JP4250485B2 - Developer carrier - Google Patents

Description

  The present invention relates to a developer carrier used in a developing device for developing and developing a latent image formed on an image carrier such as an electrophotographic photosensitive member or an electrostatic recording derivative.

  The development method in electrophotography is roughly divided into a method using a two-component developer in which a small amount of toner and a carrier are mixed, and a method using a so-called one-component developer that is used for development alone without using a carrier. There is. In either case, the developer is carried and conveyed by the developer carrying member, and moves to the developing region facing the latent image carrying member.

  As the developer carrier used for the development described above, conventionally, for example, a metal, an alloy thereof, or a compound thereof is molded into a cylindrical shape, and the surface is processed to have a predetermined surface roughness by electrolysis, blasting, file, or the like. Used.

  When such a developer carrier is used in a one-component developer, the developer present in the vicinity of the surface of the developer carrier in the developer layer formed on the surface of the developer carrier by the regulating member has a very high charge. Therefore, the developer is strongly attracted to the surface of the carrier by the mirroring force, and therefore, there is no opportunity for friction between the toner and the carrier, so that the developer cannot have a suitable charge. Under such circumstances, sufficient development and transfer are not performed, resulting in an image with many image density unevenness and character scattering.

  In recent years, it has been desired to fix the developer at a low temperature for energy saving and to reduce the particle size for high-definition image formation. Therefore, the above method is insufficient for such a model. For example, to lower the temperature of the developer, the Tg of the developer tends to be set lower, and low melting point substances such as wax tend to be added more frequently, which is affected by the temperature rise of the main body. The developer is likely to be fused on the developer carrying member, and as a result, a decrease in image density, white stripes, blotches, and the like occur. In addition, Patent Document 1 and Patent Document 2 propose using a toner having a small particle diameter in order to achieve high image quality and high definition. In such a toner having a small particle diameter, the surface area per unit mass is large, so the surface charge tends to be large, and the toner adheres to the developer carrier due to the so-called charge-up phenomenon. The developer supplied to the toner is less likely to be charged, the charge amount of the developer is likely to be non-uniform, and the sleeve ghost is likely to occur on the image, and the solid or halftone image is non-uniform such as a streak-like image or a haze-like image It is easy to become.

  As a method for solving such a phenomenon, in Patent Document 3 and Patent Document 4, a coating layer in which conductive fine powder such as crystalline graphite and carbon is dispersed in a resin is provided on a metal substrate. There has been proposed a method of using a developing sleeve in a developing device. By using this method, it is recognized that the above phenomenon is greatly reduced.

  However, with this method, when a large amount of the above powder is added, the surface of the coating layer has lubricity due to the addition effect of crystalline graphite, so it is sufficient for charge-up and sleeve ghosting. However, the charge imparting ability to the toner becomes insufficient, and it is difficult to obtain a sufficient image density particularly in a high temperature and high humidity environment. In addition, the shape of the coating layer is irregular because of its irregular shape such as scales and needles, and the hardness of the crystalline graphite is low, so that the crystalline graphite itself is worn and detached on the surface of the coating layer. When the durability is advanced, the surface roughness and the surface composition of the coating layer are changed, and the toner is not easily transported and the toner is easily non-uniformly charged.

  On the other hand, when the addition amount is small, the effect of the conductive fine powder such as crystalline graphite and carbon is thin, and there remains a problem that it is insufficient for charge-up and sleeve ghost.

  Patent Document 5 proposes a developing sleeve in which a conductive coating layer in which conductive fine powders such as crystalline graphite and carbon and spherical particles are dispersed in a resin is provided on a metal substrate. In this developing sleeve, the abrasion resistance of the coating layer is improved to some extent, the shape of the surface of the coating layer is made uniform, and the change in surface roughness due to durability is relatively small, so that the toner coating on the sleeve is stabilized. The toner charge can be made uniform, and the image quality without problems in sleeve ghost, image density, image density unevenness, etc. tends to be stabilized. However, this developing sleeve is also insufficient for abrasion resistance, uniform charging to the toner, and stabilization of the charge imparting ability to the toner, and for further long-term durability, the spherical particles and crystallinity of the coating layer are insufficient. Changes in the surface roughness of the coating layer and non-uniformity of the roughness caused by abrasion or falling off of the graphite, resulting in toner contamination of the coating layer and toner fusing, etc. It becomes unstable and causes image defects.

  In Patent Document 6, the spherical particles dispersed in the conductive coating layer are low specific gravity and conductive spherical particles, and thus the conductive spherical particles are uniformly dispersed in the conductive coating layer. A developing sleeve capable of improving the wear resistance of the layer and the shape of the surface of the coating layer to improve the uniform chargeability of the toner, and can suppress toner contamination and toner fusion even when the coating layer is somewhat worn. Proposed. However, this developing sleeve is not perfect in terms of abrasion resistance, uniform charging to the toner and ability to impart toner to the toner, and there is conductive spherical particles on the surface of the coating layer for further long-term durability. Conductive particles such as crystalline graphite are likely to wear or fall off from the parts that do not, and this wear and wear off of the coating layer is promoted to cause toner contamination and toner fusion, resulting in unstable toner charging. It causes image defects. Further, when this developing sleeve is used, the ability to impart high charge to the toner is insufficient, and sufficient toner to obtain a high image density is obtained for a toner that has deteriorated due to repeated frictional charging on the developing sleeve. In some cases, the charge amount cannot be applied.

Japanese Patent Laid-Open No. 1-112253 JP-A-2-284158 Japanese Patent Laid-Open No. 2-105181 JP-A-3-36570 Japanese Patent Laid-Open No. 3-200986 JP-A-8-240981

  The object of the present invention is that the resin coating layer on the surface of the developer carrying member has a uniform surface shape, the wear of the resin coating layer is low even after durable use, and the durability is high. Since there is little variation in image quality and the change in the surface roughness of the coating layer can be suppressed, problems such as image density reduction and image density unevenness caused by these results do not occur, and there is no uniform image density unevenness. It is an object of the present invention to provide a developer carrying member that can stably obtain a high-quality image with high quality.

  Another object of the present invention is to provide a high and uniform charge to the developer on the developer carrying member even with durable use, to prevent overcharge to the developer, and to stabilize the developer charge. It is intended to provide a developer carrying member that is less likely to cause image density reduction, fogging, scattering, and the like resulting from these results, and that can provide stable image quality over a long period of time.

  Further, the object of the present invention is to produce a high-quality image that is uniform, free from uneven density, and has high image density, without causing problems such as density reduction, image density unevenness, sleeve ghost and fog even under different environmental conditions. Is to provide a developer carrying member capable of stably obtaining the developer.

  Furthermore, an object of the present invention is to control toner non-uniform charging and to reduce toner adhesion by reducing toner adhesion on the surface of a developer carrying member, which appears when a toner having a small particle diameter or a spherical toner is used. It is to provide a developer carrying member capable of giving sufficient charge to the toner.

  The object of the present invention is achieved by the following means.

(I) In a developer carrier used in a developing device that develops a latent image formed on a latent image carrier with a developer carried on the developer carrier and visualizes the latent image,
The developer carrier has at least a substrate and a conductive coating layer formed on the substrate surface,
The conductive coating layer contains at least a binder resin, graphitized particles dispersed in the binder resin,
The graphitized particles are obtained by firing particles consisting of a single phase consisting of bulk mesophase pitch or mesocarbon microbeads so that the degree of graphitization P (002) is 0.20 ≦ P (002) ≦ 0.95 . The graphitized particles are further characterized in that the graphitized particles have a volume average particle size of 0.5 to 4.0 μm, and the proportion of particles having a volume average of 10 μm or more is 5.0% or less. Developer carrier.

(II) The developer carrying member according to (I), wherein the relationship between the volume average particle diameter of the graphitized particles and the degree of graphitization P (002) satisfies the following formula.
−0.0464ln (X) + 0.3143 ≦ Y ≦ −0.0464ln (X)
+0.7643
0.5 ≦ X ≦ 4.0
[Wherein, X is the volume average diameter of the graphitized particles (μm), Y is the degree of graphitization of the graphitized particles P (002)]

(III) black-lead content particles bulk mesophase pitch Cima other consists mesocarbon microbeads, particles composed of a single phase, which was obtained by firing at 2,000 to 3,500 ° C. in an inert atmosphere The developer carrying member according to any one of (I) to (II), wherein:

(IV) the conductive coating layer, characterized in that it has a center line average roughness Ra of 0.3 to 2.0 (I) ~ (III) a developer carrying member according.

  According to the present invention, even in continuous copying over a long period of time, the roughness of the surface of the developer carrying member can be kept constant and uniform, and the wear of the resin coating layer is small and high durability makes it uniform. It is possible to provide a developer carrier capable of stably obtaining a high-quality image with high density and no density unevenness.

  Furthermore, according to the present invention, it is possible to impart a high and uniform charge to the developer on the developer carrying member, to prevent the developer from being overcharged and to keep the developer charged stably. Thus, it is possible to provide a developer carrying member that is unlikely to cause image density reduction, fogging, or scattering resulting from these results.

  In addition, according to the present invention, even under different environmental conditions, there are no problems such as density reduction, image density unevenness, sleeve ghosting and fogging, uniform and non-uniform density, and high-quality images with high image density. Can be provided in a stable manner.

  Furthermore, according to the present invention, the toner adhesion to the surface of the developer carrying member, which appears when using a toner having a small particle diameter or a spherical toner, can be reduced, and the toner can be sufficiently charged while controlling uneven charging of the toner. It is possible to provide a developer carrying member capable of giving a sufficient charge.

  As a result of intensive studies on the above problems, the present inventors have added graphitized particles having the above graphitization degree and particle size distribution to the resin coating layer on the surface of the developer carrying member. Since the graphitized particles have a small particle size, few coarse particles, and a small variation in particle size, the inventors have found that the unevenness of the surface of the initial developer carrier and the variation in material composition are small. In addition, when durable use is performed, the carrier and toner on the developer carrier and external additives such as magnetic materials and abrasives contained in the toner, as well as the force from the developer layer thickness regulating member, etc. As a result, the wear of the resin coating layer on the surface of the developer carrying member proceeds, but the graphitized particles used in the present invention are in addition to the above matters, compared with the previously used crystalline graphite having a high degree of graphitization. Because it is relatively hard and hard to wear, and the hardness difference from the binder resin is small, it is less likely to be scraped unevenly even if it is scraped or drops off due to durability. We found an effect that makes it difficult to change. Further, the graphitized particles having the graphitization degree as described above have an effect that toner fusion to the sleeve is difficult to occur due to further lubricity. Further, the present inventors have found that the inclusion of the graphitized particles of the present invention in the resin coating layer has an effect of imparting uniform and high charge to the toner without causing toner contamination or toner charge-up.

  Next, the configuration of the developer carrier used in the present invention will be described in more detail.

The developer carrier of the present invention comprises a substrate and a conductive coating layer (hereinafter sometimes referred to as “resin coating layer”) .

  The base of the developer carrying member includes a cylindrical member, a columnar member, a belt-like member, etc., but in a developing method that does not contact the drum, a rigid cylindrical tube or a solid rod such as metal is preferably used. It is done. As such a substrate, a non-magnetic metal or alloy such as aluminum, stainless steel, or brass, which is molded into a cylindrical shape or a cylindrical shape, and subjected to polishing, grinding, or the like, is preferably used. These substrates are used after being molded or processed with high accuracy in order to improve the uniformity of the image. For example, the straightness in the longitudinal direction is preferably 30 μm or less, or 20 μm or less, more preferably 10 μm or less. The gap between the sleeve and the photosensitive drum is swung, for example, abutting the vertical surface through a uniform spacer, and the sleeve is rotated. In this case, the fluctuation of the gap with the vertical surface is preferably 30 μm or less or 20 μm or less, more preferably 10 μm or less. Aluminum is preferably used because of material cost and ease of processing.

  Further, as the substrate having an elastic layer, a core member and a cylindrical member having a layer structure containing rubber or elastomer such as urethane, EPDM, silicone, etc. are particularly preferable in the case of a developing method in which a developer carrying member is brought into direct contact with a drum. Used.

  Next, a basic configuration of the conductive coating layer in the developer carrier of the present invention will be described. FIG. 1 schematically shows an example, in which graphitized particles 21 having a specific degree of graphitization and particle size used in the present invention are dispersed in a resin layer 24 on an aluminum cylindrical base 26. In this case, the graphitized particles 21 form small irregularities, and also serve to adjust the contact charging opportunity between the toner particle surface and the resin of the coating layer and the graphitized particles 21 and the releasability with the toner.

  In FIG. 2, the conductivity is further increased by adding conductive fine particles 23 in addition to graphitized particles 21 in the binder resin. It does not contribute much. However, not only the conductive fine particles 23 but also a mode in which minute irregularities are formed by another added solid particle is included.

  FIG. 3 shows a model diagram in which spherical particles 25 are further added to the binder resin in order to give relatively large irregularities to the surface of the resin coating layer 24, and the graphitized particles 21 are formed on the surface of the resin coating layer 24. Small irregularities are formed. Such a configuration is advantageous when used in a developing device in which the developer regulating member is elastically pressed against the developer carrying member (via toner). That is, the spherical particles 25 on the surface of the resin coating layer 24 regulate the pressure contact force of the elastic regulating member to control the toner conveyance amount to control the contact opportunity between the toner and the developer carrier, and the graphitized particles 21. Forms small irregularities, and also serves to adjust the contact charging opportunity between the toner particle surface and the resin of the coating layer and the graphitized particles 21 and the releasability with the toner.

  Next, the material which comprises the coating layer of this invention is demonstrated.

  First, the graphitized particles used for the resin coating layer coated on the surface of the substrate constituting the developer carrying member of the present invention will be described.

  The graphitized particles used in the present invention maintain a uniform surface roughness on the coating layer surface of the developer carrier, and at the same time, even when the coating layer surface is worn, there is little change in the surface roughness of the coating layer, In addition, it is added to make it difficult to cause toner contamination and toner fusion. Further, the graphitized particles have an effect of enhancing the charge imparting property to the toner.

In the present invention, the graphitization degree P (002) of the graphitized particles dispersed in the coating layer of the developer carrier satisfies 0.20 ≦ P (002) ≦ 0.95. The degree of graphitization P (002) is said to be the Franklin p-value. By measuring the lattice spacing d (002) obtained from the X-ray diffraction diagram of graphite, d (002) = 3.440-0. 0.086 (1-P ² ). This p value indicates the proportion of the disordered portion of the carbon hexagonal mesh plane stack, and the smaller the p value, the greater the degree of graphitization.

  The graphitized particles are formed in a coating layer on the surface of the developer carrying member in Patent Document 3, Patent Document 4, and the like. The raw material and manufacturing process of the graphitized particles are different from those of artificial graphite obtained by baking at about 2500 to 3000 ° C. and crystalline graphite made of natural graphite. Therefore, although the graphitized particles have a slightly lower degree of graphitization than the previously used crystalline graphite, they have high conductivity and lubricity like the previously used crystalline graphite. Unlike crystalline graphite scaly or needle-like shapes, which are conventionally used, it is characterized by being massive and having relatively high hardness.

  Further, the graphitized particles differ from the low specific gravity and conductive spherical particles described in Patent Document 6 in terms of the lubricity and charge imparting characteristics of the particles themselves due to the difference in raw material and manufacturing method. The low specific gravity and conductive spherical particles described in Patent Document 6 are spherical resins such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile. The particle surface is coated with bulk mesophase pitch by a mechanochemical method, and the coated particles are heat-treated in an oxidizing atmosphere and then baked in an inert atmosphere or vacuum to be carbonized and / or graphitized. . Accordingly, since the spherical resin particles themselves are difficult to graphitize, the inside of the particles is carbonized even if the surface is graphitized, and the degree of graphitization P (002) of the particles themselves is not crystalline. The crystallinity as a particle is small. Therefore, when the conductive spherical particles are dispersed in the resin coating layer, the surface roughness is uniformly imparted and the durability thereof is improved. Is excellent. However, the graphitized particles used in the present invention do not have the function of exerting characteristics such as uniform lubricity, conductivity, and charge imparting properties on the surface of the coating layer.

  That is, when the graphitized particles having the characteristics used in the present invention as described above are used, it becomes possible to disperse uniformly and finely in the resin coating layer, and the uneven shape that the graphitized particles form on the surface of the resin coating layer. Is small and uniform surface roughness, and wear resistance can be imparted to the surface of the coating layer while maintaining excellent lubricity. In addition, since the shape of the graphitized particles themselves is difficult to change, even if the coating resin content in the resin coating layer is scraped off or the particles themselves fall off due to the influence thereof, the particle size is small and coarse. Therefore, the change in the uneven shape on the surface of the coating layer can be suppressed to a small level, and the hardness of the graphitized particles of the present invention is smaller than that of the conventionally used crystalline graphite compared to the binder resin. Therefore, even if it is shaved, it is less likely to be shaved unevenly, so that changes in the surface composition and shape of the resin coating layer can be kept small.

  Further, when the graphitized particles are finely and uniformly dispersed in the resin coating layer, the dispersibility of the rough particles contained in the resin coating is improved in order to improve toner transportability and wear resistance. This improves the effect of preventing toner fusion due to wear resistance and durability of the resin coating layer.

  When the degree of graphitization P (002) of the graphitized particles of the present invention exceeds 0.95, the wear resistance is excellent, but the conductivity and lubricity are lowered and toner charge-up occurs. In some cases, image quality such as sleeve ghosting, fogging, and image density is likely to deteriorate. Further, when an elastic regulation blade is used, blade scratches may occur, and lines and density unevenness are likely to occur in the image. . When P (002) is less than 0.20, the wear resistance of the graphitized particles is deteriorated, so that the wear resistance of the coating layer surface, the mechanical strength of the resin coating layer, and the charge imparting property to the toner are decreased. End up.

  In the present invention, the graphitized particles dispersed in the coating layer of the developer carrier have a volume average particle size of 0.5 to 4.0 μm, and the abundance of particles of 10 μm or more is 5.0% by volume or less. If the volume average particle diameter of the graphitized particles is less than 0.5 μm, the effect of imparting uniform roughness to the surface and the effect of improving the charging performance are small, and the rapid and uniform charging to the developer becomes insufficient, and the coating This is not preferable because toner charge-up, toner contamination, and toner fusion occur due to layer wear, and ghosts and image density are likely to deteriorate. When the volume average particle size exceeds 4.0 μm, the fine unevenness imparting effect is weakened and the surface roughness tends to be uneven, and the wear of the coating layer is likely to vary during durable use. Unevenness, toner contamination and fusion are likely to occur. Further, even if the volume average particle size is 0.5 to 4.0 μm or more, if there are many particles having a size of 10 μm or more, in addition to the above-described phenomenon, when using an elastic blade, blade damage occurs due to durability. In some cases, streaks, density unevenness, and the like are likely to occur in the image, so that coarse particles must be suppressed to 5.0% or less in the volume distribution of the particles.

Furthermore, in the present invention, it is preferable that the relationship between the volume average particle diameter of the graphitized particles present in the resin coating layer and the degree of graphitization P (002) satisfies the following formula.
−0.0464ln (X) + 0.3143 ≦ Y ≦ −0.0464ln (X)
+0.7643
0.5 ≦ X ≦ 4.0
[Wherein, X is the volume average diameter of the graphitized particles (μm), Y is the degree of graphitization of the graphitized particles P (002)]

  In layered minerals such as graphite, it has been recognized that the stacking of layers is irregular due to shear stress during grinding and pulverization, and the distance between layers is changed. Also in the present invention, when controlling the particle size in the pulverization / classification step, etc. in the manufacturing process of the graphitized particles, or when dispersing the graphitized particles in the resin solution, the particle size of the graphitized particles is reduced. As graphing proceeds, the graphitization degree tends to decrease slightly. The above formula takes into account the dispersion particle size dependence on the degree of graphitization of the graphitized particles after dispersion, and in the case of Y <−0.0464ln (X) +0.3143, the wear resistance of the graphitized particles. This tends to decrease the wear resistance of the surface of the coating layer, the mechanical strength of the resin coating layer, and the charge imparting property to the toner. Further, when Y> −0.0464ln (X) +0.7643, the wear resistance is excellent, but the toner may be charged up due to a decrease in conductivity and lubricity. Image quality such as ghosting, fogging, and image density is likely to deteriorate, and when an elastic blade is used, blade scratches may occur, and stripes and density unevenness are likely to occur in the image.

  As a method for obtaining the graphitized particles of the present invention, the following methods are preferable, but are not necessarily limited to these methods.

  As a method for obtaining particularly preferred graphitized particles used in the present invention, graphitization is performed by using optically anisotropic particles such as mesocarbon microbeads and bulk mesophase pitch as raw materials, and particles comprising a single phase. It is preferable to make the graphitized particles have a desired graphitization degree and maintain a lump shape.

  The optical anisotropy of the above-mentioned raw material is caused by the lamination of aromatic molecules, and the ordering is further developed by the graphitization treatment, and graphitized particles having a high degree of graphitization are obtained. When using the above-mentioned bulk mesophase pitch, it is preferable to use a material that softens and melts under heating in order to obtain graphitized particles that are massive and have a high degree of graphitization.

  A typical method for obtaining the above-mentioned bulk mesophase pitch is, for example, a mesophase pitch obtained by extracting β-resin by solvent fractionation from coal tar pitch or the like, and performing hydrogenation and heavy processing. is there. Further, it is a mesophase pitch obtained by pulverizing after the heavy treatment and then removing the solvent-soluble component with benzene or toluene.

  This bulk mesophase pitch preferably has a quinoline soluble content of 95% by mass or more. When the amount less than 95% by mass is used, the inside of the particles is hardly liquid phase carbonized, and solid phase carbonization causes the particles to remain in a crushed state and a spherical shape cannot be obtained.

  Next, as a method of graphitizing using the mesophase pitch, first, the bulk mesophase pitch is finely pulverized to 2 to 25 μm, and this is heat-treated at about 200 to 350 ° C. in air. Oxidize. By this oxidation treatment, only the surface of the bulk mesophase pitch is infusible, and melting and fusion during the graphitizing heat treatment in the next step are prevented. The oxidized bulk mesophase pitch preferably has an oxygen content of 5 to 15% by mass. If it is less than 5% by mass, fusion between particles during heat treatment is severe, which is not preferable. If it exceeds 15% by mass, the inside of the particle is oxidized, and it is difficult to obtain a spherical product in a crushed shape. .

  Next, desired graphitized particles are obtained by heat-treating the oxidized bulk mesophase pitch at about 2000 to 3500 ° C. in an inert atmosphere such as nitrogen or argon.

  A typical method for obtaining mesocarbon microbeads, which are another preferable raw material for obtaining graphitized particles, is, for example, a coal-based heavy oil or a petroleum-based heavy oil at a temperature of 300 to 500 ° C. After heat treatment and polycondensation to produce crude mesocarbon microbeads, the reaction product is subjected to filtration, stationary sedimentation, centrifugation, etc. to separate the mesocarbon microbeads, and then benzene, toluene, xylene It is obtained by washing with a solvent such as

  As a method of graphitizing using the above-mentioned mesocarbon microbeads, firstly, the mesocarbon microbeads after drying are mechanically dispersed with a gentle force that does not cause destruction. This is preferable in order to obtain a uniform particle size.

  The mesocarbon microbeads that have finished the primary dispersion are subjected to primary heat treatment at a temperature of 200 to 1500 ° C. in an inert atmosphere and carbonized. In order to prevent coalescence of the particles after graphitization and obtain a uniform particle size, it is preferable that the carbide after the primary heat treatment is mechanically dispersed with a mild force that does not destroy the carbide.

  The carbide after the secondary dispersion treatment is subjected to secondary heat treatment at about 2000 to 3500 ° C. in an inert atmosphere, whereby desired graphitized particles are obtained.

  Moreover, in order to make the surface shape of the resin coating layer uniform, it is preferable that the graphitized particles obtained from any of the above raw materials have a uniform particle size distribution to some extent by classification, regardless of the production method.

  In any method for producing graphitized particles using any raw material, the firing temperature of the graphitized particles is preferably 2000 to 3500 ° C, more preferably 2300 to 3200 ° C.

  When the firing temperature is less than 2000 ° C., the graphitized particles are insufficiently graphitized, and the conductivity and lubricity may be reduced, resulting in toner charge-up, sleeve ghost, fog, image density. The image quality such as the image quality is liable to deteriorate, and when an elastic blade is used, the blade may be damaged, and the image is likely to have streaks and density unevenness. When the firing temperature exceeds 3500 ° C., the graphitized particles may have a too high degree of graphitization, and as a result, the hardness of the graphitized particles decreases, and the wear resistance of the graphitized particles deteriorates. Abrasion properties, mechanical strength of the resin coating layer, and charge imparting property to the toner are likely to be lowered.

  As the binder resin material of the resin coating layer constituting the developer carrying member of the present invention, generally known resins can be used. For example, thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, fiber resins, acrylic resins, epoxy resins, polyester resins, alkyd resins Thermal or photo-curable resins such as phenol resin, melamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, etc. can be used. Among them, those with releasability such as silicone resin and fluororesin, or excellent mechanical properties such as polyethersulfone, polycarbonate, polyphenylene oxide, polyamide, phenol, polyester, polyurethane, styrene resin, acrylic resin Is more preferable.

  In the present invention, in order to adjust the volume resistance of the resin coating layer to the above value, other conductive fine particles may be dispersed in the resin coating layer in combination with the graphitized particles.

  The conductive fine particles preferably have a volume average particle diameter of 1 μm or less, more preferably 0.01 to 0.8 μm. If the number average particle size of the conductive fine particles dispersed in the resin coating layer in combination with the graphitized particles exceeds 1 μm, it becomes difficult to control the volume resistance of the resin coating layer to a low level, and the charge of the toner is increased. The toner contamination is likely to occur.

  Examples of the conductive fine particles that can be used in the present invention include carbon black such as furnace black, lamp black, thermal black, acetylene black, channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, potassium titanate. Metal oxides such as antimony oxide and indium oxide; metals such as aluminum, copper, silver and nickel; inorganic fillers such as graphite, metal fibers and carbon fibers.

  The graphitized particles used in the present invention have lubricity, but lubricating particles may be further added separately. Examples of the lubricating particles include graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and fatty acid metal salts such as zinc stearate. These lubricating particles preferably have a volume average particle diameter of preferably about 0.5 to 4.0 μm. When the volume average particle diameter of the lubricating particles is less than 0.5 μm, it is not preferable because sufficient lubricity is hardly obtained. When the volume average particle diameter exceeds 4.0 μm, the effect of imparting uniform roughness to the surface is reduced, and the wear of the coating layer tends to vary during durable use, which is not preferable from the viewpoint of wear resistance.

  In the present invention, solid particles for forming irregularities may be added to the resin coating layer in order to maintain developer transportability by forming relatively large irregularities. The solid particles used in the present invention are preferably spherical. Due to the spherical particles, the transportability of the developer becomes uniform compared to the amorphous particles.

  In the present invention, the spherical particles give relatively large irregularities on the surface of the resin coating layer, and the graphitized particles form fine irregularities on the surface of the resin coating layer. This configuration is particularly advantageous when used in a developing device in which the developer regulating member is elastically pressed against the developer via toner. Spherical particles present on the surface of the resin coating layer have the effect of controlling the contact force between the toner and the developer carrier by controlling the toner conveying amount by regulating the pressure contact force of the elastic regulating member, and the graphitized particles are small. By forming irregularities, it also serves to adjust the contact charging opportunity between the toner and the resin of the coating layer and the graphitized particles and the releasability of the toner. Further, since the spherical particles act as a spacer to reduce stress on the surface of the coating layer, the spherical particles have an effect of improving the wear resistance of the coating layer and making it difficult to cause toner fusion.

  The spherical particles used in the present invention have a volume average particle size of 1 to 20 μm, preferably 2 to 15 μm. If the volume average particle diameter of the spherical particles is less than 1 μm, the effect of forming irregularities on the surface of the coating layer is small, and there are cases where the developer transportability is not sufficient. When the transportability is not sufficiently obtained, the developer is not sufficiently charged uniformly, and the resin coating layer is likely to be worn more easily, resulting in toner charge-up, toner contamination, and toner fusion. This is likely to cause ghost deterioration and image density reduction. When the volume average particle diameter exceeds 20 μm, the surface roughness of the coating layer becomes too large, and the developer is excessively conveyed or non-uniform, which makes it difficult to sufficiently charge the toner. In such a case, image streaking, fading, and low density are likely to occur due to non-uniform frictional charging. Further, since the convex portions formed by the spherical particles become too high, the projections of the spherical particles themselves may damage the blades when an elastic blade is used, and density unevenness, streaks, etc. are likely to occur on the image.

Also, the true density of the spherical particles used in the present invention, 3 g / cm ³ or less, preferably 2.7 g / cm ³ or less, it is better and more preferably from 0.9~2.3g / cm ^3. That is, when the true density of the spherical particles exceeds ³ g / cm ³ , the dispersibility of the spherical particles in the coating layer becomes insufficient, so that it becomes difficult to impart uniform roughness to the surface of the coating layer. The uniform charging and the strength of the coating layer are not preferable. Even when the true density of the spherical particles is less than 0.9 g / cm ³ , the dispersibility of the spherical particles in the coating layer becomes insufficient, such being undesirable.

  In the present invention, the spherical shape in the conductive spherical particles means that the ratio of the major axis / minor axis of the particles is about 1.0 to 1.5. In the present invention, the ratio of major axis / minor axis is preferred. It is preferable to use particles having a particle size of 1.0 to 1.2. When the ratio of the major axis / minor axis of the spherical particles exceeds 1.5, the dispersibility of the spherical particles in the resin coating layer is reduced, and the surface shape of the coating layer is likely to be non-uniform, resulting in toner friction. Charge is likely to be non-uniform, and non-uniform shaving of the resin coating layer is likely to occur.

  As the spherical particles used in the present invention, known spherical particles can be used. Examples include spherical resin particles, spherical metal oxide particles, and spherical carbonized particles. As the spherical particles, for example, spherical resin particles obtained by suspension polymerization, dispersion polymerization, or the like are used. Spherical resin particles can obtain a suitable surface roughness with a smaller addition amount, and a uniform surface shape can be easily obtained. Examples of such spherical particles include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, silicone resin particles, phenol resin particles, and polyurethane resins. Resin particles, styrene resin particles, benzoguanamine particles, and the like. The resin particles obtained by the pulverization method may be used after thermally or physically spheroidizing.

In the present invention, it is particularly preferable to use conductive particles among the spherical particles. That is, by imparting conductivity to the particles, it is difficult to accumulate charges on the particle surface due to the conductivity, and it is possible to reduce toner adhesion and improve the chargeability of the toner. In the present invention, the conductivity of the particles is preferably a particle having a volume resistance of 10 ⁶ Ω · cm or less, more preferably 10 ⁻³ to 10 ⁶ Ω · cm. When the volume resistance of such particles exceeds 10 ⁶ Ω · cm, toner contamination and fusion are likely to occur due to the spherical particles exposed on the surface of the coating layer due to abrasion as well as rapid and uniform charging. It becomes hard to be broken. Furthermore, the true density of the particles is more preferably about 3000 kg / m ³ or less. Even when conductive, if the true density of the particles is too high, the amount added to form the same roughness will increase, and the difference in true density from the resin or resin composition will increase. The dispersed state of the particles tends to be non-uniform, and therefore the dispersed state is not uniform even in the formed coating layer. Further, it is more preferable that the particles are spherical, since the contact area with the developer regulating member to be pressed is reduced, so that an increase in sleeve rotation torque due to frictional force and adhesion of toner can be reduced. In particular, when conductive spherical particles as shown below are used, a better effect can be obtained.

  That is, as a particularly preferable method for obtaining conductive spherical particles, for example, low-density and well-conductive spherical carbon particles obtained by carbonizing and / or graphitizing by firing resin-based spherical particles or mesocarbon microbeads are obtained. A method is mentioned. Examples of the resin used for the resin-based spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile.

  In addition, mesocarbon microbeads can be usually produced by washing spherical crystals formed in the process of heating and firing the medium pitch with a large amount of a solvent such as tar, medium oil, and quinoline.

  More preferable methods for obtaining conductive spherical particles include a mechanochemical method on the surface of spherical resin particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile. And a method of obtaining conductive spherical carbon particles by coating the bulk mesophase pitch with, and heat-treating the coated particles in an oxidizing atmosphere, followed by firing in an inert atmosphere or vacuum to carbonize and / or graphitize. It is done. Spherical carbon particles obtained by this method are more preferred because they improve the conductivity because the crystallization of the coating of the spherical carbon particles obtained by the graphitization proceeds.

  In addition, as described above, since the spherical resin particle itself is a material that is difficult to graphitize, the inside of the particle is carbonized even if the surface is graphitized, and the degree of graphitization P (002) of the particle itself is a crystal. Therefore, the crystallinity as a particle is small. Therefore, when the conductive spherical particles are dispersed in the resin coating layer, the surface roughness is uniformly imparted and the durability thereof is improved. Is excellent. However, the graphitized particles used in the present invention do not have the function of exerting characteristics such as uniform lubricity, conductivity, and charge imparting properties on the surface of the coating layer.

  The conductive spherical carbon particles obtained by the above-described method can control the conductivity of the spherical carbon particles obtained by changing the firing conditions in any method, and are preferably used in the present invention. . In addition, the spherical carbon particles obtained by the above-described method may contain conductive metals and / or metal oxides as long as the true density of the conductive spherical particles does not become too high in order to further increase the conductivity. It may be plated.

  Next, the composition ratio of each component constituting the resin coating layer will be described, which is a particularly preferable range in the present invention.

  The content of the graphitized particles contained in the resin coating layer is preferably 2 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the coating resin, and particularly preferable results are given. When the content of the graphitized particles is less than 2 parts by mass, the effect of adding the graphitized particles is small, and it is difficult to form necessary convex portions, and the lubricity effect cannot be exhibited. When the amount exceeds 200 parts by mass, the adhesion between the graphitized particles and the resin coating layer may be too low, and the wear resistance may deteriorate.

  The content in the case where solid particles for forming irregularities are used in combination in the resin coating layer is preferably 2 to 60 parts by mass, more preferably 2 to 40 parts by mass with respect to 100 parts by mass of the coating resin. A particularly favorable result is given in the range. When the content of coarse particles is less than 2 parts by mass, the effect of adding coarse particles is small and the necessary convex portions are difficult to be formed. When the content exceeds 60 parts by mass, the adhesion between the coarse particles and the resin coating layer May become too low and wear resistance may deteriorate.

  The content in the case of containing the lubricating particles in combination with the resin coating layer is preferably 5 to 120 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the coating resin. Give the result. When the content of the lubricating particles exceeds 120 parts by mass, a decrease in the coating strength is observed, and when the content is less than 5 parts by mass, the effect as the lubricating particles tends not to be exhibited when used for a long period of time. .

  When the conductive fine particles are contained in combination in the resin coating layer, the content is preferably 40 parts by mass or less, more preferably 2 to 35 parts by mass with respect to 100 parts by mass of the coating resin. Particularly favorable results are obtained. That is, when the content of the conductive fine particles exceeds 40 parts by mass, a decrease in the film strength is recognized, which is not preferable.

  For these dispersions, generally known dispersion apparatuses such as paint shakers, sand mills, attritors, dyno mills, pearl mills and the like are preferably used. As a method for forming the resin coating layer on the developer carrier, the conductive support and the spray gun are rotated while the conductive support is set up perpendicular to the moving direction of the spray gun and the conductive support is rotated. It is obtained by applying a paint to a substrate by an air spray method using a paint in which the above materials are dispersed while keeping the distance from the nozzle tip constant and raising the spray gun at a constant speed. In general, in the air spray method, a coating layer having a good dispersion can be obtained by stably forming a paint into fine particle droplets. By drying and curing this with a high-temperature dryer, a developer carrier having a resin coating layer on the surface can be obtained.

In the present invention, the volume resistance of the resin coating layer of the developer carrier is preferably 10 ⁴ Ωcm or less, more preferably 10 ³ to 10 ⁻² Ωcm. When the volume resistance of the coating layer exceeds 10 ⁴ Ωcm, the toner is likely to be charged up, and the resin coating layer is likely to be contaminated with toner. The volume resistance of the resin coating layer was measured by forming a coating layer having a thickness of 7 to 20 μm on a PET sheet having a thickness of 100 μm, and attaching a 4-terminal probe to Lorester AP (manufactured by Mitsubishi Yuka Co., Ltd.).

The layer thickness of the resin coating layer having the above-described structure is preferably 25 μm or less, more preferably 20 μm or less, and further preferably 4 to 20 μm in order to obtain a uniform film thickness. It is not limited. Although these layer thicknesses depend on the outer diameter of the substrate and the material used for the resin coating layer, they can be obtained when the adhesion mass is about 4000 to 20000 mg / m ² .

  Next, the developing device, the image forming apparatus, and the process cartridge of the present invention in which the developer carrier of the present invention as described above is incorporated will be described. FIG. 4 is a schematic diagram of a developing device according to an embodiment having the developer carrying member of the present invention. In FIG. 4, an electrostatic latent image holding body that holds an electrostatic latent image formed by a known process, for example, the electrophotographic photosensitive drum 1 is rotated in the direction of arrow B. The developing sleeve 8 as a developer carrying member carries a one-component developer 4 having magnetic toner supplied by a hopper 3 as a developer container and rotates in the direction of arrow A, thereby developing the developing sleeve 8 and the photosensitive sleeve. The developer 4 is transported to the development area D where the drum 1 faces. As shown in FIG. 4, a magnet roller 5 in which a magnet is inscribed is disposed in the developing sleeve 8 in order to magnetically attract and hold the developer 4 on the developing sleeve 8. A developing sleeve 8 used in the developing device of the present invention has a conductive coating layer 7 coated on a metal cylindrical tube 6 as a substrate. In the hopper 3, a stirring blade 10 for stirring the developer 4 is provided. A gap 12 indicates that the developing sleeve 8 and the magnet roller 5 are in a non-contact state.

  The developer 4 obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 1 by friction between the magnetic toners and the conductive coating layer 7 on the developing sleeve 8. In the example of FIG. 4, in order to regulate the layer thickness of the developer 4 conveyed to the development region D, a magnetic regulation blade 2 made of a ferromagnetic metal as a developer layer thickness regulation member is provided from the surface of the development sleeve 8. It is suspended from the hopper 3 so as to face the developing sleeve 8 with a gap width of about 50 to 500 μm. A magnetic force line from the magnetic pole N <b> 1 of the magnet roller 5 concentrates on the magnetic regulation blade 2, whereby a thin layer of the developer 4 is formed on the developing sleeve 8. In the present invention, a non-magnetic blade can be used instead of the magnetic regulating blade 2. Thus, the thickness of the thin layer of the developer 4 formed on the developing sleeve 8 is preferably thinner than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing region D.

  The developer carrying member of the present invention is also applied to a developing device in which the thickness of the developer layer is not less than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing region D, that is, a contact type developing device. The developer carrier of the invention can be applied. In order to avoid complicated description, the following description will be made by taking the non-contact type developing apparatus as described above as an example.

  A developing bias voltage is applied to the developing sleeve 8 by a developing bias power source 9 as a biasing means in order to fly the one-component developer 4 having magnetic toner carried on the developing sleeve 8. When a DC voltage is used as the developing bias voltage, a voltage having an intermediate value between the potential of the image portion of the electrostatic latent image (the region visualized by the developer 4 attached) and the potential of the background portion is set to the developing sleeve 8. It is preferable to apply to. In order to increase the density of the developed image or to improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately reversed in the developing region D. In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having an intermediate value between the potential of the developed image portion and the potential of the background portion is superimposed.

  In the case of so-called regular development, toner that is charged with the opposite polarity to the polarity of the electrostatic latent image is used for visualization by attaching toner to the high potential portion of the electrostatic latent image having a high potential portion and a low potential portion. To do. In the case of so-called reversal development, a toner that is charged to the same polarity as the polarity of the electrostatic latent image is used for visualization by attaching toner to the low potential portion of the electrostatic latent image having a high potential portion and a low potential portion. To do. High potential and low potential are expressions based on absolute values. In any of these cases, the developer 4 is charged at least by friction with the developing sleeve 8.

  FIG. 5 is a schematic configuration diagram showing another embodiment of the developing device of the present invention, and FIG. 6 is a schematic configuration diagram showing still another embodiment of the developing device of the present invention. 5 and 6, the developer layer thickness regulating member for regulating the layer thickness of the developer 4 on the developing sleeve 8 is a material having rubber elasticity such as urethane rubber or silicone rubber, or phosphor bronze. An elastic regulating blade 11 made of an elastic plate made of a material having metal elasticity such as stainless steel is used, and the elastic regulating blade 11 is pressed in the direction opposite to the rotation direction of the developing sleeve 8 in the developing device of FIG. 6 is characterized in that the elastic regulating blade 11 is in pressure contact with the rotation direction of the developing sleeve 8 in the forward direction. In these developing devices, the developer layer thickness regulating member is elastically pressed against the developing sleeve 8 via the developer layer, thereby forming a thin layer of developer on the developing sleeve. A thinner developer layer can be formed on the sleeve 8 than in the case of the example shown in FIG.

  5 and 6 is the same as that of the developing apparatus shown in FIG. 4, and the components having the same reference numerals basically indicate the same members. FIGS. 4 to 6 are merely schematic illustrations of the developing device of the present invention, and it goes without saying that there are various forms in the shape of the developer container (hopper 3), the presence or absence of the stirring blade 10, and the arrangement of the magnetic poles. Yes. Of course, in these apparatuses, when a non-magnetic one-component developer is used as a developer, it can also be used for development using a two-component developer containing a toner and a carrier.

  Next, the toner used in the developing device of the present invention will be described. The toner is a fine powder in which a resin, a release agent, a charge control agent, a colorant, and the like are mainly melt-kneaded, solidified, pulverized, and then classified to obtain a uniform particle size distribution. As the binder resin used for the toner, generally known resins can be used.

  For example, styrene such as styrene, α-methylstyrene, p-chlorostyrene, and substituted homopolymers thereof; styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-ethyl acrylate copolymer, styrene -Butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-dimethylaminoethyl copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer Polymer, styrene-dimethylaminoethyl methacrylate copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-maleic acid Copolymer, styrene-maleic acid ester Copolymers such as styrene copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl acetate, polyethylene, polypropylene polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, phenol resin, aliphatic or fat Cyclic hydrocarbon resins, aromatic petroleum resins, paraffin wax, carnauba wax and the like can be used alone or in combination.

  The toner may contain a pigment. For example, carbon black, nigrosine dye, lamp black, Sudan Black SM, First Yellow G, Benzidine Yellow, Pigment Yellow, India First Orange, Irgadin Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Permanent Bordeaux FRR, Pigment Orange R, Risor Red 2G, Lake Red C, Rhodamine FB, Rhodamine B Lake, Methyl Bio Red B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green B, Phthalocyanine Green, Oil Yellow GG, Pomelo First Yellow CGG, Kaya Set Y963, Kaya Set YG, Pomelo First Orange RR, Oil Scarlet, Orazole Bra Down B, pomelo First Scarlet CG, Oil Pink OP, etc. can be applied.

  In order to use the toner as a magnetic toner, magnetic powder may be contained in the toner. As such magnetic powder, a substance that is magnetized in a magnetic field is used, and there are powders of ferromagnetic metals such as iron, cobalt, and nickel, and alloys and compounds such as magnetite, hematite, and ferrite. The content of the magnetic powder is preferably 15 to 70% by mass with respect to the toner mass.

  Waxes can be incorporated into the toner for the purpose of improving releasability during fixing and improving fixing properties. Examples of such waxes include paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, carnauba wax and derivatives thereof, and the derivatives include oxides, Includes block copolymers with vinyl monomers and graft modified products. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes, mineral waxes, petrolactams, and the like can also be used.

  If necessary, the toner may contain a charge control agent. Charge control agents include negative charge control agents and positive charge control agents. For example, there are the following substances that control the toner to be negatively charged. For example, organometallic complexes and chelate compounds are effective, and there are monoazo metal complexes, acetylacetone metal complexes, aromatic hydroxycarboxylic acids, and aromatic dicarboxylic acid metal complexes. Other examples include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

  Examples of substances for positively charging the toner include the following. Modified products with nigrosine and fatty acid metal salts, etc., quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and oniums such as phosphonium salts which are analogs thereof Salts and lake lake pigments (such as phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide), higher fatty acid metal salts Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guanidi Compounds, imidazole compounds.

  The toner is used by externally adding a powder such as an inorganic fine powder as necessary for the purpose of improving fluidity. Examples of such fine powder include silica fine powder, metal oxides such as alumina, titania, germanium oxide and zirconium oxide; carbides such as silicon carbide and titanium carbide; and inorganic fine powders such as nitrides such as silicon nitride and germanium nitride. The body is used.

  These fine powders can be used after being organically treated with an organosilicon compound, a titanium coupling agent or the like. Examples of organosilicon compounds include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane, benzyldimethylchlorosilane, bromo. Methyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane , Diphenyldiethoxysilane, hexamethyldisiloxane, 1,3-divinyltetramethyldisiloxane 1,3-diphenyltetramethyldisiloxane, and dimethylpolysiloxane having 2 to 12 siloxane units per molecule and containing hydroxyl groups bonded to one Si at each terminal unit .

  Moreover, you may use what processed the untreated fine powder with the nitrogen-containing silane coupling agent. In particular, a positive toner is preferable. Examples of such treating agents include aminopropyltrimethoxysilane, aminopropyltriethoxysilane, dimethylaminopropyltrimethoxysilane, diethylaminopropyltrimethoxysilane, dipropylaminopropyltrimethoxysilane, dibutylaminopropyltrimethoxysilane, Monobutylaminopropyltrimethoxysilane, dioctylaminopropyltrimethoxysilane, dibutylaminopropyldimethoxysilane, dibutylaminopropylmonomethoxysilane, dimethylaminophenyltrimethoxysilane, trimethoxysilyl-γ-propylphenylamine, trimethoxysilyl-γ -Propylbenzylamine, trimethoxysilyl-γ-propylpiperidine, trimethoxysilyl-γ-propylmorpholine, tri There are Tokishishiriru -γ- propyl imidazole.

  Examples of the method for treating the inorganic fine powder with the silane coupling agent include 1) a spray method, 2) an organic solvent method, and 3) an aqueous solution method. In general, the treatment by a spray method is a method in which a pigment is stirred and an aqueous solution or solvent solution of a coupling agent is sprayed thereon, and then water or solvent is removed and dried at about 120 to 130 ° C. In addition, the treatment by the organic solvent method is to dissolve a coupling agent in an organic solvent (alcohol, benzene, halogenated hydrocarbon, etc.) containing a hydrolysis catalyst together with a small amount of water, and soak the pigment in this. Solid-liquid separation is performed by filtration or pressing and dried at about 120 to 130 ° C. In the aqueous solution method, a coupling agent of about 0.5% is hydrolyzed in water or a water-solvent having a constant pH, and the pigment is immersed therein, followed by solid-liquid separation and drying in the same manner. .

It is also possible to use fine powder treated with silicone oil as another organic treatment. Preferred silicone oils are those having a viscosity at 25 ° C. of about 0.5 to 10000 mm ² / sec, preferably 1 to 1000 mm ² / sec. For example, methyl hydrogen silicone oil, dimethyl silicone oil, phenyl methyl silicone Examples thereof include oil, chlorophenylmethyl silicone oil, alkyl-modified silicone oil, fatty acid-modified silicone oil, polyoxyalkylene-modified silicone oil, and fluorine-modified silicone oil.

  Moreover, you may use the silicone oil which has a nitrogen atom in a side chain. In particular, a positive toner is preferable. The treatment with silicone oil can be performed, for example, as follows. If necessary, the pigment is vigorously disturbed while being heated, and the silicone oil or solution thereof is sprayed or vaporized and sprayed, or the pigment is made into a slurry and the silicone oil or its solution is stirred while stirring. It can be easily treated by dropping the solution. These silicone oils are used singly or as a mixture of two or more or in combination or multiple treatments. Moreover, you may use together with the process by a silane coupling agent.

  Such a toner is preferably used after being subjected to a spheroidizing treatment and a surface smoothing treatment by various methods. As such a method, for example, in a device having a stirring blade or a blade and a liner or a casing, the surface is smoothed by a mechanical force when the toner is passed through a minute gap between the blade and the liner. Or a method of spheroidizing the toner, a method of suspending the toner in warm water to spheroidize, a method of exposing the toner to a hot air stream and spheroidizing.

  Further, as a method for producing a spherical toner, there is a method in which a mixture containing a monomer as a toner binder resin as a main component is suspended in water and polymerized to form a toner. As a general method, a polymerizable monomer, a colorant, a polymerization initiator, and if necessary, a crosslinking agent, a charge control agent, a release agent, and other additives are uniformly dissolved or dispersed in a single amount. After forming the body composition, the monomer composition is dispersed in a continuous layer containing a dispersion stabilizer, for example, an aqueous phase to an appropriate particle size using an appropriate stirrer, and further subjected to a polymerization reaction. This is a method for obtaining a developer having a desired particle size.

  The toner can be mixed with a carrier and used as a two-component developer. Carrier materials include, for example, magnetic metals such as iron, nickel, cobalt, alloys thereof, alloys containing rare earths, hematite, magnetite, manganese-zinc ferrite, nickel-zinc ferrite, manganese-magnesium Soft ferrites such as ferrite and lithium ferrite, iron-based oxides such as copper-zinc ferrite, and mixtures thereof, as well as ceramic particles such as glass and silicon carbide, resin powder, and resin powder containing magnetic materials Usually, it is used as a granular material having an average particle size of about 20 to 300 μm.

  Such a carrier may use the above-mentioned granular materials directly as carrier particles, but in order to adjust the triboelectric charge of the toner or prevent toner spent on the carrier, silicone resin, fluororesin, The surface of the particles can be appropriately coated with a coating agent such as an acrylic resin or a phenol resin, and used.

  The physical property measurement method according to the present invention will be described below.

(1) Graphitization degree of graphitized particles p (002)
The degree of graphitization p (002) is determined by measuring the lattice spacing d (002) obtained from the X-ray diffraction spectrum of graphite using a powerful fully automatic X-ray diffractometer “MXP18” system manufactured by Mac Science. (002) = 3.440-0.086 (1-P2).

The lattice interval d (002) is CuKα as an X-ray source, and the CuKβ line is removed by a nickel filter. High-purity silicone was used as a standard substance, and calculation was performed from the peak positions of C (002) and Si (111) diffraction patterns. The main measurement conditions are as follows.
X-ray generator: 18 kW
Goniometer: Horizontal goniometer Monochromator: Working tube voltage: 30.0kV
Tube current: 10.0mA
Measurement method: Continuous method Scan axis: 2θ / θ
Sampling interval: 0.020 deg
Scan speed: 6.000 deg / min
Divergence slit: 0.50deg
Scattering slit: 0.50deg
Receiving slit: 0.30mm

(2) Measurement of Toner and Resin Particle Size 0.1 to 5 ml of a surfactant (alkylbenzene sulfonate) is added to 100 to 150 ml of the electrolyte solution, and 2 to 20 mg of a measurement sample is added thereto. The electrolytic solution in which the sample is suspended is dispersed for 1 to 3 minutes using an ultrasonic disperser, and the volume is set to 0. The particle size distribution of 3 to 40 μm is measured. The number average particle diameter and the weight average particle diameter measured under these conditions are determined by computer processing, and the cumulative ratio of the number average particle diameter less than or equal to the ½ double diameter cumulative distribution is calculated from the number-based particle size distribution. Find the cumulative value below the double diameter cumulative distribution. Similarly, a cumulative ratio equal to or greater than the double diameter cumulative distribution of the weight average particle diameter is calculated from the volume-based particle size distribution, and a cumulative value equal to or greater than the double diameter cumulative distribution is obtained.

(3) Measurement of centerline average roughness (Ra) of developer carrier surface The arithmetic average roughness (Ra) of the developer carrier surface is measured based on the surface roughness of JIS B0601, Surf by Kosaka Laboratory. Using a coder SE-3500, the measurement conditions were as follows: cut-off 0.8 mm, evaluation length 4 mm, feed rate 0.5 mm / s, each of 3 points in the axial direction and 3 points in the circumferential direction = 9 points. Average values were taken.

(4) Measurement of volume resistance of resin coating layer A conductive resin coating layer is formed with a thickness of 7 to 20 μm on a 100 μm-thick PET sheet, and the resistivity meter Loresta AP or Hiresta IP (both manufactured by Mitsubishi Chemical) is used. The volume resistance value was measured using a four-terminal probe. The measurement environment was 20 to 25 ° C. and 50 to 60% RH.

(5) Measurement of particle size of conductive particles The particle size of conductive particles such as graphitized particles is measured using a Coulter LS-230 type particle size distribution meter (manufactured by Coulter, Inc.) of a laser diffraction type particle size distribution meter. As a measuring method, a small amount module is used, and isopropyl alcohol (IPA) is used as a measuring solvent. Wash the measurement system of the particle size distribution analyzer with IPA for about 5 minutes, and execute the background function after washing.

  Next, 1 to 25 mg of a measurement sample is added to 50 ml of IPA. The solution in which the sample is suspended is subjected to dispersion treatment for about 1 to 3 minutes with an ultrasonic disperser to obtain a sample solution. The sample solution is gradually added to the measurement system of the measurement device, and the PIDS on the screen of the device is Measurement is performed by adjusting the sample concentration in the measurement system to be 45 to 55%, and the volume average particle diameter calculated from the volume distribution is obtained.

(6) Measurement of amount of abrasion of resin coating layer The outer diameter before and after the coating layer was formed was measured with a laser length measuring device (manufactured by KEYENCE Corporation: controller LS-5500, sensor head LS5040T). From the measured values before and after that, the average value of 30 points was taken as the scraping amount (μm).

  EXAMPLES Hereinafter, although a manufacture example and an Example demonstrate this invention concretely, this does not limit this invention at all. In addition, all the parts in the following mixing | blending are a mass part.

Example 1
In Examples 1-1 to 6 and Comparative Examples 1-1 to 5, evaluation was performed using a developer carrier having a surface layer structure as shown in FIG. 2 as an example. The basic structure is a structure in which the graphitized particles of the present invention are dispersed in a resin. The graphitized particles form small irregularities, and the contact charging opportunity between the toner particle surface and the resin of the coating layer and the graphitized particles and the toner The mold releasability is adjusted. Further, conductive fine particles are further added for resistance adjustment, but the conductive fine particles themselves do not contribute much to the formation of substantial unevenness.

  In evaluating the developer carrier, a commercially available laser beam printer LaserJet 4100 (manufactured by Hured Packard) was used, and the developer was evaluated using the following one-component developer E-1. The modified LaserJet 4100 used in this experiment is based on the LaserJet 4100, and the sleeve peripheral speed is 1.6 times faster than the drum peripheral speed. The cartridge is modified to increase the capacity of the toner container, and the contact pressure of the elastic blade as the developer regulating member (contact load (gf / cm) in the axial direction of the developer carrying member) The setting was set to 15 gf / cm. Furthermore, mechanical strength reinforcement is added to the main body and the cartridge, respectively. An image signal was sent from an external character generator (CG), and the image was output and output. Each time the amount of toner decreased, a continuous durability test up to 15,000 sheets was performed while replenishing magnetic toner, and evaluation was performed.

[Toner Production Example 1]
The following one-component developers were used.

・ Styrene-acrylic resin 100 parts ・ Magnetite 100 parts ・ 3,5-di-tert-butyl salicylate chromium complex 1 part ・ Low molecular weight polypropylene 5 parts The above materials are kneaded, pulverized and classified by a general dry toner manufacturing method. And a fine powder having a number average particle diameter of 5.8 μm was obtained. To 100 parts of the fine powder, 1.0 part of hydrophobic colloidal silica was externally added to obtain a magnetic toner, and this magnetic toner was designated as a one-component developer E-1.

<Example 1-1>
A developing sleeve was produced by the method described below. First, a coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
・ Resol type phenolic resin (50% methanol solution) 300 parts ・ Graphitized particles A-1 100 parts ・ Carbon black 10 parts ・ Isopropyl alcohol 430 parts As a graphitized particle, β-resin is extracted from coal tar pitch by solvent fractionation. This was subjected to hydrogenation and heavy treatment, and then the solvent-soluble component was removed with toluene to obtain a mesophase pitch. The bulk mesophase pitch powder is finely pulverized, oxidized in air at about 300 ° C., heat-treated at 3000 ° C. in a nitrogen atmosphere, and further classified to obtain graphitized particles A− 1 was used.

  The above material was dispersed in a sand mill using glass beads. As a dispersion method, a sand mill in which 100 parts of graphitized particles A-1 and 200 parts of isopropyl alcohol are added to 200 parts of a resol type phenolic resin solution (containing 50% methanol), and glass beads having a diameter of 1 mm are used as media particles. To obtain paint intermediate I-1. The volume average particle diameter of the graphitized particles in I-1 was 2.22 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0.15%, and the degree of graphitization P (002) was 0.42. Table 1 lists the physical properties of the graphitized particles dispersed in the paint intermediate used in this example. FIG. 7 shows the relationship between the dispersed particle diameter of the graphitized particles used in this example and the degree of graphitization P (002).

  In addition, 30 parts of isopropyl alcohol and 10 parts of carbon black were added to 100 parts of the remaining resol type phenol resin solution (containing 50% methanol), and the mixture was dispersed in a sand mill using glass beads having a diameter of 0.5 mm as media particles. Got. The coating intermediate I-1, the coating intermediate J and 200 parts of isopropyl alcohol were mixed and stirred to obtain a coating liquid P-1.

  A conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 16 mmφ by spraying using the above coating solution, and subsequently heated at 150 ° C. for 30 minutes in a hot air drying oven to cure the conductive coating layer. Developer carrier D-1 was prepared and evaluated. As a result of the image evaluation, as shown in Tables 3 to 5, good developability was able to be obtained from start to finish in any environment.

[Evaluation]
Durability tests were conducted on the evaluation items listed below, and the developer carriers of Examples and Comparative Examples were evaluated. Table 4 shows the evaluation results of durability of image density, durability fog and durability ghost under low temperature and low humidity. Table 5 shows the durability of image density under high temperature and high humidity, durability of character sharpness, evaluation of durability ghost, blade scratches / fusion (streaks), evaluation of density uniformity, and results.

  Durability environment is 15 ° C / 10% RH low temperature / low humidity environment (L / L), 23 ° C / 60% RH normal temperature / normal humidity environment (N / N), and 30 ° C / 85% RH high temperature. / It carried out about three durable environments under high humidity environment (H / H).

<Evaluation method>
(1) Image Density For the image density, a reflection densitometer RD918 (manufactured by Macbeth Co., Ltd.) was used, and the density of the solid black portion at the time of solid printing was measured at five points, and the average value was used as the image density.

(2) Ghost: An image in which a solid white and a solid black part are adjacent is developed at the leading edge of the image (the first rotation of the sleeve), and the density difference between the solid white mark and the solid black mark appearing on the second half or less halftone is mainly used. Visual comparison was made and used as a reference for image density measurement. The evaluation results were displayed with the following indices.
A: No difference in shading is observed.
B: A slight shade difference can be confirmed depending on the viewing angle.
C: The difference in density can be confirmed visually, but the difference in image density is within 0.01.
D: Although the difference in density is not so clear that the edge is not clear, it is practically OK level.
E: The difference in shading is slightly clear and the practical level is the lower limit.
F: The density difference can be clearly confirmed, and can be confirmed as an image density difference. Inferior to practical level.
G: The density difference is considerably large, and the density difference on the reflection densitometer is 0.05 or more.

(3) Abrasion resistance of the coating layer The arithmetic average roughness (Ra) of the surface of the developer carrying member was measured before and after durability. Further, a laser dimension measuring device manufactured by KEYENCE Corp. was used for measuring the amount of abrasion (film abrasion) of the conductive coating layer. Using the controller LS-5500 and the sensor head LS-5040T, the sensor unit was separately fixed to an apparatus equipped with a sleeve fixing jig and a sleeve feeding mechanism, and the average value of the outer diameter of the sleeve was measured. The measurement was divided into 30 with respect to the longitudinal direction of the sleeve and measured at 30 points. Further, after rotating the sleeve by 90 ° in the circumferential direction, measurements were further made at 30 points, a total of 60 points, and the average value was taken. The outer diameter of the sleeve before application of the surface coating layer was measured in advance, the outer diameter after forming the surface coating layer and the outer diameter after durable use were measured, and the difference between them was taken as the coating film thickness and the amount of abrasion.

(4) Contamination resistance of the resin coating layer The surface of the developer carrier after durability was observed at about 200 times using an ultra-deep shape measurement microscope manufactured by KEYENCE, and the degree of toner contamination was determined based on the following criteria. evaluated.
A: Only minor contamination is observed.
B: Some contamination is observed.
C: Contamination is partially observed.
D: Significant contamination is observed.

(5) Image streaks / unevenness In particular, the following criteria were evaluated for linear and belt-like streaks that occur in the half-tone and run in the image traveling direction.
A: Neither image nor sleeve can be confirmed at all.
B: Although it can be confirmed slightly by looking closely, it can hardly be confirmed at first glance.
C: Slightly confirmed with halftone, but no problem with solid black.
D: At halftone, streaks can be confirmed, but with solid black, it can be confirmed slightly.
E: Even with a solid black image, a difference in shading can be confirmed, but it is practical.
F: Contrast difference which is a practical problem in the whole solid black image is conspicuous.
G: An image having a low density and a large amount of streaks.

(6) Blade scratches Blade scratch A: Minor and no effect on the image.
Blade scratch B: Slightly conspicuous, but no effect on image.
Blade scratch C: Conspicuous scratches occur in several places and appear as slight streaks on the image.
Blade scratch D: A lot of very conspicuous scratches are generated and appear as noticeable streaks on the image.

<Example 1-2>
As the graphitized particles, the graphitized particles A-2 in which the classification conditions were changed by the same production method as in A-1 were used, and the other materials and mixing ratios were the same as in Example 1, and the same as in Example 1. The intermediate I-2 was obtained by dispersing by the above method. The volume average particle diameter of the graphitized particles in I-2 was 3.75 μm, the abundance ratio of particles of 10 μm or more in the volume average was 3.53%, and the degree of graphitization P (002) was 0.39. Further, a coating liquid P-2 was produced in the same manner as in Example 1-1, and a developer carrier D-2 was produced by the same method.

<Example 1-3>
As graphitized particles, β-resin was extracted from coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch. . The bulk mesophase pitch powder was pulverized, oxidized in air at about 300 ° C., heat-treated at 2000 ° C. in a nitrogen atmosphere, and further classified, A-3 was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate I-3. The volume average particle diameter of the graphitized particles in I-3 was 2.88 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0.22%, and the degree of graphitization P (002) was 0.94. Further, a coating liquid P-3 was prepared in the same manner as in Example 1-1, and a developer carrier D-3 was prepared by the same method.

<Example 1-4>
As graphitized particles, β-resin was extracted from coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch. . The bulk mesophase pitch powder was pulverized, oxidized in air at about 300 ° C., heat-treated at 3200 ° C. in a nitrogen atmosphere, and further classified, A-4 was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate I-4. The volume average particle diameter of the graphitized particles in I-4 was 3.92 μm, the abundance ratio of particles of 10 μm or more in the volume average was 4.09%, and the degree of graphitization P (002) was 0.23. Further, a coating liquid P-4 was produced in the same manner as in Example 1-1, and a developer carrier D-4 was produced by the same method.

<Example 1-5>
Mesocarbon microbeads obtained by heat treating coal-based heavy oil as graphitized particles are washed and dried, then mechanically dispersed in an atomizer mill, and subjected to primary heat treatment at 1200 ° C. in a nitrogen atmosphere. And carbonized. Subsequently, secondary dispersion was performed with an atomizer mill, and then A-5 obtained by heat treatment at 2800 ° C. in a nitrogen atmosphere and further classification was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate I-5. The volume average particle diameter of the graphitized particles in I-5 was 2.98 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0.61%, and the degree of graphitization P (002) was 0.37. Further, a coating liquid P-5 was produced in the same manner as in Example 1-1, and a developer carrier D-5 was produced by the same method.

<Example 1-6>
Mesocarbon microbeads obtained by heat treating coal-based heavy oil as graphitized particles are washed and dried, then mechanically dispersed in an atomizer mill, and subjected to primary heat treatment at 1200 ° C. in a nitrogen atmosphere. And carbonized. Next, secondary dispersion was performed with an atomizer mill, and then A-6 obtained by heat treatment at 2400 ° C. in a nitrogen atmosphere and further classification was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate I-6. The volume average particle diameter of the graphitized particles in I-6 was 3.85 μm, the abundance ratio of particles of 10 μm or more in the volume average was 2.65%, and the degree of graphitization P (002) was 0.69. Further, a coating liquid P-6 was produced in the same manner as in Example 1-1, and a developer carrier D-6 was produced by the same method.

(Comparative Example 1-1)
As graphitized particles, β-resin was extracted from coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch. . The bulk mesophase pitch powder was finely pulverized, oxidized in air at about 300 ° C., then heat-treated at 1800 ° C. in a nitrogen atmosphere, and further classified, a-1 was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate i-1. The volume average particle diameter of the graphitized particles in i-1 was 3.75 μm, the abundance ratio of particles of 10 μm or more in the volume average was 2.73%, and the degree of graphitization P (002) was 0.99. Further, a coating liquid p-1 was prepared in the same manner as in Example 1-1, and a developer carrier d-1 was prepared by the same method.

(Comparative Example 1-2)
Mesocarbon microbeads obtained by heat treating coal-based heavy oil as graphitized particles are washed and dried, then mechanically dispersed in an atomizer mill, and subjected to primary heat treatment at 1200 ° C. in a nitrogen atmosphere. And carbonized. Next, secondary dispersion was performed with an atomizer mill, and then heat treatment was performed at 2400 ° C. in a nitrogen atmosphere, and a-2 obtained by further classification was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate i-2. The volume average particle diameter of the graphitized particles in i-2 was 8.89 μm, the abundance ratio of particles of 10 μm or more in the volume average was 10.48%, and the degree of graphitization P (002) was 0.72. Further, a coating liquid p-2 was prepared in the same manner as in Example 1-1, and a developer carrier d-2 was prepared by the same method.

(Comparative Example 1-3)
As graphitized particles, a-3 obtained by graphitizing by calcining coke and tar pitch at about 2800 ° C. and further classification was used. Others were the same materials and blending ratio as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate i-3. The volume average particle diameter of graphitized particles in i-3 was 3.88 μm, the abundance ratio of particles of 10 μm or more in the volume average was 4.82%, and the degree of graphitization P (002) was 0.10. Further, a coating liquid p-3 was prepared in the same manner as in Example 1, and a developer carrier d-3 was prepared in the same manner.

(Comparative Example 1-4)
As the graphitized particles, the graphitized particles a-4 in which the classification conditions were changed by the same production method as that of a-3 were used, and the other materials and mixing ratios were the same as in Example 1, and the same as in Example 1. The intermediate i-4 was obtained by dispersing by the method. The volume average particle diameter of the graphitized particles in i-4 was 7.43 μm, the abundance ratio of particles having a volume average of 10 μm or more was 19.94%, and the degree of graphitization P (002) was 0.06. Further, dispersion was performed in the same manner as in Example 1-1 to prepare a coating liquid p-4, and a developer carrier d-4 was prepared by the same method.

(Comparative Example 1-5)
As graphitized particles, a-5 obtained by graphitizing spherical carbon resin particles by firing at 2200 ° C. in a nitrogen atmosphere and further classifying them was used. The other materials and mixing ratios were the same as in Example 1, and dispersion was performed in the same manner as in Example 1 to obtain Intermediate i-5. The volume average particle diameter of the graphitized particles in i-9 was 3.87 μm, the abundance ratio of particles of 10 μm or more in the volume average was 4.56%, and the graphitization degree P (002) was not measurable. Further, dispersion was performed in the same manner as in Example 1-1 to prepare a coating liquid p-5, and a developer carrier d-5 was prepared in the same manner.

Example 2
In Examples 2-1 to 5 and Comparative Examples 2-1 to 4, evaluation was performed using a developer carrier having a surface layer structure as shown in FIG. As a basic configuration, in addition to graphitized particles, spherical particles are further added to the binder resin in order to give relatively large irregularities to the surface of the resin coating layer. The spherical particles on the surface of the resin coating layer regulate the pressure contact force of the elastic regulating member and control the toner conveyance amount to control the contact opportunity between the toner and the developer carrying member, and the graphitized particles are the same as in Example 1. Small irregularities are formed to adjust the contact charging opportunity between the toner particle surface and the resin and graphitized particles of the coating layer and the releasability from the toner.

  In evaluating the developer carrier, a commercially available laser beam printer LaserJet 4100 (manufactured by Hured Packard) was used, and the developer was evaluated using the one-component developer E-1. The LaserJet 4100 remodeling machine used in Example 2 is based on the LaserJet 4100 and is a modification of the A4 vertical feed 25-sheet machine equivalent to 35 sheets, with a process speed of 151 mm / sec. To 245 mm / sec. The sleeve peripheral speed was 1.5 times the drum peripheral speed. Furthermore, in order to increase the capacity of the toner container and prevent unevenness of the regulation of the developer due to the increase in speed, the regulating member is reinforced with a metal plate to increase the blade pressure contact force. Further, mechanical strength reinforcement is added to the main body and the cartridge, respectively. An image signal was sent from an external character generator (CG), and the image was output and output. Each time a residual toner check on the cartridge was displayed, a continuous durability test of up to 20,000 sheets was performed while replenishing magnetic toner, and evaluation was performed.

<Example 2-1>
A developing sleeve was produced by the method described below. First, a coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resole type phenolic resin (50% methanol solution) 300 parts Graphitized particles A-1 100 parts Carbon black 10 parts Conductive spherical particles C-1 30 parts Isopropyl alcohol 500 parts Example 2 compared to Example 1 In this example, conductive spherical particles were added for the purpose of further improving the durability of the resin coating layer and further stabilizing the toner transportability.

As the conductive spherical particles, 14 parts of a coal-based bulk mesophase pitch powder having a number average particle diameter of 2 μm or less using 100 parts of spherical phenol resin particles having a volume average particle diameter of 5.2 μm and a lycaic machine (automatic mortar, manufactured by Ishikawa Factory). Sphere-conductive carbon having a volume average particle diameter of 6.9 μm obtained by subjecting to a uniform coating, heat stabilization treatment at 280 ° C. in air, and graphitizing by firing at 2000 ° C. in a nitrogen atmosphere and further classification. Particles (spherical particles C-1) were used. The true density of the spherical particles C-1 was 1.48 g / cm ³ , the volume resistance was 8.5 × 10 ⁻² Ω · cm, and the ratio of major axis / minor axis of the spherical particles was 1.07.

  The above material was dispersed in a sand mill using glass beads. Conductive spherical particles C-1 are added to the coating material intermediate J used in Example 1, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. To this solution, the intermediate I-1 used in Example 1-1 and the remaining isopropyl alcohol were added and stirred to obtain a coating liquid P-1.

  Using the above coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 16 mmφ by the spray method in the same manner as in Example 1, followed by heating in a hot air drying furnace at 150 ° C. for 30 minutes to make the conductive The coating layer was cured to produce developer carrier D-7. Using the developer carrier of D-7, a durability evaluation test was conducted in the same manner as in Example 1. Evaluation items were the same as those in Example 1.

  As a result of the image evaluation, as shown in Table 4, good developability was obtained from beginning to end under any environment.

<Example 2-2>
As the graphitized particles, the graphitized particles A-2 (intermediate I-2) used in Example 1-2 were used, and the other materials and mixing ratios were the same as those in Example 2-1. A coating liquid P-8 was produced in the same manner as in Example 2-1, and a developer carrier D-8 was produced.

<Example 2-3>
As the graphitized particles, the graphitized particles A-4 (intermediate I-4) used in Example 1-4 were used, and the other materials and mixing ratios were the same as those in Example 2-1. A coating liquid P-9 was produced in the same manner as in Example 2-1, and a developer carrier D-9 was produced.

<Example 2-4>
As the graphitized particles, the graphitized particles A-6 (intermediate I-6) used in Example 1-6 were used, and the other materials and blending ratios were the same as those in Example 2-1. A coating liquid P-10 was produced in the same manner as in Example 2-1, and a developer carrier D-10 was produced.

<Example 2-5>
As the graphitized particles, the graphitized particles A-7 in which the classification conditions were changed by the same production method as in A-1 were used, and the other materials and mixing ratios were the same as in Example 2, and the same as in Example 2. Intermediate I-7 was obtained by dispersing according to the above method. The volume average particle diameter of the graphitized particles in I-3 was 1.29 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0%, and the degree of graphitization P (002) was 0.49. Further, dispersion was performed in the same manner as in Example 1 to prepare a coating liquid P-11, and a developer carrier D-11 was prepared in the same manner.

(Comparative Example 2-1)
As the graphitized particles, the graphitized particles a-1 (intermediate i-1) used in Comparative Example 1-1 were used, and the other materials and mixing ratios were the same as those in Example 2-1. A coating liquid p-6 was produced in the same manner as in Example 2-1, and a developer carrier d-6 was produced.

(Comparative Example 2-2)
As the graphitized particles, the graphitized particles a-3 (intermediate i-3) used in Comparative Example 1-3 were used, and the other materials and mixing ratios were the same as those in Example 2-1. A coating liquid p-7 was produced in the same manner as in Example 2-1, and a developer carrying member d-7 was produced.

(Comparative Example 2-3)
As the graphitized particles, the graphitized particles a-4 (intermediate i-4) used in Comparative Example 1-4 were used, and the other materials and mixing ratios were the same as those in Example 2-1. A coating liquid p-8 was produced in the same manner as in Example 2-1, and a developer carrying member d-8 was produced.

(Comparative Example 2-4)
As graphitized particles, β-resin was extracted from coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch. . The bulk mesophase pitch powder was finely pulverized, oxidized in air at about 300 ° C., then heat-treated at 3500 ° C. in a nitrogen atmosphere, and further classified, a-6 was used. The other materials and mixing ratios were the same as in Example 2, and dispersion was performed in the same manner as in Example 2 to obtain Intermediate i-6. The volume average particle diameter of the graphitized particles in i-6 was 1.94 μm, the abundance ratio of particles having a volume average of 10 μm or more was 0.06%, and the degree of graphitization P (002) was 0.16. Further, dispersion was carried out in the same manner as in Example 1 to prepare a coating liquid p-9, and a developer carrier d-9 was prepared by the same method.

Example 3
In Examples 3-1 to 3-1 and Comparative Examples 3-1 to 3-3, a magnetic regulating blade made of a ferromagnetic metal was used as a developer layer thickness regulating member as shown in FIG. In evaluating the developer carrier, a Canon copier IR6000 modified from 60 sheets to 70 sheets was used, and the developer was evaluated using the one-component developer E-2. It was.

[Toner Production Example 2]
The following toner was used.

・ Styrene-acrylic resin: 100 parts ・ Magnetite: 90 parts ・ Negative charge control agent (azo-based iron complex): 2 parts ・ Hydrocarbon wax: 3 parts Melt-kneading dispersion was performed with an extruder. After cooling the kneaded product, it was finely pulverized by a pulverizer using a jet stream, and further classified using an air stream classifier to obtain a fine powder having a number average particle size of 6.4 μm. Next, hydrophobic colloidal silica was externally added and mixed with 100 parts of the classified product using a 1.0 part Henschel mixer to obtain toner E-2 of the present invention.

<Example 3-1>
A developing sleeve was produced by the method described below. First, a coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenol resin (50% methanol solution) 600 parts Graphitized particles A-1 90 parts Carbon black 10 parts Charge control particles B-1 30 parts Conductive spherical particles C-1 20 parts Isopropyl alcohol 300 parts The quaternary ammonium salt of the following formula was used as the charge controllable particle B-1.

  The above material was dispersed in a sand mill using glass beads. As a dispersion method, the conductive spherical particles C-1, carbon black, charge control particles B-1, and conductive spherical particles C-1 were mixed with 400 parts of a resol type phenol resin solution (containing 50% methanol) and isopropyl alcohol. 100 parts are added to the added solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. Intermediate I-1 used in Example 1 was added to this solution and stirred to obtain a coating liquid P-12.

  Using the above coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 24.5 mmφ by spraying, followed by heating at 150 ° C. for 30 minutes in a hot air drying oven to cure the conductive coating layer. Thus, developer carrier D-12 was produced. A magnet was attached to the developer carrying member, and a stainless steel flange was fitted, so that it could be attached to the developing device of a Canon copier IR6000 modified machine.

  While supplying magnetic toner E-2, continuous durability up to 500,000 sheets was performed and evaluated. Evaluation was based on comprehensive image evaluation and durability of the coating layer. Environment is 24 ° C / 10% normal temperature low humidity (N / L) environment, 24 ° C / 55% normal temperature normal humidity (N / N) environment, 30 ° C / 80% high temperature high humidity (H / H) environment I went. The results are shown in Table 5. Good results were obtained for both image and durability.

[Evaluation]
(1) Image density The density of a solid black image was measured with a reflection densitometer RD918 (manufactured by Macbeth), and an average value of five points was taken as the image density.

(2) Fog and reversal fog Measure the reflectance of the solid white image, and further measure the reflectance of the unused transfer paper (the worst value of the reflectance of the solid white image-the highest reflectance of the unused transfer paper. Value) was the fog density. The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku). However, when the measured value is judged visually, 1.5 or less is a level that can hardly be visually confirmed, about 2.0 to 3.0 is a level that can be confirmed by looking closely, and if it exceeds 4.0, fogging appears at a glance. It is a level that can be confirmed.

(3) Character scattering Using a character chart with an image ratio of about 6.0%, the characters on the obtained image were magnified about 100 times with an optical microscope, the degree of scattering was observed, and the evaluation results were ranked A to E. Indicated by indicators.

(4) Image streaks and unevenness Solid black images and halftone (HT) images were developed, and streaks and unevenness were visually observed in the respective images, and the evaluation results were indicated by A to E rank indices.

(5) Resistant resistance of resin coating layer The surface of the developer carrier after durability was observed at about 200 times using an ultra-deep shape measuring microscope manufactured by KEYENCE, and the degree of toner contamination was determined based on the following criteria. evaluated.
A: Only minor contamination is observed.
B: Some contamination is observed.
C: Contamination is partially observed.
D: Significant contamination is observed.

(6) Abrasion resistance of the coating layer The arithmetic average roughness (Ra) of the surface of the developer carrier and the amount of abrasion (film abrasion) of the conductive coating layer were measured before and after durability.

<Example 3-2>
As graphitized particles, graphitized particles A-8 in which classification conditions were changed by the same production method as A-4 were used, and the other materials and blending ratios were the same as those in Example 3-1. Dispersion of the coating intermediate was performed in the same manner as in Example 1-1 to obtain Intermediate I-8. The volume average particle diameter of the graphitized particles in I-8 was 1.47 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0%, and the degree of graphitization P (002) was 0.75. Further, a coating liquid P-13 was produced in the same manner as in Example 3-1, and a developer carrier D-13 was produced by the same method. Using the developer carrier of D-13, a durability evaluation test was conducted in the same manner as in Example 3-1.

<Example 3-3>
Mesocarbon microbeads obtained by heat treating coal-based heavy oil as graphitized particles are washed and dried, then mechanically dispersed in an atomizer mill, and subjected to primary heat treatment at 1200 ° C. in a nitrogen atmosphere. And carbonized. Next, secondary dispersion was performed with an atomizer mill, and then heat treatment was performed at 3200 ° C. in a nitrogen atmosphere, and further classified, A-10 obtained was used.

  Others were the same materials and blending ratio as in Example 3-1, and the dispersion of the coating intermediate was performed in the same manner as in Example 1-1 to obtain Intermediate I-9. The volume average particle diameter of the graphitized particles in I-9 was 1.38 μm, the abundance ratio of particles of 10 μm or more in the volume average was 0%, and the degree of graphitization P (002) was 0.33. Further, a coating liquid P-14 was produced in the same manner as in Example 3-1, a developer carrier D-14 was produced in the same manner, and a durability evaluation test was performed.

(Comparative Example 3-1)
As the graphitized particles, the graphitized particles a-1 (intermediate i-1) used in Comparative Example 1-1 were used, and the other materials and mixing ratios were the same as those in Example 3-1. A coating liquid p-10 was produced in the same manner as in Example 3-1, a developer carrier d-10 was produced, and a durability evaluation test was performed.

(Comparative Example 3-2)
As the graphitized particles, the graphitized particles a-4 (intermediate i-4) used in Comparative Example 1-4 were used, and the other materials and mixing ratios were the same as those in Example 3-1. A coating liquid p-11 was produced in the same manner as in Example 3-1, a developer carrier d-11 was produced, and a durability evaluation test was performed.

(Comparative Example 3-3)
As graphitized particles, β-resin was extracted from coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch. . The bulk mesophase pitch powder was finely pulverized, oxidized in air at about 300 ° C., then heat-treated at 3000 ° C. in a nitrogen atmosphere, and further classified, a-7 was used. The other materials and mixing ratios were the same as in Example 1-1, and dispersion was performed in the same manner as in Example 1-1 to obtain Intermediate i-7. The volume average particle diameter of the graphitized particles in i-7 was 6.82 μm, the abundance ratio of particles of 10 μm or more in the volume average was 9.77%, and the degree of graphitization P (002) was 0.32. Further, a coating liquid p-12 was produced in the same manner as in Example 3-1, a developer carrier d-12 was produced, and a durability evaluation test was performed.

FIG. 3 is a schematic diagram illustrating an example of a configuration of a developer carrier surface layer of the present invention. FIG. 3 is a schematic diagram illustrating an example of a configuration of a developer carrier surface layer of the present invention. FIG. 3 is a schematic diagram illustrating an example of a configuration of a developer carrier surface layer of the present invention. It is an example of the schematic diagram of the image development apparatus used for this invention. It is an example of the schematic diagram of the image development apparatus used for this invention. It is an example of the schematic diagram of the image development apparatus used for this invention. The relationship between the dispersion particle diameter of the graphitized particle used for the Example of this invention and the graphitization degree P (002) is shown.

Explanation of symbols

1: Electrophotographic photosensitive drum 2, 11: Developer layer thickness regulating member 3: Hopper (toner container)
4: Magnetic toner 5: Magnet 6: Metal cylindrical tube 7: Resin coating layer 8: Development sleeve 9: Power supply 10: Toner stirring blade 21: Graphitized particles 23: Conductive fine particles 24: Resin coating layer 25: Spherical particles 26 : Cylindrical substrate

Claims (4)

In the developer carrier used in the developing device that develops the latent image formed on the latent image carrier with the developer carried on the developer carrier and visualizes the latent image,
The developer carrier has at least a substrate and a conductive coating layer formed on the substrate surface,
The conductive coating layer contains at least a binder resin, graphitized particles dispersed in the binder resin,
The graphitized particles are obtained by firing particles consisting of a single phase consisting of bulk mesophase pitch or mesocarbon microbeads so that the degree of graphitization P (002) is 0.20 ≦ P (002) ≦ 0.95 . The graphitized particles are further characterized in that the graphitized particles have a volume average particle size of 0.5 to 4.0 μm, and the proportion of particles having a volume average of 10 μm or more is 5.0% or less. Developer carrier. The developer carrier according to claim 1, wherein the relationship between the volume average particle diameter of the graphitized particles and the degree of graphitization P (002) satisfies the following formula.
−0.0464ln (X) + 0.3143 ≦ Y ≦ −0.0464ln (X)
+0.7643
0.5 ≦ X ≦ 4.0
[Wherein, X is the volume average diameter of the graphitized particles (μm), Y is the degree of graphitization of the graphitized particles P (002)] The graphitized particles are obtained by firing particles composed of a single phase composed of bulk mesophase pitch or mesocarbon microbeads at 2000 to 3500 ° C. in an inert atmosphere. The developer carrying member according to claim 1 . Conductive coating layer, the developer carrying member according to any one of claims 1 to 3, characterized in that it has a center line average roughness Ra of 0.3 to 2.0.

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