JP2013167727A - Carrier for electrostatic charge image development, electrostatic charge image developer, process cartridge, image forming apparatus, and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier for electrostatic charge image development and an electrostatic charge image developer that further suppress the occurrence of white streaks after a long period of printing under high temperature and high humidity compared to the case not having the present configuration.SOLUTION: A carrier for electrostatic charge image development includes at least a coating resin layer on a magnetic core particle; and the coating resin contains a hydride obtained by hydrogenating a part or all of double bonds in an aromatic petroleum resin structurally containing indene. An electrostatic charge image developer contains the carrier for electrostatic charge image development, and a toner for electrostatic charge image development including external additive particles having the volume average particle diameter of 50 nm or more and 200 nm or less.

Description

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

  Electrophotographic methods for visualizing image information through electrostatic charge images are currently used in various fields. In conventional electrophotography, an electrostatic charge image is formed on a latent image holding member (photosensitive member) or an electrostatic recording member using various means, and electrophotographic particles called toner are attached to the electrostatic charge image. In general, a method for developing and visualizing an electrostatic charge image is used. The developer used here is a two-component developer that imparts an appropriate amount of positive or negative charge to the toner by mutually frictionally charging both toner particles and toner particles, and a toner alone such as a magnetic toner. Are roughly classified into one-component developers used in the above. In particular, two-component developers are widely used for reasons such as ease of design because the carrier itself has functions such as stirring, transport, and charging, and the functions required for the developer can be separated. ing.

  In recent years, there has been a demand for higher image quality of images formed by electrophotographic image forming apparatuses, higher process speed, and long-term stability. Increasingly, the stabilization of the amount of charge and the stabilization of the charge amount depending on the usage environment have been studied. Carriers have been studied to reduce the size and distribution of the particles, and various studies have been made to increase the functionality of the core material composition and the coating resin composition in order to equalize and stabilize the charge amount.

  In order to obtain high image quality, it is desired that the toner is charged as uniformly as possible with a desired charge amount as a characteristic required for the carrier. In order to obtain this characteristic, it is required to keep the mixing property of the carrier and the toner as uniform as possible and to make the characteristic of the carrier surface as uniform as possible. If the mixing is insufficient or the carrier surface is non-uniform, the charge amount may be non-uniform. Further, when the carrier core material is exposed, the charging ability is lowered and the resistance is also lowered, so that uniform charging may not be obtained.

  In response to these problems, the carrier deteriorates during use, that is, changes in charging due to the use environment, carrier charging ability declines due to adhesion of toner and toner external additives during the process, carrier coating resin peeling due to stress, coating Studies have been made on the decrease in charging ability due to wear of the resin.

  For example, in Patent Document 1, the shape factor of the carrier core material is defined, and the coating fat layer contains a resin component obtained by crosslinking a thermoplastic resin component and a guanamine resin to prevent film peeling. In Patent Document 2, It has been proposed that it is possible to improve the spent property and the abrasion resistance of the coating by having a crosslinked coating of N-alkoxyalkylated polyamide and silicone resin. Patent Document 3 proposes a method in which the resin coating layer contains a polymer obtained by copolymerizing an aliphatic hydrocarbon component and an aromatic hydrocarbon component to prevent spent toner on the carrier for a long period of time. .

JP 2006-251354 A Japanese Patent No. 4139285 Japanese Patent Laid-Open No. 11-344839

  An object of the present invention is to provide a carrier for developing an electrostatic image in which generation of white streaks is suppressed after long-term printing under high temperature and high humidity.

  The electrostatic charge image developing carrier, electrostatic charge image developer, process cartridge, image forming apparatus, and image forming method of the present invention have the following characteristics.

  (1) An electrostatic charge image having a coating resin layer on at least a magnetic core particle, and the coating resin includes a hydride obtained by hydrogenating some or all double bonds of an aromatic petroleum resin structurally containing indene. It is a carrier for development.

  (2) The electrostatic charge image developing carrier according to (1), wherein the coating resin includes an alicyclic methacrylate resin or a cyclic olefin resin.

  (3) The electrostatic image developing carrier according to (1) or (2), wherein the content of the hydride is 3% by mass or more and 50% by mass or less with respect to 100% by mass of the coating resin.

  (4) The electrostatic charge image developing carrier according to any one of (1) to (3), wherein resin particles are dispersed in the coating resin.

  (5) An electrostatic charge image developing toner comprising the electrostatic charge image developing carrier according to any one of (1) to (4) above and external additive particles having a volume average particle diameter of 50 nm to 200 nm. And an electrostatic charge image developer.

  (6) A developing unit that stores the electrostatic image developer according to (5) and develops the electrostatic image formed on the surface of the latent image holding body with the electrostatic image developer to form a toner image. And a process cartridge that is detachably attached to the image forming apparatus.

  (7) A latent image holding member, a charging unit for charging the surface of the latent image holding member, an electrostatic charge image forming unit for forming an electrostatic charge image on the surface of the latent image holding member, and the electrostatic charge image. And developing means for forming a toner image by developing with the electrostatic charge image developer, transfer means for transferring the toner image to a recording medium, and fixing means for fixing the toner image to the recording medium. An image forming apparatus.

  (8) A charging step for charging the surface of the latent image holding member, an electrostatic charge image forming step for forming an electrostatic charge image on the surface of the latent image holding member, and the electrostatic charge image according to (5) above. An image forming method comprising: a developing step of developing with a developer to form a toner image; a transferring step of transferring the toner image onto a recording medium; and a fixing step of fixing the toner image on the recording medium.

  According to the first aspect of the present invention, the occurrence of white streaks after long-term printing under high temperature and high humidity is suppressed as compared with the electrostatic charge image developing carrier not having this configuration.

  According to the second aspect of the present invention, the occurrence of white streaks after long-term printing under high temperature and high humidity is further suppressed as compared with the case without this configuration.

  According to the third aspect of the present invention, there is provided an electrostatic charge image developing carrier in which the occurrence of white streaks after long-term printing under high temperature and high humidity is suppressed as compared with the case without this configuration.

  According to the invention which concerns on Claim 4, compared with the case where the resin particle is not disperse | distributed to coating resin, the inhibitory effect of the white stripe generation | occurrence | production after a long-term printing under high temperature and high humidity is large.

  According to the invention which concerns on Claim 5, compared with the case where it does not have this structure, generation | occurrence | production of the white streak after long-term printing under high temperature and high humidity is suppressed.

  According to the invention of claim 6, compared to the case without this configuration, the handling of the electrostatic charge image developer that suppresses the generation of white streaks after long-term printing under high temperature and high humidity is facilitated. The adaptability to the image forming apparatus having the above configuration can be improved.

  According to the invention which concerns on Claim 7, generation | occurrence | production of the white streak after long-term printing under high temperature and high humidity is suppressed compared with the case where this structure is not provided.

  According to the eighth aspect of the present invention, the occurrence of white streaks after long-term printing under high temperature and high humidity is suppressed as compared with the case without this configuration.

1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment. It is a schematic block diagram which shows the image forming apparatus which concerns on 2nd embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

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

<Carrier for developing electrostatic image>
The carrier for developing an electrostatic image according to the present embodiment (hereinafter sometimes simply referred to as “carrier”) includes a magnetic core material particle and an aromatic petroleum resin containing indene in a part or all of the double bonds. And a coating resin containing a hydride obtained by hydrogenation.

  With the increase in printing speed by electrophotography and the diversification of the usage environment, when a developer containing a carrier having a resin coating layer is used over a long period of time in a high-temperature and high-humidity environment, the resin coating layer is scraped and the core is removed. The magnetic material powder is exposed, which may cause deterioration of the printed image. This phenomenon is prominent when used at high temperatures and high humidity. In particular, in printing after continuous use in a high temperature and high humidity environment, the carrier with the core material exposed is developed, and the charging roll, photoconductor and photoconductor cleaning are performed. The member may be damaged, and an image defect that causes the image to fall in a white streak may occur.

  As a result of diligent research, the present inventor has found that in an electrostatic charge image developing carrier having a magnetic core particle and a resin coating layer covering the magnetic core particle, the resin coating has a low water absorption even in a high-temperature and high-humidity environment. By containing an aromatic petroleum resin in which some or all double bonds that can improve the adhesion between the core particles and the core particles are contained, the charging ability fluctuation of the carrier due to temperature and humidity changes is suppressed, It has been found that a stable toner charge amount can be obtained over a long period of time in a high-temperature and high-humidity environment, and a carrier with less image defects such as the occurrence of white streaks due to the exposure of core particles during long-term use can be obtained. .

  The carrier according to the present embodiment includes magnetic core particles and a coating resin containing a hydride obtained by hydrogenating some or all double bonds of an aromatic petroleum resin containing structurally indene. Hereinafter, the configuration of the carrier according to the present embodiment will be described.

  In the present embodiment, the magnetic core particles generally include magnetic metal, magnetic oxide, or resin particles in which magnetic particles are dispersed internally. However, since these are hydrophilic and have the disadvantage that the chargeability is lowered under high humidity, the chargeable environmental fluctuation is large, and since they are high surface energy materials, they are easily contaminated with toner components and maintain the chargeability. There is a problem that the nature is bad. Therefore, the above-mentioned problems relating to charging are improved by coating the carrier surface with a resin having hydrophobicity or low surface energy. On the other hand, if the surface of the core material is coated with an insulating resin at a high coverage, the electrical resistance as a carrier increases, and the reproducibility of a solid image may deteriorate. For this reason, it is necessary to disperse the charge control agent and the conductive material in the coating layer in order to avoid an increase in electric resistance.

  In the resin coating process of coating the resin coating layer on the surface of the magnetic core particles, a typical method is to add a resin and a conductive material to a resin-soluble solvent to form a coating layer forming solution. A dipping method in which particles are immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the magnetic core particles, and a coating layer forming solution in a state where the magnetic core particles are suspended by flowing air The fluidized bed method for spraying, the kneader coater method in which the magnetic core particles and the coating layer forming solution are mixed in the kneader coater, and then the solvent is removed.In this embodiment, the kneader coater method is used. It is desirable.

  The magnetic core particles used in the present embodiment are not particularly limited, but for example, magnetic metals such as iron, steel, nickel and cobalt, magnetic oxides such as ferrite and magnetite, and internal dispersion of magnetic particles Resin particles and the like. In the present embodiment, it is necessary to use a magnetic material, and examples include one in which magnetic powder is used alone as a core material, and one in which magnetic powder is granulated and dispersed in a resin. The volume average particle diameter of the magnetic core particles is preferably 20 μm or more and 100 μm or less. If the volume average particle diameter of the magnetic core particles is less than 20 μm, there is a problem that the toner is easily developed together with the toner when used as a carrier. If the volume average particle diameter exceeds 100 μm, the toner cannot be uniformly charged when used as a carrier. There is a problem that.

  As the coating resin used in the present embodiment, it is essential to contain a hydride obtained by hydrogenating some or all double bonds of an aromatic petroleum resin containing indene. The aromatic petroleum resin used in the present embodiment is a polymer of a C9 fraction called a C9 petroleum resin. The polymerizable monomer used as a raw material is a C9 fraction (generally referred to as naphtha pyrolysis heavy oil) having a boiling point of about 140 ° C. to 280 ° C. at a normal pressure among cracked oil fractions obtained by thermal cracking or catalytic cracking. Specifically, styrene, α-methylstyrene, β-methylstyrene, vinyltoluene, indene, alkylindene, dicyclopentadiene, ethylbenzene, trimethylbenzene, naphthalene and the like are mainly exemplified. Moreover, the hydride applied as a coating resin has a structure of a hydrogenated aromatic petroleum resin in which some or all double bonds are hydrogenated in an aromatic petroleum resin containing indene. .

  A general means can be adopted for the production method of the aromatic petroleum resin. For example, polymerization is performed at a temperature of about −60 ° C. to 60 ° C. using a non-phenolic Friedel-Crafts catalyst of about 0.01% by mass to 5% by mass with respect to 100 parts by mass of C9 fraction (polymerizable monomer). 0.1 parts by mass to 20 parts by mass of a basic substance is added to 100 parts by mass of the obtained polymer oil, and a neutralization reaction is performed at 10 ° C to 100 ° C. As the basic substance, calcium hydroxide, sodium hydroxide, potassium hydroxide, aqueous ammonia solution or the like is used. After neutralization with these basic substances, washing with water is performed as necessary. Thereafter, 0.1 parts by mass to 20 parts by mass of activated clay is further added, and after the clay treatment is performed at 10 ° C. to 100 ° C., the activated clay is separated by filtration, and the polymer oil is distilled to remove unreacted components. Is manufactured by. In addition, when using a molecular weight modifier, the usage-amount is about 0.01 mass%-3 mass% of C9 fraction.

  The component ratio of these polymerizable monomers is not particularly limited. Further, it may be copolymerized with a C5 fraction, specifically, isoprene, piperylene or benzofuran monomer.

  The aromatic petroleum resin of the present invention needs to be partially or fully hydrogenated. Hydrogenation improves the thermal stability and improves the strength when used at high temperatures while ensuring the adhesion of petroleum resins. Further, the reduction of double bonds improves the water absorption and improves the stability at high temperature and high humidity. The hydrogenation method can be obtained by hydrogenation to an arbitrary hydrogenation rate by a general hydrogenation method. Hydrogenation of an aromatic petroleum resin can be measured by proton NMR measurement and confirming a double bond signal.

The hydrogenation rate of the aromatic ring is not particularly limited, but in general, the higher the hydrogenation rate, the better the various stability (heating stability). The hydrogenation reaction is performed by appropriately adjusting the conditions in the presence of a hydrogenation catalyst so that the hydrogenation rate of the aromatic petroleum resin becomes a target level. As a hydrogenation catalyst, various well-known things, such as metals, such as nickel, palladium, platinum, cobalt, rhodium, ruthenium, or metal compounds, such as these oxides and sulfides, can be used. Conditions of the hydrogenation reaction, the hydrogenation pressure is normally 30Kg ^/ cm ² ~300Kg ^/ cm 2 in the range of about, the reaction temperature is in a range of usually 0.99 ° C. to 320 degree ° C.. As the solvent, cyclohexane, n-hexane, n-heptane, decalin and the like can be used.

  The molecular weight of the hydrogenated aromatic petroleum resin used in the embodiment is desirably 300 to 4000 in terms of number average molecular weight. This molecular weight ensures the low water absorption and environmental variability of the aromatic petroleum resin in which some or all of the double bonds are hydrogenated, and is excellent in adhesion to the magnetic core particles and is coated. The hardness of the resin can be kept moderate. If the number average molecular weight of the hydrogenated aromatic petroleum resin is less than 300, the adhesiveness becomes strong, and the carrier fluidity at high temperature becomes poor. On the other hand, when the number average molecular weight of the hydrogenated aromatic petroleum resin exceeds 4000, the adhesion to the core particles cannot be obtained.

  As a method for measuring the molecular weight of the hydrogenated aromatic petroleum resin 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 with an ultrasonic disperser. The coating resin extract from which insoluble matter such as conductive powder is separated by filtration is dried to obtain a coating resin. 20 mg of the recovered coating resin was dissolved in 10 mL of chloroform and filtered, and then measured using two TSK-GEL Multipore HXL-M columns with a GPC system (manufactured by Tosoh Corporation) equipped with an FTIR detector. From the measured chromatogram, the molecular weight was calculated using the absorption peak of the aromatic petroleum resin or hydrogenated aromatic petroleum resin, and the number average molecular weight Mn was taken as the molecular weight.

  As this coating resin, it is desirable to use a hydrogenated aromatic petroleum resin in combination with other resins, rather than using it alone. The mixing ratio of the hydrogenated aromatic petroleum resin is preferably 3% by mass or more and 50% by mass or less, more preferably 5% by mass or more and 30% by mass or less, with respect to 100% by mass of the coating resin. When the mixing ratio of the hydrogenated aromatic petroleum resin is less than 3% by mass with respect to 100% by mass of the coating resin, there is a problem in that the adhesion between the core material and the coating resin cannot be sufficiently increased, and exceeds 50% by mass. There is a problem that the strength of the coating resin layer cannot be maintained. Examples of the resin to be mixed include polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, polyvinyl ketone, polyacrylate, vinyl chloride-vinyl acetate copolymer, styrene. -Acrylic acid copolymer, straight silicone resin composed of organosiloxane bond or modified product thereof, fluorine resin, polyester, polyurethane, polycarbonate, phenol resin, amino resin, melamine resin, benzoguanamine resin, urea resin, amide resin, epoxy resin, etc. However, the present invention is not limited to these examples. In particular, acrylic resins and olefin resins having good compatibility with hydrogenated aromatic petroleum resins are desirable, and it is particularly desirable to use alicyclic methacrylic ester resins and cyclic olefin resins having low hygroscopicity.

  Examples of the charge control agent that may be contained in the resin coating layer according to this embodiment include nigrosine dyes, benzimidazole compounds, quaternary ammonium salt compounds, alkoxylated amines, alkylamides, molybdate chelate pigments, and triphenyl. Any known compound such as a methane compound, a salicylic acid metal salt complex, an azo chromium complex, or copper phthalocyanine may be used. Particularly desirable are quaternary ammonium salt compounds, alkoxylated amines and alkylamides.

  The addition amount of the charge control agent used in the present embodiment is desirably 0.001 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the magnetic core particles. More desirably, it is 0.01 parts by mass or more and 0.5 parts by mass or less. When the addition amount of the charge control agent exceeds 5 parts by mass, the strength of the resin coating layer is lowered, and the carrier may be easily deteriorated due to stress during use. When the addition amount of the charge control agent is less than 0.001 part by mass, not only the function of the charge control agent cannot be fully exerted, but also the dispersibility of the conductive material may not be improved.

  In addition, addition of resin particles is preferable for suppressing charge reduction. The resin particles to be used are not particularly limited, but particles containing nitrogen element are particularly preferable. Of these, urea resins, urethane resins, melamine resins, guanamine resins, and amide resins are preferable because they have high positive chargeability and high resin hardness, and therefore, a decrease in charge amount due to peeling of the resin coating layer is suppressed. The amount of resin particles used is preferably 0.01 parts by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the magnetic core particles. More desirably, it is 0.1 parts by mass or more and 0.5 parts by mass or less. When the addition amount of the resin particles exceeds 5 parts by mass, the strength of the resin coating layer is lowered and the carrier may be easily deteriorated due to stress during use. If the amount of the resin particles added is less than 0.01 part by mass, the function of suppressing the decrease in charge amount may not be sufficiently exhibited.

  In this embodiment, as the conductive material, metals such as gold, silver, copper, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, tin oxide doped with antimony, tin Indium oxide doped with aluminum, zinc oxide doped with aluminum, resin particles coated with metal, carbon black and the like. 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 resin in order to make the carrier volume specific resistance a desired characteristic. More preferred. It is preferable for the content to be 0.01 parts by mass or more because a resistance adjusting effect can be obtained. Further, it is preferable that the content is 10 parts by mass or less because the conductive material does not come off.

  The solvent used for the preparation of the coating layer forming solution is not particularly limited as long as it dissolves the coating resin, and examples thereof include aromatic hydrocarbons such as toluene and xylene, chloroform, and carbon tetrachloride. Although it is possible to use a halide such as, it is preferable to use toluene from the viewpoint of safety.

  The average film thickness of the resin coating layer is usually 0.1 μm or more and 10 μm or less, but is desirably 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 this embodiment is 10 ⁶ Ω · cm or more and 10 ¹⁴ Ω · cm or less at 1000 V corresponding to the upper and lower limits of a normal development contrast potential in order to achieve high image quality. It is desirable that it is 10 ⁸ Ω · cm or more and 10 ¹³ Ω · cm or less. If the volume specific resistance of the carrier is less than 10 ⁶ Ω · cm, the reproducibility of fine lines is poor, and the amount of carrier transferred to the photoconductor (latent image carrier) increases, which may easily damage the photoconductor. is there. On the other hand, if the volume specific resistance of the carrier is larger than 10 ¹⁴ Ω · cm, reproduction of a black solid image or a halftone image may be deteriorated.

  The volume average particle size (hereinafter sometimes simply referred to as “average particle size”) of the carrier according to the present embodiment is desirably 20 μm or more and 100 μm or less. If the volume average particle size of the carrier is less than 20 μm, there is a problem that the toner is easily developed together with the toner, and if it exceeds 100 μm, the toner cannot be uniformly charged.

<Electrostatic image developer>
The electrostatic charge image developer according to the present embodiment (hereinafter sometimes simply referred to as “developer”) includes the electrostatic charge image developing carrier according to the present embodiment and the electrostatic charge image developing toner (hereinafter referred to as “developer”). (Sometimes referred to simply as “toner”). The developer according to this embodiment is prepared by mixing the carrier and toner according to this embodiment at an appropriate blending ratio. The carrier content ((carrier) / (carrier + toner) × 100) is preferably in the range of 85% by mass to 99% by mass, more preferably in the range of 87% by mass to 98% by mass, and still more preferably 89%. The range is from mass% to 97 mass%.

Hereinafter, the toner used for the electrostatic charge image developer according to the exemplary embodiment will be described.
The toner used in this embodiment contains at least a binder resin and a colorant, and if necessary, a release agent and other components. In addition to the so-called toner particles having the above-described configuration, an external additive (hereinafter sometimes simply referred to as “external additive”) is added to the toner used in the exemplary embodiment for various purposes. Is desirable.

  For the toner used in this embodiment, a known binder resin, various colorants, and the like may be used. As the binder resin in the toner used in this embodiment, in addition to the polyester resin, polyolefin resin, copolymer of styrene and acrylic acid or methacrylic acid, polyvinyl chloride, phenol resin, acrylic resin, methacrylic resin, poly Using vinyl acetate, silicone resin, modified polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin, polyether polyol resin, etc. alone Or may be used in combination.

  Examples of the colorant in the toner used in the exemplary embodiment include cyan colorants such as C.I. I. Pigment Blue 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 13, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 17, 23, 60, 65, 73, 83, 180, C.I. I. Vat cyan 1, 3 and 20, etc., bitumen, cobalt blue, alkali blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated products of phthalocyanine blue, fast sky blue, indanthrene blue BC cyan pigment, C.I. I. Cyan dyes such as solvent cyan 79 and 162 may be used.

  Examples of magenta colorants include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90 112, 114, 122, 123, 163, 184, 202, 206, 207, and 209, pigment violet 19 magenta pigments, C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 30, 49, 81, 82, 83, 84, 100, 109, 121, C . I. Disper thread 9, C.I. I. Basic Red 1, 2, 9, 9, 13, 14, 15, 17, 17, 18, 22, 23, 24, 27, 29, 32, 34, the same 35, 36, 37, 38, 39, 40, etc. Magenta dyes, etc., Bengala, Cadmium Red, Lead Tan, Mercury Sulfide, Cadmium, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red, Calcium Salt, lake red D, brilliant carmine 6B, eosin lake, rotamin lake B, alizarin lake, brilliant carmine 3B and the like may be used.

  Examples of yellow colorants include C.I. I. Yellow pigments such as CI Pigment Yellow 2, 3, 3, 15, 16, 17, 97, 180, 185, and 139 may be used.

  Further, in the case of black toner, for example, carbon black, activated carbon, titanium black, magnetic powder, Mn-containing nonmagnetic powder, or the like may be used as the colorant.

  The toner used in the exemplary embodiment may contain a charge control agent, and nigrosine, a quaternary ammonium salt, an organometallic complex, a chelate complex, or the like may be used.

Furthermore, in this embodiment, various resin powders and inorganic compounds may be added as external additives to the surface of the toner particles as a surface modifier. As the resin powder, spherical particles such as PMMA, nylon, melamine, benzoguanamine, and fluorine-based resin can be used. Examples of various known inorganic compounds include SiO ₂ , TiO ₂ , Al ₂ O ₃ , MgO, CuO, ZnO, SnO ₂ , CeO ₂ , Fe ₂ O ₃ , BaO, CaO, K ₂ O, and Na ₂ O. , ZrO ₂ , CaO · SiO ₂ , CaCO ₃ , K ₂ O (TiO ₂ ) n, MgCO ₃ , Al ₂ O ₃ · 2SiO ₂ , BaSO ₄ , MgSO _{4 and the} like, preferably SiO ₂ , Examples thereof include TiO ₂ and Al ₂ O _3, but are not limited to these, and one or more of these may be used in combination. The volume average particle size of the external additive is preferably 0.2 μm or less, and the addition amount of the external additive is in the range of 0.1% by mass to 20% by mass with respect to 100% by mass of the toner particles. Can be used.

  In particular, in the present embodiment, the surface modifier is necessary for obtaining a stable print quality over a long period of time, but causes embedding, deformation, and polishing of the carrier surface. In particular, the volume average particle size is 50 nm or more and 200 nm or less. The effect is large when it is a particle. When additive particles having a particle size in this range are used, the carrier of the present invention has a particularly great effect of suppressing surface burying, deformation and polishing.

  Furthermore, it is desirable that the toner used in this embodiment contains a release agent. Examples of the release agent include ester wax, polyethylene, polypropylene or a copolymer of polyethylene and polypropylene, polyglycerin wax, microcrystalline wax, paraffin wax, carnauba wax, sazol wax, montanic acid ester wax, deoxidized carnauba wax, Unsaturated fatty acids such as palmitic acid, stearic acid, montanic acid, blandic acid, eleostearic acid, valinalic acid, stearic alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, seryl alcohol, melyl alcohol, or even longer chains Saturated alcohols such as long-chain alkyl alcohols having the following alkyl groups; Polyhydric alcohols such as sorbitol; Linoleic acid amide, oleic acid amide, Lauri Fatty acid amides such as acid amides; Saturated fatty acid bisamides such as methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, hexamethylene bis stearic acid amide, ethylene bis oleic acid amide, hexamethylene bis oleic acid Unsaturated fatty acid amides such as amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, N ′ distearyl isophthalic acid amide, etc. Aromatic bisamides; Fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (commonly referred to as metal soap); aliphatic hydrocarbon wax and vinyl such as styrene and acrylic acid Waxes obtained by grafting by using a monomer, behenic acid monoglyceride fatty acids with polyhydric alcohols partial esters of such; methyl ester compounds having hydroxyl groups obtained by and hydrogenated vegetable oils and the like.

  In the present embodiment, the method for producing the toner (toner particles) is not particularly limited, but it is desirable to produce the toner (toner particles) by a wet production method in order to obtain high image quality. As a wet manufacturing method, the polymerizable monomer of the binder resin is emulsion-polymerized, and the formed binder resin dispersion is mixed with a dispersion of a colorant, a release agent, and, if necessary, a charge control agent. An emulsion aggregation method in which toner particles are obtained by agglomeration and heat fusion; a solution of a polymerizable monomer and a colorant, a release agent, and a charge control agent as required in order to obtain a binder resin in an aqueous solvent Suspension polymerization method in which the polymer is suspended and polymerized; a suspension method in which a binder resin, a colorant, a release agent, and a charge control agent, if necessary, are suspended in an aqueous solvent and granulated; etc. Is mentioned. Further, a manufacturing method may be performed in which the toner particles obtained by the above method are used as a core, and resin particles are further adhered and heat-fused to have a core-shell structure. Further, toner particles obtained by a general pulverization classification method may be used.

<Image Forming Apparatus, Image Forming Method, and Process Cartridge>
The image forming apparatus according to the present embodiment includes a latent image holding member, a charging unit that charges the surface of the latent image holding member, an electrostatic charge image forming unit that forms an electrostatic charge image on the surface of the latent image holding member, Developing means for developing an electrostatic charge image with the electrostatic charge image developer according to the present embodiment to form a toner image, transfer means for transferring the toner image to a recording medium, and fixing the toner image on the recording medium Fixing means. The image forming apparatus according to the present embodiment may include a latent image holding member cleaning unit that cleans the surface of the latent image holding member as necessary.

  In this image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that can be attached to and detached from the main body of the image forming apparatus. The process cartridge contains the electrostatic charge image developer according to the present embodiment, and develops the electrostatic charge image formed on the surface of the latent image holding body with the electrostatic charge image developer to form a toner image. And a process cartridge according to the present embodiment that is detachably attached to the image forming apparatus is preferably used.

  A charging process for charging the surface of the latent image holding body, an electrostatic charge image forming process for forming an electrostatic charge image on the surface of the latent image holding body, and the electrostatic charge image according to the present embodiment. A developing step of developing with the electrostatic charge image developer according to the invention to form a toner image, a transfer step of transferring the toner image to a recording medium, and a fixing step of fixing the toner image to the recording medium. The image forming method according to the embodiment is performed.

  Hereinafter, an example of the image forming apparatus according to the present embodiment will be described, but the present invention is not limited thereto.

  FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus according to the first embodiment. The image forming apparatus 301 includes a charging unit 310, an exposure unit 312, an electrophotographic photosensitive member 314 that is a latent image holding member, a developing unit 316, a transfer unit 318, a cleaning unit 320, and a fixing unit 322. .

  In the image forming apparatus 301, around the electrophotographic photosensitive member 314, a charging unit 310 that is a charging unit that charges the surface of the electrophotographic photosensitive member 314 and the charged electrophotographic photosensitive member 314 are exposed according to image information. An exposure unit 312 that is an electrostatic image forming unit that forms an electrostatic image, a developing unit 316 that is a developing unit that develops the electrostatic image with a developer to form a toner image, and the surface of the electrophotographic photoreceptor 314 The transfer unit 318 that is a transfer unit that transfers the toner image formed on the surface of the recording medium 324 and foreign matters such as toner remaining on the surface of the electrophotographic photosensitive member 314 after the transfer are removed to remove the toner image. And a cleaning unit 320 which is a latent image holding member cleaning means for cleaning the surface of the toner image is arranged in this order. A fixing unit 322 that is a fixing unit that fixes the toner image transferred to the recording medium 324 is disposed on the side of the transfer unit 318.

  The operation of the image forming apparatus 301 according to this embodiment will be described. First, the surface of the electrophotographic photosensitive member 314 is charged by the charging unit 310 (charging process). Next, light is applied to the surface of the electrophotographic photosensitive member 314 by the exposure unit 312, and the charged charge in the exposed part is removed, and an electrostatic image is formed according to image information (electrostatic image formation). Process). Thereafter, the electrostatic charge image is developed by the developing unit 316, and a toner image is formed on the surface of the electrophotographic photosensitive member 314 (development process). For example, in the case of a digital electrophotographic copying machine using an organic photoconductor as the electrophotographic photoconductor 314 and using a laser beam as the exposure unit 312, the surface of the electrophotographic photoconductor 314 is negatively charged by the charging unit 310. Then, a digital latent image is formed in a dot shape by the laser beam light, and a toner is applied to a portion irradiated with the laser beam light by the developing unit 316 to be visualized. In this case, a negative bias is applied to the developing unit 316. Next, a recording medium 324 such as paper is superimposed on the toner image at the transfer unit 318, and a charge having a polarity opposite to that of the toner is applied to the recording medium 324 from the back side of the recording medium 324. 324 is transferred (transfer process). The transferred toner image is heated and pressed by a fixing member in the fixing unit 322, and is fused and fixed to the recording medium 324 (fixing step). On the other hand, foreign matters such as toner remaining on the surface of the electrophotographic photosensitive member 314 without being transferred are removed by the cleaning unit 320 (cleaning step). One cycle is completed in a series of processes from charging to cleaning. In FIG. 1, the toner image is directly transferred to the recording medium 324 such as paper by the transfer unit 318, but may be transferred via a transfer body such as an intermediate transfer body.

  Hereinafter, the charging unit, latent image holding member, electrostatic charge image forming unit (exposure unit), developing unit, transfer unit, latent image holding unit cleaning unit, and fixing unit in the image forming apparatus 301 of FIG. 1 will be described.

(Charging means)
As the charging unit 310 serving as a charging unit, for example, a charger such as a corotron as shown in FIG. 1 is used, but a conductive or semiconductive charging roll may be used. A contact charger using a conductive or semiconductive charging roll may apply a direct current to the electrophotographic photosensitive member 314 or may apply an alternating current superimposed thereon. For example, such a charging unit 310 charges the surface of the electrophotographic photosensitive member 314 by generating a discharge in a minute space near the contact portion with the electrophotographic photosensitive member 314. Normally, it is charged to −300V or more and −1000V or less. The conductive or semiconductive charging roll may have a single layer structure or a multiple structure. Further, a mechanism for cleaning the surface of the charging roll may be provided.

(Latent image carrier)
The latent image holding member has a function of forming at least a latent image (electrostatic charge image). As the latent image holding member, an electrophotographic photosensitive member is preferably exemplified. The electrophotographic photoreceptor 314 has a coating film containing an organic photoreceptor or the like on the outer peripheral surface of a cylindrical conductive substrate. The coating film is a substrate in which a subbing layer and a photosensitive layer including a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are formed in this order, if necessary. is there. The order of stacking the charge generation layer and the charge transport layer may be reversed. These are laminated photoconductors in which a charge generation material and a charge transport material are contained in separate layers (charge generation layer, charge transport layer), but both the charge generation material and the charge transport material are the same. It may be a single layer type photoreceptor included in the above layer, and is preferably a laminated type photoreceptor. Further, an intermediate layer may be provided between the undercoat layer and the photosensitive layer. In addition, other types of photosensitive layers such as an amorphous silicon photosensitive film may be used in addition to the organic photoreceptor.

(Static charge image forming means)
The exposure unit 312 that is an electrostatic charge image forming unit (exposure unit) is not particularly limited. For example, a light source such as a semiconductor laser beam, an LED beam, or a liquid crystal shutter beam is provided on the surface of the latent image holding member to obtain a desired image pattern. And optical system equipment that exposes the light.

(Development means)
The developing unit 316 serving as a developing unit has a function of developing a latent image formed on the latent image holding member with a developer containing toner to form a toner image. Such a developing device is not particularly limited as long as it has the above-described function, and may be selected according to the purpose. For example, an electrostatic image developing toner is electrophotographic using a brush, a roller, or the like. A known developing device having a function of adhering to the photoreceptor 314 may be used. The electrophotographic photosensitive member 314 normally uses a DC voltage, but may be used with an AC voltage superimposed thereon.

(Transfer means)
As the transfer unit 318 serving as a transfer unit, for example, a charge having a polarity opposite to that of the toner is applied to the recording medium 324 from the back side of the recording medium 324 as illustrated in FIG. A transfer roll and a transfer roll pressing device using a conductive roll or a semiconductive roll that transfers directly in contact with the recording medium 324 may be used. A direct current may be applied to the transfer roll as a transfer current applied to the latent image holding member, or an alternating current may be applied in a superimposed manner. The transfer roll may be arbitrarily set according to the width of the image area to be charged, the shape of the transfer charger, the opening width, the process speed (circumferential speed), and the like. Further, a single layer foam roll or the like is suitably used as a transfer roll for cost reduction. As a transfer method, a method of directly transferring to a recording medium 324 such as paper or a method of transferring to a recording medium 324 via an intermediate transfer member may be used.

  A known intermediate transfer member may be used as the intermediate transfer member. Materials used for the intermediate transfer member include polycarbonate resin (PC), polyvinylidene fluoride (PVDF), polyalkylene phthalate, PC / polyalkylene terephthalate (PAT) blend material, ethylene tetrafluoroethylene copolymer (ETFE) / PC, ETFE / PAT, blend material of PC / PAT, and the like can be mentioned. From the viewpoint of mechanical strength, an intermediate transfer belt using a thermosetting polyimide resin is desirable.

(Latent image holder cleaning means)
As for the cleaning unit 320 which is a latent image holding member cleaning means, as long as it cleans foreign matter such as residual toner on the latent image holding member, a blade cleaning method, a brush cleaning method, a roll cleaning method, etc. You can choose.

(Fixing means)
The fixing unit 322 as a fixing unit (image fixing device) fixes a toner image transferred to the recording medium 324 by heating, pressing, or heating and pressing, and includes a fixing member.

(recoding media)
Examples of the recording medium 324 to which the toner image is transferred include plain paper, an OHP sheet, and the like used for electrophotographic copying machines, printers, and the like. In order to further improve the smoothness of the image surface after fixing, the surface of the recording medium is also preferably smooth. For example, coated paper with the surface of plain paper coated with resin, art paper for printing, etc. are used. May be.

  Further, in combination with trickle development proposed in Japanese Examined Patent Publication No. 2-21591, stable image formation can be achieved for a long time.

  FIG. 2 is a schematic configuration diagram illustrating a four-tandem color image forming apparatus that is an image forming apparatus according to the second embodiment. The image forming apparatus shown in FIG. 2 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 main body of the image forming apparatus.

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

  Since the first to fourth units 10Y, 10M, 10C, and 10K described above have the same configuration, here, the first image that forms the yellow image disposed on the upstream side in the intermediate transfer belt traveling direction is formed. The unit 10Y will be described as a representative. Note that the second to fourth components are denoted by reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) in the same parts as the first unit 10Y. Description of 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 photosensitive member 1Y, a charging roller 2Y for charging the surface of the photosensitive member 1Y to a predetermined potential, and the charged surface is exposed by a laser beam 3Y based on the color-separated image signal to form an electrostatic charge image. An exposure device (electrostatic image forming means) 3 for forming, a developing device (developing means) 4Y for supplying the charged toner to the electrostatic image and developing the electrostatic image, and transferring the developed toner image onto the intermediate transfer belt 20 A primary transfer roller 5Y (primary transfer unit) that performs the transfer and a photoconductor cleaning device (cleaning unit) 6Y that removes toner remaining on the surface of the photoconductor 1Y after the primary transfer are sequentially arranged.

  The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

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

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

  In the developing device 4Y, for example, 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 charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. .

  From the viewpoint of development efficiency, image graininess, gradation reproducibility, and the like, a bias potential (development bias) in which an AC component is superimposed on a DC component may be applied to the developer holder. Specifically, when the developer holder DC applied voltage Vdc is −300 to −700 V, the developer holder AC voltage peak width Vp-p may be in the range of 0.5 to 2.0 kV. The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

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

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

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

  Thereafter, the recording paper P is fed to the pressure contact portion (nip portion) of the pair of fixing rolls in the fixing device (roll-type fixing means) 28, the toner image is heated, and the color-superposed toner image is melted to record the recording paper. Fixed onto P.

  Examples of the recording medium to which the toner image is transferred include plain paper, OHP sheet, and the like used for electrophotographic copying machines and printers.

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

  The image forming apparatus exemplified above is configured to transfer the toner image onto the recording paper P via the intermediate transfer belt 20, but the present invention is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

  FIG. 3 is a schematic configuration diagram showing an embodiment of a preferred example of a process cartridge containing an electrostatic charge image developer according to this embodiment. The process cartridge 200 includes, together with the developing device 111, a photosensitive member 107, a charging roller 108, a photosensitive member cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure using an attachment rail 116. Combined and integrated. In FIG. 2, reference numeral 300 indicates a recording medium.

  The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus.

  The process cartridge 200 shown in FIG. 3 includes a photosensitive member 107, a charging device 108, a developing device 111, a cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. The devices may be selectively combined. In the process cartridge according to the present embodiment, in addition to the developing device 111, the photosensitive member 107, the charging device 108, the cleaning device (cleaning means) 113, the opening 118 for exposure, and the opening for static elimination exposure. You may provide at least 1 sort (s) selected from the group comprised from 117.

  Next, the toner cartridge will be described. The toner cartridge is detachably attached to the image forming apparatus, and contains at least toner to be supplied to a developing unit provided in the image forming apparatus. The toner cartridge only needs to contain at least toner, and may contain developer, for example, depending on the mechanism of the image forming apparatus.

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

  Hereinafter, although an Example and a comparative example are given and this embodiment is described in detail in detail, this embodiment is not limited to the following examples. Unless otherwise specified, “part” and “%” are based on mass.

[Preparation of hydrogenated petroleum resin 1]
Petroleum resin Petcoal 150 (Tosoh Co., Ltd. styrene / vinyl toluene / indene copolymer resin, Mn = 1200) 100 parts Nickel-diatomaceous earth catalyst 2 parts The above components were charged in an autoclave, hydrogen pressure 200 kg / cm ² , reaction temperature The hydrogenation reaction was performed under the conditions of 270 ° C. and reaction time of 5 hours. After completion of the reaction, the obtained resin was dissolved in 300 parts of cyclohexane, the catalyst was removed by filtration, and the solvent was removed under heating and reduced pressure to obtain hydrogenated petroleum resin 1 (Mn = 1250).

[Preparation of hydrogenated petroleum resin 2]
Hydrogenation in the same manner as the preparation of hydrogenated petroleum resin 1 except that the petroleum resin is changed from Petol 150 to PetroTac 100 (Tosoh styrene / vinyl toluene / indene / isoprene / piperylene copolymer resin, Mn = 1000). Petroleum resin 2 was obtained (Mn = 1050).

[Preparation of coating layer forming solution 1]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyl toluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.) ・ ・ 3 parts: cyclohexyl methacrylate resin ・ 12 parts, carbon ・ ・... 2 parts, Cross-linked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.) ... 1 part A solution obtained by charging the above materials into a container equipped with a stirrer and stirring at 50 ° C for 2 hours Carbon and crosslinked melamine resin particles were stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 1.

[Preparation of coating layer forming solution 2]
A coating layer forming solution 2 was obtained in the same manner as in the preparation of the coating layer forming solution 1 except that the alkone 135 was changed to the hydrogenated petroleum resin 1.

[Preparation of coating layer forming solution 3]
A coating layer forming solution 3 was obtained in the same manner as in the preparation of the coating layer forming solution 1 except that the alkone 135 was changed to the hydrogenated petroleum resin 2.

[Preparation of coating layer forming solution 4]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyltoluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.) ・ ・ 3 parts ・ Cycloolefin resin ・ 12 parts ・ Carbon ・ ・... 2 parts, cross-linked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.) ... 1 part A solution obtained by charging the above materials into a container equipped with a stirrer and stirring at 90 ° C for 2 hours Carbon and crosslinked melamine resin particles were stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 4.

[Preparation of coating layer forming solution 5]
A coating layer forming solution 4 was obtained in the same manner as in the preparation of the coating layer forming solution 1 except that the alkone 135 was changed to the petol 150.

[Preparation of coating layer forming solution 6]
・ Toluene: 85 parts ・ Cyclohexyl methacrylate resin ・ 15 parts ・ Carbon: 2 parts ・ Crosslinked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.) ... 1 part Container with stirrer The above material was added to the solution, and the solution obtained by stirring at 90 ° C. for 2 hours, carbon, and crosslinked melamine resin particles were stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 6.

[Preparation of coating layer forming solution 7]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyltoluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.), 0.5 part, cyclohexyl methacrylate resin, 14.5 parts・ Carbon: 2 parts ・ Crosslinked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.): 1 part The above materials are put in a container equipped with a stirrer and stirred at 50 ° C. for 2 hours. The dissolved solution, carbon, and crosslinked melamine resin particles were stirred and dispersed with a sand mill for 30 minutes to obtain a coating layer forming solution 7.

[Preparation of coating layer forming solution 8]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyltoluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.) ・ 7.5 parts ・ cyclohexyl methacrylate resin ・ 7.5 parts・ Carbon: 2 parts ・ Crosslinked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.): 1 part The above materials are put in a container equipped with a stirrer and stirred at 50 ° C. for 2 hours. The dissolved solution, carbon, and crosslinked melamine resin particles were stirred and dispersed with a sand mill for 30 minutes to obtain a coating layer forming solution 8.

[Preparation of coating layer forming solution 9]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyl toluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.) ・ ・ 9 parts ・ Cyclohexyl methacrylate resin ・ 6 parts ・ Carbon ・ ・... 2 parts, Cross-linked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.) ... 1 part A solution obtained by charging the above materials into a container equipped with a stirrer and stirring at 50 ° C for 2 hours Carbon and crosslinked melamine resin particles were stirred and dispersed in a sand mill for 30 minutes to obtain a coating layer forming solution 9.

[Preparation of coating layer forming solution 10]
・ Toluene: 85 parts ・ Alcon 135 (hydrogenated styrene, vinyltoluene, indene copolymer resin, Mn = 860, manufactured by Arakawa Chemical Industries, Ltd.) ・ 3 parts ・ Methyl methacrylate / styrene copolymer resin ・ 12 parts・ Carbon: 2 parts ・ Crosslinked melamine resin particles (Eposta S: manufactured by Nippon Shokubai Co., Ltd.): 1 part The above materials are put in a container equipped with a stirrer and stirred at 50 ° C. for 2 hours. The dissolved solution, carbon, and crosslinked melamine resin particles were stirred and dispersed with a sand mill for 30 minutes to obtain a coating layer forming solution 10.

<Example 1>
[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) ・ ・ ・ 100 parts ・ Coating layer forming solution 1... 12 parts Ferrite particles (magnetic core material particles) and coating layer forming solution 1 are put into a kneader, heated to 60 ° C., stirred at a temperature of 60 ° C. for 10 minutes, and then reduced in pressure to reduce toluene. Distilled off. The mixture was further heated to 70 ° C. and decompressed to distill off toluene. Carrier 1 was obtained by sieving the resin-coated layer-formed carrier with a mesh having an opening of 75 μm.

(Preparation of developer)
10 parts of externally added toner (volume average particle size 5.5 μm) prepared by the emulsion aggregation method and 100 parts of carrier 1 are stirred for 20 minutes at 40 rpm using a V blender, and sieved using a sieve of 125 μm mesh. And developer 1 was obtained.

[Evaluation of carrier and developer]
Using the above developer 1, Fuji Xerox Copier Docu Center Color 500 modified machine printed 100000 1% printing chart in 35 ° C 85% HR environment, initial (10th), 10000, 50000 Evaluation of image quality (thin line reproducibility) and white streak after printing for 80000 sheets and 100,000 sheets and for 72 hours after printing 100,000 sheets. When halftone image quality degradation is clearly understood by visual inspection x, when it is slightly worrisome by visual inspection, △, when it is not understood at all, ○, white streak is 5 or more, 1 or more and 4 or less is △, no occurrence Was evaluated as ○. The obtained results are shown in Table 1.

  A 5 cm × 5 cm chart perpendicular to the developing direction was output as a 1 on 1 off image at a resolution of 2400 dpi on the upper left, center and lower right of the A4 paper with the above-mentioned modified machine. The grade of the output sample was evaluated from the distance at which the line interval was the narrowest due to toner scattering, etc., with a magnifier with a scale of x100. When the distance decreases due to scattering, and the increase due to thin line thinning is hardly observed, ○, when there is a decrease or increase, △ when the thin line can be confirmed, △, when the thin line distance cannot be determined or missing is observed × As a grade evaluation. The obtained results are shown in Table 1.

The coverage is measured by the following method. As the X-ray electron spectroscopic analyzer, ESCA-9000MX manufactured by NEC Corporation is used, and the carrier is fixed to the sample holder and inserted into the ESCA chamber. The degree of vacuum of the chamber is set to 1 × 10 ⁻⁶ Pa or less, Mg—Kα is used as an excitation source, and the output is set to 200 W. Under the above conditions, the XPS spectra of the magnetic particles and the carrier are measured, and the coverage is calculated from the ratio of the area intensity of the detected Fe peak (2p3 / 2) based on the following formula.
Coverage = F2 / F1 × 100
(F1: Fe area strength of magnetic particles, F2: Fe area strength of carriers).
The obtained results are shown in Table 2 as the rate of change when the initial value is 100.

<Examples 2 to 4>
Carriers 2 to 4 and developers 2 to 4 were prepared in the same manner as in Example 1 except that the coating layer forming solution 1 of Example 1 was changed to coating layer forming solutions 2 to 4, and the examples were evaluated. It was. The obtained results are shown in Tables 1 and 2.

<Examples 5 to 8>
Carriers 5 to 8 and developers 5 to 8 were prepared in the same manner as in Example 1 except that the coating layer forming solution 1 of Example 1 was changed to coating layer forming solutions 7 to 10, and the examples were evaluated. It was. The obtained results are shown in Tables 1 and 2.

<Comparative Examples 1 and 2>
Carriers 5 to 6 and developers 5 to 6 were prepared in the same manner as in Example 1 except that the coating layer forming solution 1 of Example 1 was changed to coating layer forming solutions 5 to 6, and the examples were evaluated. It was. The obtained results are shown in Tables 1 and 2.

  As the results of Examples 1 to 8 show, by using a hydride obtained by hydrogenating some or all double bonds of an aromatic petroleum resin structurally containing indene as a coating resin, It can be seen that a developer that has good fine line reproducibility after use and after standing and is less likely to cause white streak is obtained.

  1Y, 1M, 1C, 1K, 107, 314 photoconductor (electrophotographic photoconductor), 2Y, 2M, 2C, 2K, 108, 310 charging roller (charging unit), 3Y, 3M, 3C, 3K laser beam, 3, 110, 312 Exposure device (exposure unit), 4Y, 4M, 4C, 4K, 111, 316 Development device (development unit), 5Y, 5M, 5C, 5K, 318 Primary transfer roller (transfer unit), 6Y, 6M, 6C, 6K, 113, 320 Photoconductor cleaning device (cleaning unit), 8Y, 8M, 8C, 8K toner cartridge, 10Y, 10M, 10C, 10K unit, 20 intermediate transfer belt, 22 drive roller, 24 support roller, 26 2 Next transfer roller, 28, 115, 322 Fixing device (fixing unit), 30 Intermediate transfer member cleaning device, 112 Transfer device, 116 Mounting Rail, 117 opening for static elimination exposure, 118 opening for exposure, 200 process cartridge, P, 300, 324 recording paper (recording medium).

Claims (8)

  An electrostatic charge characterized by having a coating resin layer on at least the magnetic core particles, and the coating resin includes a hydride obtained by hydrogenating an aromatic petroleum resin structurally containing indene partially or all double bonds. Image development carrier.   The electrostatic charge image developing carrier according to claim 1, wherein the coating resin contains an alicyclic methacrylate resin or a cyclic olefin resin.   3. The electrostatic charge image developing carrier according to claim 1, wherein the content of the hydride is 3% by mass to 50% by mass with respect to 100% by mass of the coating resin.   The electrostatic charge image developing carrier according to claim 1, wherein resin particles are dispersed in the coating resin.   5. The electrostatic charge image developing carrier according to claim 1, and an electrostatic charge image developing toner having external additive particles having a volume average particle diameter of 50 nm to 200 nm. Electrostatic image developer. A developing means for storing the electrostatic charge image developer according to claim 5 and developing the electrostatic charge image formed on the surface of the latent image holding member with the electrostatic charge image developer to form a toner image,
A process cartridge attached to and detached from the image forming apparatus.   6. The latent image holding member, a charging unit that charges the surface of the latent image holding member, an electrostatic charge image forming unit that forms an electrostatic charge image on the surface of the latent image holding member, and the electrostatic charge image according to claim 5. An image forming apparatus comprising: a developing unit that develops a toner image by developing with an electrostatic charge image developer; a transfer unit that transfers the toner image to a recording medium; and a fixing unit that fixes the toner image on the recording medium. .   6. A charging step of charging the surface of the latent image holding member, an electrostatic charge image forming step of forming an electrostatic charge image on the surface of the latent image holding member, and developing the electrostatic charge image with the electrostatic charge image developer according to claim 5. An image forming method comprising: a developing step for forming a toner image; a transfer step for transferring the toner image onto a recording medium; and a fixing step for fixing the toner image on the recording medium.

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