action of an aqueous medium neutralized with. In the crystalline polyester and the amorphous polyester resin, the functional group that can become a hydrophilic group by neutralization is an acidic group such as a carboxyl group or a sulfone group. As the neutralizing agent, for example, sodium hydroxide, potassium hydroxide, water Examples thereof include inorganic bases such as lithium oxide, calcium hydroxide, sodium carbonate and ammonia, and organic bases such as diethylamine, triethylamine and isopropylamine.

  When a polyester resin that does not disperse in water, that is, does not have self-water dispersibility, is used as a binder resin, the resin solution and / or an aqueous medium mixed with the resin solution as described later will be ionic. Disperse with polymer electrolytes such as surfactants, polymer acids, polymer bases, etc., heat above melting point, and process with a homogenizer or pressure discharge type disperser that can apply a strong shearing force. Of particles. When this ionic surfactant or polymer electrolyte is used, the concentration in the aqueous medium should be about 0.5 to 5% by mass.

  The non-crystalline polyester resin and the crystalline polyester resin may be blended with a release agent, or may be blended by dissolving in an appropriate solvent. They may be blended after merging. In the case of this melt-mixed blend, the toner is preferably prepared by a pulverization method. When blended after dissolving in a solvent, a toner production method in which wet granulation is performed together with a solvent and a dispersion stabilizer is preferable. When they are mixed together as an emulsion, there is no particular limitation. A wet manufacturing method for producing toner particles in water, such as a turbidity method, is preferable because it can control the shape of the developer so as not to cause toner destruction. In particular, it is desirable to prepare a toner by an aggregation and coalescence method of an emulsion that allows easy shape control and resin coating layer formation. In order to control the particle diameter and form the surface coating layer, it is desirable to prepare a toner by an aggregation and coalescence method of emulsions.

  Examples of the emulsifier used when forming the emulsified particles include a homogenizer, a homomixer, a cavitron, a clear mix, a pressure kneader, an extruder, and a media disperser.

[Developer for developing electrostatic image]
The two-component electrostatic latent image developer is prepared by combining the electrostatic latent image developing carrier of the present embodiment described above and the toner. The mixing ratio of the electrostatic latent image developing toner and the carrier in the electrostatic latent image developer is not particularly limited and is appropriately selected according to the purpose.

[Image forming apparatus]
Next, the image forming apparatus of the present embodiment will be described.

  FIG. 1 is a schematic diagram illustrating a configuration example of an image forming apparatus for forming an image by the image forming method of the present embodiment. In the illustrated image forming apparatus 200, four electrophotographic photosensitive members 401 a to 401 d are disposed in parallel in the housing 400 along the intermediate transfer belt 409. The electrophotographic photoreceptors 401a to 401d form, for example, images in which the electrophotographic photoreceptor 401a is yellow, the electrophotographic photoreceptor 401b is magenta, the electrophotographic photoreceptor 401c is cyan, and the electrophotographic photoreceptor 401d is black. Is possible.

  Each of the electrophotographic photosensitive members 401a to 401d can be rotated in a predetermined direction (counterclockwise on the paper surface), and the charging rolls 402a to 402d, the developing devices 404a to 404d, and the primary transfer roll 410a along the rotation direction. To 410d and cleaning blades 415a to 415d are arranged. Each of the developing devices 404a to 404d can be supplied with toner of four colors of black, yellow, magenta and cyan accommodated in the toner cartridges 405a to 405d, and the primary transfer rolls 410a to 410d are respectively intermediate transfer belts. 409 is in contact with the electrophotographic photoreceptors 401a to 401d.

  Further, an exposure device 403 is disposed at a predetermined position in the housing 400, and it becomes possible to irradiate the surfaces of the charged electrophotographic photoreceptors 401a to 401d with a light beam emitted from the exposure device 403. ing. Accordingly, charging, exposure, development, primary transfer, and cleaning are sequentially performed in the rotation process of the electrophotographic photosensitive members 401a to 401d, and the toner images of the respective colors are transferred onto the intermediate transfer belt 409 in an overlapping manner.

  Here, the charging rolls 402a to 402d contact the surface of the electrophotographic photoreceptors 401a to 401d with a conductive member (charging roll), and apply a voltage uniformly to the photoreceptor to charge the photoreceptor surface to a predetermined potential. (Charging process). In addition to the charging roll shown in this embodiment, charging by a contact charging method may be performed using a charging brush, a charging film, a charging tube, or the like. Moreover, you may charge by the non-contact system using a corotron or a scorotron.

  As the exposure apparatus 403, an optical system apparatus or the like that can expose a light source such as a semiconductor laser, an LED (light emitting diode), a liquid crystal shutter, or the like on the surfaces of the electrophotographic photosensitive members 401a to 401d can be used. Among these, when an exposure apparatus capable of exposing non-interference light is used, interference fringes between the electroconductive substrates of the electrophotographic photoreceptors 401a to 401d and the photosensitive layer can be prevented.

  The developing devices 404a to 404d can be performed using a general developing device that develops the above-described two-component electrostatic latent image developer in contact or non-contact (development process). Such a developing device is not particularly limited as long as a two-component electrostatic image developing developer is used, and a known one can be appropriately selected according to the purpose. In the primary transfer process, a primary transfer bias having a polarity opposite to that of the toner carried on the image carrier is applied to the primary transfer rolls 410a to 410d, so that each color toner is transferred from the image carrier to the intermediate transfer belt 409. The primary transfer is performed sequentially.

  The cleaning blades 415a to 415d are for removing residual toner adhering to the surface of the electrophotographic photosensitive member after the transfer process, and the electrophotographic photosensitive member cleaned by this cleaning process is repeatedly used in the above-described image forming process. Is done. Examples of the material for the cleaning blade include urethane rubber, neoprene rubber, and silicone rubber.

  The intermediate transfer belt 409 is supported with a predetermined tension by a drive roll 406, a backup roll 408, and a tension roll 407, and can rotate without causing deflection due to the rotation of these rolls. Further, the secondary transfer roll 413 is disposed so as to contact the backup roll 408 via the intermediate transfer belt 409.

  By applying a secondary transfer bias having a reverse polarity to the toner on the intermediate transfer member to the secondary transfer roll 413, the toner is secondarily transferred from the intermediate transfer belt to the recording medium. The intermediate transfer belt 409 that has passed between the backup roll 408 and the secondary transfer roll 413 is cleaned by, for example, a cleaning blade 416 disposed near the drive roll 406 or a static eliminator (not shown). It is repeatedly used for the next image forming process. A tray (transfer medium tray) 411 is provided at a predetermined position in the housing 400, and the transfer medium 500 such as paper in the tray 411 is transferred to the intermediate transfer belt 409 and the secondary transfer roll by the transfer roll 412. Then, the paper is sequentially transferred between the two fixing rolls 414 that are in contact with each other and the two fixing rolls 414, and then discharged to the outside of the housing 400.

[Image forming method]
The image forming method in the present embodiment includes at least the step of charging the image carrier, the step of forming a latent image on the image carrier, and the development for electrostatic charge development described above for the latent image on the latent image carrier. A step of developing using an agent, a primary transfer step of transferring the developed toner image onto the intermediate transfer member, and a secondary transfer step of transferring the toner image transferred to the intermediate transfer member onto a recording medium. And a step of fixing the toner image by heat and pressure. The developer is a developer containing at least the electrostatic image developing toner of the present invention. The developer may be either a one-component system or a two-component system.

  As each of the above steps, a known step in the image forming method can be used.

  As the latent image holding member, for example, an electrophotographic photosensitive member and a dielectric recording member can be used. In the case of an electrophotographic photosensitive member, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic latent image (latent image forming step). Next, the toner particles are adhered to the electrostatic latent image in contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image on the electrophotographic photosensitive member (developing step). The formed toner image is transferred onto the surface of a transfer medium such as paper using a corotron charger or the like (transfer process). Further, if necessary, the toner image transferred to the surface of the transfer material is heat-fixed by a fixing device to form a final toner image.

  In the heat fixing by the fixing device, a release agent is supplied to a fixing member in an ordinary fixing device in order to prevent an offset or the like, but the fixing device of the image forming apparatus in the present embodiment In this case, it is not necessary to supply a release agent, and fixing is performed without oil.

  The method for supplying the release agent to the surface of the roller or belt, which is a fixing member used for heat fixing, is not particularly limited. For example, a pad method using a pad impregnated with a liquid release agent, a web method, a roller method. Non-contact shower method (spray method) and the like, among which the web method and roller method are preferable. These methods are advantageous in that the release agent can be supplied uniformly and it is easy to control the supply amount. In order to supply the release agent uniformly to the entire fixing member by a shower method, it is necessary to use a separate blade or the like.

  Examples of the transfer target (recording material) to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines, printers, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these.

  First, in this example, each measurement was performed as follows.

-Particle size and particle size distribution measurement method-
The particle size (also referred to as “particle size”) and particle size distribution measurement (also referred to as “particle size distribution measurement”) will be described.

  When the particle diameter to be measured was 2 μm or more, Coulter Multisizer-II type (manufactured by Beckman-Coulter) was used as the measuring apparatus, and ISOTON-II (manufactured by Beckman-Coulter) was used as the electrolyte.

  As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This was added to 100 ml of the electrolytic solution.

  The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles having a diameter of 2 to 60 μm is measured using a Coulter Multisizer-II type with an aperture diameter of 100 μm. Average distribution and number average distribution were obtained. The number of particles to be measured was 50,000.

  The particle size distribution of the toner was determined by the following method. For the particle size range (channel) obtained by dividing the measured particle size distribution, draw the volume cumulative distribution from the smaller particle size, define the cumulative volume particle size to be 16% cumulative as D16v, and the cumulative volume to be 50% cumulative. The particle size is defined as D50v. Further, the cumulative volume particle size that is 84% cumulative is defined as D84v.

The volume average particle size in the present invention is D50v, and the volume average particle size index GSDv is calculated by the following equation.
Formula: GSDv = {(D84v) / (D16v)} ^0.5

  Moreover, when the particle diameter to measure was less than 2 micrometers, it measured using the laser diffraction type particle size distribution measuring apparatus (LA-700: made by Horiba, Ltd.). As a measurement method, a sample in a dispersion is adjusted to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This is put into the cell until an appropriate concentration is reached, waits for about 2 minutes, and is measured when the concentration in the cell becomes almost stable. The obtained volume average particle diameter for each channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  When measuring powders such as external additives, 2 g of a measurement sample is added to 50 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, and 2 with an ultrasonic disperser (1,000 Hz). A sample was prepared by dispersing for a minute, and the measurement was performed in the same manner as the above dispersion.

-Measuring method of glass transition temperature-
The glass transition temperature of the toner was determined by DSC (Differential Scanning Calorimetry) measurement method, and was determined from the main maximum peak measured according to ASTM D3418-8.

  DSC-7 manufactured by Perkin Elmer Co. can be used for measurement of the main maximum peak. The temperature correction of the detection part of this apparatus uses the melting point of indium and zinc, and the correction of heat quantity uses the heat of fusion of indium. As the sample, an aluminum pan was used, an empty pan was set as a control, and the measurement was performed at a heating rate of 10 ° C./min.

-Measurement method of molecular weight and molecular weight distribution of toner and resin particles-
The molecular weight distribution is performed under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)” apparatus, and two columns use “TSKgel, SuperHM-H (manufactured by Tosoh Corporation, 6.0 mm ID × 15 cm)”. , THF (tetrahydrofuran) was used as an eluent. As experimental conditions, an experiment was performed using a sample concentration of 0.5%, a flow rate of 0.6 ml / min, a sample injection amount of 10 μl, a measurement temperature of 40 ° C., and an IR detector. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

-Dynamic viscoelasticity measurement-
Using “Dynamic Viscoelasticity Measuring Device DMA” manufactured by T.A. Instrument Japan Co., Ltd., increasing from 30 ° C. to 130 ° C. at 2 ° C. per minute at a shear rate of 3.14 rad / sec. Measured by warming.

-Presence or absence of voids in the carrier coating layer-
The cross section of the carrier was photographed and observed with a scanning transmission electron microscope (STEM). Moreover, the porosity in the coating layer was obtained by binarizing an image obtained by STEM using an image processing analyzer LUZEX AP (manufactured by Nireco), and measuring the porosity per unit area.

-Electrical resistance of carrier-
Resistance measured dynamically under developing conditions with a magnetic brush. The aluminum electrode drum having the same dimensions as the photoconductor drum is replaced with a photoconductor drum, particles are supplied onto the developing sleeve to form a magnetic brush, and the magnetic brush is slid against the electrode drum. By applying a voltage (500 V) between them and measuring the current flowing between them, the resistance of the carrier particles was determined by the following equation.

DVR (Ωcm) = (V / I) × (N × L / Dsd)
DVR: Carrier resistance (Ωcm)
V: Voltage between developing sleeve and drum (V)
I: Measurement current value (A)
N: Development nip width (cm)
L: Development sleeve length (cm)
Dsd: Distance between developing sleeve and drum (cm)
The measurement was performed at V = 500 V, N = 1 cm, L = 6 cm, and Dsd = 0.6 mm.

  Although the more specific comparative example and Example in this invention are demonstrated below, the following Examples do not limit the content of this invention at all. In the following description, “part” means “part by mass” unless otherwise specified.

Example 1 to Example 6 and Comparative Example 1
[Example of carrier production]
-Production of carrier (A)-
Mn—Mg ferrite core particles (core material, average particle size: 35 μm) 100 parts by mass polyhexyl methacrylate homopolymer 2.25 parts by mass (weight average molecular weight: 20000, volume average particle size: 250 nm)
0.94 parts by mass of white conductive powder (titania, TTT-65C manufactured by Titanium Industry Co., Ltd., volume particle size: 30 nm)
The above raw materials are put into a high-speed mixer equipped with stirring blades (“Nobilta NOB-130”: manufactured by Hosokawa Micron Co., Ltd.), the stirring blades are rotated at 2,000 rpm, and stirred and mixed at 50 ° C. for 1 hour. A mixture in which the coating resin and magnesium oxide particles were adhered to the surface of was prepared. The mixture was fractionated by passing through a mesh having an opening of 75 μm to prepare a carrier (A).

-Production of carrier (B)-
A poly (hexyl methacrylate-methyl methacrylate) copolymer (weight average molecular weight: 40,000, CHMA: MMA molar ratio = 80: 20, volume average particle size: 250 nm) was used in place of the polyhexyl methacrylate homopolymer. Produced carrier (B) according to the production of carrier (A).

-Production of carrier (C)-
A poly (hexyl methacrylate-methyl methacrylate) copolymer (weight average molecular weight: 80000, CHMA: MMA molar ratio = 50: 50, volume average particle size: 250 nm) was used in place of the polyhexyl methacrylate homopolymer. Produced carrier (C) in accordance with production of carrier (A).

-Production of carrier (D)-
A polyhexyl methacrylate homopolymer (weight average molecular weight: 100,000, volume average particle size: 250 nm) was used in place of the polyhexyl methacrylate monopolymer (weight average molecular weight: 200,000, volume average particle size: 250 nm). The carrier (D) was produced according to the production of the carrier (A).

-Production of carrier (E)-
Instead of white conductive powder (titania, volume average particle size: 40 nm), carbon black ("Vulcan XC-72R": manufactured by Ishifuku Metal Industry Co., Ltd.) 0.47 parts, polyhexyl methacrylate monopolymer A carrier (E) was produced according to the production of the carrier (A) except that the amount was 2.61 parts.

-Production of carrier (F)-
A carrier (F) was produced in accordance with the production of the carrier (A) except that 1.91 parts of white conductive powder (zinc oxide, passet 23-K manufactured by Hux Itec Corp., volume average particle size: 200 nm) was used.

-Production of carrier (G)-
A resin coating layer forming raw material solution (a) comprising the following components was stirred / dispersed with a stirrer for 60 minutes to prepare a coating layer forming raw material solution (a). Further, the resin coating layer forming raw material solution (a) and 100 parts by weight of Mn—Mg ferrite core particles (core material, average particle size: 65 μm) were placed in a vacuum degassing kneader and stirred at 70 ° C. for 30 minutes. Thereafter, the pressure was further reduced to deaerate and dry. Further, a carrier (G) was produced by passing through a mesh having an opening of 75 μm.
<Resin coating layer forming raw material solution (a)>
Toluene: 18 parts by weight Polyhexyl methacrylate homopolymer (weight average molecular weight: 200,000): 2.25 parts by weight White conductive powder: 0.94 parts by weight (titania, STT-65C manufactured by Titanium Industry Co., Ltd., volume particle size: 30nm)

[Example of toner production]
-Production of binder resin-
<Synthesis of Amorphous Polyester Resin (A)>
Bisphenol A ethylene oxide 2 mol adduct: 15 mol%
Bisphenol A propylene oxide 2 mol adduct: 35 mol%
Terephthalic acid: 50 mol%
A monomer having the above composition ratio is charged into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectifying column, and the temperature is raised to 190 ° C. over 1 hour, so that the reaction system does not vary. After confirming that the mixture was stirred, 1.0 mass% of titanium tetraethoxide was added to 100 mass parts with the total amount of the three components as 100 mass parts. Further, while distilling off the generated water, it took 6 hours from the same temperature to increase the temperature to 240 ° C., and continued the dehydration condensation reaction at 240 ° C. for another 2.5 hours, with a glass transition point of 63 ° C. and a weight average molecular weight. An amorphous polyester resin (A) having (Mw) 17000 was obtained.

<Synthesis of crystalline polyester resin (A)>
Crystalline polyester obtained by mixing 679.4 parts of succinic acid, 450.5 parts of butanediol, 40.6 parts of fumaric acid, and 2.5 parts of dibutyltin, heating to 240 ° C. under reduced pressure and dehydrating for 6 hours. Resin (A) was obtained. It was 14000 when the weight average molecular weight (Mw) of the obtained crystalline polyester resin (A) was measured by the above-mentioned method. Moreover, it was 91 degreeC when the endothermic peak temperature of the obtained crystalline polyester resin (A) was measured using the differential scanning calorimeter (DSC) by the above-mentioned measuring method.

-Preparation of cyan colorant dispersion-
C. I. Pigment Blue 15: 3 (manufactured by Dainichi Seika Co., Ltd.) 30 parts by mass ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku) 3 parts by mass ion-exchanged water 70 parts by mass The above components are mixed and passed through an ultrasonic disperser for 10 passes. A pigment dispersion was obtained. The number average particle diameter of the dispersed pigment was 130 nm.

-Preparation of release agent dispersion-
Ester wax WE5 (manufactured by Nippon Oil & Fats Co., Ltd.) 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen RK): 5 parts Ion-exchanged water: 200 parts Dispersing with a Manton Gorin high-pressure homogenizer (Gorin) and dispersing a release agent having an average particle size of 0.21 μm after dispersion using IKA: Ultra Turrax T50) Liquid (1) (release agent concentration: 26% by mass) was prepared.

(Preparation of Toner 1)
Amorphous polyester resin (A) 12.8 parts by weight Crystalline polyester resin (A) 100 parts by weight Cyan colorant dispersion 15.0 parts by weight Anionic surfactant (Dowfax 2A1 20% aqueous solution) 4.1 parts by weight 12 parts by weight of mold dispersion The above composition is mixed with a powder using a Henschel mixer, this is heat-kneaded with an extruder at a set temperature of 100 ° C., and after cooling, coarsely pulverized, finely pulverized, classified, and the volume average particle diameter D50 is Toner mother particles of 8.2 μm were obtained.

  A toner was obtained by mixing 100 parts by mass of the toner base particles and 0.7 parts by mass of silica particles treated with dimethyl silicone oil (trade name: RY200, manufactured by Nippon Aerosil Co., Ltd.) using a Henschel mixer.

-Preparation of developer-
Next, 8 parts by mass of the externally added toner and 100 parts by mass of each of the carriers (A) to (G) were mixed to prepare a two-component developer.

[Evaluation item]
With a developer for electrostatic latent image development, a photoreceptor, and an image forming method, 100 sheets at high temperature and high humidity (30 ° C., 85% RH) using a DocuCentreColor400CP remodeling machine (manufactured by Fuji Xerox Co., Ltd.) shown in FIG. A print test (image area: 5%) of 10,000 sheets and 50,000 sheets was performed, and fine line reproducibility was evaluated.

[Evaluation of fine line reproducibility]
The line breaks and line edge sharpness at the time of producing a 60 μm thin line image were determined by observing with a digital microscope VH-6200 (manufactured by Keyence Corporation). The specific evaluation criteria are as follows, and it is acceptable up to ○.
A: The fine line is uniformly filled with toner, and the edge portion is not disturbed.
○: The fine line is uniformly filled with the toner, but slight jaggedness is observed at the edge portion.
X: The fine line is almost uniformly filled with toner, but the jaggedness is noticeable at the edge portion.

  As an application example of the present invention, there is application to an image forming apparatus such as a copying machine or a printer using an electrophotographic system.

  DESCRIPTION OF SYMBOLS 10 Electrostatic charge image developing carrier, 12 core material, 14 organic resin particle, 16 conductive particle, 18 void, 200 image forming apparatus, 400 housing, 401a to 401d electrophotographic photosensitive member, 402a to 402d charging roll, 403 exposure apparatus 404a to 404d Developing device, 405a to 405d Toner cartridge, 406 Drive roll, 407 Tension roll, 408 Backup roll, 409 Intermediate transfer belt, 410a to 410d Primary transfer roll, 411 Tray (transfer medium tray), 412 Transfer roll 413 Secondary transfer roll, 414 Fixing roll, 415a to 415d, 416 Cleaning blade, 500 Transfer medium.

Claims (7)

An electrostatic charge image developing carrier comprising a coating layer formed by adhering at least conductive particles and organic resin particles on a core material;
The coating layer has a gap,
The resin of the organic resin particles is in a molten state under a shear rate of 3.14 rad / sec and a temperature change condition of 2 ° C. per minute at the time of dynamic viscoelasticity measurement, and the loss elastic modulus G ′ The storage elastic modulus G ′ when the ratio tan δ of “to storage elastic modulus G” is minimal is 1.2 × 10 ⁵ Pa or less,
An electrostatic charge image developing carrier, wherein the electrostatic charge image developing carrier has an electric resistance of 10 ¹¹ Ω · cm or less in an electric field of 500 V / cm.   2. The electrostatic charge image developing carrier according to claim 1, wherein the resin of the organic resin particles is a resin polymerized using 50 mol% or more of hexyl methacrylate.   The electrostatic charge image developing carrier according to claim 1, wherein the conductive particles are white conductive powder.   The electrostatic charge image developing carrier coating layer according to any one of claims 1 to 3, wherein the electrostatic charge image developing carrier coating layer is formed by applying a mechanical impact force. Method.   4. A developer for developing an electrostatic image comprising the carrier for developing an electrostatic image according to claim 1 and a toner. A latent image carrier,
Charging means for charging the latent image carrier;
Exposure means for exposing the charged latent image carrier to form an electrostatic latent image on the latent image carrier;
Developing means for developing the electrostatic latent image with the electrostatic charge image developing developer according to claim 5 to form a toner image;
Transfer means for transferring the toner image from the latent image holding member to a transfer target;
At least one selected from the group consisting of cleaning means for removing toner remaining on the surface of the image carrier;
A process cartridge comprising: A latent image forming unit that forms a latent image on the latent image carrier, a developing unit that develops the latent image using a developer for developing an electrostatic image, and a developed toner image via an intermediate transfer member or An image forming apparatus comprising: transfer means for transferring onto a transfer body without intervention; and fixing means for fixing a toner image on the transfer body;
The image forming apparatus according to claim 5, wherein the developer for developing an electrostatic charge image is the developer for developing an electrostatic charge image according to claim 5.