JP2006276714A - Development method and developer carrier used for the development method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a development method achieving stable charging ability, even under a high humidity or low humidity environment, free of problems, such as decrease in density, fog or sleeve ghost for a long time, and stably giving an image which is uniform and free of density unevenness, has high image density and high definition, and to provide a developer carrier used for the development method. <P>SOLUTION: The developer carrier has at least a conductive resin-coating layer on a substrate surface, where the average A of universal hardness HU of the surface of the conductive resin-coating layer and its standard deviation are 300 N/mm<SP>2</SP>to 800 N/mm<SP>2</SP>and less than 30 N/mm<SP>2</SP>, respectively. The developer comprises toner particles containing at least a binder resin and iron oxide, and toner particles having such a structure that 70 number% or higher of the iron oxide contained in each individual toner particle is present from the surface of the toner particle to a depth of 0.2 time as the circle-equivalent diameter C of its projected area are contained with 40 to 95 number% of the toner. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developing method for visualizing a latent image formed on an electrostatic latent image carrier in a recording method using electrophotography, electrostatic recording, magnetic recording, toner jet recording, or the like. And a developer carrying member used in the developing method.

  Electrophotography generally uses a photoconductive substance, forms an electrostatic latent image on an electrostatic latent image carrier (photoconductor) by various means, and then converts the electrostatic latent image into a developer ( The toner image is visualized with a toner, and if necessary, the toner image is transferred onto a transfer material such as paper, and then fixed by heating, pressure, solvent vapor or the like to obtain a copy.

  In recent years, there are a large number of devices using electrophotography such as printers and facsimiles in addition to conventional copying machines. The development methods are roughly classified into a two-component development method using carrier particles and a one-component development method using no carrier particles. The one-component development method includes a magnetic one-component development method in which magnetic particles are encapsulated in toner and the developer is carried and conveyed by the action of magnetic force, and the developer is caused by the action of triboelectric charge of the developer without using magnetic particles. There is a non-magnetic one-component developing method in which the toner is carried on a developer carrying member (developing sleeve). In the magnetic one-component development system, a colorant such as carbon black is not used, and magnetic particles can also be used as a colorant.

  The two-component development system requires carrier particles such as glass beads and iron powder, or because the toner concentration in the developer must be kept constant. Therefore, the developing device is large, heavy, and has a complicated configuration. Further, in the two-component development method, the toner component is likely to adhere (spent) to the carrier, so that the carrier replacement frequency increases.

  In this respect, in the one-component development method, such a carrier and the complicated configuration described above are unnecessary, the developing device itself can be reduced in size and weight, and further, since the carrier does not need to be replaced, it can be used for a long time. There is an advantage that maintenance is not necessary.

  On the other hand, since the magnetic one-component development method uses dark black magnetic particles for the toner, it is difficult to colorize the two-component development method, and the two-component development method can finely adjust the development state using a density detection device. It is preferable for color development. However, in recent years, it has been demanded to reduce the size of the copying apparatus for the purpose of reducing the weight and size of the electrophotographic apparatus. For this reason, a developing apparatus using a one-component developing system has been increasingly used. Yes.

  However, the magnetic one-component development method has an unstable element related to the magnetic one-component developer to be used. This is because the magnetic developer (magnetic toner) contains a considerable amount of fine powdery magnetic material mixed and dispersed, and a part of the magnetic material is exposed on the surface of the toner particles. This affects the fluidity and tribocharging properties, and as a result, various characteristics required for the magnetic toner such as the development characteristics and durability of the magnetic toner fluctuate and the toner itself deteriorates.

  The above-mentioned problems occur in the conventional magnetic toner containing a magnetic material, and it is considered that the magnetic material is exposed on the surface of the magnetic toner. By exposing magnetic fine particles having a relatively low resistance compared to the binder resin constituting the toner on the surface of the magnetic toner, the toner has a lower chargeability and lower fluidity. A decrease in image density due to peeling of the magnetic material due to rubbing between particles, a developer carrier and a developer layer thickness regulating member, and a so-called `` sleeve ghost '' that is a history of a copy pattern on the developing sleeve occurs, Detrimental effects such as appearing on the formed image occur.

  This sleeve ghost is as shown in FIG. 2, and since the non-printing portion (white background) has continued, the portion (X) where only thin development is performed even if copying or printing is performed, and copying is not performed. This is a phenomenon in which density unevenness occurs in a portion (Y) where dark development is performed because it has been continued.

  Consider the mechanism of sleeve ghost formation. In the developing step, the newly charged toner is supplied to the portion where the developer (toner) is consumed on the developer carrying member (developing sleeve), and the next development is performed. At this time, the amount of charge differs between the toner that is not consumed and remains on the developing sleeve, and the newly supplied toner. A toner with a higher charge amount has a higher ability to fly to an electrostatic latent image on the photoreceptor, but at the same time, there is a tendency to be strongly restrained electrostatically by the mirroring force acting between the toner and the developing sleeve. . As described above, the developing ability is determined by the balance between the flying ability and the reflection ability.

  In general, the case where the newly supplied charged toner is higher in the developing capacity than the toner remaining on the developing sleeve without being consumed is shown in FIG. In contrast to this, when the positive ghost is generated and the newly supplied toner has a developing ability lower than that of the toner remaining on the developing sleeve, the non-printing portion (white background) is contrary to FIG. Therefore, compared to the portion where the toner has not been replaced, a negative ghost is generated in which the portion where the toner has been replaced because the copying or printing has been continued has a lower density. Negative ghosts are particularly likely to occur when continuous printing or the like is being carried out at the initial stage of use where the rising of the toner charge tends to be insufficient, and the positive ghost is used to some extent.

  Many proposals have been made regarding the deterioration of the image characteristics accompanying the exposure of the magnetic material from the viewpoint of the toner prescription and structure. Among these, the toner formulation includes an improvement of a magnetic material. A magnetic toner using magnetic iron oxide containing silicon element has been proposed (see, for example, Patent Document 1). However, here, the silicon element is intentionally only present in the inside, and there is still a point to be improved in the fluidity of the magnetic toner.

  Moreover, the technique which controls the shape of magnetic iron oxide to a spherical shape by adding a silicate is developed (for example, refer patent document 2). The magnetic iron oxide obtained by this method uses silicate for particle shape control, so that a large amount of silicate element is distributed inside the magnetic iron oxide, and the amount of silicate element present on the magnetic iron oxide surface Since the magnetic iron oxide has a high smoothness and the fluidity of the magnetic toner is improved to some extent, the adhesion between the binder resin constituting the magnetic toner and the magnetic iron oxide is insufficient.

  Furthermore, a method for producing triiron tetroxide in which a hydroxosilicate solution is added during the oxidation reaction has also been proposed (see, for example, Patent Document 3). The triiron tetroxide obtained by this method exists in the vicinity of the surface and has a problem that the surface is weak against mechanical impact such as friction.

  On the other hand, as an approach from the viewpoint of the toner particle structure, for example, a special toner in which magnetic fine particles are contained only in a specific portion inside the particle is known. Specifically, it is a pressure fixing toner manufactured by a two-step to three-step process in which a magnetic material is dry-attached after the core particles are manufactured, and then a shell layer is formed, and the magnetic material exists only in the toner intermediate layer. (For example, refer to Patent Documents 4 and 5). In addition, a toner having a structure in which a resin layer having no magnetic particles is formed with a thickness of a certain amount or more near the toner particle surface has been developed (see, for example, Patent Document 6).

  Recently, LED (light emitting diode) printers and LBP (laser beam printers) have become mainstream in the market, and the direction of technology is higher resolution, that is, what was conventionally 300 dpi or 400 dpi, 600 dpi, It has become 800 dpi or 1200 dpi. Accordingly, the development method is also required to have higher definition. In addition, digital copying machines have become mainstream, and designs aiming at so-called multi-functions that can be used simultaneously as facsimiles and printers are becoming mainstream. For this reason, the difference between a copying machine and a printer is gradually disappearing, and a high-resolution and high-definition developing method is also required here.

  In order to cope with this problem, a reduction in the particle size of the toner has been proposed, and toner having a central particle size of about 5 μm to 9 μm has become mainstream as high resolution is required. However, it has been found that there are various problems in achieving the high resolution and high definition by promoting the reduction of the toner particle size.

  First, the charge-up phenomenon in a low temperature and low humidity environment, that is, the amount of triboelectric charge tends to be excessive. As a result of the study by the present inventors, the toner in which the magnetic particles are contained only in a specific portion inside the particles as described above is essentially free from the magnetic material on the surface. It was found that since the surface is covered with the resin, the surface has a high resistance and directly reflects the charging characteristics of the resin. Therefore, the charge-up phenomenon is more likely to occur as the toner particle size decreases and the specific surface area increases.

  Patent Document 4 shows that by adjusting the type / addition amount of the magnetic material and the thickness of the shell portion, the magnetic material can be present in the vicinity of the toner surface layer, and the surface resistance can be reduced to some extent. However, since there is a restriction that there can be no more than one magnetic layer on the core surface, only low magnetic force toner can be obtained. For this reason, it is difficult to stably contain an amount of magnetic material that can withstand the restrictions imposed by the magnetic force of the one-component developing method with a small particle size toner.

  Another problem is that toner particles having a relatively large particle diameter are likely to remain in the developing container due to long-term use, and image density or image quality is liable to decrease. This is because the toner in which the magnetic particles are contained only in a specific portion inside the particles as described above is necessary and sufficient because the volume in which the magnetic particles can be present is small particularly in the case of a small particle size toner. It seems to be derived from the fact that it is difficult to enclose a large amount of magnetic particles.

  That is, in such a developer, the ratio of the surface resin layer in which no magnetic particles are present differs between toner particles having a large particle size and small toner particles in the particle size distribution, and the magnetic material contained corresponding to this is different. The content of will also be different. Therefore, selective developability depending on the particle size occurs, that is, the developability varies depending on the toner particle size difference. Therefore, when printing or copying over a long period of time using a magnetic developer having a non-uniform particle size, toner particles having a high magnetic substance content ratio and difficult to develop, that is, toner particles having a large particle size are likely to remain in the developing container, This will cause adverse effects such as a decrease in image density and image quality, and fogging.

  In addition, reproducibility in a low image density range is also important in order to achieve high image quality, but the toner coloring power, that is, dispersibility of magnetic particles is further improved by reducing the toner particle size. An improvement is desired. As described above, a magnetic developer (magnetic toner) that satisfies the prevention of image quality deterioration due to exposure of the magnetic material and the securing of coloring power accompanying the reduction in the particle size of the toner has not been disclosed so far.

  On the other hand, as a means for improving the developability, an approach from a developer carrying member (developing sleeve) is also taken.

  Conventionally, as a developer carrying member (developing sleeve), for example, a metal, an alloy thereof or a compound thereof is formed into a cylindrical shape, and the surface thereof is processed to have a predetermined surface roughness by electrolysis, blasting, file, or the like. Has been used. However, in this case, the developer existing in the vicinity of the surface of the developer carrier in the developer layer formed on the surface of the developer carrier by the developer layer thickness regulating member has a very high charge. It will be strongly attracted by the mirror power on the surface of the carrier. As a result, there is no opportunity for friction between the toner and the developer carrying member, so that the developer cannot hold a suitable charge. Under such circumstances, sufficient development and transfer were not performed, and the obtained image had many density unevenness and character scattering.

  In order to prevent the generation of such an excessively charged developer and the strong adhesion of the developer, a conductive material such as carbon or crystalline graphite or a solid lubricant such as graphite is dispersed in the resin. A method of forming a resin coating layer on the metal developer carrying member has been proposed (see, for example, Patent Document 7).

  When a resin coating layer in which such crystalline graphite is dispersed is used, the resin coating layer surface has lubricity based on the scaly structure of crystalline graphite. However, since the crystalline graphite is in the form of flakes, the surface shape of the resin coating layer becomes non-uniform and the hardness of the crystalline graphite is low. When the durability of the resin coating layer is increased (used for a long period of time), the surface roughness and surface composition of the resin coating layer change, resulting in poor toner transport and poor charging of the toner. Uniformity may occur.

In order to solve such a problem, a developer carrier in which a resin coating layer containing graphite particles and having a specific hardness distribution is formed on a substrate surface has been proposed (see, for example, Patent Document 8). When a conventionally well-known toner is used, the durability can be improved by having such a hard resin coating layer. However, when a hard and hard-to-deform toner is used, the resin coating layer is used. There are cases in which shaving and wear occur, and it is necessary to further improve the durability.
Japanese Unexamined Patent Publication No. 63-279352 Japanese Patent Publication No. 03-009045 Japanese Patent Laid-Open No. 61-034070 JP 60-003647 A JP 63-089867 A JP 07-209904 A JP-A-01-277265 JP 2003-323039 A

  As described above, the level of the development surface can be improved to some extent by combining conventional examples related to the developer and the developer carrier, but it is not sufficient.

  Accordingly, an object of the present invention is to have stable charging ability even in a high humidity or low humidity environment, without causing problems such as density reduction, fogging and sleeve ghosting, uniform and non-uniform density, and high image quality. It is an object of the present invention to provide a developing method capable of stably obtaining a high-definition image at a density and a developer carrying member that can be used in the developing method.

  Another object of the present invention is to provide a developing method and a developing method that are less likely to cause deterioration of the resin coating layer on the surface of the developer carrying member due to long-term use, have high durability, and provide stable image quality throughout. It is an object to provide a developer carrier that can be used.

  Another object of the present invention is to provide a high and uniform charge to the developer on the developer carrying member even during continuous copying over a long period of time, and to provide a stable charge without the occurrence of a charge-up phenomenon. Another object of the present invention is to provide a developer carrying member and a developing device capable of obtaining a high-quality image having a reduced image density during the endurance and a uniform density free of unevenness and fog.

  In addition, the present invention provides a developing method capable of obtaining sufficient image density and reproducibility even for minute isolated dots, and achieving low toner consumption, and a developer carrier that can be used in the developing method. It is one of the purposes to provide.

  As a result of intensive investigations on the uniformization and stabilization of the charge in the durability test in the development method using a magnetic developer, the present inventors have, as a result, developed a developer-carrying member on the surface of the developer carrying member on the surface coating physical property test. It has been found that it is effective to have a conductive resin coating layer in which the average value A and the standard deviation σ obtained from the hardness distribution of the hardness HU have specific values. The universal hardness is defined in ISO / FDIS14577.

  Furthermore, with regard to magnetic one-component developers, paying attention to the presence of iron oxide contained in the toner particles, there is no surface exposure of the magnetic material, and there is a structure in which the magnetic material is concentrated in the vicinity of the surface by a certain amount. It turned out that it is a preferable form.

  Then, by adopting a developing method using both the developer carrying member and the magnetic developer, it was found that not only image characteristics such as developability can be satisfied, but also high durability can be sufficiently imparted. Invented.

  That is, the present invention has the following configuration.

(1) A developer container for containing a developer, a developer supplied from the developer container on the surface, a developer carrier held rotatably, and a developer amount on the developer carrier At least a developer layer thickness regulating member for regulating is provided, and the developer carried to the development area facing the electrostatic latent image carrier is conveyed and formed on the electrostatic latent image carrier by the developer. In the developing method for visualizing the electrostatic latent image, (a) the developer carrier has at least a conductive resin coating layer on the surface of the substrate, and the surface of the conductive resin coating layer has a universal hardness of HU. the average value a and a standard deviation σ of less than 300N / mm ² ~800N / mm ² and 30 N / mm ^2, made of (i) the developer, toner particles containing at least a binder resin and iron oxide, Breaking toner particles using a transmission electron microscope When 70% or more of the iron oxides contained in the toner particles are observed, the toner particles existing from the surface of the toner particles observed to a depth 0.2 times the projected area equivalent diameter C are observed. A developing method comprising 40% by number to 95% by number.

  (2) The developing method according to (1) above, wherein graphitized particles are contained in the conductive resin coating layer of the developer carrying member.

  (3) The developing method according to (2) above, wherein the graphitization degree p (002) of the graphitized particles contained in the conductive resin coating layer of the developer carrying member is 0.20 to 0.95.

  (4) The above (2) or (2), wherein the graphitized particles contained in the conductive resin coating layer of the developer carrier are obtained by graphitizing bulk mesophase pitch particles or mesocarbon microbead particles. 3) Development method.

  (5) The developing method according to the above (1) to (4), wherein the resin coating layer of the developer carrier further contains particles for forming irregularities on the surface.

  (6) The toner particle has a ratio (R / Q) of the content R of iron element to the content Q of carbon element present on the surface of the toner particle measured by X-ray photoelectron spectroscopy analysis is less than 0.001; The above-mentioned (1) to (1), wherein the toner particle contains 50% by number or more of toner particles satisfying the relationship of the projected area equivalent diameter C of the toner particles and the minimum value D of the distance between the iron oxide and the toner particle surface D / C ≦ 0.02. 5) Development method.

  (7) The developing method according to the above (1) to (5), wherein the average circularity of toner particles having an equivalent circle diameter of 3 μm to 400 μm measured by a flow type particle image measuring apparatus is 0.970 or more.

  (8) The developer comprises toner particles containing at least a binder resin, iron oxide, and a sulfur-containing resin, and the sulfur-containing resin has a structural unit derived from at least a sulfonic acid group-containing (meth) acrylamide. The developing method of (1) to (7) above.

(9) A developer carrying member used in the development method according to any one of (1) to (8) above, having at least a conductive resin coating layer on the surface of the substrate, and the surface of the conductive resin coating layer a developing agent carrier, wherein an average value a and a standard deviation σ of the universal hardness HU is each less than 300N / mm ² ~800N / mm ² and 30 N / mm ^2.

  The toner particles of the magnetic developer that can be used in the present invention are hard and tend to be more difficult to deform than conventional ones. In the development process, the magnetic intermediate layer of the magnetic substance is particularly encapsulated wax or low molecular weight / low. Since it is possible to prevent the Tg resin from exuding, it is effective in preventing toner fusion to the conductive resin coating layer on the surface of the developer carrying member. However, repeated rubbing with the surface of the developer carrying member during durability over a long period of time induces abrasion on the conductive resin coating layer on the surface of the developer carrying member, and is uniform with respect to the magnetic developer. Although there was an adverse effect that charging could not be performed, the average value A and the standard deviation σ of the universal hardness HU in the surface film physical property test of the conductive resin coating layer seem to have specific values as in the present invention. Therefore, the wear of the conductive resin coating layer can be reduced, and further high durability can be maintained.

  First, the configuration of the conductive resin coating layer in the developer carrier of the present invention will be described.

  FIG. 1 is a schematic cross-sectional view of the configuration of the developer carrier of the present invention.

The developer carrier of the present invention comprises at least a cylindrical or endless belt-like substrate 1 and a conductive resin coating layer 2. When the surface of the conductive resin coating layer 2 was measured universal hardness HU defined in ISO / FDIS14577, it and its standard deviation and the average value A is 300N / mm ² ~800N / mm ² It is essential that σ is less than 30 N / mm ² .

In the present invention, the universal hardness HU of the surface of the conductive resin coating layer is a square pyramid having a facing angle of 136 ° according to the Fisherscope H100V (trade name) manufactured by Fisher Instruments in accordance with ISO / FDIS14577. Using a diamond indenter, the measurement load was stepped and pushed into the film, and the indentation depth h (unit: mm) in the applied state was detected and read, and the test load F (unit: N) ) And the indentation depth h, the following formula (1) is used. Here, the coefficient K is 1 / 26.43.
HU = K × F / h ² [N / mm ² ] Formula (1)

  The universal hardness HU can be measured with a load smaller than other hardnesses (for example, Rockwell hardness, Vickers hardness, etc.), and even for materials having elasticity and plasticity, elastic deformation and plastic deformation Therefore, it is preferable for evaluating the hardness of the conductive resin layer.

When the average value A of the universal hardness HU on the surface of the conductive resin coating layer is less than 300 N / mm ² , the conductive resin coating layer has insufficient friction resistance and becomes easy to be scraped. An image defect will occur. If the average value A exceeds 800 N / mm ² , the surface of the developer layer thickness regulating member, particularly the elastic regulation blade type, is easily scratched at the initial stage of use, and the developer carrying member is Coat unevenness occurs in the toner, causing image deterioration such as streaks or unevenness in a solid image. That is, it is preferable that the average value A of the universal hardness HU of the conductive resin coat layer surface is in the range of ^{300N / mm 2 ~800N / mm 2} . Further, in order to suppress over further prolonged the image degradation, the mean value A is more preferably in the range of ^{350N / mm 2 ~700N / mm 2} .

And when the standard deviation (sigma) calculated | required from the hardness distribution of the universal hardness measured value HU of the conductive resin coating layer surface is 30 N / mm < ² > or more, in a conductive resin coating layer, a high hardness location and a low hardness location Will be scattered everywhere. For this reason, even if the shape of the surface of the conductive resin coating layer in the initial stage of use is uniform, as the durability progresses, the surface of the conductive resin coating layer is selectively worn away from low-hardness locations, and the magnetic developer becomes On the other hand, uniform charging cannot be performed. As a result, the low-temperature and low-humidity causes adverse effects such as deterioration of fog and character scattering, and the high-temperature and high-humidity causes a decrease in density.

  The developer-carrying member of the present invention has a structure as shown in FIG. 1, and in the conductive resin coating layer, conductivity imparting particles, graphitized particles, unevenness forming particles, and the like are arranged in a binder resin. This is shown in FIG.

  FIG. 3 is a schematic cross-sectional view showing a state in which a conductive resin coating layer that can be used in the present invention is formed.

  A conductive resin coating layer 2 is formed on a substrate 1 made of a metal cylindrical tube or the like, and the conductive resin coating layer 2 is composed of a conductivity-imparting particle a, a graphitized particle c, and irregularities in a binder resin b. Forming particles d are arranged. FIG. 3A shows a form in which the conductivity imparting particles a are dispersed in the binder resin b. FIG. 3B shows a configuration in which conductivity is further imparted by adding graphitized particles c in addition to the conductivity imparting particles a in the binder resin b, and the graphitized particles c are imparted with conductivity. In addition to this, it contributes to the formation of relatively small irregularities on the surface of the coating layer, the releasability to the toner particles and the charge imparting property to the toner particles. However, not only the graphitized particle c but also a mode in which minute irregularities are formed by another added solid particle is included.

  3 (c) and 3 (d) are obtained by further adding irregularity-forming particles d.

  In FIG. 3 (c), the unevenness forming particle d is further added to the binder resin b in order to give a relatively large unevenness to the surface of the resin coating layer 2, and the graphitized particle c is a resin coating layer. 2 has small irregularities on the surface. 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 particles). That is, the pressing force of the elastic regulating member is regulated by the irregularity-forming particles d on the surface of the resin coating layer 2 and the conductivity imparting particles a form small irregularities so that the contact charging opportunity between the toner particles and the resin coating layer It also plays a role of adjusting releasability with the toner particles.

  On the other hand, in FIG. 3 (d), both the graphitized particles c and the unevenness forming particles d contribute to the formation of unevenness on the surface of the resin coating layer 2. Such a form is useful, for example, when the irregularity-forming particles d are intended to have other functions such as conductivity, charge imparting property, and wear resistance in addition to imparting irregularities.

  Here, as the base of the developer carrying member, there are a cylindrical member, a belt-like member, etc., but in a developing method that is not in contact with the electrostatic latent image carrying member, a rigid cylindrical tube such as a 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, polished, ground, etc., is preferably used. Aluminum is preferably used because of material cost and ease of processing.

  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, and the gap between the developer carrying member and the electrostatic latent image carrying member may be shaken, for example, through a uniform spacer with respect to the vertical plane. When the abutment and the developer carrying member are rotated, 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.

  In addition, as a substrate having an elastic layer, a core member and a cylindrical member having a layer structure including rubber and elastomer such as urethane rubber, EPDM, and silicone rubber are used. In particular, a developer carrier is directly attached to an electrostatic latent image carrier. It is preferably used in the case of a developing method for contact.

  As the binder resin of the conductive resin coating layer constituting the developer carrying member of the present invention, generally known resins can be used. For example, phenolic resin, epoxy resin, polyester resin, alkyd resin, melamine resin, benzoguanamine resin, polyurethane resin, urea resin, silicone resin, polyimide resin, or other heat or photo-curing resin, styrene resin, vinyl resin, polyether A thermoplastic resin such as a sulfone resin, a polycarbonate resin, a polyphenylene oxide resin, a polyamide resin, a fluororesin, a fiber-based resin, and an acrylic resin can be used. Among them, phenol resin, polyether sulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, polyester resin, polyurethane resin, styrenic resin, acrylic resin having excellent mechanical properties, or silicone resin, fluororesin Those having such releasability are preferably used. Furthermore, a phenol resin, a silicone resin, a polyamide resin, an acrylic resin, an epoxy resin, a melamine resin, a benzoguanamine resin, and the like are preferable from the viewpoint of imparting triboelectric charge to the developer.

The conductive resin coating layer formed on the developer carrier by the above-described forming material is a developer carrier that is generated when the developer is fixed on the developer carrier by charge-up or the developer is charged up. In order to prevent poor application of frictional charge from the surface to the developer, the volume resistance value of the resin coating layer is preferably 10 ⁴ Ω · cm or less, more preferably 10 ³ Ω · cm or less. If the volume resistance value of the conductive resin coating layer on the surface of the developer carrying member exceeds 10 ⁴ Ω · cm, it is easy to cause poor frictional charging to the developer. As a result, blotches (spot images and wave pattern images) and A decrease in image density is likely to occur.

  In order to adjust the resistance value of the resin coating layer to the above value, it is preferable to include the following conductivity imparting particles in the resin coating layer. Examples of the conductivity-imparting particles used in this case include fine powders of metals such as aluminum, copper, nickel and silver, antimony oxide, indium oxide, tin oxide, titanium oxide, zinc oxide, molybdenum oxide, and potassium titanate. Preferred are conductive metal oxides such as carbon black, various carbon fibers, furnace black, lamp black, thermal black, acetylene black, channel black, and other conductive carbon blacks, and further metal fibers.

  Of these, conductive carbon black, especially conductive amorphous carbon, is particularly excellent in electrical conductivity, and it can be filled to any degree by simply filling the polymer material with conductivity and controlling the amount added. It is preferably used because the degree can be obtained. In addition, the dispersion stability and coating stability are also improved due to the thixotropic effect of the paint.

  Moreover, although the addition amount of electroconductive carbon black changes also with the particle sizes, it is preferable to set it as the range of 1 mass part-100 mass parts with respect to 100 mass parts of binder resin. If the amount is less than 1 part by mass, it is usually difficult to lower the resistance value of the resin coating layer to a desired level, and there is a high possibility that toner adheres to the binder resin used for the resin coating layer. If it exceeds 100 parts by mass, the strength (wearability) of the resin coating layer may decrease.

  Further, in order for the conductive resin coating layer to have the coating strength specified in the present application, it is necessary that the graphitized particles are disposed in the conductive resin coating layer. It is preferable that it is p (002) 0.20-0.95.

The graphitization degree p (002) is said to be the Franklin p value, and is obtained from the graphite lattice interval d (002) obtained from the X-ray diffraction diagram of the graphitized particles by the following formula (2). This p (002) value indicates the proportion of disordered portions of the stack of carbon hexagonal mesh planes. The smaller this value, the greater the degree of graphitization.
d (002) = 3.440-0.086 (1 -p 2) (2)

  When p (002) of the graphitized particles is more than 0.95, the wear resistance is excellent, but the conductivity and lubricity may be reduced to induce developer charge-up. In addition, the image quality such as fogging and image density is likely to deteriorate, and when an elastic blade is used, blade scratches may occur or streaks / density unevenness may occur in the image. When p (002) is less than 0.20, the graphitized particles are inferior in wear resistance, so that the wear resistance on the surface of the conductive resin coating layer and the mechanical strength of the conductive resin coating layer are reduced. May end up. Thus, by making p (002) of graphitized particles into a specific range, it has good conductivity and high lubricity, and prevents a decrease in mechanical strength of the conductive resin coating layer. The effect that the selective chipping of the layer can be suppressed is obtained.

  Graphitized particles that can be used in the present invention include graphite and graphitized particles obtained by firing mesocarbon microbead particles or bulk mesophase pitch particles.

  Of these, natural graphite and artificial graphite are known, and any graphite can be used as long as its p (002) value is within a predetermined range. In artificial graphite, pitch coke is hardened with tar pitch or the like and fired once at about 1200 ° C., and then put into a graphitization furnace, and treated at a high temperature of about 2300 ° C., so that carbon crystals grow and change into graphite. . Natural graphite is one that is completely graphitized by natural geothermal heat and underground high pressure for a long time. These graphites have a wide range of industrial uses because they have various excellent properties. Graphite is a dark gray or black glossy, very soft, slippery crystalline mineral that is used for pencils and other materials, and has excellent heat resistance, chemical stability, lubricity, and fire resistance. It is used in the form of powder, solid and paint. Some crystal structures belong to the hexagonal system and other rhombohedral systems, and have a complete layered structure. Regarding electrical characteristics, free electrons exist between carbon and carbon bonds, making it a good conductor of electricity. Furthermore, graphite has anisotropy in the crystal structure as seen in “cleavability”, which is one of the structural properties, and when it appears on the surface of the conductive resin coating layer, it has lubricity on the surface. It is also a preferable material because it can be imparted. In addition, when adding graphite, it is necessary to make the universal hardness HU of the surface of a conductive resin coating layer into the range of this invention.

  In the present invention, graphitized particles obtained by firing mesocarbon microbead particles or bulk mesophase pitch particles are preferred as graphitized particles. The graphitized particles differ from the graphite in raw materials and manufacturing processes. Therefore, although the graphitized particles have a slightly lower degree of graphitization than crystalline graphite, they have high conductivity and lubricity similar to crystalline graphite, and the shape of the particles is crystalline graphite flakes or needles. Unlike the shape, it is a block shape or a substantially spherical shape, and the particle itself has a relatively high hardness. Therefore, since the graphitized particles having such characteristics are easily dispersed uniformly in the conductive resin coating layer, the surface of the conductive resin coating layer is given uniform surface roughness and wear resistance, and the particles themselves. Even if the conductive resin coating layer is scraped due to its shape being difficult to change, or even if the particles themselves fall off due to the effect, the particles may protrude or be exposed again from the conductive resin coating layer. When crystalline graphite is used without causing toner charge-up when the surface shape change can be suppressed and graphitized particles are arranged in the conductive resin coating layer on the surface of the developer carrier. As a result, the ability to impart triboelectric charge to the toner can be improved.

  Usually, an organic compound having a boiling point of 500 ° C. or higher is carbonized via a solid phase or a liquid phase when heated in an inert gas phase under normal pressure, but begins to decompose at a temperature up to about 200 ° C., Cyclization occurs in the residue, followed by aromatization up to 400 ° C. Beyond this temperature, aromatic polycondensation proceeds. Among them, those that are liquid at this temperature, such as condensed polycyclic aromatics and pitches that are a mixture thereof, form a liquid crystal state composed of condensed polycyclic aromatic planar molecules at 400 ° C. or higher. This liquid crystal is called mesophase. In the mesophase, the polymer is further polymerized up to 500 ° C. and solidifies while forming a layered structure. The layered structure is highly selective and has a property of being easily graphitized by high-temperature treatment.

  Therefore, the crystallinity of the graphitized particles is increased by graphitizing using optically anisotropic particles such as mesocarbon microbead particles and bulk mesophase pitch particles as raw materials, and consisting of a single phase. In addition, a lump shape or a substantially spherical shape can be maintained. The optical anisotropy of the above-mentioned raw materials is caused by the lamination of aromatic molecules, and the order is further developed by graphitization treatment, and graphitized particles having high crystallinity are obtained.

  A typical method for obtaining mesocarbon microbead particles is, for example, heat treatment of a heavy coal oil or petroleum heavy oil at a temperature of 300 ° C. to 500 ° C. and polycondensation to obtain crude mesocarbon microbead particles. By separating the mesocarbon microbead particles by subjecting the reaction product to treatment such as filtration, stationary sedimentation, and centrifugation, washing with a solvent such as benzene, toluene, xylene, and drying. The method of obtaining is mentioned.

  As a method of graphitizing using mesocarbon microbead particles, first, the mesocarbon microbead particles that have been dried are first dispersed mechanically with a gentle force that does not cause destruction. Is preferable for preventing coalescence and obtaining uniform particle size. The mesocarbon microbead particles that have finished the primary dispersion are subjected to primary heat treatment at a temperature of 200 ° C. 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 that has undergone the secondary dispersion treatment is subjected to secondary heat treatment at 2000 ° C. to 3500 ° C. in an inert atmosphere to obtain desired graphitized particles.

  As a method for obtaining bulk mesophase pitch particles, for example, there is a method obtained by extracting β-resin by solvent fractionation from coal tar pitch or the like, and performing hydrogenation and heavy treatment. Furthermore, after this heavy treatment, it can be obtained by pulverizing and then removing the solvent-soluble component with benzene or toluene. The obtained bulk mesophase pitch particles preferably have a quinoline soluble content of 95% by mass or more. That is, in the case where the quinoline-soluble component is less than 95% by mass, the inside of the particle is difficult to be liquid phase carbonized, and solid phase carbonization causes the particle to remain in a crushed state and a spherical shape may not be obtained.

  As a method of graphitizing using bulk mesophase pitch particles, first, bulk mesophase pitch particles are finely pulverized to 2 μm to 25 μm, heat-treated in air at 200 ° C. to 350 ° C., and lightly oxidized. . By this oxidation treatment, the bulk mesophase pitch particles are infusible only on the surface, and melting and fusion during the graphitizing heat treatment in the next step are prevented. The oxidized mesophase pitch particles preferably have an oxygen content of 5% by mass to 15% by mass. If the amount is less than 5% by mass, the fusion of the particles during heat treatment may be promoted. If the amount exceeds 15% by mass, the inside of the particle is oxidized, and the shape is graphitized in a crushed state. It may be difficult to obtain.

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

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

  When the firing temperature is less than 2000 ° C., graphitization of the graphitized particles is insufficient, and the electrical conductivity and lubricity may be reduced to cause toner charge-up, sleeve ghost, fog, image density, etc. The image quality of the image is likely to deteriorate, and when an elastic blade is used, blade scratches may occur, and streaks, density unevenness, etc. are likely to occur in the image. On the other hand, when the firing temperature is higher than 3500 ° C., the degree of graphitization of the graphitized particles may become too high, so that the hardness of the graphitized particles is lowered and the conductivity of the graphitized particles is deteriorated due to deterioration of wear resistance. The abrasion resistance on the surface of the resin coating layer, the mechanical strength of the conductive resin coating layer, and the charge imparting property to the toner may be reduced.

  In addition, the surface of the conductive resin coating layer can maintain a uniform particle size distribution by classification regardless of which method is used for the graphitized particles obtained from any of the above raw materials. It is preferable for making the shape uniform.

  In the present invention, the graphitized particles preferably have a volume average particle size of 0.5 μm to 30 μm, and more preferably 1 μm to 25 μm. When the volume average particle size 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 magnetic developer becomes insufficient, and the conductive resin coating Toner charge-up due to layer abrasion, toner contamination, and toner fusion occur, and the ghost is liable to deteriorate and the image density tends to decrease. When the volume average particle size exceeds 30 μm, the surface of the conductive resin coating layer becomes too rough, and it becomes difficult to sufficiently charge the magnetic developer. Mechanical strength may decrease.

  In order to form irregularities on the surface of the conductive resin coating layer, it is possible to contain irregularities-forming particles in the conductive resin coating layer. As the irregularity forming particles used for that purpose, for example, polymethyl methacrylate, polyethyl acrylate, polybutadiene, polyethylene, polypropylene, polystyrene and other vinyl polymers and copolymers, phenol resins, polyamide resins, fluorine resins, silicone resins Resin particles such as polyester resin, oxide particles such as alumina, zinc oxide, silicone, titanium oxide and tin oxide, conductive particles such as carbonized particles, resin particles subjected to conductive treatment, and others such as imidazole compounds It is also possible to use various organic compounds in the form of particles. In this case, the imidazole compound also serves to impart triboelectric charge to the toner. In addition, for the purpose of imparting functions such as wear resistance, conductivity, and hydrophobicity, an inorganic fine powder such as a metal oxide may be adhered to the particle surface.

  Among these, the unevenness forming particles are carbonized particles, particularly described in Japanese Patent Application Laid-Open No. 08-240981 in order to make the hardness distribution of the conductive resin coating layer on the developer bearing member within the range specified in the present application. It is more preferable to use the conductive spherical particles.

The unevenness-forming particles that can be used in the present invention are particles having a volume resistance of 10 ⁶ Ω · cm or less, more preferably 10 ⁻³ Ω · cm to 10 ⁶ Ω · cm. When the volume resistance of the unevenness forming particles exceeds 10 ⁶ Ω · cm, the developer exposed to the surface of the conductive resin coating layer due to abrasion tends to cause contamination and fusion of the developer, and prompt and uniform Charging may be difficult to perform. Furthermore, the true density of the particles is more preferably ³ g / cm ³ or less. Even if conductive, if the true density of the particles is too high, the amount added must be increased to form the same roughness, and the difference in true density from the resin or resin composition will be large. The dispersion state of the particles at the time tends to be non-uniform, and therefore the dispersion state may be non-uniform even in the formed conductive resin coating layer. Also, if the particles are spherical, the contact area with the developer layer thickness regulating member to be pressed is reduced, so the increase in the rotational torque of the developer carrier due to frictional force and the adhesion of the developer are reduced. This is more preferable.

  Further, the particle diameter of the unevenness forming particles is preferably 0.3 μm to 30 μm in terms of volume average particle diameter. If the surface roughness is less than 0.3 μm, it is difficult to form uniform surface irregularities, and if the surface roughness is to be increased, the amount added becomes excessive, the conductive resin coating layer becomes brittle, and wear resistance may be reduced. On the other hand, if it exceeds 30 μm, the particles protrude too much from the surface of the developer carrying member, so that the thickness of the developer layer becomes too large and the charge of the developer tends to decrease or become non-uniform and biased. In some cases, this may become a point of leakage to the electrostatic latent image carrier (photosensitive drum).

  In order to control the charging series of the conductive resin coating layer, it is preferable to add a charge control agent to the conductive resin coating layer. For controlling the negative charge, for example, an organometallic complex and a chelate compound are effective, and there are a monoazo metal complex, an acetylacetone metal complex, an aromatic hydroxycarboxylic acid, and an aromatic dicarboxylic acid metal complex. Others include aromatic hydroxycarboxylic acids, aromatic mono- and polycarboxylic acids and their metal salts, anhydrides, esters, and phenol derivatives such as bisphenol.

  Among these charge control agents, when a developer (toner particles) having a high sphericity is used, a quaternary ammonium salt compound that is positively charged with respect to iron powder is coated with a conductive resin as the charge control agent. The inclusion in the layer is preferable from the viewpoint of improving the good charge imparting property to the magnetic developer used in the present invention. At this time, the conductive resin coating layer has at least one of an amino group, ═NH group, and —NH— bond in the resin structure. It is further preferable at this point.

  By providing a conductive resin coating layer containing the quaternary ammonium salt compound on the developer carrier, the developer (toner particles) having a high degree of spheroidization works to prevent excessive charging. It is possible to control the application of triboelectric charge. This prevents the developer from being charged up on the developer carrier, and prevents the toner particles from fusing to the surface of the conductive resin coating layer, thereby maintaining the high charging stability of the developer, resulting in environmental stability. In addition, it is possible to provide a high-definition image having long-term stability, which is preferable.

  Although this clear reason is not certain, the quaternary ammonium salt compound which is preferably used in the present invention and is itself positively charged with respect to the iron powder has an amino group in the structure when added. ═NH or —NH— uniformly dispersed in a resin containing at least one of —NH— and further incorporated into the structure of the resin when forming a coating, and the binder resin composition itself having such a compound is negative. It is thought that it will become charged.

  As the quaternary ammonium salt compound having the above-mentioned function suitably used in the present invention, any quaternary ammonium salt compound may be used as long as it has a positive chargeability with respect to iron powder. The compound represented by 1) is mentioned.

（式中、Ｒ１〜Ｒ４は、それぞれ独立に、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、アルキル基を表し、Ｘ^-は酸イオンを表す。）

(In the formula, R1 to R4 each independently represents an alkyl group which may have a substituent, an aryl group which may have a substituent, or an alkyl group, and X ⁻ represents an acid ion.)

Specific examples of the X ⁻ acid ion in the general formula (1) include an organic sulfate ion, an organic sulfonate ion, an organic phosphate ion, a molybdate ion, a tungstate ion, a molybdenum atom, or a heteropolyacid ion containing a tungsten atom. Is preferred.

  Specific examples of the quaternary ammonium salt compound that is preferably used in the present invention and is positively charged with respect to iron powder include those shown in Tables 1 to 3 below. Of course, the present invention is not limited to these examples.

  In addition, as a preferred resin containing at least one of an amino group, = NH or -NH- in the structure in combination with the quaternary ammonium salt, it is produced using a nitrogen-containing compound such as ammonia as a catalyst in the production process. And phenol resins, polyamide resins, epoxy resins using polyamide as a curing agent, urethane resins, and copolymers containing these resins in part. The quaternary ammonium salt compound is easily taken into the structure of the coating resin when the mixture with the coating resin is formed.

  Moreover, there are the following substances for positively charging.

  Modified products by 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 their lake pigments (including phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide); metal salts of higher fatty acids Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guani Emissions compounds; imidazole compounds.

  Among these, an imidazole compound is preferable because it has excellent dispersibility in the conductive resin coating layer and can impart appropriate positive chargeability to the conductive resin coating layer.

  In particular, among the imidazole compounds, an imidazole compound represented by the following general formula (2) or (3) is more preferable in terms of rapid and uniform chargeability of the developer (toner) and strength of the conductive resin coating layer.

〔式中、Ｒ５およびＲ６は、それぞれ独立に水素原子、アルキル基、アラルキル基またはアリール基を表し、Ｒ７およびＲ８はそれぞれ独立に炭素数が３〜３０の直鎖状アルキル基を表す。〕

[Wherein, R5 and R6 each independently represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, and R7 and R8 each independently represent a linear alkyl group having 3 to 30 carbon atoms. ]

〔式中、Ｒ９およびＲ１０は、それぞれ独立に水素原子、アルキル基、アラルキル基またはアリール基を表し、Ｒ１１は、炭素数が３〜３０の直鎖状アルキル基を表す。〕

[Wherein, R9 and R10 each independently represent a hydrogen atom, an alkyl group, an aralkyl group or an aryl group, and R11 represents a linear alkyl group having 3 to 30 carbon atoms. ]

  Further, it is also possible to add a polymer obtained by copolymerizing a monomer having a polar group to a base monomer and polymerizing it to an appropriate molecular weight to the conductive resin coating layer and use it as a resin control agent.

  For example, the negatively chargeable resin control agent includes a copolymer of at least a vinyl polymerizable monomer and a sulfonic acid-containing acrylamide monomer. More specifically, as the vinyl polymerizable monomer, styrene, α-methylstyrene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, iso-butyl methacrylate, cyclohexyl (Meth) acrylate, dimethyl (amino) ethyl methacrylate, diethyl (amino) methacrylate, hydroxyethyl (meth) acrylate, (meth) acrylic acid, vinyl acetate, vinyl propionate, etc., these may be used alone or in combination of two or more Can be used in mixing. Preferably, a combination of styrene and an acrylic ester or methacrylic ester is used.

  Examples of the sulfonic acid-containing acrylamide monomer include 2-acrylamide propane sulfonic acid, 2-acrylamide-n-butane sulfonic acid, 2-acrylamide-n-hexane sulfonic acid, 2-acrylamide-n-octane sulfonic acid, 2 Acrylamide-n-dodecanesulfonic acid, 2-acrylamide-n-tetradecanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 2-acrylamido-2-phenylpropanesulfonic acid, 2-acrylamido-2,2,4 -Trimethylpentanesulfonic acid, 2-acrylamido-2-methylphenylethanesulfonic acid, 2-acrylamido-2- (4-chlorophenyl) propanesulfonic acid, 2-acrylamido-2-carboxymethylpropanesulfonic acid, 2-acrylic acid Amido-2- (2-pyridyl) propanesulfonic acid, 2-acrylamido-1-methylpropanesulfonic acid, 3-acrylamido-3-methylbutanesulfonic acid, 2-methacrylamide-n-decanesulfonic acid, 2-methacrylamide -N-tetradecanesulfonic acid etc. can be mentioned. 2-acrylamido-2-methylpropanesulfonic acid is preferred.

  Further, the positively chargeable resin control agent includes at least a copolymer of a vinyl polymerizable monomer and a nitrogen-containing vinyl monomer. More specifically, typical examples of nitrogen-containing vinyl monomers include p-dimethylaminostyrene, dimethylaminomethyl acrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminomethyl acrylate, diethylaminoethyl acrylate, dimethylaminomethyl methacrylate, Dimethylaminomethyl methacrylate, dimethylaminopropyl methacrylate, diethylaminomethyl methacrylate, diethylaminoethyl methacrylate, and the like. Further, N-vinylimidazole, N-vinylbenzimidazole, N-vinylcarbazole, N-vinylpyrrole, N-vinylpiperidine, N -Nitrogen-containing heterocyclic N-vinyl compounds such as vinylmorpholine and N-vinylindoleIn particular, it is preferable to use a nitrogen-containing vinyl monomer or a quaternary ammonium group-containing vinyl monomer represented by the following general formula (4) such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate.

〔但し、Ｒ１２〜Ｒ１４は水素原子あるいは炭素数１〜４の飽和炭化水素基を示し、ｎは１〜４の整数を示す。〕

[However, R12-R14 shows a hydrogen atom or a C1-C4 saturated hydrocarbon group, and n shows the integer of 1-4. ]

  The structure of the quaternary ammonium group-containing vinyl monomer used in the present invention is not particularly limited as long as it is copolymerizable with a vinyl polymerizable monomer. Is a quaternary ammonium group-containing vinyl monomer represented by the following general formula (5).

〔式中、Ｒ１６は、水素原子またはメチル基を示し、Ｒ１７は、炭素数１〜４のアルキレン基を示し、Ｒ１８〜Ｒ２０は、メチル基、エチル基またはプロピル基を示し、Ｘ１は、−ＣＯＯ−または−ＣＯＮＨ−を示し、Ａ^-は、Ｃｌ^-、（１／２）ＳＯ₄ ^2-のようなアニオンを示す。〕

[Wherein R16 represents a hydrogen atom or a methyl group, R17 represents an alkylene group having 1 to 4 carbon atoms, R18 to R20 each represents a methyl group, an ethyl group or a propyl group, and X1 represents —COO - or shows a -CONH-, a ^{- is,} Cl -, indicating the (1/2) sO ₄ ^2- anions, such as. ]

  The surface roughness of the conductive resin coating layer on the surface of the developer carrying member preferably used in the present invention is generally the arithmetic average roughness Ra specified in JIS B0601-2001. It is preferably in the range of 0.3 to 3.5 μm. When Ra is less than 0.3 μm, sufficient transportability of the developer cannot be obtained, and image density thin due to insufficient developer, scattering or blotch due to excessive charging of the developer tends to occur. On the other hand, when Ra is larger than 3.5 μm, the frictional charge is not uniformly applied to the developer, and stripe unevenness, reversal fogging, and image density thin due to insufficient charging are likely to occur.

  Furthermore, in the present invention, a solid lubricant can be mixed into the conductive resin coating layer in order to further reduce the adhesion of the developer to the surface of the developer carrying member. Examples of the solid lubricant that can be used at this time include molybdenum disulfide, boron nitride, graphite fluoride, silver-selenium niobium, calcium chloride-graphite, and talc. The amount of these solid lubricants that can be used in the present invention is preferably in the range of 1 to 100 parts by mass with respect to 100 parts by mass of the binder resin. If the amount is less than 1 part by mass, the effect of improving the adhesion of the developer to the surface of the binder resin of the conductive resin coating layer is small, and if it exceeds 100 parts by mass, a material containing a large amount of fine powder having a particle size especially in the submicron order is included. When used, the strength (abrasion resistance) of the conductive resin coating layer may decrease. These lubricating particles preferably have a volume average particle diameter of 0.2 μm to 20 μm, more preferably 1 μm to 15 μm. When the volume average particle diameter of the lubricating particles is less than 0.2 μm, it is difficult to obtain sufficient lubricity, and when the volume average particle diameter exceeds 20 μm, the shape of the surface of the conductive resin coating layer is reduced. The influence is large and the surface property tends to be non-uniform, which may be insufficient in terms of uniform charging of the developer and the strength of the conductive resin coating layer.

  As a method for forming the conductive resin coating layer of the present invention, for example, each component can be dispersed and mixed in a solvent to form a paint, which can be obtained by coating on the substrate. For dispersion mixing of each component, a known dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, a pearl mill or the like can be suitably used. Moreover, as a coating method, well-known methods, such as a dipping method, a spray method, and a roll coat method, are applicable.

  By adopting such a structure of the conductive resin coating layer, the conductive resin coating layer is not selectively scraped, and the surface of the conductive resin coating layer can be removed even when scraping occurs due to repeated use over a long period of time. The surface of the conductive resin coating layer is prevented from changing, and the amount of charge of the magnetic developer and the amount of developer on the developer carrier are reduced. The effect of further stabilizing the coating amount can be exhibited. Although details will be described later, when a magnetic developer having a structure in which a certain amount of iron oxide contained in toner particles is concentrated in the vicinity of the surface is used as in the present invention, It is particularly effective.

  Next, the magnetic developer that can be used in the present invention will be described.

  The magnetic developer used in the present invention comprises toner particles containing at least a binder resin and iron oxide, and is contained in individual toner particles in cross-sectional observation of the toner particles using a transmission electron microscope (TEM). 40% to 95% of toner particles satisfying a structure in which 70% by number or more of the iron oxide is present from the surface of the toner particles to a depth 0.2 times the projected area equivalent diameter C, The content is preferably 60% by number to 95% by number. In other words, a certain amount of toner particles having a structure in which iron oxide (magnetic material) is concentrated and present in the very vicinity of the surface of the toner particles exists. Since the rigidity of the toner particles is remarkably improved by adopting such a configuration having a substantially magnetic capsule structure (hereinafter sometimes referred to as “mag intermediate layer”), the inner layer In addition, wax and low molecular weight / low Tg resin can be encapsulated in a larger amount than before, so that not only the fixing property can be improved, but also external additives are less embedded in the toner particles during durable use. Therefore, durability can be improved.

  If the structure in which 70% by number or more of iron oxide exists from the surface of the toner particle to a depth 0.2 times the projected area equivalent diameter C is not satisfied, the variation in the state of presence of the magnetic substance in the toner particle is large. Thus, sufficient development stability as the effect of the present invention cannot be obtained.

  Further, toner particles having the above-mentioned mag intermediate layer (toner particles in which 70% by number or more of iron oxide exists from the surface of the toner particles to a depth 0.2 times the projected area equivalent diameter C) are less than 40% by number. In this case, since the capsule structure of the magnetic material is not sufficient, variations in the presence state of the magnetic material are likely to occur, the effect of the present invention cannot be obtained with respect to durability, and deterioration of the external additive on the toner particle surface is promoted. In other words, the developability deteriorates with durability.

  Further, when the ratio of the toner particles having the above-mentioned mag intermediate layer exceeds 95% by number, a large number of triboelectric charge leak sites exist near the toner particle surface, and as a result, the charge easily escapes from the toner particle surface. As a result, sufficient charge cannot be imparted to the developer.

  In addition, the magnetic developer that can be used in the present invention is a ratio of the content R of iron element to the content Q of carbon element present on the toner particle surface (R / Q) measured by X-ray photoelectron spectroscopy. Toner particles satisfying the relationship of D / C ≦ 0.02, where C is the projected area equivalent diameter of the toner particles and D is the minimum distance between the iron oxide and the toner particle surface. Is preferably present in an amount of 50% by number or more.

  When the R / Q is 0.001 or more, the ratio of iron oxide particles exposed on the surface of the toner particles is increased, and the image density due to fogging and durability especially at high temperature and high humidity or lower due to moisture absorption of the magnetic material or leakage of charging. Is likely to occur.

  Further, when the number of toner particles satisfying the relationship of D / C ≦ 0.02 is less than 50% by number, most of the toner particles have almost no iron oxide particles outside the boundary line of D / C = 0.02. It will not exist. That is, since the toner particle surface has high resistance and the charging characteristics of the binder resin are easily reflected directly, the image density may be deteriorated due to fogging or charge-up particularly under low temperature and low humidity.

  In addition, regarding the toner particle structure of the magnetic developer that can be used in the present invention, a method of highly hydrophobizing iron oxide particles and a uniform processing method thereof, and further adding a polar substance having a specific saponification value, By combining with the direct polymerization method in the medium, the uneven distribution of iron oxide particles in the toner particles can be controlled in one step.

  This has been difficult to achieve with conventional magnetic developers using magnetic iron oxide, and means that can be achieved with a simple process is not disclosed. One reason for this is that the magnetic iron oxide used could not be sufficiently and uniformly hydrophobized.

  When the magnetic developer is produced, the dispersibility of the magnetic iron oxide particles in the binder resin can be improved by using magnetic iron oxide having a hydrophobic surface. Even when a large amount of magnetic iron oxide is exposed on the surface of the toner particles, if the surface of the magnetic iron oxide is uniformly hydrophobized, it is difficult to impair the charging performance of the developer in any environment.

  Thus, various methods for hydrophobizing the surface of magnetic iron oxide particles have been proposed. However, it has been difficult to obtain magnetic iron oxide sufficiently and uniformly hydrophobized by the conventional methods. In addition, when a large amount of a treatment agent or the like is used, or a treatment agent with high viscosity is used, the degree of hydrophobicity is certainly increased, but adverse effects such as coalescence of particles occur, resulting in hydrophobicity. It was difficult to achieve both a good balance with dispersibility.

  Generally, since untreated iron oxide has hydrophilicity, it is necessary to hydrophobize hydrophilic iron oxide in order to obtain hydrophobic iron oxide. A conventional developer using such iron oxide cannot be uniformly hydrophobized, and its charging ability fluctuates depending on the environment and lacks stability.

  On the other hand, the iron oxide that can be used in the present invention has a very high level of hydrophobicity uniformity. For example, when hydrophobizing, iron oxide is firstly converted in an aqueous medium. It is iron oxide obtained by surface-treating while hydrolyzing the coupling agent while dispersing to a particle size. Compared with treatment in the gas phase, the hydrophobization method in an aqueous medium is less likely to cause coalescence between the iron oxide particles, and the repulsive action between the iron oxide particles due to the hydrophobization treatment works. Since the surface treatment is performed almost in the state of primary particles, highly uniform hydrophobicity can be achieved.

  The method of treating the surface of iron oxide while hydrolyzing the coupling agent in an aqueous medium does not require the use of a coupling agent that generates a gas, such as chlorosilanes and silazanes. In this case, since the iron oxide particles can be easily combined with each other and a highly viscous coupling agent that has been difficult to be treated can be used, the effect of hydrophobization is very large.

Examples of coupling agents that can be used for the surface treatment of iron oxide particles in the present invention include silane coupling agents and titanium coupling agents. More preferred is a silane coupling agent represented by the following general formula (6).
(R21O) _m SiR22 _(4-m) (6)
[Wherein R21 represents an alkyl group, R22 represents a hydrocarbon group such as an alkyl group, a vinyl group, a glycidoxy group or a methacryl group, and m represents an integer of 1 to 3. ]

  For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltriacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, isobutyltrimethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, Examples thereof include trimethylmethoxysilane, hydroxypropyltrimethoxysilane, phenyltrimethoxysilane, n-hexadecyltrimethoxysilane, and n-octadecyltrimethoxysilane.

In particular, the iron oxide particles may be hydrophobized in an aqueous medium using an alkyltrialkoxysilane coupling agent represented by the following general formula (7).
C _p H _{2p + 1} Si (OC _q H _{2q + 1} ) ₃ (7)
(In the formula, p represents an integer of 2 to 20, and q represents an integer of 1 to 3.)

  When p in the general formula (7) is smaller than 2, the hydrophobic treatment is easy, but it is difficult to sufficiently impart hydrophobicity, and it is possible to suppress the exposure of the iron oxide particles from the toner particles. It becomes difficult. On the other hand, when p is larger than 20, the hydrophobicity is sufficient, but the coalescence between the iron oxide particles increases, making it difficult to uniformly disperse the iron oxide particles in the toner. Tends to deteriorate the selective developability. On the other hand, when q is larger than 3, the reactivity of the silane coupling agent is lowered and the hydrophobicity is not sufficiently performed.

  In particular, p in the general formula (7) is an integer of 2 to 20 (more preferably, an integer of 3 to 15), and q is an integer of 1 to 3 (more preferably, an integer of 1 or 2). A certain alkyltrialkoxysilane coupling agent may be used.

  The amount used in the treatment is 0.05 parts by mass to 20 parts by mass, preferably 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of iron oxide, from the viewpoint of the effect of the treatment, productivity and the like. Is good.

  The aqueous medium here is a medium containing water as a main component. Specific examples of the aqueous medium include water itself, water added with a small amount of a surfactant, water added with a pH adjuster, water added with an organic solvent, and the like. The surfactant used here is preferably a nonionic surfactant such as polyvinyl alcohol. As addition amount of surfactant, it is good to set it as 0.1 mass%-5 mass% with respect to water. Examples of the pH adjuster include inorganic acids such as hydrochloric acid.

  Stirring is performed, for example, with a mixer having a stirring blade (specifically, a high shear force mixing device such as an attritor or a TK homomixer) so that the iron oxide particles become primary particles in an aqueous medium. Good to do.

  Since the surface of the iron oxide particles obtained in this way is uniformly hydrophobized, when used as a toner material, the dispersibility in the toner particles is very good, and in addition, the iron oxide particles have a low cohesiveness. Therefore, even toner particles in which iron oxide is unevenly distributed near the surface that can be used in the present invention are not exposed from the surface of the toner particles. Therefore, by using such iron oxide, the ratio (R / Q) of the content R of iron element to the content Q of carbon element present on the toner particle surface measured by X-ray photoelectron spectroscopy is 0. This results in good developability.

  The iron oxide that can be used in the magnetic developer that can be used in the present invention can be produced, for example, by the following method.

  An aqueous solution containing ferrous hydroxide is prepared by adding at least an equivalent amount of alkali such as sodium hydroxide to a ferrous salt aqueous solution such as an aqueous ferrous sulfate solution. Air was blown in while maintaining the pH of the prepared aqueous solution at 7 or higher, preferably 8 to 10, and the aqueous ferrous hydroxide was oxidized while heating the aqueous solution to 70 ° C. or higher. First, a seed crystal is formed.

  Next, an aqueous solution containing about 1 equivalent of ferrous sulfate is added to the slurry-like liquid containing seed crystals based on the amount of alkali added previously. While maintaining the pH of the liquid at 6 to 10, the reaction of ferrous hydroxide proceeds while blowing air, and magnetic iron oxide particles are grown with the seed crystal as the core. Since the pH of the liquid shifts to the acidic side as the oxidation reaction proceeds, it is preferable to add an alkali such as an aqueous sodium hydroxide solution as appropriate so that the pH of the liquid does not drop below 6. Adjust the pH of the solution at the end of the oxidation reaction, stir well so that the magnetic iron oxide becomes primary particles, add a coupling agent, stir well, stir and filter / dry after stirring, lightly disintegrate By doing so, hydrophobized magnetic iron oxide particles can be obtained. After the oxidation reaction, filtration and washing are performed to obtain iron oxide particles, which are re-dispersed in another aqueous medium without being dried, and then the pH of the re-dispersed liquid is adjusted and silane coupling is performed with sufficient stirring. An agent may be added to perform the coupling treatment.

  In any case, it is important that the untreated iron oxide particles produced in the aqueous solution be hydrophobized in the state of the water-containing slurry before passing through the drying step. This is because if untreated iron oxide particles are dried as they are, coalescence between the particles cannot be avoided. Even if wet-hydrophobic treatment is performed on such agglomerated powder, uniform hydrophobization is possible. This is because processing is difficult.

  The ferrous salt used in the ferrous salt aqueous solution in the production of iron oxide is generally iron sulfate produced as a by-product in the production of sulfuric acid titanium, and the use of iron sulfate produced as a by-product in the surface cleaning of steel sheets. In addition to ferrous sulfate, iron chloride or the like can be used.

  In the method for producing magnetic iron oxide by the aqueous solution method, a ferrous sulfate aqueous solution having an iron concentration of 0.5 mol / liter to 2 mol / liter is generally used from the viewpoint of suppressing the increase in viscosity during the reaction and the solubility of iron sulfate. Generally, the lower the iron sulfate concentration, the finer the particle size of the product. Further, in the reaction, the larger the amount of air and the lower the reaction temperature, the easier it becomes to form fine particles.

  In addition, as the shape of iron oxide, there are octahedron, hexahedron, spherical shape, needle shape, scale shape, and the like, but those having less anisotropy such as octahedron, hexahedron, spherical shape, and irregular shape increase the image density. Preferred above. Such a shape of the iron oxide can be confirmed by an electron microscope or the like. As the particle size of the iron oxide particles, it is preferable that the volume average particle size is 0.1 μm to 0.3 μm, and the number of particles having a volume particle size in the range of 0.03 μm to 0.1 μm is 40% by number or less. .

  When an image is obtained from a magnetic toner using iron oxide particles having a volume average particle size of less than 0.1 μm, the color of the image shifts to reddish, and the blackness of the image is insufficient. There is a strong tendency to taste strongly. Furthermore, since the surface area of the iron oxide particles increases, the dispersibility in the binder resin may deteriorate. Further, the density of an image to be obtained from the amount of iron oxide particles added may be insufficient.

  On the other hand, if the volume average particle diameter of the iron oxide particles exceeds 0.3 μm, the mass per particle increases, so the probability of exposure to the toner particle surface increases due to the difference in specific gravity with the binder resin during production. There is.

  In addition, when the number of particles of 0.1 μm or less of the iron oxide in the toner particles exceeds 40% by number, the surface area of the iron oxide particles is increased, the dispersibility is lowered, and agglomerates are easily generated in the toner. The chargeability of the toner may be impaired.

  By using the hydrophobized iron oxide particles thus produced as a developer (toner particles), a magnetic developer having excellent image characteristics can be obtained.

  Japanese Patent Publication No. 60-3181 discloses a method for producing a magnetic polymer toner containing magnetic fine particles obtained by wet-treating the surface of a dry powdery untreated magnetic material with a silane coupling agent. As described above, since this untreated dry magnetic powder cannot avoid the coalescence of particles due to primary agglomeration in the drying process at the time of production, even if wet surface treatment is performed, the individual particles are brought into the medium. It cannot be dispersed and it is difficult to make individual magnetic particles hydrophobic. Therefore, it is difficult to obtain sufficient developability even when toner is formed using such a surface-treated magnetic material.

The iron oxide that can be used in the magnetic developer (magnetic toner particles) that can be used in the present invention may contain elements such as phosphorus, cobalt, nickel, copper, magnesium, manganese, aluminum, and silicon. , Iron trioxide and γ-iron oxide as main components, and these can be used alone or in combination of two or more. These iron oxide, the BET specific surface area preferably by nitrogen adsorption method was 2m ² / g~30m ² / g, more preferably 3m ² / g~28m ² / g, further its Mohs hardness is 5-7 Those are preferred.

  The amount of iron oxide added is preferably 10 parts by mass to 200 parts by mass, more preferably 20 parts by mass to 180 parts by mass with respect to 100 parts by mass of the binder resin. If the added amount of iron oxide is less than 10 parts by mass, the coloring power of the developer is poor and fogging is difficult to control. On the other hand, if it exceeds 200 parts by mass, the retention force by the magnetic force on the developer carrier is increased. It becomes difficult to reduce developability and to uniformly disperse iron oxide in individual toner particles.

  It is difficult to control the internal structure of the toner particles even with the hydrophobic iron oxide as described above. To obtain the iron oxide distribution structure as in the present invention using only the hydrophobic iron oxide, the core particles are designed. Then, a multi-step process such as adding iron oxide particles is necessary.

  Therefore, as a result of intensive investigations, the present inventors have found that in a direct polymerization system in an aqueous medium, a polar compound having a saponification value of 20 to 200 is further added to the iron oxide to uniformly disperse therein. Has been found to be segregated near the surface.

  The polar compound having a saponification value of 20 to 200 may be a resin having a carboxylic acid derivative group such as acrylic acid, methacrylic acid or abietic acid, or a sulfur acid group such as a sulfone group or a sulfate group, or a modified product thereof. As specific monomer components constituting such a resin, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, acrylic Acrylic esters such as 2-chloroethyl acid, phenyl acrylate, etc .; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-propyl methacrylate, n-octyl methacrylate, dodecyl methacrylate , 2-ethylhexyl methacrylate, methacrylic acid Methacrylic acid esters such as thearyl, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; maleic acids such as maleic anhydride and maleic acid half ester; sulfur acid groups such as sulfonic acid; abietic acid and the like Illustrated.

  Among these compounds, a resin having a maleic acid component is preferable because it can exhibit the effects of the present invention in a very small amount, and is preferable because it is excellent in compatibility with the binder resin without impairing the chargeability. In particular, maleic anhydride copolymers represented by the following general formulas (8) and (9) or ring-opening compounds thereof are particularly preferred, and the effects of the present invention are further exhibited.

（式（８）および（９）中、Ａはアルキレン基を示し、Ｒは水素原子または炭素数１〜２０のアルキル基を示す。ｎは１〜２０の整数を示し、ｘ、ｙおよびｚは夫々各成分の共重合比を示す。）

(In formulas (8) and (9), A represents an alkylene group, R represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, n represents an integer of 1 to 20, and x, y, and z represent (The copolymerization ratio of each component is shown.)

  The amount of the polar compound added to the toner particles is preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the binder resin. If the addition amount of the polar compound is less than 0.001 part by mass, the added effect is not exhibited. If the addition amount exceeds 10 parts by mass, the absolute value of the charge amount is likely to decrease due to charge leakage, and fog and image density decrease. Such harmful effects are likely to occur.

  In order to reduce toner adhesion to the non-image area on the electrostatic latent image carrier, it is necessary that the developer (toner particles) have sufficient chargeability and uniformity. Furthermore, when using toner particles having a small particle diameter from the viewpoint of improving the image quality, the adhesion force of the toner particles increases, so that the shape of the toner particles also adheres to the non-image area on the electrostatic latent image carrier. It has a big effect. That is, the closer the toner particles are to a spherical shape and the uniform the shape, the smaller the adhesion area of the particles, and the toner adhesion to the non-image portion on the electrostatic latent image carrier can be reduced. From the above, the average circularity (described later) of the toner particles used in the present invention is preferably 0.970 or more.

  The weight average particle size of the toner particles used in the present invention is preferably 3 μm to 10 μm. When the weight average particle diameter of the toner particles exceeds 10 μm, the reproducibility of the fine dot image is lowered, and the configuration of the present invention is more susceptible to particle size fluctuations in more durable use. In some cases, the charging stability at the lower level cannot be fully exhibited. On the other hand, when the weight average particle diameter of the toner particles is less than 3 μm, even if the special structure of the present invention is used, deterioration of external additives or the like is likely to occur due to a decrease in fluidity, and fogging due to poor charging, density reduction. Such a problem may occur.

  The developer (toner particles) that can be used in the present invention can also be produced by a conventional pulverization method. In this case, in order to obtain a capsule structure of iron oxide in the toner particles as in the present invention. Is disadvantageous in terms of yield and cost because it requires a multi-step process.

  On the other hand, in a toner production method (hereinafter simply referred to as “polymerization method”) obtained by directly polymerizing a monomer system in an aqueous medium, a polar-nonpolar component is used from the viewpoint of affinity with the aqueous medium. Therefore, the iron oxide capsule structure of the present invention can be obtained in one step, which is preferable. In particular, in the present invention, the use of a small amount of the above polar compound can improve the stabilization of the droplets during polymerization and sharpen the particle size distribution, which is preferable from the viewpoint of yield.

  As a polymerizable monomer that is a raw material of a binder resin of a developer (toner particle) that can be used in the present invention, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxy Styrene monomers such as styrene and p-ethylstyrene, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic acid 2-ethylhexyl, stearyl acrylate, 2-chloroethyl acrylate, acrylic esters such as phenyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid n-octyl, dodecyl methacrylate, methacrylate 2-ethylhexyl, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid esters such as diethylaminoethyl methacrylate, acrylonitrile, methacrylonitrile, and other monomers acrylamide. These monomers can be used alone or in admixture of two or more. Among the above-mentioned monomers, styrene or a styrene derivative is preferably used alone or mixed with other monomers from the viewpoint of the developing characteristics and durability of the toner.

  Furthermore, in the developer (toner particles) that can be used in the present invention, a sulfur-containing resin is included as a charge control agent for a polar polymer because it is highly compatible with other components and can be uniformly charged. Is a preferred form. Among these sulfur-containing resins, it is particularly preferable to contain at least a component derived from a sulfonic acid group-containing (meth) acrylamide monomer. In particular, as the monomer, 2-acrylamido-2-methylpropane is preferred in terms of chargeability. Sulfonic acid (AMPS) and 2-methacrylamido-2-methylpropane sulfonic acid are preferred. Moreover, as a monomer which makes a copolymer with the said monomer, a monofunctional polymerizable monomer and a polyfunctional polymerizable monomer can be used.

  As a monofunctional polymerizable monomer, styrene: α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene , P-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p- Styrene derivatives such as phenylstyrene; methyl acrylate, ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2 -Ethylhexyl acrylate Acrylic polymerizable monomers such as N-octyl acrylate, n-nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate Body; methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-butyl methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n- Octyl methacrylate, n-nonyl methacrylate, diethyl phosphate ethyl methacrylate Methacrylate, methacrylic polymerizable monomers such as dibutyl phosphate ethyl methacrylate; methylene aliphatic monocarboxylic acid esters; vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, vinyl formate; And vinyl ethers such as ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropyl ketone.

  As polyfunctional polymerizable monomers, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tripropylene glycol diacrylate Acrylate, polypropylene glycol diacrylate, 2,2'-bis (4- (acryloxydiethoxy) phenyl) propane, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol di Methacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol Methacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, polypropylene glycol dimethacrylate, 2,2′-bis (4- (methacryloxy-diethoxy) phenyl) propane, 2 , 2'-bis (4-methacryloxy-polyethoxy) phenyl) propane, trimethylolpropane trimethacrylate, tetramethylolmethane tetramethacrylate, divinylbenzene, divinylnaphthalene, divinyl ether and the like.

  As the resin having a sulfonic acid group-containing (meth) acrylamide, the above-mentioned monomers can be used, but it is more preferable that a styrene derivative is contained as a monomer.

  There are bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, ionic polymerization, dispersion polymerization, and the like as methods for producing the resin having the sulfonic acid group-containing (meth) acrylamide monomer. Solution polymerization is preferable because it is easy to uniformly mix a monomer containing a group.

The resin having the sulfonic acid group-containing (meth) acrylamide monomer has a structure represented by the following general formula (10).
XCONHR23 (SO ₃ ⁻ ) _n · mY ^{+ k} (10)
[In formula (10), X represents a polymer moiety derived from a polymerizable monomer, R 23 represents an n-valent hydrocarbon group having 1 to 6 carbon atoms, Y ⁺ represents a counter ion, and k represents It is a valence of a counter ion, and m and n are numbers satisfying n = k × m. ]

  The counter ion is preferably a hydrogen cation, a sodium cation, a potassium cation, a calcium cation, an ammonium cation or the like, and more preferably a hydrogen cation.

  In addition, since the resin containing a component derived from a sulfonic acid group-containing (meth) acrylamide has a high polarity, the charge transfer speed at the time of frictional charging of the toner particles is improved by incorporating it in the toner particles, so Can be prevented from being charged up and a decrease in charge amount under high humidity.

  This sulfur-containing resin is a polymer compound comprising a copolymer containing 2 to 20% by mass of a component derived from a sulfonic acid group-containing (meth) acrylamide monomer. The addition amount of the sulfur-containing resin is preferably 0.1 to 1.8 parts by mass with respect to 100 parts by mass of the binder resin in the toner particles in terms of charging performance of the toner particles.

  When the copolymerization ratio of the sulfonic acid group-containing (meth) acrylamide monomer in the sulfur-containing resin is less than 2% by mass, a ghost image appears by generating a solid image at the initial stage of durability, particularly when the charge rises. There is. When the content exceeds 20% by mass, even if the content of the sulfur-containing resin in the toner particles is reduced, the toner is charged up. In particular, the fog characteristics are deteriorated and blotches are observed in a low temperature and low humidity environment. Sometimes.

  The above charge-up phenomenon is likely to occur even when the amount of sulfur-containing resin added exceeds 1.8 parts by mass with respect to 100 parts by mass of the binder resin in the toner. The amount is difficult to increase, and the necessary and sufficient charge control action may not be obtained.

  In order to obtain good charging performance of toner particles, a charge control agent made of a resin containing a sulfonic acid group-containing (meth) acrylamide in a certain range should be present in the toner particles in a certain range. Is considered important.

  The content of the resin having a sulfonic acid group in the toner can be measured using a capillary electrophoresis method or the like.

  Moreover, it is preferable that the weight average molecular weight (Mw) of sulfur-containing resin is 2000-15000. When the molecular weight is low and the Mw is less than 2000, the fluidity of the toner deteriorates, and the toner may deteriorate due to embedding of an external additive particularly in continuous use. On the other hand, when Mw exceeds 15000, the dispersibility of iron oxide in the toner particles is deteriorated, which may cause deterioration of charging ability and coloring power.

  The toner particles that can be used in the present invention also contain a release agent (wax component) as one of preferred usage forms.

  Usable waxes include paraffin wax, microcrystalline wax, petroleum wax such as petrolactam and derivatives thereof, montan wax and derivatives thereof, hydrocarbon wax and derivatives thereof by Fischer-Tropsch method, polyolefin wax represented by polyethylene And natural derivatives such as carnauba wax and candelilla wax and derivatives thereof. Derivatives here include oxides, block copolymers with vinyl monomers, and graft modified products. Furthermore, fatty acids such as higher fatty alcohols, stearic acid and palmitic acid or compounds thereof, acid amide waxes, ester waxes, ketone waxes, hydrogenated castor oil and derivatives thereof, plant-based waxes and animal waxes can also be used.

  In the present invention, when the toner particles are produced, a resin may be added to the monomer system for polymerization. For example, since monomers are water-soluble, they cannot be used because they dissolve in an aqueous suspension and cause emulsion polymerization, and cannot contain simple functional groups containing amino groups, carboxylic acid groups, hydroxyl groups, glycidyl groups, and nitrile groups. When it is desired to introduce the monomer component into the toner, a random copolymer of these and a vinyl compound such as styrene or ethylene, a block copolymer, or a copolymer such as a graft copolymer, or a polyester, It can be used in the form of a polycondensate such as polyamide, or a polyaddition polymer such as polyether or polyimine. The amount used is suitably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the polymerizable monomer. If the amount used is less than 1 part by mass, the effect of addition is small, whereas if it is used in excess of 20 parts by mass, it becomes difficult to design various physical properties of the polymerized toner.

  In addition to the sulfur-containing resin, a charge control agent may be added to the developer (toner particles) that can be used in the present invention in order to control charging characteristics. As the charge control agent, conventionally known ones can be used, and those having a particularly high charging speed and capable of stably maintaining a constant charge amount can be preferably used.

  However, when the toner particles are produced by a direct polymerization method, a charge control agent having a low polymerization inhibition property and substantially free from a solubilized product in an aqueous dispersion medium is particularly preferable.

  Specific examples of such compounds include metal compounds of aromatic carboxylic acids such as salicylic acid, alkylsalicylic acid, dialkylsalicylic acid, naphthoic acid, and dicarboxylic acid, metal salts or metal complexes of azo dyes or azo pigments as negatively chargeable charge control agents. , A polymer compound having a sulfonic acid or carboxylic acid group in the side chain, a boron compound, a urea compound, a silicon compound, a calixarene, etc., and a quaternary ammonium salt as the positively chargeable charge control agent, the quaternary ammonium salt And a polymer compound having a side chain, a guanidine compound, a nigrosine compound, an imidazole compound, and the like.

  The amount of use of these charge control agents is determined by the toner production method including the type of binder resin, the presence or absence of other additives, and the dispersion method, and is not uniquely limited. Preferably, the range of 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass is appropriate for 100 parts by mass of the binder resin.

  When the magnetic developer (magnetic toner particles) used in the present invention is produced by a polymerization method, a polymerization initiator having a half-life of 0.5 hour to 30 hours during the polymerization reaction is added to the polymerizable monomer in an amount of 0. When the polymerization reaction is carried out using an addition amount of 5% by mass to 20% by mass, it is possible to obtain a polymer having a maximum between 10,000 and 100,000 in molecular weight. Properties can be imparted.

  Examples of polymerization initiators include 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile) Azo or diazo polymerization initiators such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile; benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate , Peroxide polymerization initiators such as cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide.

  Moreover, you may add a crosslinking agent, As a preferable addition amount, it is 0.001 mass%-15 mass% of a polymerizable monomer.

  In the production of toner particles by a polymerization method, in a polymerizable monomer, iron oxide, a sulfur-containing resin, a polar compound having a saponification value of 20 to 200, a colorant, a release agent, a plasticizer, a binder, a charge Components necessary for the toner such as a control agent and a crosslinking agent and other additives such as an organic solvent and a dispersant added to lower the viscosity of the polymer produced by the polymerization reaction are added as appropriate, and the homogenizer, ball mill, colloid mill And uniformly dissolved or dispersed by a dispersing machine such as an ultrasonic dispersing machine. The monomer system thus obtained is dispersed / suspended in an aqueous medium containing a dispersion stabilizer. At this time, the particle size of the obtained toner particles becomes sharper by using a high-speed disperser such as a high-speed stirrer or an ultrasonic disperser to obtain a desired toner particle size all at once. As the timing of addition of the polymerization initiator, it may be added simultaneously with the addition of other additives in the polymerizable monomer, or may be mixed immediately before being dispersed in the aqueous medium. Also, a polymerization initiator dissolved in a polymerizable monomer or solvent can be added immediately after granulation and before starting the polymerization reaction.

  As the dispersion stabilizer used here, known surfactants, organic or inorganic dispersants can be used, and among them, inorganic dispersants hardly generate harmful ultra fine powders, and dispersion stability is obtained due to their steric hindrance. Even if the reaction temperature is changed, the stability is not easily lost, the cleaning is easy, and the toner particles are not adversely affected. Examples of such inorganic dispersants include polyvalent metal phosphates such as calcium phosphate, magnesium phosphate, aluminum phosphate and zinc phosphate; carbonates such as calcium carbonate and magnesium carbonate; calcium metasuccinate, calcium sulfate and barium sulfate. And inorganic oxides such as calcium hydroxide, magnesium hydroxide, aluminum hydroxide, silica, bentonite, and alumina.

  These inorganic dispersants are preferably used in an amount of 0.2 to 20 parts by mass alone or in combination of two or more with respect to 100 parts by mass of the polymerizable monomer. When producing more finely divided toner particles having an average particle size of 5 μm or less, 0.001 to 0.1 parts by mass of a surfactant may be used in combination.

  Examples of the surfactant include sodium dodecylbenzene sulfate, sodium tetradecyl sulfate, sodium pentadecyl sulfate, sodium octyl sulfate, sodium oleate, sodium laurate, sodium stearate, and potassium stearate.

  When these inorganic dispersants are used, they may be used as they are, but in order to obtain finer particles, the inorganic dispersant particles can be generated in an aqueous medium. For example, in the case of calcium phosphate, a sodium phosphate aqueous solution and a calcium chloride aqueous solution can be mixed with high-speed stirring to produce water-insoluble calcium phosphate, which enables more uniform and fine dispersion. At this time, water-soluble sodium chloride salt is by-produced at the same time. However, when water-soluble salt is present in the aqueous medium, dissolution of the polymerizable monomer in water is suppressed, and ultrafine toner particles based on emulsion polymerization are used. This is more convenient because it becomes difficult to occur. Since it becomes an obstacle when removing the remaining polymerizable monomer at the end of the polymerization reaction, it is better to replace the aqueous medium or desalinate with an ion exchange resin. The inorganic dispersant can be almost completely removed by dissolving with an acid or alkali after completion of the polymerization.

  In the polymerization step, the polymerization temperature is set to 40 ° C or higher, generally 50 ° C to 90 ° C. When the polymerization is carried out in this temperature range, the release agent and wax to be sealed inside are precipitated by phase separation, and the encapsulation is more complete. In order to consume the remaining polymerizable monomer, it is possible to raise the reaction temperature to 90 ° C. to 150 ° C. at the end of the polymerization reaction.

  The polymerized toner particles are filtered, washed and dried by a known method after the polymerization is completed, and further, a classification process is performed after the production process to remove coarse powder and fine powder. is there.

  In addition, it is preferable that the toner particles that can be used in the present invention have an inorganic fine powder or a hydrophobic inorganic fine powder externally added to and mixed with the toner particles as a fluidity improver. For example, it is preferable to add and use titanium oxide fine powder, silica fine powder, and alumina fine powder.

The inorganic fine powder has a specific surface area by nitrogen adsorption measured by BET method is 30 m ² / g or more is preferred because especially 50m ² / g~400m ² / g those ranges give good results.

  Among these, silica fine powder is preferable. As the silica fine powder, either a so-called dry method produced by vapor phase oxidation of a silicon halide compound or a so-called wet silica produced from water silica or the like, which is called fumed silica, can be used. Dry silica having few silanol groups on the surface and inside and having no production residue is preferable.

  Further, the silica fine powder is preferably hydrophobized because of its characteristics in a high temperature and high humidity environment. When the inorganic fine powder added to the toner particles absorbs moisture, the charge amount of the toner particles decreases and the image density decreases. Hydrophobizing treatment is performed by treating with an organosilicon compound that reacts or physically adsorbs with silica fine powder. As a preferred method, the dry silica fine powder produced by vapor phase oxidation of a silicon halide compound is treated with a silane coupling agent, or with a silane coupling agent and simultaneously with an organosilicon compound such as silicone oil. A method is mentioned.

  Examples of silane coupling agents used for hydrophobizing silica fine powder include hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, and allylphenyl. Dichlorosilane, benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilane mercaptan, trimethylsilyl mercaptan, triorganosilyl acrylate, vinyldimethyl Acetoxysilane, dimethylethoxysilane, dimethyldimethoxysilane, diphenyldiethoxysilane, hexamethyldisiloxane, 1, Examples include 3-divinyltetramethyldisiloxane and 1,3-diphenyltetramethyldisiloxane.

Moreover, a silicone oil is mentioned as an organosilicon compound. Preferred silicone oils, are used as the 25 kinematic viscosity at ℃ approximately ^{30mm 2 / s (cSt) ~1,000mm} 2 / s (cSt), for example, dimethyl silicone oil, methylphenyl silicone oil, alpha-methylstyrene-modified Silicone oil, chlorophenyl silicone oil, and fluorine-modified silicone oil are preferred.

  Silicone oil treatment can be performed by, for example, mixing silica fine powder treated with a silane coupling agent and silicone oil directly using a mixer such as a Henschel mixer, or jetting silica-silica oil as a base. It may be by the method. Alternatively, the silicone oil may be dissolved or dispersed in a suitable solvent, and then the base silica fine powder is mixed to remove the solvent.

  Furthermore, the magnetic toner particles that can be used in the present invention may be mixed with an external additive other than the fluidity improver, if necessary.

For example for the purpose of improving the cleaning property, the primary particle size exceeds 30 nm (preferably less than 50m a specific surface area ² / g) particles, more preferably a primary particle diameter of more than 50 nm (preferably specific surface area of 30 m ² / It is also a preferred form that inorganic particles or organic particles that are nearly spherical with a particle size less than g) are further added to the toner particles. For example, it is preferable to use spherical silica particles and spherical resin particles.

  Still other additives such as lubricant powders such as fluororesin powder, zinc stearate powder, polyvinylidene fluoride powder; or abrasives such as cerium oxide powder, silicon carbide powder, strontium titanate powder, strontium silicate powder; Anti-caking agent; or conductivity-imparting agent such as carbon black powder, zinc oxide powder, tin oxide powder; organic fine particles having opposite polarity and inorganic fine particles can also be added in small amounts as developability improvers. These additives can also be used after hydrophobizing the surface.

  The external additive as described above is used in an amount of 0.05 to 5 parts by weight, preferably 0.1 to 4 parts by weight, based on 100 parts by weight of the toner particles.

  When the magnetic developer (magnetic toner particles) of the present invention is produced by a pulverization method, a known method is used. For example, a binder resin, a polar compound having a saponification value of 20 to 200, iron oxide particles, release particles, and the like are used. Mix the mold agent, charge control agent, and optionally the colorant, and other additives with a mixer such as a Henschel mixer or ball mill, and then melt them using a heat kneader such as a heating roll, kneader, or extruder. Magnetic toner particles can be obtained by dispersing or dissolving other toner materials such as iron oxide while kneading and mixing the resins with each other, cooling and solidifying, pulverizing, classification, and surface treatment as necessary. Can do. Either the classification or the surface treatment may be performed first. In the classification step, it is preferable to use a multi-division classifier in terms of production efficiency.

  The pulverization step can be performed by a method using a known pulverizer such as a mechanical impact type or a jet type. Further, in order to obtain magnetic toner particles having a specific circularity, it is preferable to perform treatment by further pulverizing by applying heat or applying mechanical impact as an auxiliary. Further, a hot water bath method in which finely pulverized (classified as necessary) magnetic toner particles are dispersed in hot water, a method of passing in a hot air stream, or the like may be used.

  As a means for applying a mechanical impact force, for example, a method using a mechanical impact type pulverizer such as a kryptron system (trade name) manufactured by Kawasaki Heavy Industries, Ltd. or a turbo mill (trade name) manufactured by Turbo Industry Co., Ltd. The magnetic toner particles are centrifuged inside the casing by blades that rotate at high speed, such as devices such as Mechano-Fusion System (trade name) manufactured by Hosokawa Micron Co., Ltd., and Hybridization System (trade name) manufactured by Nara Machinery Co., Ltd. Examples include a method in which a mechanical impact force is applied to magnetic toner particles by a force such as a compression force or a friction force.

  In the case of using the mechanical impact method, the treatment temperature is preferably set to a temperature near the glass transition point Tg (Tg ± 30 ° C.) of the magnetic toner particles from the viewpoint of aggregation prevention and productivity. More preferably, it is particularly effective to improve the transfer efficiency to perform at a temperature in the range of the glass transition point Tg ± 20 ° C. of the magnetic toner particles.

  FIG. 4 is a schematic diagram of a developing device according to an embodiment for realizing the developing method of the present invention.

  In FIG. 4, an electrostatic latent image carrier formed by a known process, for example, a photosensitive drum 601 rotates in the arrow B direction. The developing sleeve 608 carries a magnetic one-component developer having magnetic toner particles supplied to the developing container 603 and rotates in the direction of arrow A so that the developing sleeve 608 and the photosensitive drum 601 face each other. The developer is conveyed to region D. In the developer carrier 610, a magnet (magnet roller) 609 is disposed in the developing sleeve 608 in order to magnetically attract and hold the developer on the developing sleeve 608.

  A developing sleeve 608 used in the developing method of the present invention has a conductive resin coating layer 607 coated on a metal cylindrical tube 606 as a base. Magnetic developer is fed into the developer container 603 via a developer supply member (such as a screw) 612 from a developer supply container (not shown). The developing container 603 is divided into a first chamber 614 and a second chamber 615, and the magnetic developer fed into the first chamber 614 has a gap formed between the developing container 603 and the partition member 604 by the stirring and conveying member 605. The magnetic developer passes through the second chamber 615 and is carried on the developing sleeve 608 by the magnetic force of the magnet roller 609. A stirring member 611 is provided in the second chamber 615 to prevent the magnetic developer from staying.

  The magnetic developer obtains a triboelectric charge capable of developing the electrostatic latent image on the photosensitive drum 601 by friction between the magnetic toner particles and the conductive resin coating layer 607 on the developing sleeve 608. In this example, in order to regulate the layer thickness of the developer conveyed to the development area D, a magnetic regulation blade (doctor blade) 602 made of a ferromagnetic metal as a developer layer thickness regulation member is provided on the surface of the development sleeve 608. To 50 μm to 500 μm, and is attached to the developing container 603 so as to face the developing sleeve 608. A magnetic force line from the magnetic pole N <b> 1 of the magnet roller 609 is concentrated on the magnetic regulation blade 602, whereby a thin layer of developer is formed on the developing sleeve 608. Note that a nonmagnetic restricting blade may be used instead of the magnetic restricting blade 602.

  In this manner, the thickness of the magnetic developer thin layer formed on the developing sleeve 608 is preferably smaller than the minimum gap between the developing sleeve 608 and the photosensitive drum 601 in the developing region D.

  The developer carrying member of the present invention is particularly effective when incorporated in a developing device that develops an electrostatic latent image with a thin layer of magnetic developer as described above, that is, a non-contact developing device. In D, the developer carrying member of the present invention can be applied to a developing device in which the thickness of the magnetic developer layer is equal to or larger than the minimum gap between the developing sleeve 608 and the photosensitive drum 601, a so-called contact type developing device. it can. In the following description, a non-contact developing device is taken as an example in order to avoid complicated description.

  In order to cause the magnetic developer carried on the developing sleeve 608 to fly, a developing bias voltage is applied to the developing sleeve 608 from a developing bias power source 613 as bias means. When a DC voltage is used as the developing bias voltage, a voltage having a value between the potential of the image portion of the electrostatic latent image (the region visualized as the developer adheres) and the potential of the background portion is applied to the developing sleeve 608. It is preferable to apply.

  In order to increase the density of the developed image and improve the gradation, an alternating bias voltage may be applied to the developing sleeve 608 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 608 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.

  At this time, in the case of regular development in which a magnetic developer is attached to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion and visualized, the magnetic charge is charged to a polarity opposite to the polarity of the electrostatic latent image. In the case of reversal development that uses a developer and visualizes it by attaching a magnetic developer to the low potential part of an electrostatic latent image having a high potential part and a low potential part, the polarity is the same as the polarity of the electrostatic latent image. Use a charged magnetic developer. In this case, the high potential and the low potential are expressed by absolute values. In either case, the magnetic developer (magnetic toner particles) is charged by friction with at least the surface of the developing sleeve 608 (conductive resin coating layer 607).

  FIG. 4 shows an example of a magnetic blade disposed away from the developing sleeve as a developer layer thickness regulating member that regulates the layer thickness of the developer on the developing sleeve 608. As shown in FIG. Further, an elastic regulating blade made of an elastic plate made of a material having rubber elasticity such as urethane rubber or silicone rubber, or a material having metal elasticity such as phosphor bronze or stainless steel is used, and the elastic regulating blade 616 is developed. The sleeve 608 may be used in contact with or pressure-contacted with a developer via a developer. In the present invention, particularly in a system having this form, the wear resistance and the charge imparting ability are remarkably superior as compared with the prior art. An effect can be obtained. This is because, in a developing device of a type in which the regulating blade is in contact with or pressed against, the toner layer forms a thin layer of the developer on the developing sleeve 608 while being subjected to stronger regulation. Although a thinner developer layer can be formed than in the case of the apparatus example 4, the load on the conductive resin coating layer 607 on the surface of the developing sleeve 608 is increased, and the conductive resin coating layer 607 is easily worn. . In the present invention, even in such a system, wear of the conductive resin coating layer 607 can be reduced, so that high durability can be achieved. The contact pressure of the elastic regulating blade 616 with respect to the developing sleeve 608 is a linear pressure of 5 g / cm to 50 g / cm to stabilize the regulation of the magnetic developer and to make the magnetic developer layer thickness suitable. It is preferable at the point which can do. When the contact pressure of the elastic regulating blade 616 is less than the linear pressure of 5 g / cm, the regulation ability to the magnetic developer is weakened, and it tends to cause fogging and developer leakage, and the linear pressure exceeds 50 g / cm. In this case, damage to the developer is increased, and the developer is likely to be deteriorated and fused to the sleeve and the blade.

  FIGS. 4 and 5 are merely illustrative examples of a developing device that can be used in the developing method of the present invention. In addition to the developer layer thickness regulating member described above, the shape and agitation of the developing container (hopper) 603 are illustrated. Needless to say, there are various forms such as the presence / absence of the blades 605 and 611, the arrangement of the magnetic poles, the shape of the supply member 612, and the presence / absence of the supply container.

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

(1) Universal hardness HU on the surface of the conductive resin coating layer
The universal hardness HU of the surface of the conductive resin coating layer is a hardness value obtained from a surface coating physical property test using a Fisherscope H100V (trade name) manufactured by Fischer Instruments in accordance with ISO / FDIS14577. Using a square pyramid diamond indenter with an angle of 136 °, a measurement load F (unit: N) is applied stepwise to the hardness measurement sample, and the indentation depth h with the load applied is h (Unit: mm) is a value calculated by the following formula (1) after being electrically detected and read.
HU = K × F / h ² [N / mm ² ] Formula (1)
Here, K is a constant and is 1 / 26.43.

  As the measurement sample, a sample in which a conductive resin coating layer is formed on the substrate surface is used. However, in order to improve the measurement accuracy, the conductive resin coating layer surface should be smooth. It is still more preferable to measure after performing a chemical treatment. Therefore, in the present invention, the surface of the conductive resin coating layer was subjected to a polishing process using a # 2000 polishing tape, and the surface roughness Ra after the polishing process was adjusted to be 0.2 μm or less. .

  In the present invention, the test load F and the maximum indentation depth h of the indenter are not affected by the surface roughness of the surface of the conductive resin coating layer and are not affected by the underlying substrate. Measurement was performed by applying a test load F so that the maximum indentation depth h of the indenter was about 1 μm to 2 μm. The measurement environment was 23 ° C. and 50%, the number of measurements was 100 at different measurement points, the average value obtained from the measurement values was A, and the standard deviation was σ.

(2) Arithmetic average roughness Ra of the surface of the conductive resin coating layer
Arithmetic average roughness Ra of the surface of the conductive resin coating layer is cut off by 0.8 mm cut off by Surfcorder SE-3500 (trade name) manufactured by Kosaka Laboratory Co., Ltd. based on JIS-B0601-2001. Measurement was performed for 3 points in the axial direction × 3 points in the circumferential direction = 9 points under the conditions of 8 mm and a feed rate of 0.5 mm / s, and the average value was defined as Ra.

(3) Graphitization degree of graphitized particles p (002)
The graphitization degree p (002) is determined by a lattice spacing d (002) of graphite obtained from an X-ray diffraction spectrum of graphitized particles by a powerful fully automatic X-ray diffractometer “MXP18” system (trade name) manufactured by Mac Science. ) And measured from d (002) = 3.440-0.086 (1-p ² ). For the lattice spacing d (002), high-purity silicon was used as a standard material, and a value corrected from the peak position Si (111) of the measured diffraction pattern was used.

Main measurement conditions:
X-ray generator; 18kW
Measurement X-ray; CuKα (CuKβ is removed by nickel filter)
Goniometer; Horizontal goniometer Monochromator; Use Tube voltage / tube current; 30.0kV / 10.0mA
Measurement method; Continuous method Scan axis; 2θ / θ
Sampling interval; 0.020deg
Scanning speed; 6.000 deg / min
Divergent slit; 0.50deg
Scattering slit; 0.50deg
Light receiving slit; 0.30mm

(4) Particle size of graphitized particles and unevenness-forming particles The particle size of graphitized particles and unevenness-forming particles is determined by the Coulter LS-130 or LS-230 type particle size distribution meter (trade name, both) , Manufactured by Beckman Coulter, Inc.).

  As a measuring method, an aqueous module was used, and isopropyl alcohol was used as a measuring solvent. First, the measurement system of the particle size distribution analyzer is washed with isopropyl alcohol for about 5 minutes, 10 mg to 25 mg of sodium sulfite is added to the measurement system as an antifoaming agent, a background function is executed, and then 50 ml of isopropyl alcohol is added. 3 to 4 drops of a surfactant was added, 5 to 25 mg of a measurement sample was further added, and then a dispersion treatment was performed for 1 to 3 minutes with an ultrasonic disperser to obtain a sample solution. Measurement was performed by gradually adding the sample solution into the measurement system of the measurement apparatus and adjusting the sample concentration in the measurement system so that the PIDS on the screen of the apparatus was 45% to 55%. Using this measured value, the volume average particle diameter calculated from the volume distribution was obtained and used as these particle diameters.

(5) Volume resistance value of the conductive resin coating layer The volume resistance value of the conductive resin coating layer is the same as that constituting the conductive resin coating layer on the developer carrier on a PET sheet having a thickness of 100 μm. A coating layer having a thickness of 7 μm to 20 μm was formed using the coating solution, and measurement was performed by attaching a 4-terminal probe to a resistivity meter Lorester AP (trade name, manufactured by Mitsubishi Yuka Co., Ltd.). The measurement environment was 20 ° C. to 25 ° C. and 50% RH to 60% RH.

(6) Volume resistance of particles A granular sample is put in an aluminum ring of 40 mmφ, pressure-molded at 2500 N, and 4 with a resistivity meter Lorester AP or Hiresta IP (trade name, both manufactured by Mitsubishi Yuka Co., Ltd.). The volume resistance value was measured using a terminal probe. The measurement environment was 20 ° C. to 25 ° C. and 50% RH to 60% RH.

(7) True density of spherical particles The true density of spherical particles was measured using a dry densitometer AccuPick 1330 (trade name, manufactured by Shimadzu Corporation).

(8) Film thickness and amount of abrasion of conductive resin coating layer For measurement of the film thickness and amount of abrasion (film abrasion) of the conductive resin coating layer, a laser dimension measuring device LS5000 (trade name) manufactured by KEYENCE Corp. was used. In addition, using the controller LS-5500 and sensor head LS-5040T, the sensor unit is separately fixed to a device equipped with a sleeve fixing jig and a sleeve feeding mechanism, and the outer diameter of the sleeve is divided into 30 parts in the longitudinal direction of the sleeve. Measure 30 points, further 30 points after rotating the sleeve 90 ° in the circumferential direction, a total of 60 points, and determine the average value. On the other hand, the outer diameter of the sleeve before forming the surface coating layer was measured in advance, and the film thickness of the conductive resin film was calculated from the difference from the outer diameter after forming the surface coating layer. Further, after the endurance use, the outer diameter was measured again, and the shaving amount was calculated from the difference.

(9) Weight average particle size and particle size distribution of toner particles The weight average particle size and particle size distribution of the toner particles were measured by a Coulter counter method. As the apparatus, Coulter Counter TA-II, Coulter Multisizer II or Coulter Multisizer III (all trade names) sold by Beckman Coulter, Inc. were used.

  The measurement sample was dispersed in an electrolytic solution containing a surfactant (preferably, alkylbenzene sulfonate) as a dispersant, and the dispersion was placed in a measurement liquid reservoir for measurement. As this electrolytic solution, a 1% NaCl aqueous solution using primary sodium chloride is used. As a commercial product, for example, ISOTON R-II (trade name, Beckman Coulter, Inc.) can be used.

  0.1 ml to 5 ml of a surfactant (alkylbenzene sulfonate solution) is added to 100 ml to 150 ml of the electrolytic solution, and then 2 mg to 20 mg of a measurement sample is added. The electrolytic solution in which the sample is suspended is dispersed for 1 to 3 minutes with an ultrasonic disperser, set in the particle size distribution measuring apparatus, and the volume and number of toner particles of 2.00 μm or more are measured using a 100 μm aperture. . From this measurement result, a volume distribution-number distribution is calculated. Next, the weight-based weight average particle diameter (D4) obtained from the volume distribution (with the median value of each channel as a representative value for each channel) is calculated.

  As channels, 2.00 μm to less than 2.52 μm; 2.52 μm to less than 3.17 μm; 3.17 μm to less than 4.00 μm; 4.00 μm to less than 5.04 μm; 5.04 μm to less than 6.35 μm; 6.35 μm to less than 8.00 μm; 8.00 μm to less than 10.08 μm; 10.08 μm to less than 12.70 μm; 12.70 μm to less than 16.00 μm; 16.00 μm to less than 20.20 μm; 13 channels of less than 40 μm; 25.40 μm to less than 32.00 μm; 32.00 μm to less than 40.30 μm were used.

(10) Ratio of iron oxide distribution in toner particles, projected particle equivalent diameter C of toner particles, and minimum value D of distance between iron oxide and toner particle surface (D / C)
The projected particle equivalent diameter C of the toner particles and the distribution of iron oxide in the toner particles are dispersed in an epoxy resin (room temperature curable) and cured, and then flakes with a microtome equipped with a diamond blade. Was obtained with a transmission electron microscope (in the present invention, Hitachi H-600 type (trade name) manufactured by Hitachi, Ltd., with an acceleration voltage of 100 kV), and a transmission electron microscope photograph was obtained from the photograph as follows. In order to perform highly accurate measurement, it is desirable that the photographic magnification of the transmission electron microscope is 10,000 to 20,000 times.

  The equivalent circle diameter is obtained from the cross-sectional area of the toner particles obtained from the micrograph, and this is designated as “projected area equivalent diameter C”, of which ± 10 of the weight average particle diameter obtained by the method using the Coulter Counter in (9) above. %, 100 particles are selected as evaluation particles, the distribution of iron oxide particles present in the cross section of each particle is observed, and 0.2% from the surface of the equivalent circle diameter of each particle is observed. The number of toner particles having 70% or more iron oxide particles up to double the depth is measured (iron oxide distribution). On the other hand, for each toner particle, the minimum value D of the distance between the surface and the iron oxide particle surface is obtained, and the ratio of particles having a ratio D / C of 0.02 or less is measured.

(11) Ratio of iron element content R to carbon element content Q present on the toner surface (R / Q)
In the present invention, the carbon element content Q and the iron element content R present on the toner surface are obtained from Physical Electronics Industries, Inc. ESCA (X-ray photoelectron spectroscopic analysis) apparatus 1600S type (trade name) manufactured by KK) was used, and surface composition analysis was performed with an X-ray source MgKα (400 W) and a spectral region of 800 μmφ.

  The carbon element is obtained from the peak top measured at a binding energy of 283 eV to 293 eV, and the iron element is obtained from the peak top measured at a binding energy of 706 eV to 730 eV, and the relative sensitivity factor attached to the apparatus is used. The surface atomic concentration (atomic%) was calculated.

  Incidentally, toner particles are used as a measurement sample. However, when an external additive was added to the toner particles, the measurement was performed after removing the external additive adhering to the toner particle surface using a solvent such as isopropyl alcohol that does not dissolve the toner particles.

(12) Average circularity of toner particles The average circularity is used as a simple method for quantitatively expressing the shape of particles, and is a flow type particle image analyzer “FPIA-1000” manufactured by Toago Medical Electronics. The circularity (Ji) of particles i having an equivalent circle diameter of 3 μm or more was determined by the following equation (3). Here, Ei (μm) is the perimeter of the projected image of the particle i, and Ki (μm) is the perimeter of a circle having the same projected area as the particle i.
Circularity of particle i Ji = Ki / Ei Formula (3)

Next, a value obtained by dividing the total sum of the circularity (Ji) of all the measured particles by the total number of particles n is defined as an average circularity J by the following equation (4).
Average circularity J = (1 / n) × ΣJi = (1 / n) × Σ (Ki / Ei) Equation (4)

  The measuring device “FPIA-1000” calculates the circularity of each particle, and then calculates the average circularity and the mode circularity, and the circularity is 0.40 to 1.00 depending on the obtained circularity. Is divided into classes divided into 61 at intervals of 0.010, and a calculation method is used in which the average circularity is calculated using the center value and frequency of the division points. The error between the average circularity value calculated by this calculation method and the average circularity value calculated by the above-described calculation formula that directly uses the circularity of each particle is very small and can be substantially ignored. Therefore, in the present invention, a value directly output from the apparatus using such a calculation method that is partially changed using the concept of the calculation formula that directly uses the circularity of each particle described above. It was adopted.

  The average circularity is an index of the degree of unevenness of the particles, and is 1.000 when the particles are completely spherical, and becomes a smaller value as the developer surface shape becomes more complicated.

  As a specific measuring method, about 5 mg of a developer is dispersed in 10 ml of water in which about 0.1 mg of a surfactant is dissolved to prepare a dispersed sample solution, and ultrasonic waves (20 kHz, 50 W) are irradiated for 5 minutes. The particle dispersion concentration is 5000 / μl to 20000 / μl. Next, measurement is performed with the above-mentioned apparatus, and the average circularity is obtained from the circularity of particles having an equivalent circle diameter of 3 μm or more.

  The measurement followed the manual attached to the measuring device. The outline is as follows.

  The sample dispersion is passed through a flow path (expanded along the flow direction) of a flat and flat flow cell (thickness: about 200 μm). The strobe and the CCD camera are mounted so as to be positioned on the opposite sides of the flow cell so as to form an optical path that passes through the thickness of the flow cell. While the sample dispersion is flowing, strobe light is irradiated at 1/30 second intervals to obtain an image of the particles flowing through the flow cell, so that each particle has a certain range parallel to the flow cell. Photographed as a two-dimensional image. From the area of the two-dimensional image of each particle, the diameter of a circle having the same area is calculated as the equivalent circle diameter. The circularity of each particle is calculated from the projected area of the two-dimensional image of each particle and the perimeter of the projected image using the above circularity calculation formula.

  In this measurement, the reason why the circularity is measured only for the particle group having an equivalent circle diameter of 3 μm or more is that the particle group of the external additive existing independently of the toner particles in the particle group having an equivalent circle diameter of less than 3 μm. This is because the circularity of the toner particle group cannot be accurately estimated due to the influence of such a large amount.

(13) Saponification value measurement method Saponification value (mg of potassium hydroxide required to neutralize free fatty acid, resin acid, etc. contained in 1 g of sample) is a basic operation according to JIS-K0070. Ask for.

(13-1) Reagent solvent: Ethyl ether-ethyl alcohol mixed solution (1 + 1 or 2 + 1) or benzene-ethyl alcohol mixed solution (1 + 1 or 2 + 1). These solutions should be neutralized with 0.1N potassium hydroxide ethyl alcohol solution using phenolphthalein as an indicator just before use.
Phenolphthalein solution: 1 g of phenolphthalein is dissolved in 100 ml of ethyl alcohol (95 v / v%).
0.1N potassium hydroxide-ethyl alcohol solution: Dissolve 7.0 g of potassium hydroxide in as little water as possible, add ethyl alcohol (95 v / v%) to 1 liter, leave it for 2 to 3 days, and filter. The standardization is performed in accordance with JIS K8006 (basic matters concerning titration during the reagent content test).

(13-2) Operation Weigh correctly 1 to 20 g of sample, add 100 ml of solvent and a few drops of phenolphthalein solution as an indicator, and shake well until the sample is completely dissolved. In the case of a solid sample, dissolve it by heating on a water bath. After cooling, an excess amount of 0.1N potassium hydroxide-ethyl alcohol solution (100 ml to 200 ml) is added thereto, and the mixture is heated to reflux for 1 hour to saponify, and then cooled. The obtained solution is back titrated with a 0.1N hydrochloric acid aqueous solution, and the end point of neutralization is determined when the indicator's slight red color disappears for 30 seconds. In addition, a blank experiment will be performed in parallel with this test.

(13-3) Calculation Formula The saponification value is calculated according to the following formula (5).
ZA = {(ZB)-(ZC)} * 5.611 * f / S Formula (5)
Here, ZA: saponification value ZB: addition amount of 0.1N hydrochloric acid aqueous solution in blank test (ml)
ZC: 0.1N aqueous hydrochloric acid added in this test (ml)
f: Factor of 0.1N hydrochloric acid aqueous solution S: Sample (g)

(14) Degree of hydrophobicity of iron oxide particles The degree of hydrophobicity of iron oxide particles is determined when iron oxide particles are dispersed in water and methanol is gradually added while stirring, so that all of the iron oxide particles sink. It is represented by the methanol concentration (volume%) of the methanol-water mixed solvent (when iron oxide particles are no longer confirmed on the liquid surface) or the amount of alcohol added to the predetermined amount of water. This measurement method (methanol titration test) is an experimental test for confirming the degree of hydrophobicity of a magnetic powder having a hydrophobic surface.

  Specifically, 0.1 g of iron oxide particles are added to 50 ml of water in a 250 ml beaker, and methanol is titrated from the bottom while gently stirring. Titration is carried out with gentle stirring. The end point of titration is when no suspended particles of iron oxide particles are observed on the liquid surface. The degree of hydrophobicity can be expressed as the amount of methanol when reaching the end of sedimentation or the volume percentage of methanol in the water mixture.

(15) Molecular Weight of Sulfur-Containing Resin The weight average molecular weight of the sulfur-containing resin was measured by gel permeation chromatography (GPC) using tetrahydrofuran and determined as a polystyrene conversion value. Specifically, the following method was followed. RI was used as a detector.

<Sample preparation>
About 10 mg of the sample was dissolved in 5 ml of tetrahydrofuran and allowed to stand at 25 ° C. for 16 hours, and then filtered through a membrane filter having a pore size of 0.45 μm to prepare a sample.

<Device>
A high-speed GPC HPLC8120 GPC (trade name, manufactured by Tosoh Corporation) was used as an apparatus.

<Measurement conditions>
Temperature: 35 ° C
Solvent: Tetrahydrofuran Flow rate: 1.0 ml / min
Concentration: 0.2% by mass
Sample injection volume: 100 μl
Column: Showa Denko Co., Ltd. GPC column (Showex GPC KF806M (trade name)) 30 cm 2

<Calibration curve>
TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10, F-4, F-2, F manufactured by Tosoh Corporation -1, A-5000, A-2500, A-1000 and A-500 (all trade names) were used as standard polystyrene samples to prepare a calibration curve.

  Next, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto. In the following, “parts” means all parts by mass unless otherwise specified.

  First, the manufacture example is shown about the graphitized particle | grains, uneven | corrugated formation particle | grains, and image development sleeve which are used by a following example and a comparative example.

Reference Example 1 (Production of graphitized particles A-1)
Mesocarbon microbeads obtained by heat treatment of heavy coal oil were washed and dried, then mechanically dispersed with an atomizer mill and carbonized by primary heat treatment at 1200 ° C. in a nitrogen atmosphere. . Subsequently, secondary dispersion was performed with an atomizer mill, followed by heat treatment at 2800 ° C. in a nitrogen atmosphere, and further classified to collect graphitized particles having a volume average particle size of 3.5 μm, thereby obtaining graphitized particles A-1.

Reference Example 2 (Production of graphitized particles A-2)
The β-resin was extracted from the coal tar pitch by solvent fractionation, hydrogenated and subjected to heavy treatment, and then the solvent-soluble component was removed with toluene to obtain a mesophase pitch. The mesophase pitch is finely pulverized, and the particles are oxidized in air at about 800 ° C., then calcined and graphitized at 3000 ° C. in a nitrogen atmosphere, and further classified to a volume average particle size of 2.9 μm graphite. The graphitized particles were collected, and the graphitized particles were designated as A-2.

Reference Examples 3 to 6 (Production of graphitized particles A-3 to A-6)
A volume average particle size of 0.7 μm (graphitized particles A-3), 5.9 μm (graphitized particles A-4), 10.3 μm (as in Reference Example 1 except that the firing temperature and classification conditions were changed) Graphitized particles having a graphitized particle A-5) or 7.8 μm (graphitized particle A-6) were prepared.

Reference Example 7 (Production of graphitized particles A-7)
As a raw material for graphitized particles, a mixture of coke and tar pitch is used, and the mixture is kneaded at a temperature equal to or higher than the softening point of tar pitch, extruded, and subjected to primary firing at 1000 ° C. in a nitrogen atmosphere to be carbonized. Subsequently, impregnated with coal tar pitch, followed by secondary firing at 2800 ° C. in a nitrogen atmosphere, graphitized, and further pulverized and classified to collect graphitized particles having a volume average particle diameter of 7.1 μm. -7 was obtained.

  The physical properties of the graphitized particles A-1 to A-7 prepared above were measured and are shown in Table 4.

Reference Example 8 (Production of irregularity-forming particles B-1)
A β-resin was extracted from coal tar pitch by solvent fractionation, subjected to hydrogenation and heavy treatment, and then solvent-soluble content was removed with toluene to obtain mesophase pitch powder. The mesophase pitch powder is finely pulverized, oxidized in air at about 300 ° C., then heat treated at 3000 ° C. in a nitrogen atmosphere, and further classified to form irregularities forming particles having a volume average particle size of 5.4 μm. Collected to obtain irregularity-forming particles B-1.

Reference Example 9 (Production of irregularity-forming particles B-2)
The mesocarbon microbeads obtained by heat-treating heavy coal-based oil were washed and dried, and then mechanically dispersed by an atomizer mill and subjected to carbonization by primary heat treatment at 1200 ° C. in a nitrogen atmosphere. Next, after secondary dispersion with an atomizer mill, heat treatment was performed at 2400 ° C. in a nitrogen atmosphere, and further classified to collect irregularity-forming particles having a volume average particle diameter of 10.5 μm, thereby obtaining irregular-shaped particles B-2. It was.

Reference Example 10 (Production of irregularity-forming particles B-3)
100 parts of spherical phenol resin particles having a volume average particle diameter of 5.5 μm are uniformly coated with 15 parts of bulk mesophase pitch particles having a volume average particle diameter of 1 μm to 2 μm using a lykai machine (automatic mortar, manufactured by Ishikawa Factory). After heat stabilization treatment at 350 ° C. in the middle, it was fired at 2300 ° C. in a nitrogen atmosphere, and further classified to collect spherical conductive carbon particles having a volume average diameter of 6.0 μm to obtain unevenness forming particles B-3.

Reference Example 11 (Production of irregularity-forming particles B-4)
100 parts of PMMA resin and 25 parts of carbon black are melt-mixed, kneaded, pulverized, and classified to obtain carbon black-dispersed PMMA resin particles having a volume average particle diameter of 7.1 μm, and then a hybridizer (trade name, Nara). Spherical carbon black-dispersed PMMA resin particles were produced by performing spheronization using a machine (manufactured by Machine Co., Ltd.). The spherical carbon black-dispersed PMMA resin particles were used as irregularity forming particles B-4.

Reference Example 12 (Production of irregularity-forming particles B-5)
After classifying the silicone resin particles, spheronization treatment was performed using a hybridizer to produce silicone resin particles having a volume average particle size of 6.5 μm. This silicone resin particle was designated as unevenness forming particle B-5.

  The physical properties of the unevenness-forming particles B-1 to B-5 and alumina (the unevenness-forming particle B-6) produced above were measured and are shown in Table 5.

Reference Example 13 (Production of developing sleeve S-1)
Resol type phenol resin (solid content 50 mass% methanol solution) 160 parts, graphitized particles A-1 (produced in Reference Example 1) 36 parts, conductive carbon black (trade name: Conductex 975, manufactured by Columbia Carbon Co., Ltd.) 4 Parts, irregularity-forming particles B-1 (prepared in Reference Example 8), 10 parts, imidazole compound (in formula (2), R5 = R6 = CH ₃ , R7 = R8 = (CH ₂ ) ₁₀ CH ₃ ) Glass beads having a diameter of 1 mm were added to 6 parts and 120 parts of methanol, dispersed for 2 hours with a sand mill, and separated with a sieve, and then the solid content was adjusted to 35% by mass with methanol to obtain a coating solution. .

  This coating liquid is vertically standing and rotating at a constant speed, and the upper and lower end portions are masked, and the grinding is performed on an aluminum cylinder having a thickness of 2 mm, an outer diameter of 20 mmφ, and an arithmetic average roughness Ra = 0.2 μm. A conductive resin coating layer was formed on the tube by applying the spray gun while descending at a constant speed. Then, it heated at 150 degreeC for 30 minute (s) with the hot air drying furnace, the conductive resin coating layer was hardened, and developing sleeve S-1 was created. Table 6 shows the formulation and physical properties of the conductive resin coating layer of the developing sleeve S-1.

Reference Examples 14 to 28 (production sleeves S-2 to S-16)
Developing sleeves S-2 to S-16 were prepared in the same manner as in Reference Example 13 except that the coating liquid was prepared with the material configuration and mixing ratio shown in Table 6. The developing sleeves S-12 to S-16 were aluminum cylindrical bases that were ground to a thickness of 2 mm, an outer diameter of 24.5 mmφ, and an arithmetic average roughness Ra = 0.3 μm. Table 6 shows the formulation and physical properties of the conductive resin coating layer of these developing sleeves.

  Next, production examples of components of a magnetic one-component developer used in the following Examples and Comparative Examples, and production examples of the developer are shown.

Reference Example 29 (Production of surface-treated iron oxide particles G-1)
An aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 to 1.1 equivalents of a caustic soda solution with respect to iron ions in an aqueous ferrous sulfate solution. While maintaining the pH of this aqueous solution at around 9, air was blown and an oxidation reaction was carried out at 80 ° C. to 90 ° C. to prepare a slurry liquid for generating seed crystals.

  Next, after adding ferrous sulfate aqueous solution so that it becomes 0.9 equivalent to 1.2 equivalent to the initial alkali amount (sodium component of caustic soda) to this slurry liquid, the slurry liquid is maintained at around pH 8, The oxidation reaction was promoted while blowing air, the pH was adjusted to about 6 at the end of the oxidation reaction, and 0.6 parts of n-hexyltrimethoxysilane coupling agent was added to 100 parts of iron oxide with sufficient stirring. Ring treatment was performed. The produced hydrophobic iron oxide particles are washed, filtered and dried by a conventional method, and then the slightly agglomerated particles are crushed to obtain surface-treated iron oxide particles having an average particle size of 0.19 μm and a hydrophobicity of 87 G-1 was obtained.

Reference Example 30 (Production of surface-treated iron oxide particles G-2)
In Reference Example 29, the ferrous sulfate aqueous solution was added to the slurry liquid so as to be 0.9 equivalent to 1.2 equivalent relative to the initial alkali amount (sodium component of caustic soda), and then the slurry liquid was maintained at about pH 8. The oxidation reaction was advanced while blowing air, and the pH was adjusted to about 6 at the end of the oxidation reaction to complete the oxidation reaction. The generated particles were washed, filtered, and dried by a conventional method, and then the aggregated particles were crushed to obtain iron oxide particles G-3. The obtained iron oxide particles G-3 were hydrophobized with an n-hexyltrimethoxysilane coupling agent (adjusted to 0.6 parts with respect to 100 parts of iron oxide) diluted 10 times with methanol in the gas phase. The surface-treated iron oxide particles G-2 were obtained by processing. This surface-treated iron oxide G-2 had an average particle size of 0.20 μm and a hydrophobicity of 67.

Reference Example 31 (Production of sulfur-containing polymer P-1)
In a reaction vessel equipped with a reflux tube, a stirrer, a thermometer, a nitrogen introduction tube, a dropping device and a decompression device, 250 parts of methanol as a solvent, 150 parts of 2-butanone and 100 parts of 2-propanol, and 92.5 parts of styrene as a monomer 2 parts of 2-ethylhexyl acrylate and 2.5 parts of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) were added and heated to reflux temperature with stirring. A solution prepared by dissolving 4.0 parts of t-butylperoxy-2-ethylhexanoate in 20 parts of 2-butanone as a polymerization initiator was added dropwise thereto over 30 minutes, and then stirring was continued for 4 hours. A solution prepared by dissolving 0.40 part of t-butylperoxy-2-ethylhexanoate in 20 parts of 2-butanone was added dropwise over 30 minutes, and the mixture was further stirred for 5 hours to complete the polymerization. The polymer obtained after the solvent was distilled off under reduced pressure was pulverized to 100 μm or less using a cutter mill equipped with a 100 μm screen to obtain a sulfur-containing polymer P-1. Table 7 shows the physical properties of the obtained sulfur-containing polymer P-1.

Reference Examples 32 and 33 (Production of sulfur-containing polymers P-2 and P-3)
A sulfur-containing polymer P-2 and a sulfur-containing polymer P-3 were obtained in the same manner as in Reference Example 31 except that the monomer species and the amount used were changed as shown in Table 7. Table 7 shows the physical properties of the obtained sulfur-containing polymer P-2 and sulfur-containing polymer P-3.

Reference Example 34 (Production of Magnetic Developer T-1)
After warming the 0.1M-Na ₃ PO ₄ aqueous solution 451 parts of the closing and 60 ° C. in deionized water 709 parts, Ca ₃ (PO ₄₎ was added to 1.0 M-CaCl ₂ aqueous solution 67.7 parts ₂ An aqueous medium containing was prepared.

  78 parts of styrene, 22 parts of n-butyl acrylate, 0.5 part of divinylbenzene, 2 parts of saturated polyester resin (acid value 8, peak molecular weight (Mp) 12000), surface-treated iron oxide particles G-1 (produced in Reference Example 29) ) 80 parts and 0.1 part of a styrene-maleic anhydride copolymer (saponification number: 15, peak molecular weight (Mp) 3000) as a polar compound, an attritor (trade name, manufactured by Mitsui Miike Chemical Co., Ltd.) Was uniformly dispersed and mixed. This monomer composition was heated to 60 ° C., and 10 parts of ester wax (72 ° C. maximum value of endothermic peak in DSC) was added, mixed and dissolved therein, and polymerization initiator t-butylperoxy 2-ethyl was added thereto. A polymerizable monomer composition was prepared by dissolving 3 parts of hexanoate.

This polymerizable monomer composition was put into the above-mentioned aqueous medium, and at 60 ° C. and N ₂ atmosphere for 15 minutes at 10,000 rpm with a TK homomixer (trade name, manufactured by Tokushu Kika Kogyo Co., Ltd.). Stir, disperse and suspend. Then, it reacted at 80 degreeC for 1.5 hours, stirring with a paddle stirring blade.

  Next, a solution in which 10 parts of styrene, 3 parts of a sulfur-containing polymer P-1 (prepared in Reference Example 31) and 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) were uniformly dissolved, The solution was dropped into the above suspension at 80 ° C., and polymerization was further performed for 4.5 hours.

After completion of the reaction, distillation was further performed at 80 ° C. for 2 hours, after which the suspension was cooled, hydrochloric acid was added to dissolve the dispersant Ca ₃ (PO ₄ ) ₂ , filtered, washed with water and dried to obtain a weight average particle. Black particles having a diameter of 6.5 μm were obtained.

Black particles 100 obtained by treating silica with a primary particle size of 12 nm with hexamethyldisilazane and then with silicone oil to obtain 1.2 parts of hydrophobic silica fine powder having a BET value of 120 m ² / g after treatment. In addition to the above, a Henschel mixer (Mitsui Miike Chemical Co., Ltd.) was sufficiently mixed to prepare a magnetic developer T-1. Table 8 shows the physical properties of this magnetic developer T-1.

Reference Example 35 (Production of magnetic developer T-2)
After warming the 0.1M-Na ₃ PO ₄ aqueous solution 451 parts of the closing and 60 ° C. in deionized water 709 parts, Ca ₃ (PO ₄₎ was added to 1.0 M-CaCl ₂ aqueous solution 67.7 parts ₂ An aqueous medium containing was prepared.

  78 parts of styrene, 22 parts of n-butyl acrylate, 0.5 part of divinylbenzene, 2 parts of saturated polyester resin (acid value 8, peak molecular weight (Mp) 12000), 2 parts of negative charge control agent (monoazo iron complex compound) 80 parts of surface-treated iron oxide particles G-1 (prepared in Reference Example 29) and 0.05 part of a styrene-maleic anhydride copolymer (saponification number: 15, peak molecular weight (Mp) 3000) as a polar compound The mixture was uniformly dispersed and mixed with a lighter. This monomer composition was heated to 60 ° C., and 10 parts of ester wax (72 ° C. maximum value of endothermic peak in DSC) was added, mixed and dissolved therein, and polymerization initiator t-butylperoxy 2-ethyl was added thereto. A polymerizable monomer composition was prepared by dissolving 3 parts of hexanoate.

This polymerizable monomer composition was put into the above aqueous medium, and suspended at 60 ° C. and N ₂ atmosphere with a TK homomixer at 10,000 rpm for 15 minutes. Thereafter, the mixture was reacted at 80 ° C. for 1.5 hours while stirring with a paddle stirring blade.

After completion of the reaction, stirring was further continued at 80 ° C. for 8 hours. Thereafter, the suspension was cooled, hydrochloric acid was added to dissolve the dispersant Ca ₃ (PO ₄ ) ₂ , filtered, washed with water, and dried to obtain black particles having a weight average particle diameter of 7.1 μm.

100 parts of the black particles and silica having a primary particle diameter of 12 nm were treated with hexamethyldisilazane and then treated with silicone oil, and 1.1 parts of hydrophobic silica fine powder having a BET value of 120 m ² / g after the treatment was obtained. The magnetic developer T-2 was prepared by mixing with a Henschel mixer. Table 8 shows the physical properties of this magnetic developer T-2.

Reference Example 36 (Production of magnetic developer T-3)
Styrene / n-butyl acrylate copolymer (monomer ratio: 78/22, Mn = 25000, Mw / Mn = 2.5) 100 parts, saturated polyester resin (acid value 8, peak molecular weight (Mp) 12000) 2 parts, Sulfur-containing polymer P-1 (prepared in Reference Example 31) 5 parts, surface-treated iron oxide particles G-1 (prepared in Reference Example 29) 20 parts, styrene-maleic anhydride copolymer (saponification number) as a polar compound : 15, 0.07 part of peak molecular weight (Mp) 3000) and 5 parts of ester wax (maximum endothermic peak 72 ° C. in DSC) were premixed with a Henschel mixer and then melted with a biaxial extruder heated to 130 ° C. The kneaded and cooled kneaded product was coarsely pulverized with a hammer mill to obtain a coarsely pulverized toner product. The obtained coarsely pulverized product was mechanically pulverized using a mechanical pulverizer turbo mill (trade name, manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces). The finely pulverized product and the resulting finely pulverized product are classified and removed at the same time using a multi-division classifier using the Coanda effect (manufactured by Nittetsu Mining Co., Ltd., elbow jet classifier (trade name)). Toner particles were obtained. Thereafter, 60 parts of the surface-treated iron oxide particles G-1 (prepared in Reference Example 29) are mixed with 100 parts of the toner particles by a Henschel mixer and externally added to the surface of the toner particles. The iron oxide particles were fixed on the surface of the toner particles using a temperature of 55 ° C. and a rotary processing blade peripheral speed of 90 m / sec) to obtain iron oxide fixed toner particles.

  After 8 parts of emulsified particles (particle size 0.05 μm) made of styrene-methacrylic acid copolymer were externally added to 100 parts of the iron oxide fixed toner particles, an impact surface treatment apparatus (treatment temperature 55 ° C., rotary type). Using a processing blade peripheral speed of 90 m / sec), fixing and film formation were carried out to obtain coated toner particles. Hydrophobic colloidal silica was externally added to 100 parts of the resulting coated toner particles in the same manner as in Reference Example 34 to prepare a magnetic developer T-3 having a weight average particle diameter of 7.2 μm. Table 8 shows the physical properties of this magnetic developer T-3.

Reference Example 37 (Production of magnetic developer T-4)
Styrene / n-butyl acrylate copolymer (monomer ratio: 78/22, Mn = 25000, Mw / Mn = 2.5) 100 parts, saturated polyester resin 2 parts, sulfur-containing polymer P-1 (produced in Reference Example) ) 5 parts, 80 parts of surface-treated magnetic powder G-1 (prepared in Reference Example 29), styrene-maleic anhydride copolymer (saponification number: 15, peak molecular weight (Mp) 3000) 0.07 as a polar compound And 5 parts of ester wax (maximum endothermic peak of DSC 72 ° C.) are premixed with a Henschel mixer, then melt-kneaded with a biaxial extruder heated to 130 ° C., and the cooled kneaded product is coarsely crushed with a hammer mill Thus, a coarsely pulverized toner was obtained. The coarsely pulverized product was finely pulverized with a jet mill, and the resulting finely pulverized product was classified by air to obtain toner particles having a weight average particle size of 7.0 μm. To 100 parts of the toner particles, 1.0 part of the same silica as used in Reference Example 34 was added and mixed with a Henschel mixer to prepare a magnetic developer T-4. Table 8 shows the physical properties of this magnetic developer T-4.

Reference Example 38 (Production of magnetic developer T-5)
Toner particles were obtained in the same manner as in Reference Example 34 except that the hydrophobic iron oxide G-1 was not added. 40 parts of untreated surface iron oxide (iron oxide particles G-3, produced in Reference Example 30) are externally added to 100 parts of the obtained toner particles, and an impact surface treatment apparatus (treatment temperature 55 ° C., rotary treatment). Iron oxide particles were fixed to the surface of the toner particles at a blade peripheral speed of 90 m / sec) to obtain iron oxide fixed toner particles.

  20 parts of emulsified particles (particle size 0.05 μm) made of styrene-methacrylic acid copolymer and 40 parts of iron oxide particles G-3 (produced in Reference Example 30) After the addition, the emulsified particles and iron oxide particles were fixed and formed into a film with an impact surface treatment apparatus (treatment temperature 55 ° C., rotary treatment blade peripheral speed 90 m / sec) to obtain coated toner particles. Hydrophobic colloidal silica was externally added to 100 parts of the obtained coated toner particles in the same manner as in Reference Example 34 to prepare a magnetic developer T-5 having a weight average particle diameter of 7.1 μm. Table 8 shows the physical properties of this magnetic developer T-5.

Reference Example 39 (Production of magnetic developer T-6)
The surface-treated magnetic powder G-2 (produced in Reference Example 30) is used instead of the surface-treated magnetic powder G-1, and the sulfur-containing polymer P-2 is used instead of the sulfur-containing polymer P-1. Except for the above, suspension polymerization was performed in the same manner as in Reference Example 34 to obtain black particles having a weight average particle diameter of 7.5 μm. To 100 parts of the black particles, 1.5 parts of negatively charged hydrophobic silica fine powder (BET 300 m ² / g) treated with hexamethyldisilazane and dimethyl silicone oil and 0.5 part of strontium titanate were added, and Henschel was added. The magnetic developer T-6 was obtained by mixing with a mixer. Table 8 shows the physical properties of this magnetic developer T-6.

Reference Example 40 (Production of magnetic developer T-7)
Suspension polymerization was carried out in the same manner as in Reference Example 39 except that a sulfur-containing polymer P-3 (produced in Reference Example 33) was used instead of the sulfur-containing polymer P-2, and a weight average particle size of 7 Obtained 1 μm black particles. To 100 parts of the black particles, 1.8 parts of negatively charged hydrophobic silica fine powder (BET 300 m ² / g) treated with hexamethyldisilazane and dimethyl silicone oil and 0.7 part of strontium titanate were added, and Henschel was added. The magnetic developer T-7 was obtained by mixing with a mixer. Table 8 shows the physical properties of this magnetic developer-7 (T-7).

Reference Example 41 (Production of magnetic developer T-8)
After externally adding 30 parts of emulsified particles (styrene-methacrylic acid, particle size 0.05 μm) to 100 parts of the black particles obtained in Reference Example 39, an impact surface treatment apparatus (treatment temperature 50 ° C., rotary type) Using a processing blade peripheral speed of 90 m / sec), the emulsified particles were repeatedly fixed and formed into a film to obtain coated toner particles. To 100 parts of the resulting coated toner particles, 1.5 parts of negatively charged hydrophobic silica fine powder (BET 300 m ² / g) treated with hexamethyldisilazane and dimethylsilicone oil and 0.5 part of strontium titanate were removed. In addition, a magnetic developer T-8 was obtained. Table 8 shows the physical properties of this magnetic developer T-8.

Reference Example 42 (Production of magnetic developer T-9)
Toner particles were obtained in the same manner as in Reference Example 39, except that the hydrophobic iron oxide G-2 was not added. 40 parts of untreated iron oxide (iron oxide particles G-3, Reference Example 30) are externally added to 100 parts of the obtained toner particles, and an impact surface treatment apparatus (treatment temperature 55 ° C., rotating treatment blade circumference). The iron oxide particles were fixed to the surface of the toner particles using a speed of 90 m / sec) to obtain iron oxide fixed toner particles.

  To 100 parts of the iron oxide fixed toner particles, 20 parts of emulsion particles (particle size 0.05 μm) made of styrene-methacrylic acid copolymer and 40 parts of iron oxide particles G-3 (manufactured in Reference Example 30) are externally added. After that, the emulsified particles and the iron oxide particles were fixed and formed into a film with an impact surface treatment apparatus (treatment temperature 55 ° C., rotary treatment blade peripheral speed 90 m / sec) to obtain coated toner particles. External coating treatment was performed on 100 parts of the obtained coated toner particles in the same manner as in Reference Example 39 to obtain a magnetic developer T-9 having a weight average particle diameter of 7.1 μm. Table 8 shows the physical properties of this magnetic developer T-9.

Example 1
A magnet net roller was attached to the developing sleeve S-1 created in Reference Example 13, and a flange was fitted to obtain a developer carrier. This developer carrier was incorporated into a developer of a Canon digital copying machine IR2000 (230V machine specification) using an OPC drum, and the magnetic developer T-1 produced in Reference Example 34 as a developer in this developer. For the supply. Three sets of such sets are prepared, and each is at room temperature and normal humidity environment (23 ° C., 50% RH; N / N), low temperature and low humidity environment (15 ° C., 10% RH; L / L), and high temperature and high humidity environment ( At 32 ° C. and 85% RH (H / H), 150,000 sheets were imaged (durability) in an intermittent mode of 1 sheet / 10 seconds. In the image evaluation, test charts were drawn according to the respective image evaluation items at the initial stage (10th image printing) and after the end of durability, and image evaluation was performed as follows. In any environment, good developability was obtained from beginning to end. Further, the following performance of the developing sleeve was also evaluated. The developing device used here is roughly as shown in FIG. 5, and an elastic blade made of urethane rubber was used as a developer layer thickness regulating member. Table 9 shows the results of image evaluation and performance evaluation.

  Evaluation items, evaluation methods and evaluation criteria are as follows.

(1) Image Density A copy density of a 5 mmφ black circle on a test chart with an image ratio of 5.5% is measured by a reflection densitometer RD918 (manufactured by Macbeth), and an average value of 10 points is taken. Concentration.

(2) Fog The reflectance of the solid white image portion in the appropriate image was randomly measured with a reflectometer (TC-6DS, manufactured by Tokyo Denshoku Co., Ltd.). The fog density was obtained by subtracting the reflectance (average value at 10 locations) of unused transfer paper from the worst value of this measured value, and evaluated according to the following criteria.
A: Less than 1% (fogging is not recognized visually)
B: 1% to 2% (Fog is not recognized unless it is watched)
C: 2% to 3% (although there is fog, there is no practical problem)
D: Over 3% (fogging is conspicuous and NG level)

(3) Dot reproducibility An image output test was performed using a test chart having a checker pattern of 80 μm × 50 μm (FIG. 6), and the presence or absence of defects in the image part (black part) was observed with a microscope, and evaluated according to the following criteria: did.
A: 2 or less defects in 100 B: 3 to 5 defects in 100 C: 6 to 10 defects in 100 D: 11 or more defects in 100

(4) Sleeve ghost After drawing a strip-shaped solid black portion (Fig. 7 (a)) of width x x length l, halftone (Fig. 7 (b)) of width y (however,> x) x length l ). The image density of this halftone image is shown in FIG. 7C (region a) (part after the length z of the rotation of the developing sleeve from the image formation start point), region a (rotation of the developing sleeve from the image formation start point). And a region c (a portion where only a halftone is imaged from the image formation start point to the length z of one rotation of the developing sleeve). Each image density was measured, and the sleeve ghost was evaluated on the basis of the following standard based on the density difference (degree of shading) that appeared.
A: No difference in density is observed (density difference is less than 0.02)
B: A slight density difference is observed between the area A and the area C (the density difference is 0.02 or more and less than 0.04).
C: A slight density difference is observed in each of the areas A, A, and C (the density difference is 0.04 or more and less than 0.07).
D: A remarkable density difference is observed (the density difference is 0.07 or more)

(5) Change in the surface roughness Ra of the developer carrier The surface roughness Ra of the developer carrier was measured before and after the endurance, and the amount of Ra (ΔRa) was used to determine the surface roughness Ra of the developer carrier according to the following criteria. Abrasion resistance was evaluated.
A: Extremely good wear resistance (ΔRa is less than 0.10 μm)
B: Abrasion resistance is relatively good (ΔRa is 0.10 μm or more and less than 0.20 μm)
C: Although wear resistance is slightly weak, there is no practical problem (ΔRa is 0.20 μm or more and less than 0.35 μm)
D: Abrasion resistance is weak, causing a problem even in practical use (ΔRa is 0.35 μm or more)

(6) Abrasion resistance of conductive resin coating layer The film thickness of the conductive resin coating layer on the surface of the developer carrying member was measured before and after durability, and the amount of abrasion of the conductive resin coating layer was measured from the difference.

Examples 2-10, Comparative Examples 1-5
Using the developing sleeves S-1 to S-10 and the magnetic developers T-1 to T-5 shown in Table 6, image evaluation and performance evaluation were performed by the same evaluation method as in Example 1. Table 9 shows the evaluation results.

Examples 11-15, Comparative Examples 6-8
Canon digital copying machine IR6000 using developing sleeves S-11 to S-15 and magnetic developers T-6 to T-9 shown in Table 10 and using an amorphous silicon drum as an electrostatic latent image carrier as a copying machine. Was used. Durability was based on performing 600,000 prints in continuous mode. This developing device is roughly as shown in FIG. 4, and a magnetic blade having a thickness of 0.6 mm was used as a developer layer thickness regulating member. The results of evaluation are shown in Table 10.

FIG. 2 is a schematic cross-sectional view of a developer carrying member (developing sleeve) of the present invention. It is a schematic diagram for demonstrating the copy image in which the sleeve ghost produced. FIG. 3 is a schematic cross-sectional view of a conductive resin coating layer of the developer carrying member (developing sleeve) of the present invention. FIG. 2 is a schematic explanatory view showing a one-component developing device using a magnetic blade. FIG. 2 is a schematic explanatory view showing a one-component developing device using an elastic blade. It is explanatory drawing of the checker pattern for testing dot reproducibility. It is a schematic diagram of the print image used for evaluation of a sleeve ghost.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductive resin coating layer 601 Electrostatic latent image carrier (photosensitive drum)
602 Developer layer thickness regulating member (developing blade) made of ferromagnetic metal
603 Development container 604 Partition member 605 Stirring conveyance member 606 Base 607 Conductive resin coating layer 608 Development sleeve 609 Magnet (magnet roller)
610 Developer carrier 611 Agitating and conveying member 612 Developer supply member 613 Development bias power source 614 First chamber 615 Second chamber 616 Developer layer thickness regulating member (developing blade) made of an elastic body
a Conductivity-providing particles b Binder resin c Graphitized particles d Concavity and convexity formation particles l Black solid, halftone and evaluation length of sleeve ghost evaluation x Black solid width of sleeve ghost evaluation y Halftone width of sleeve ghost evaluation z Sleeve ghost Length of one rotation of the developing sleeve at the time of evaluation D Development area (X) Area where only thin development is performed (Y) Area where dark development is performed A Area of sleeve ghost evaluation A Area of sleeve ghost evaluation Y Sleeve ghost Evaluation area

Claims (15)

A developer container for containing the developer, a developer carrier that supports the developer on the surface and is rotatably supported, and a developer layer thickness regulating member that regulates the amount of the developer on the developer carrier. Development that transports a developer carried to a development region facing at least the electrostatic latent image carrier and visualizes the electrostatic latent image formed on the electrostatic latent image carrier by the developer. In the method
(A) The developer carrying member has at least a conductive resin coating layer on the substrate surface, and the surface of the conductive resin coating layer has an average value A of universal hardness HU and a standard deviation σ of 300 N / mm ² respectively. ~ 800 N / mm ² and less than 30 N / mm ² ,
(A) The developer is composed of toner particles containing at least a binder resin and iron oxide. When the cross section of the toner particles is observed using a transmission electron microscope, the developer is one of the iron oxides contained in the toner particles. Development is characterized in that it contains 40% to 95% of toner particles existing from the surface of the observed toner particles to a depth 0.2 times the projected area equivalent diameter C. Method.   The developing method according to claim 1, wherein graphitized particles are contained in the conductive resin coating layer of the developer carrying member.   The developing method according to claim 2, wherein the graphitization degree p (002) of the graphitized particles contained in the conductive resin coating layer of the developer carrying member is 0.20 to 0.95.   The developing method according to claim 2 or 3, wherein the graphitized particles contained in the conductive resin coating layer of the developer carrying member are obtained by graphitizing bulk mesophase pitch particles.   The developing method according to claim 2 or 3, wherein the graphitized particles contained in the conductive resin coating layer of the developer carrying member are obtained by graphitizing mesocarbon microbead particles.   The developing method according to any one of claims 1 to 5, wherein particles for forming irregularities on the surface are further contained in the resin coating layer of the developer carrying member.   The toner particle has a ratio (R / Q) of the content R of iron element to the content Q of carbon element present on the surface of the toner particle measured by X-ray photoelectron spectroscopy analysis (R / Q) is less than 0.001, 7. The toner particle according to claim 1, wherein the toner particle contains a projected area equivalent diameter C and toner particles satisfying a relationship of D / C ≦ 0.02 of a minimum distance D between the iron oxide and the toner particle surface. The developing method according to item.   The developing method according to claim 1, wherein the average circularity of toner particles having an equivalent circle diameter of 3 μm to 400 μm measured by a flow type particle image measuring apparatus is 0.970 or more.   2. The developer comprises toner particles containing at least a binder resin, iron oxide, and a sulfur-containing resin, and the sulfur-containing resin has a structural unit derived from at least a sulfonic acid group-containing (meth) acrylamide. The developing method of any one of -8. A developer carrying member for use in the developing method according to claim 1, which has at least a conductive resin coating layer on a surface of the substrate, and the surface of the conductive resin coating layer has a universal hard surface. a developer carrying member, characterized in that the average value a and a standard deviation σ of the HU is each less than 300N / mm ² ~800N / mm ² and 30 N / mm ^2.   The developer carrier according to claim 10, wherein at least graphitized particles are contained in the conductive resin coating layer.   The developer carrier according to claim 11, wherein the graphitized particles contained in the conductive resin coating layer have a graphitization degree p (002) of 0.20 to 0.95.   The developer carrier according to claim 11 or 12, wherein the graphitized particles contained in the conductive resin coating layer are obtained by graphitizing bulk mesophase pitch particles.   The developer carrying member according to claim 11 or 12, wherein the graphitized particles contained in the conductive resin coating layer are obtained by graphitizing mesocarbon microbead particles.   The developer carrying member according to any one of claims 10 to 14, wherein particles for forming irregularities on the surface are further contained in the resin coating layer.

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