JP2009109869A - Developer carrier and developing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer carrier capable of obtaining a high quality image stably without causing problems such as image density decrease, sleeve ghost, nonuniform image density, and blotch even under different environmental conditions, and to provide a developing method using the developer carrier. <P>SOLUTION: The developer carrier includes at least a substrate and a conductive covering layer as a surface layer. The conductive covering layer carries, on its surface, inorganic particles including perovskite crystals, at least the one of which to be selected from fatty acid or fatty acid metal salt is present on the surface and whose particle shape is rectangular parallelepiped. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

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

  Conventionally, development methods in electrophotography are mainly divided into a one-component development method and a two-component development method. However, if it is necessary to reduce the size of the copying apparatus for the purpose of reducing the weight and size of the electrophotographic apparatus, one-component development is required. In many cases, a developing device using a method is used. As a developing device using the one-component developing method, an electrostatic latent image is formed on the surface of a photosensitive drum as an electrostatic latent image carrier, and the toner is positively or negatively rubbed by friction between the developer carrier (developing sleeve) and the toner. Gives a negative charge. By this method and / or friction between the developer layer thickness regulating member (developing blade) for regulating the toner coat amount on the developing sleeve and the toner, positive or negative charge is given to the toner. The toner is thinly applied onto the developing sleeve and conveyed to a developing area where the photosensitive drum and the developing sleeve face each other. In the developing area, the toner is developed by flying and adhering to the electrostatic latent image on the surface of the photosensitive drum. A latent image is known which is visualized as a toner image.

  However, when such a one-component development method is used, it is difficult to adjust the charge of the toner, and various contrivances with the toner have been made, but problems related to the non-uniformity of the toner charge and the durability stability of the charge are It is not fully resolved. In particular, while the developing sleeve rotates repeatedly, the charge amount of the toner coated on the developing sleeve becomes too high due to contact with the developing sleeve. For this reason, the toner is attracted very strongly to the surface of the developing sleeve and becomes immobile on the surface of the developing sleeve, so that the so-called charge-up phenomenon that does not move from the developing sleeve to the latent image on the photosensitive drum is likely to occur particularly under low humidity. Become. When such a charge-up phenomenon occurs, the toner in the upper layer is difficult to be charged, and the development amount of the toner is reduced. As a result, the line image may become thinner or the solid image may have a lower image density. In addition, toner that is not properly charged due to charge-up may become poorly regulated and flow onto the sleeve, causing spotted or wavy unevenness (hereinafter also referred to as “blotch”). Furthermore, the toner layer formation state of the image part (toner consumption part) and the non-image part may change, and the charging state may differ. In this case, for example, when the position where the solid image having a high image density is once developed on the developing sleeve comes to the developing position during the next rotation of the developing sleeve and the halftone image is developed, a solid image trace appears on the image. In other words, a so-called sleeve ghost phenomenon is likely to occur.

  As a method for solving such a phenomenon, in Patent Document 1 and Patent Document 2, a coating layer in which conductive fine powder such as crystalline graphite and carbon is dispersed in a resin is provided on a metal substrate. A method of using a developing sleeve for a developing device has been proposed. By using this method, it is recognized that the above phenomenon is greatly reduced. However, in this method, when a large amount of the above powder is added, it is good for charge-up and sleeve ghost, but an adequate ability to impart charge to the toner is insufficient, especially in a high-temperature and high-humidity environment. Below, it is difficult to obtain a sufficient image density. Furthermore, when a large amount of the above powder is added, the coating layer becomes brittle and becomes easy to scrape, and the surface shape becomes non-uniform, and the surface roughness and surface composition of the coating layer change when the durable use is promoted. As a result, toner conveyance failure and non-uniform charge application to the toner are likely to occur. On the other hand, when the amount of the conductive fine powder added to the coating layer formed on the metal substrate of the developing sleeve is small, the effect of the conductive fine powder such as crystalline graphite and carbon is thin, and charge-up and The problem remains that measures against sleeve ghosts are insufficient.

  Patent Document 3 proposes a developing sleeve in which conductive spherical particles having a low specific gravity are dispersed in a conductive coating layer. Thereby, the conductive spherical particles are uniformly dispersed in the conductive coating layer, the wear resistance of the coating layer and the shape of the surface of the coating layer are uniformed, and the uniform charge imparting property to the toner is improved. In addition, toner contamination and toner fusion are suppressed even when the coating layer is somewhat worn. However, this developing sleeve is not perfect in terms of quick and uniform charge imparting to the toner and moderate charge imparting ability to the toner. In addition, in terms of wear resistance, in further long-term durable use, conductive particles such as crystalline graphite are likely to be worn or dropped from the portion where the conductive spherical particles do not exist on the surface of the coating layer. The wear of the coating layer is promoted from the worn and dropped portions, causing toner contamination and toner fusion, resulting in unstable toner charging and image defects.

  Further, LED and LBP printers are the mainstream in the recent market, and higher resolution is being promoted as a technology direction. Copiers are also becoming more sophisticated and, therefore, are moving towards digitalization. Since this method is mainly a method of forming an electrostatic charge image with a laser, it is also proceeding in the direction of high resolution. Therefore, with this development, a higher definition is required. For this reason, the toner is becoming smaller in particle size and finer. In such a toner having a small particle size, the surface area per unit mass is large, so that the surface charge tends to be large during the development process. Therefore, image defects such as sleeve ghost and density unevenness due to the above-described charge-up phenomenon tend to occur.

  Further, in terms of energy saving and office space saving, the printer / copier body is required to be smaller. At that time, the container for storing the toner is inevitably required to be small, and it is possible to print out a large number of sheets with a small amount, that is, low consumption that can cover the same image with a smaller amount of toner. Toners have been used. Examples of the low-consumption toner include a toner that brings the toner shape closer to a sphere by a manufacturing method such as a method of spheroidizing the toner itself by a mechanical impact force, a spray granulation method, a solution dissolution method, or a polymerization method. In such a spherical toner, the surface is smoother than that of a pulverized toner, and the magnetic material is likely to be encapsulated. Accordingly, image defects such as sleeve ghost, blotch phenomenon, and density unevenness as described above tend to occur.

  In Patent Document 4 and Patent Document 5, the following methods are proposed. By adding a quaternary ammonium salt compound that is positively charged to the iron powder in the resin to the conductive coating layer provided on the developing sleeve, it is produced by a spheroidized toner or a polymerization method. A method for preventing excessive charging such as charge-up for negative toner. By using such a method, although an effect is recognized in preventing the charge-up phenomenon and improving the charge imparting uniformity, the charging stability and the conveyance stability for the toner are still insufficient.

  On the other hand, as a method for thinly applying the toner used in the above-described one-component developing method onto the developing sleeve, there are the following methods. The developing blade abuts on the developing sleeve in a counter direction with respect to the rotation direction of the developing sleeve, and a contact pressure between the developing blade and the developing sleeve and a contact portion (nip portion) between the developing blade and the developing sleeve A method for regulating the amount of toner applied on the developing sleeve. Many developing blades are made of a hard material such as metal or synthetic resin with an elastic body such as silicon rubber or urethane rubber fixed. If the toner seal is not opened, that is, the toner is contained in the storage container. It is sealed and there is no toner on the developing sleeve. In this state, the developing blade sticks to the surface of the developing sleeve due to the contact pressure, and if the developing sleeve is rotated as it is, turning occurs and uniform toner application cannot be performed on the developing sleeve. The problem will arise. In order to prevent these problems, Patent Document 6 discloses a method in which a powder lubricant dispersed in a volatile liquid is applied to the surface of the developing blade. In Patent Document 7, a fine powder of a lubricant such as PVDF is applied on the developer carrier. Application methods have been used.

Such a lubricant is easily given frictional charge from a developing sleeve, a developing blade, or the like, and may affect the charging of the toner depending on the charging series of the lubricant. In particular, since there are many on the sleeve at the initial stage of image output, the influence on the charging of the toner becomes remarkable. If the charge series of the lubricant has a polarity opposite to that of the toner and the charge is too high, the lubricant plays the role of a carrier and extremely increases the charge of the toner. As a result, the toner is attracted very strongly to the surface of the developing sleeve and becomes immobile on the surface of the developing sleeve, and does not move from the developing sleeve to the latent image on the photosensitive drum. When such a charge-up phenomenon occurs, the charge state of the upper layer toner is likely to be non-uniform, and a sleeve ghost is likely to occur on the image. Further, since the toner development amount decreases, problems such as thin line images, uneven solid images, and low image density occur. Furthermore, toner particles that are not sufficiently charged due to charge-up are poorly regulated and flow out onto the sleeve, causing a so-called blotch phenomenon in which spots and wavy irregularities occur. On the other hand, in the case of the same polarity as that of the toner, if the charge of the lubricant is too high, the toner is insufficiently applied with tribo, and uneven image density and low image density may occur due to uneven coating. Therefore, as the lubricant, the toner is coated on the developing sleeve, and it has an appropriate shape and charging characteristics so that the initial development characteristics at the start of the development process and image defects due to uneven application of the lubricant do not occur. It is necessary to use a lubricant as appropriate. In Patent Document 8, the average particle diameter and the circularity of the lubricant are defined, and the configuration in which the chargeability of the lubricant itself can be set within an appropriate range to reduce toner charging non-uniformity and charge-up. Thus, there has been proposed a developing device capable of preventing image defects such as the above-described sleeve ghost. Patent Document 9 proposes a developer carrier capable of preventing generation of an initial sleeve ghost by attaching a titanium oxide powder having a charging polarity close to that of toner to the surface of a coating layer on the developer carrier. However, even these configurations are not perfect in terms of the ability to quickly and uniformly charge the toner. Further, Patent Document 10 proposes a method for suppressing excessive toner charging by directly applying a metal soap such as a stearic acid metal salt on a developer carrying member. However, when the toner is coated on the developer carrying member by applying a material having high lubricity, the regulation by the developing blade tends to be weakened, and the amount of toner on the developer carrying member increases rapidly at the initial stage of image output, Carpet-like coat unevenness (blotch) may occur. In particular, the tendency is remarkable for the above-described toner having a small particle diameter and a toner having a high sphericity.
Japanese Patent Laid-Open No. 2-105181 JP-A-3-36570 JP-A-8-240981 JP 2003-57951 A JP 2002-311636 A JP-A-2-298971 Japanese Patent No. 2818126 JP 11-119551 A JP 2001-215790 A JP 2003-162143 A

  As described above, the toner tends to become unstable and non-uniform as the particle size and spheroidization of the toner progresses in order to improve the performance of the electrophotographic apparatus. Seen in. In the above conventional example, although there is a temporary effect in stabilizing and uniformizing the frictional charge to the toner, the image defect due to instability / nonuniformity of the toner charge amount in the initial stage of image output, charge-up, etc. It is hard to say that it is still fully implemented as a means to improve the situation. Therefore, it is a problem to prevent further charge-up phenomenon, to improve the uniformity of charging, and to improve image defects such as sleeve ghost phenomenon, blotch and density unevenness due to them.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a developer carrying member that does not cause problems of developer charge-up and frictional charging non-uniformity and instability that occur in the initial stage of image output. In addition, image density irregularities, image streaks, sleeve ghosts, and blotches that occur with increasing developer loading do not occur, and high-quality images with high image density and low character scattering are stabilized. It is an object of the present invention to provide a developer carrier that can be obtained.

  Another object of the present invention is to provide a developer carrying member capable of obtaining a good and stable image even in repeated and durable use.

  Another object of the present invention is to provide a developer carrier that does not cause problems such as density reduction, image density unevenness, image streaks, sleeve ghosts, and blotches regardless of the initial and durability of image output even under different environmental conditions. Is to provide. Accordingly, it is an object of the present invention to provide a developer carrying member that can stably obtain a high-quality image having a high image density.

  Another object of the present invention is to provide non-uniform charging of the toner or initial toner that tends to appear when an image is formed using a toner having a high charge amount, for example, a toner having a small particle diameter or a toner having a high sphericity. It is an object of the present invention to provide a developer carrying member that controls an increase in carrying amount. At the same time, it is an object to provide a developer carrying member that can provide a stable image quality without causing charge-up by promptly applying appropriate charge to the toner.

  Furthermore, it is providing the developing method using the said developer carrier.

The developer carrier according to the present invention is a developer carrier having at least a substrate and a conductive coating layer as a surface layer,
The conductive coating layer is characterized by carrying inorganic particles made of perovskite-type crystals having a rectangular parallelepiped particle shape, on which at least one selected from fatty acids and fatty acid metal salts is present on the surface. To do.

  In the developing method according to the present invention, the developer is carried on the developer carrying member, and the developer is applied to the developing area of the electrostatic latent image carrying member arranged opposite to the developer carrying member. And transporting and developing the electrostatic latent image on the electrostatic latent image carrier with the developer.

  According to the present invention, it is possible to suppress non-uniform toner charging, image density decrease due to charge-up, image density unevenness, sleeve ghost, blotch, and the like in the initial stage of image output. In particular, even when a toner having a high charge amount, for example, a non-magnetic one-component toner, particularly a spherical toner by a polymerization method or the like is used, the toner charge on the sleeve is stably controlled and the toner layer on the sleeve is stabilized. Can be formed.

  As a result of intensive studies, the present inventors have processed inorganic particles made of perovskite crystals having a substantially rectangular parallelepiped shape, so that at least one selected from fatty acids and fatty acid metal salts is present on the surface. It has been found that the above-mentioned problems can be solved by using a developer carrying member carried on the surface of the conductive coating layer as the surface layer.

  As described above, the particles applied as a lubricant on the developing blade and the particles carried on the developer carrier may be triboelectrically charged by the developing sleeve or the developing blade in the initial stage of use and affect the toner charging. .

  By using a cuboid-shaped perovskite crystal as the inorganic particles, the contact area with the toner is increased, the charging opportunity is increased, and the toner is suitably charged.

  Further, the inorganic particles have fatty acid or fatty acid metal salt on the surface. As a result, the lubricity can be improved and the initial turning of the developing blade and the sticking to the developer carrier can be prevented. In addition, it was found that the charge-up suppressing effect on the toner is also good.

  On the other hand, when a metal soap such as a stearic acid metal salt is directly applied on the developer carrier to increase the lubricity, the lubricity between the developer carrier and the developing blade becomes too high. It was. Therefore, when the toner is coated on the developer carrying member, the regulation by the developing blade tends to be weakened. In this case, particularly at the initial stage of image output, the amount of toner on the developer carrying member may increase rapidly, and carpet-like coating unevenness (blotch) may occur. As in the present invention, it has been found that an appropriate toner coat state can be maintained by using a structure in which inorganic particles are interposed and fatty acid or a fatty acid metal salt is present on the surface of the inorganic particles.

  Next, the inorganic particles (hereinafter, also simply referred to as “inorganic particles”) on the surface of which at least one selected from fatty acids and fatty acid metal salts is used will be described in more detail.

<Inorganic particles>
Examples of inorganic particles made of a perovskite crystal having a rectangular parallelepiped shape include strontium titanate, barium titanate, and calcium titanate. In particular, strontium titanate can be preferably used.

  For example, inorganic particles composed of perovskite crystals can be reacted by adding strontium hydroxide to a titania sol dispersion obtained by adjusting the pH of a hydrous titanium oxide slurry obtained by hydrolyzing an aqueous solution of titanyl sulfate. It can be synthesized by heating to temperature. By setting the pH of the hydrous titanium oxide slurry to 0.5 to 1.0, a titania sol having a good crystallinity and a particle size can be obtained.

  For the purpose of removing ions adsorbed on the titania sol particles, an alkaline substance such as sodium hydroxide is preferably added to the dispersion of the titania sol. At this time, it is preferable that the pH of the slurry is not 7 or higher so that sodium ions and the like are not adsorbed on the surface of the hydrous titanium oxide. The reaction temperature is preferably 60 ° C. or more and 100 ° C. or less. In order to obtain a desired particle size distribution, the temperature rising rate is preferably 30 ° C./hour or less, and the reaction time is 3 hours or more and 7 hours or less. Is preferred.

  The average particle size of the primary particles of the inorganic particles used in the present invention is preferably 0.03 μm or more and 0.30 μm or less, and particularly preferably 0.04 μm or more and 0.20 μm or less. When the average particle size of the primary particles is within the above numerical range, the effect of suppressing the charge-up to the developer becomes strong, the charging of the developer is inhibited, and the image density can be prevented from being lowered.

  In addition, since it is easy to be present uniformly on the surface of the conductive coating layer of the developer carrier, it is possible to suppress toner charging unevenness, and to suppress image defects such as uneven halftone density and blotches due to local charge-up. Can do.

  In addition, the inorganic particles are not necessarily present as primary particles but may be present as aggregates. Even in this case, the content of aggregates having a particle size of 0.60 μm or more is 1% by number or less. Preferably there is. This is because it is possible to make the developer carrier surface more uniformly present.

  Furthermore, it is preferable for the inorganic particles used in the present invention that the content of particles having a rectangular parallelepiped shape is 50% by number or more because the charge control effect on the developer is more efficiently increased.

<< Fatty acid, fatty acid metal salt >>
At least one selected from fatty acids and fatty acid metal salts is present on the surface of the inorganic particles in order to exhibit the effect of preventing the initial turning of the developing blade and sticking to the developer carrier, and further the effect of suppressing the charge-up of the toner. ing.

  As the fatty acid and fatty acid metal salt, a fatty acid having 8 to 35 carbon atoms and a metal salt thereof are suitable. It is possible to maintain good adhesion between the surface of the inorganic particles and a fatty acid or a metal salt thereof while maintaining the effect of surface lubricity and charge suppression. For this reason, the effects of improving the surface lubricity and suppressing the charging associated with the use of fatty acids or fatty acid metal salts can be expressed over a longer period of time. Examples of fatty acids include stearic acid, lauric acid, sorbic acid.

  Examples of metals that form salts with these fatty acids include zinc, aluminum, and calcium.

  The preferable treatment amount of the fatty acid or the metal salt thereof with respect to the inorganic particles is 0.1% by mass or more and 15.0% by mass or less, more preferably 0.5% by mass or more and 12.0% by mass or less with respect to the inorganic particles. is there.

  As a method for causing at least one of a fatty acid and a fatty acid metal salt to be present on the surface of the inorganic particles, the inorganic particles are preferably surface-treated with the fatty acid or the fatty acid metal salt.

Specifically, the following method can be used as a method for subjecting inorganic particles to a surface treatment with a fatty acid or a metal salt thereof. That is, in an Ar gas or N ₂ gas atmosphere, a slurry of inorganic particles can be placed in an aqueous solution of fatty acid sodium to deposit fatty acid on the perovskite crystal surface. In addition, for example, in an Ar gas or N ₂ gas atmosphere, a slurry of inorganic particles is placed in a fatty acid sodium aqueous solution, and a desired metal salt aqueous solution is dropped while stirring to precipitate a fatty acid metal salt on the perovskite crystal surface. Can be adsorbed. For example, if a sodium stearate aqueous solution and aluminum sulfate are used, aluminum stearate can be adsorbed.

  As a method of supporting the inorganic particles having fatty acids and the like on the surface thereof on the surface of the developer carrier, a dispersion liquid in which the inorganic particles are dispersed in a volatile liquid that does not attack the inorganic particles is prepared. Next, a method of applying the dispersion onto the developer carrying member by a known method such as spraying, dipping, or brushing is suitably used. In this case, the coating amount of the inorganic particles on the developer carrier can be controlled by the solid content concentration of the inorganic particles in the dispersion. Also, the coating amount of the inorganic particles can be controlled depending on the coating conditions such as the spray amount and coating speed of the dispersion for the spray method, and the lifting speed of the developer carrier from the dispersion for the dipping method. .

  Moreover, a method of impregnating and applying inorganic particles to a sponge roller as shown in FIG. 1 is also preferably used. The particle coating apparatus is composed of a sponge roller 26, a developing sleeve 27, a coating container 28, and inorganic particles 29. The sponge roller 26 includes a cored bar 26b and a sponge 26a. One side of the cored bar 26b of the sponge roller 26 is rotatably supported by a bearing (not shown), and one side is a rotating shaft of a motor (not shown). And connected through gears. The sponge roller 26 is driven by a motor (not shown) and rotates in the direction of arrow F in the figure. The coating container 28 is filled with inorganic particles 29 so that the sponge of the sponge roller 26 is uniformly filled in the longitudinal direction. The sponge roller 26 holds the inorganic particles 29 on the sponge surface, and conveys the inorganic particles 29 to the developing sleeve 27 by rotation. Further, the rotation speed of the sponge roller 26 can be adjusted.

  On the other hand, the developing sleeve 27 is installed in the coating container 28 in parallel with the sponge roller 26. As for the installation position of the developing sleeve 27, both end portions in the longitudinal direction of the developing sleeve 27 are pressed by a rotatable bearing (not shown) from the direction of arrow G in the figure, and the developing sleeve 27 uniformly enters the surface of the sponge roller 26 in the longitudinal direction. A gear flange (not shown) is attached to one side of the developing sleeve 27, and the developing sleeve 27 is rotated in the direction of arrow F in the figure by mounting a gear that receives rotational driving of a motor (not shown) on the gear flange. . The rotational speed of the developing sleeve 27 can also be adjusted. That is, the sponge roller 26 and the developing sleeve 27 rotate in the counter direction with respect to each other, and coating is performed so that the inorganic particles on the sponge roller 26 are rubbed onto the developing sleeve 27. The coating amount of the inorganic particles on the developing sleeve 27 is determined by the penetration amount of the developing sleeve into the sponge roller, the rotational speed and relative speed of the developing sleeve / sponge roller, and the absolute amount of the supported particles (inorganic particles) in the coating container. Is done.

  When the developer layer thickness regulating member is used in contact with a developer carrier such as an elastic blade, the developer particles are coated on the elastic blade to assemble the developing unit, and then the developer layer The developer carrying member is rotated for a predetermined time in a state in which the toner is not coated. Accordingly, a method of coating the developer carrying member with the carrier particles on the developer layer thickness regulating part can also be suitably used. As a coating method in this case, a known method such as the method described above is used.

In the present invention, the relationship between the constant area R (mm ² ) on the surface of the conductive coating layer of the developer carrying member and the area M (mm ² ) on which the inorganic particles are carried is 0.03 ≦ M / R. It is desirable to satisfy ≦ 0.30. The area M is determined by the amount of inorganic particles applied to the developer carrier. By setting M / R within the above numerical range, it is possible to sufficiently obtain the effect of supporting inorganic particles, such as control of imparting charge to the developer. Further, charging of the developer is inhibited and image density is not lowered.

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

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

  In addition, as a base in the case of using a developing method in which the photosensitive drum is brought into direct contact, a cylindrical member having a layer configuration including a metal cored bar and rubber such as urethane, EPDM, silicone, or elastomer is preferably used. In a developing method using a magnetic developer, a magnet roller or the like in which a magnet is provided is disposed in the developer carrying body in order to magnetically attract and hold the developer on the developer carrying body. In that case, the base may be cylindrical and a magnet roller may be disposed inside the base.

<< Coating layer >>
Further, the developer carrying member used in the present invention is preferably provided with a coating layer such as metal plating or resin on the surface thereof in order to control the chargeability of the developer.

  As a method for forming the plating layer on the surface of the developer carrying member, electroplating or electroless plating can be preferably used. In particular, in electroless plating, a plating layer can be formed uniformly and accurately for chemical plating regardless of the rough surface of the convex portion.

  Specifically, the plating layer is preferably formed of a layer made of a nonmagnetic metal, alloy or metal compound selected from the group consisting of nickel, chromium, molybdenum and palladium. For example, electroless Ni-P plating, electroless Ni-B plating, electroless Pd plating, electroless Pd-P plating, electroless Cr plating, electric field Mo plating, or electroless Mo plating may be used. The physical properties of the sleeve surface are preferably non-magnetic when the sleeve has a magnet roll. The thickness of the plating layer is 0.5 μm or more and 20 μm or less, more preferably 3 μm or more and 15 μm or less. When the thickness of the plating layer is less than 0.5 μm, the layer thickness is thin, so that the effect of providing the plating layer is difficult to be exhibited. When the thickness of the plating layer exceeds 20 μm, the plating layer existing on the substrate surface It becomes difficult to maintain the thickness of the film uniformly in the longitudinal direction. For example, regarding the Ni—P plating, Ni is a ferromagnetic substance by itself, but becomes non-magnetic and non-magnetic by reacting with phosphorus or boron during electroless plating. Also in the case of electroless Cr plating, if the plating layer is 20 μm or less, it can be used sufficiently rather than actually disturbing the magnetic field of the internal magnet.

  In addition, when a resin coating layer is used for the developer carrying member of the present invention, the following generally known resins can be used as the resin material for the resin coating layer. Thermoplastic resins such as styrene resins, vinyl resins, polyethersulfone resins, polycarbonate resins, polyphenylene oxide resins, polyamide resins, fluororesins, fiber-based resins, and acrylic resins. Thermal or photo-curable resins such as epoxy resins, polyester resins, alkyd resins, phenol resins, melamine resins, polyurethane resins, urea resins, silicone resins, polyimide resins. Of these, those having releasability such as silicone resins and fluororesins are more preferred. Alternatively, those having excellent mechanical properties such as polyethersulfone resin, polycarbonate resin, polyphenylene oxide resin, polyamide resin, phenol resin, polyester resin, polyurethane resin, styrene resin, and acrylic resin are more preferable.

In the present invention, in order to prevent the developer from adhering to the developer carrying member due to charge-up or the charge imparting to the developer from the surface of the developer carrying member caused by the charge-up of the developer, the developer carrying The resin coating layer on the body surface is preferably a conductive coating layer. Further, the volume resistance value of the coating layer is preferably 10 ⁴ Ω · cm or less, more preferably 10 ³ Ω · cm or less. This is because poor charge application to the developer hardly occurs, and as a result, the occurrence of blotch can be suppressed.

  In the present invention, in order to adjust the resistance value of the coating layer to the above value, a method of forming a metal plating layer on the surface of the developer carrier as described above is preferable. Alternatively, a conductive material such as metal powder such as carbon black, crystalline graphite, aluminum, copper, nickel, silver, or metal oxide such as antimony oxide, indium oxide, or tin oxide may be included in the resin coating layer. preferable.

<<< Graphitized particles >>>
As the conductive material, graphitized particles having a graphitization degree p (002) of 0.20 or more and 0.95 or less are particularly preferable. This is because the coating strength of the resin coating layer and the lubricity of the resin coating layer surface can be improved.

  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 (002) ² ) (2)

  Graphitized particles having p (002) in a specific range are excellent in wear resistance, conductivity, and lubricity. Therefore, good conductivity can be imparted to the resin coating layer, and high lubricity can be imparted to the surface of the resin coating layer. At the same time, the mechanical strength of the resin coating layer can be prevented from being lowered, and the selective wear of the resin coating layer can be suppressed.

  Examples of graphitized particles include graphitized particles obtained by firing graphite and mesocarbon microbead particles or bulk mesophase pitch particles.

  Of these, natural graphite and artificial graphite are known. 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 “cleavage”, which is one of the structural properties, and thereby gives lubricity to the surface when it appears on the surface of the resin coating layer. This is a preferable material because it is possible.

  In the present invention, it is preferable to use graphitized particles obtained by firing mesocarbon microbead particles or bulk mesophase pitch particles as graphitized particles. The graphitized particles are different 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. Further, the shape of the particles is different from the flake shape or needle shape of crystalline graphite, and is characterized by being massive or roughly spherical, and the particle itself has a relatively high hardness. Therefore, since graphitized particles having such characteristics are easily dispersed uniformly in the resin coating layer, the surface of the resin coating layer is given uniform surface roughness and wear resistance, and the shape of the particles themselves changes. It's hard. For this reason, even if the resin coating layer is scraped or the particles themselves fall off due to the effect, the particles may protrude or be exposed again from the resin coating layer, and the change in the surface shape can be kept small. it can. In addition, if graphitized particles are arranged in the resin coating layer on the surface of the developer carrying member, the ability to impart triboelectric charge to the toner can be improved more than when crystalline graphite is used without causing toner charge-up. Is possible.

  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 fused polycyclic aromatics and pitches that are mixtures thereof, produce a liquid crystal state composed of planar molecules of condensed polycyclic aromatic 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 the property of being easily graphitized by high-temperature treatment.

  Therefore, the raw material is graphitized using optically anisotropic particles such as mesocarbon microbead particles and bulk mesophase pitch particles and having a single phase. As a result, the crystallinity of the graphitized particles can be increased, and a massive or 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 the graphitization treatment, and graphitized particles having high crystallinity are obtained.

  As a typical method for obtaining mesocarbon microbead particles, for example, crude mesocarbon microbeads are obtained by heat-treating polycondensed heavy oil or petroleum heavy oil at a temperature of 300 ° C. to 500 ° C. Generate particles. Examples include a method in which mesocarbon microbead particles are separated by subjecting the reaction product to a treatment such as filtration, stationary sedimentation, and centrifugation, and then washed with a solvent such as benzene, toluene, xylene, and dried. It is done.

  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. or higher and 1500 ° C. or lower in an inert atmosphere to be 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. or more and 3500 ° C. or less 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 or more and 25 μm or less, and heat-treated in air at 200 ° C. or more and 350 ° C. or less, and lightly. Oxidize. 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 bulk 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. or higher and 3500 ° C. or lower 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. or higher and 3500 ° C. or lower, and more preferably 2300 ° C. or higher and 3200 ° C. or lower. Thereby, the fall of the electroconductivity and lubricity of graphitized particle resulting from inadequate graphitization can be avoided. Moreover, the fall of the hardness of the graphitized particle resulting from excessive graphitization can be avoided. In addition, the graphitized particles obtained from any of the above-mentioned raw materials can have a uniform particle size distribution to some extent by classification, regardless of which method is used to obtain the surface shape of the resin coating layer. It is preferable to make it uniform.

  In the present invention, the graphitized particles preferably have a volume average particle size of 0.5 μm or more and 10 μm or less. By setting the volume average particle size within the above range, it can be avoided that minute irregularities on the surface of the resin coating layer are reduced. Further, localization of graphitized particles in the resin coating layer can be avoided. As a result, it is possible to avoid a reduction in toner releasability. In addition, toner charge-up due to abrasion of the resin coating layer, ghost deterioration, image density reduction, and the like hardly occur. Furthermore, it is possible to avoid uneven charging of the developer.

<< Coarse particles >>
Further, in the present invention, in order to make the surface roughness uniform and maintain an appropriate surface roughness in the resin coating layer, more preferable results can be obtained by adding rough particles for forming irregularities. .

  Spherical particles are preferable as the roughened particles for forming irregularities used in the present invention. By using spherical particles, a desired surface roughness can be obtained with a smaller addition amount than that of amorphous particles, and an uneven surface having a uniform surface shape can be obtained. Furthermore, even when the surface of the coating layer is worn, the change in the surface roughness of the coating layer is small, and the change in the thickness of the toner layer on the developer carrying member hardly occurs. For this reason, the effect of making the toner charge uniform, sleeve ghosting good, streaking and unevenness hardly occurring, and preventing the toner from being contaminated and fused on the developer carrying member over a long period of time. Can be demonstrated across.

The volume average particle diameter of the spherical particles used in the present invention is preferably from 0.3 μm to 30 μm for the following reasons.
-The effect of imparting a uniform surface roughness to the coating layer surface is great,
-The surface roughness of the coating layer becomes too large, the amount of toner transport increases, and the toner coating on the surface of the developing sleeve is non-uniform, making it difficult for the toner to become non-uniform.
-Protrusion of coarse particles makes it difficult for white spots and black spots due to image streaks and bias leaks to occur, and-It is difficult to reduce the mechanical strength of the coating layer.

  The spherical shape in the spherical particles used in the present invention means that the ratio of the major axis / minor axis of the particles is about 1.0 or more and 1.5 or less. In the present invention, preferably the major axis / minor axis ratio is It is preferable to use particles having a ratio of 1.0 to 1.2, particularly preferably spherical particles. The dispersibility of the spherical particles in the spherical particle coating layer is good, and the amount added can be relatively reduced in order to obtain the desired surface roughness. For this reason, the shape of the surface of the coating layer is unlikely to be uneven, which is preferable in terms of uniform charging of the toner and the strength of the coating layer.

The true density of the spherical particles used in the present invention is preferably ³ g / cm ³ or less. In order to impart an appropriate surface roughness to the coating layer, the amount of particles added can be relatively reduced, and the density difference from the binder resin is small. For this reason, the dispersibility of the spherical particles in the coating layer is unlikely to be insufficient, and the coating layer surface is unlikely to have uneven roughness. Therefore, it can be avoided that the toner is non-uniformly charged.

  Furthermore, in the present invention, it is preferable to use conductive particles as spherical particles. By imparting conductivity to the spherical particles, charges can be less likely to accumulate on the particle surface due to their conductivity compared to insulating particles. Therefore, the inclusion of such conductive spherical particles in the coating layer has the effect of uniforming the surface roughness throughout the durability, and the adhesion of the toner to the particles is reduced, so that the toner is contaminated with the sleeve. And the source of fusion is further suppressed. Therefore, it is possible to obtain the effect of further improving the chargeability to the toner and further improving the developability.

Further, the conductivity of the conductive spherical particles used in the present invention, the volume resistivity refers to the following 10 ⁶ Omega · cm, preferably, the volume resistivity is 10 ⁶ Omega · cm or less at 10 ^-3 Use particles with Ω · cm or more. By making the volume resistance value of the conductive spherical particles in the above range, the effect of making the particles conductive, that is, the spherical particles exposed on the surface of the conductive coating layer due to abrasion as the core, the toner is contaminated with the sleeve and fused. The effect of suppressing can be fully exhibited.

<< Solid lubricant >>
In addition, it is preferable to disperse the solid lubricant in combination with the spherical particles in the conductive coating layer because the surface lubricity is increased and the durability of the conductive coating layer is improved. Examples of the solid lubricant include substances composed of fatty acid metal salts such as crystalline graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and zinc stearate. Etc. Among these, crystalline graphite is preferable because it does not impair the conductivity of the conductive coating layer even when used in combination with spherical particles.

  Moreover, it is preferable that the addition amount of these solid lubricants which can be used by this invention shall be the range of 1 to 100 mass parts with respect to 100 mass parts of binder resin. The effect of improving the adhesion of the developer is high, and a decrease in strength (abrasion resistance) of the resin coating layer due to particles having a particle size on the order of submicrons can be avoided. The volume average particle diameter of these lubricating particles is preferably 0.2 μm or more and 20 μm or less, and particularly preferably 1 μm or more and 15 μm or less. This is because sufficient lubricity is obtained, the surface property of the resin coating layer is hardly non-uniform, and it is advantageous in terms of uniform charging of the developer and the strength of the resin coating layer.

<< Charge Control Agent >>
In the present invention, in order to adjust the charge imparting property of the developer carrying member, a charge control agent may be further contained in the resin coating layer. In that case, it is preferable that content of a charge control agent shall be 1 to 100 mass parts with respect to 100 mass parts of coating resin. This is because a sufficient effect of addition of the charge control agent can be obtained, and it is difficult to cause a dispersion failure and a decrease in coating strength.

Examples of charge control agents include modified products of nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and analogs thereof. Onium salts such as phosphonium salts and lake pigments thereof (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc. ),
Metal salts of higher fatty acids;
Diorganotin oxides such as butyltin oxide, dioctyltin oxide, dicyclohexyltin oxide;
Examples include diorganotin borates such as thibutyltin borate, dioctyltin borate, and dicyclohexyltin borate; guanidines and imidazole compounds.

<< Method for Forming Coating Layer >>
The resin coating layer can be formed, for example, by dispersing and mixing the components for the resin coating layer in a solvent to form a paint, coating the substrate, drying, solidifying, or curing. A known dispersion apparatus using beads such as a sand mill, a paint shaker, a dyno mill, and a pearl mill can be suitably used for dispersing and mixing each component into the coating liquid. Moreover, as a coating method, well-known methods, such as a dipping method, a spray method, and a roll coat method, are applicable.

<< Surface roughness of coating layer >>
In the present invention, as the surface roughness of the resin coating layer, arithmetic average roughness Ra (JIS B0601-2001) is preferably 0.2 μm or more and 2.5 μm or less, and preferably 0.2 μm or more and 1.5 μm or less. Is more preferable. Can avoid destabilization of the developer amount on the developer carrier, reduction of abrasion resistance and developer contamination resistance of the resin coating layer, non-uniform charging of the developer, and reduction of mechanical strength of the resin coating layer Because.

<< Thickness of coating layer >>
The thickness of the resin coating layer having the above-described structure is preferably 25 μm or less, more preferably 20 μm or less, and further preferably 4 μm or more and 20 μm or less, in order to obtain a uniform film thickness. The thickness is not limited. This thickness depends on the material used for the resin coating layer, but can be obtained if the adhesion mass is 4000 mg / m ² or more and 20000 mg / m ² or less.

<< Volume of shape of minute irregularities on coating layer surface >>
The resin coating layer of the developer carrying member of the present invention is measured on the surface area measured using a focus optical system laser in a certain area A of a minute uneven area in which no protrusion is formed by the rough particles. It is preferable that the volume B of the shape of the minute unevenness satisfies the relationship of 4.5 ≦ B / A ≦ 6.5.

  When B / A is 6.5 or less, the localization of the inorganic particles in the minute recesses on the surface of the developer carrier is reduced, and the inorganic particles can be uniformly applied to the developer carrier. Become. Further, by setting B / A to 4.5 or more, the surface of the developer carrying member has moderately minute irregularities, and the releasability from the toner surface is improved. Therefore, sleeve ghost and toner contamination due to toner charge-up are less likely to occur.

  To control B / A indicating the degree of minute unevenness in the region where the roughened particles do not form protrusions on the surface of the resin coating layer between 4.5 and 6.5 The dispersion state of the pigment in the resin coating and the coating method are preferably adjusted. As a method for controlling B / A depending on the dispersion state of the pigment, it is preferable that the pigment is dispersed in the resin coating layer so that the volume average particle diameter is 0.5 μm or more and 4.0 μm or less. When the volume average particle size is less than 0.5 μm, it becomes difficult to form a fine uneven surface with a pigment on the resin coating layer, and B / A tends to be less than 4.5. On the other hand, if the volume average particle diameter exceeds 4.0 μm, the unevenness imparted to the surface of the resin coating layer by the pigment becomes too large, and B / A tends to exceed 6.5. Control of the volume average particle size of the above graphitized particles in the resin coating is possible by adjusting the particle size distribution of the pigment used by pulverization or classification and adjusting the dispersion strength of the pigment in the resin coating. is there.

<Development method, development device>
Next, the present invention will be described in more detail with reference to preferred embodiments of the present invention.

  FIG. 2 is an example of a basic configuration around the developer carrying member used in the developing method of the present invention. As the configuration of the developer layer thickness regulating member 301, an elastic member such as urethane rubber is used, but a magnetic regulating blade made of a ferromagnetic metal or the like may be used. A developing sleeve as a developer carrying member is composed of a coating layer mainly composed of a binder resin 309 and carrier particles 310 that are inorganic particles on the surface of a metal cylindrical tube (base) 302. In the binder resin 309, the conductive agent 308, the unevenness imparting particles 306, and the lubricating particles 307 are present, and the carrier particles 310 are present on the surface of the coating layer. Further, since the developer does not intervene on the developing sleeve before the image is used, the carrier particles 310 adhere to the developer regulating member 301 at the contact point between the developing sleeve and the developer layer thickness regulating member.

  When the image is used, the developer 311 is conveyed so as to come into contact with the carrier particles 310 attached on the surface of the resin coating layer, the surface of the developing blade or the developer layer thickness regulating member 301 on the developing sleeve. By controlling the triboelectric charge held by the developer to an appropriate value at that time, it becomes possible to alleviate the toner charge-up phenomenon, and as a result, it is possible to eliminate image defects such as sleeve ghosts and blotches. Become.

  FIG. 3 is a diagram schematically showing an example of a developing device used in the developing method of the present invention. This will be described below. 3 is a latent image carrier, for example, an electrophotographic photosensitive drum, for carrying an electrostatic latent image formed by a known process, and is rotated in the direction of arrow B. The developing sleeve 8 as a developer carrying member facing the photosensitive drum 1 is composed of a metal cylindrical tube (base) 6 and a resin coating layer 7 formed on the surface thereof. In the hopper 3 for containing the toner, a stirring blade 10 for stirring the magnetic toner 4 is provided. The magnetic toner 4 as a one-component magnetic developer supplied from the hopper 3 to the developing sleeve 8 is carried on the developing sleeve 8, and the developing sleeve 8 and the photosensitive drum are rotated by the developing sleeve 8 rotating in the arrow A direction. The magnetic toner 4 is carried and conveyed to the developing area of the one opposing portion. In the developing sleeve 8, a magnet 5 for magnetically attracting and holding the magnetic toner 4 on the developing sleeve 8 is disposed. The magnetic toner 4 enables development of an electrostatic latent image on the photosensitive drum 1 (an electrostatic latent image on an electrostatic latent image carrier) by friction with the developing sleeve 8 and / or the layer thickness regulating blade 11. Obtain triboelectric charge.

  In the developing device according to the present invention, the thickness of the thin layer of the magnetic toner 4 formed by the layer thickness regulating blade 11 on the developing sleeve 8 is such that the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing portion. It is preferable that the thickness is thinner than that. That is, the developing method of the present invention is particularly effective for a developing device that develops an electrostatic latent image with such a thin toner layer, that is, a so-called non-contact developing device. A developing bias voltage is applied to the developing sleeve 8 by a power source 9 in order to fly the magnetic toner 4 which is a one-component magnetic developer carried on the developing sleeve 8. 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 by adhesion of the magnetic toner 4) and the potential of the background portion is developed. It is preferable to apply to the sleeve 8. On the other hand, in order to increase the density of the developed image or to improve the gradation, an alternating bias voltage may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately reversed in the developing portion. In this case, it is preferable to apply to the developing sleeve 8 an alternating bias voltage in which a DC voltage component having a value between the above-described image portion potential and background portion potential is superimposed. In the so-called regular development, in which toner is attached to a high potential portion of an electrostatic latent image having a high potential portion and a low potential portion for visualization, toner charged to a polarity opposite to that of the electrostatic latent image is applied. use. On the other hand, in so-called reversal development in which toner is attached to a low potential portion of an electrostatic latent image for visualization, toner charged with the same polarity as that of the electrostatic latent image is used. The high potential and the low potential are expressed by absolute values. In any case, the toner 4 is charged to a polarity for developing the electrostatic latent image by friction with the developing sleeve 8.

  FIG. 3 is merely a schematic illustration of the developing device of the present invention, and there are various forms in the shape of the developer container, the presence or absence of the stirring blade 10, the shape of the developer layer thickness regulating member, and the arrangement of the magnetic poles. Needless to say.

<Developer>
Next, the developer used in the developing device incorporating the developer carrying member of the present invention will be described.

  A developer (toner) suitable for the present invention preferably has a weight average particle diameter of 4 μm or more and 11 μm or less. If such a device is used, the charge amount, image quality, image density, and the like are balanced.

<< Binder resin >>
As the binder resin of the developer (toner), generally known resins can be used, and examples thereof include vinyl resins, polyester resins, polyurethane resins, epoxy resins, phenol resins, etc. Among them, vinyl resins, Polyester resins are preferred.

<< Charge Control Agent >>
For the purpose of improving the charging characteristics, a developer (toner) can be used by adding a charge control agent to the developer particles (internal addition) or mixing (external addition) with the developer particles. This is because the charge control agent enables optimum charge amount control according to the development system. As a positive charge control agent,
Modified products with nigrosine, triaminotriphenylmethane dyes and fatty acid metal salts;
Quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate;
Diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide;
Diorganotin borates such as dibutyl tin borate, dioctyl tin borate, dicyclohexyl tin borate and the like can be used alone or in combination of two or more.

  As the negative charge control agent, an organometallic compound and a chelate compound are effective. Examples thereof include aluminum acetylacetonate, iron (II) acetylacetonate, and 3,5-ditertiary butyl salicylate. In particular, acetylacetone metal complexes, monoazo metal complexes, naphthoic acid or salicylic acid metal complexes or salts are preferred.

<< Magnetic material >>
When the developer (toner) is a magnetic developer (toner), a magnetic material is blended. Examples of magnetic materials include the following materials.

  Iron oxide-based metal oxides such as magnetite, maghemite, and ferrite; magnetic metals such as Fe, Co, and Ni; these metals and Al, Co, Cu, Pb, Mg, Ni, Sn, Zn, Sb, Be, and Bi , Alloys with metals such as Cd, Ca, Mn, Se, Ti, W, V, and mixtures thereof.

  In addition, you may make these magnetic materials also serve as the coloring agent mentioned later.

<< Colorant >>
As the colorant blended in the developer (toner), pigments and dyes conventionally used in this field can be used, and they may be appropriately selected and used.

<< Releasing agent >>
It is preferable to incorporate a release agent in the developer (toner). Examples of release agents are
Aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, paraffin wax,
Fatty acid esters such as carnauba wax, Fischer-Tropsch wax, sazol wax, montan wax,
Including waxes containing as a main component.

<< External additive >>
Furthermore, inorganic particles such as silica, titanium oxide, and alumina are externally added to the developer (toner) in order to improve environmental stability, charging stability, developability, fluidity, storage stability, and cleaning properties. That is, it is preferably present in the vicinity of the developer surface. Among these, silica particles are preferable.

  External additives other than inorganic particles may be further added and used. For example, there are lubricants such as polytetrafluoroethylene, zinc stearate, and polyvinylidene fluoride, and abrasives such as cerium oxide, strontium titanate, and strontium silicate. Of these, polyvinylidene fluoride is preferred.

<< Method for Preparing Developer >>
In order to prepare a developer (toner), a binder resin, a pigment or dye as a colorant, a magnetic material, a release agent, and a charge control agent and other additives as necessary are used. Mix thoroughly with a mixer such as a Henschel mixer or ball mixer, then melt using a heat kneader such as a heating roll, kneader, extruder, etc. to make the resins compatible with each other, release agent, pigment, Disperse or dissolve dyes and magnetic substances. After cooling and solidification, toner particles can be obtained by pulverization and classification. Furthermore, a desired additive can be added as necessary, and mixed well by a mixer such as a Henschel mixer to obtain a developer (toner).

  When such a developer is used after being subjected to a spheroidizing treatment or a surface smoothing treatment by various methods, it is preferable because transferability is good. As such a method, for example, a developer is passed through a minute gap between the blade and the liner in an apparatus having a stirring blade or a blade and a liner or a casing. At that time, there are a method of smoothing the surface by mechanical force or spheroidizing the developer, a method of suspending the toner in hot water to spheroidize, a method of exposing the toner to a hot air current and spheroidizing, etc. is there.

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

<Measurement methods for various physical properties>
The physical property measurement method according to the present invention will be described below.

(1) Measurement of the particle size of inorganic particles and fine particles of less than 1 μm;
Using a scanning electron microscope (manufactured by Hitachi, Ltd., S4800 (trade name)), a photograph with a magnification of 50,000 was obtained, and the average of the longest side and the shortest side of the particle was defined as the particle size of the particle. When it was difficult to measure the particle size because the particles were too small, the photograph taken at 50,000 times was further enlarged to obtain a 200,000 times photograph.

  At this time, the photograph of the toner mapped with the elements contained in the inorganic particles is compared with the elemental analysis means (XMA (GENESIS 4000: EDAX Inc.)) attached to the scanning electron microscope. In contrast, 100 primary particles of inorganic particles carried on the surface of the developer carrying member were counted. At this time, the longest side and the shortest side are measured, and the average value is taken as the particle size. The 50% value of these 100 samples was used as the primary particle size.

(2) Measurement of the loading ratio M / R of the inorganic particles on the surface of the developer carrying member;
At the site observed by setting the measurement magnification of the scanning electron microscope to 50,000 times, the element was detected by the element analysis means described above. Mapping was performed on the portion where the element contained in the inorganic particles (titanium in the case of strontium titanate) was detected at the measurement site. Then, the area where the element was mapped was measured using an application “Image-Pro Plus (Media Cybernetics)” having an image analysis function. In the mapping image, binarization was performed based on the color difference of the portion where the specific element was detected, and the area M of the inorganic particle existing portion relative to the measurement image region R was calculated. Similarly, measurements were made at 20 locations, and the average value was taken as the adhesion rate.

(3) Measurement of arithmetic mean roughness (Ra) of the developer carrier surface;
The arithmetic average roughness (Ra) of the developer carrier surface was measured using a surf coder SE-3500 manufactured by Kosaka Laboratory, based on the surface roughness of JIS B0601 (2001). As measurement conditions, a cut-off of 0.8 mm, an evaluation length of 4 mm, and a feed rate of 0.5 mm / s were measured for each of 3 points in the axial direction and 3 points in the circumferential direction = 9 points, and the average value was taken.

(4) Measurement of surface shape B / A of developer carrier;
The uneven shape on the surface of the conductive resin coating layer was measured using an ultradeep shape measuring microscope VK-8500 (manufactured by KEYENCE). This device measures the shape of an object based on objective lens position information in which the amount of reflected light received by the light receiving element at the confocal position is maximized by applying the laser emitted from the light source to the object and reflecting the laser reflected from the object. Is.

Measurement conditions were set as follows.
Objective lens magnification: 100x Optical zoom magnification: 1x Digital zoom magnification: 1x RUN MODE: Lens movement pitch in the direction of color ultra-deep height: 0.1 μm
Laser gain: 716
Laser offset: -335
Shutter (camera setting): 215

The measurement is performed by appropriately selecting a region having an area A (4 × 10 ⁻¹⁰ m ² ) of 20 μm in the horizontal direction and 20 μm in the vertical direction where there are no projections formed by rough particles on the surface of the resin coating layer. It was.

The measurement results were analyzed by image analysis software VK-H1W (Version 1.07; manufactured by KEYENCE). First, an inclination correction process was performed in order to correct the overall inclination of the measurement result. Only height data was processed, and the correction method was the automatic mode of surface correction. Next, in order to remove a noise component due to measurement, smoothing by filtering was performed. The processing conditions are shown below.
Processing target: Height data Processing size: 3 × 3 area Smoothing processing execution count: Once File type: Simple average

  Next, after converting the height data obtained by the measurement into CSV text data, the average height from the bottom of the coating layer in the entire measurement part area is calculated to calculate the average height of the measurement part unevenness, The value was used as a reference plane.

Further, from the surface area / volume measurement mode in the image analysis software VK-H1W, the volume B (m ³ ) of the minute uneven portion observed in the area A (4 × 10 ⁻¹⁰ m ² ) in the measurement region was calculated. . As a measurement location, 20 or more points were measured, the average value of the volume was calculated, and B / A was obtained.

(5) Measurement of particle size of conductive particles and pigment in coating liquid;
The particle size of the conductive particles such as graphitized particles and the pigment in the coating solution was measured using a Coulter LS-230 type particle size distribution meter (manufactured by Beckman Coulter, Inc.) of a laser diffraction type particle size distribution meter. As a measuring method, a small amount module is used, and isopropyl alcohol (IPA) is used as a measuring solvent. Wash the measurement system of the particle size distribution analyzer with IPA for about 5 minutes, and execute the background function after washing. Next, 1 mg of a measurement sample is added to 50 ml of IPA. The solution in which the sample is suspended is dispersed with an ultrasonic disperser for about 1 minute to obtain a sample solution, and the sample solution is gradually added into the measurement system of the measurement device, so that the PIDS on the screen of the device is 45%. The measurement was performed by adjusting the sample concentration in the measurement system so that it was 55% or less. The volume average particle diameter calculated from the volume distribution is obtained.

(6) Measurement of toner particle size;
As a measuring device, Coulter Multisizer II (both manufactured by Beckman Coulter, Inc.) was used. As the electrolyte, first grade sodium chloride is used to prepare an approximately 1% NaCl aqueous solution. As a measurement method, 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant to 100 ml of the electrolytic aqueous solution, and 10 mg of a measurement sample is further added. The electrolyte solution in which the sample is suspended is subjected to a dispersion process for about 1 minute with an ultrasonic disperser, and the volume distribution is measured by measuring the volume and number of the measurement sample using the 100 μm aperture or the 30 μm aperture as the aperture. And the number distribution were calculated. From this result, the weight-based weight average particle diameter (D ₄ ) obtained from the volume distribution (the median value of each channel is the representative value for each channel) was obtained.

(7) Average circularity of toner particles;
The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of particles. Here, the measurement was performed using a flow type particle image analyzer (trade name: FPIA-1000; manufactured by Toago Medical Electronics Co., Ltd.). And the circularity (Ci) of each particle | grain measured about the particle group of a circle equivalent diameter of 3 micrometers or more was each calculated | required by the following formula.
Circularity (Ci) = (perimeter of a circle having the same projected area as the number of particles) / (perimeter of a projected image of particles)

  Furthermore, as shown by the following formula, the value obtained by dividing the total roundness of all particles measured by the total number of particles was defined as the average circularity.

  FPIA-1000 calculates the circularity of each particle and then calculates the average circularity and the mode circularity. The FPIA-1000 determines that the particles have a circularity of 0.40 to 1.00 at 0.010 intervals based on the obtained circularity. The class is divided into 61 classes, and the average circularity is calculated using the center value and frequency of the dividing points. However, there is very little error between each value of the average circularity calculated by this calculation method and each value of the average circularity calculated by the above-described calculation formula that directly uses the circularity of each particle. Is negligible. Therefore, in the present invention, for the reason of handling data such as a short calculation time and simplification of the calculation formula, the concept of the calculation formula that directly uses the circularity of each particle described above is used, and a partial change is made. Such a calculation method is used. The average circularity in the present invention is an index of the degree of unevenness of particles, and indicates 1.000 when the particles are perfectly spherical, and the average circularity becomes smaller as the developer surface shape becomes more complex.

  As a specific measurement 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 dispersion, and ultrasonic waves (20 kHz, 50 W) are applied to the dispersion for 5 minutes. Irradiate. The dispersion concentration was set to 5000 / μl or more and 20,000 / μl or less, and measurement was performed with the above-described apparatus to determine the average circularity of particles having a circle-equivalent diameter of 3 μm or more.

  The outline of the measurement is described in, for example, the FPIA-1000 catalog (June 1995 edition) issued by Toa Medical Electronics Co., Ltd., the manual of the measuring apparatus, etc., and 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 on the flow cell so as to be opposite to each other 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 for measuring the circularity only for the particle group having an equivalent circle diameter of 3 μm or more is as follows. That is, the particle group having an equivalent circle diameter of less than 3 μm includes a large number of external additive particle groups that exist independently of the toner particles, and the circularity of the toner particle group cannot be accurately estimated due to the influence. .

  EXAMPLES Hereinafter, although a manufacture example and an Example demonstrate this invention concretely, this does not limit this invention at all. In the examples, “part” means part by mass.

<Inorganic particle production example A>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.65 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 4.5, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Further, distilled water was added so as to be 0.5 mol / liter in terms of SrTiO ₃ .

  The slurry was heated to 83 ° C. at 6.5 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 83 ° C. After the reaction, the mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.

  Furthermore, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 6.5% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to the surface of the perovskite crystal. Zinc acid was precipitated.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with zinc stearate. The obtained strontium titanate had a substantially cubic or rectangular parallelepiped shape, an average primary particle size of 120 nm, and an aggregate content of 600 nm or more was 0.50% by number. This strontium titanate is used as inorganic particles A. Table 1 shows the physical properties of the inorganic particles A.

<Inorganic particle production example B>
The hydrous titanium oxide obtained by hydrolysis by adding aqueous ammonia to the aqueous titanium tetrachloride was washed with pure water, and 0.3% sulfuric acid was added to the hydrous titanium oxide slurry as SO _{3 with} respect to the hydrous titanium oxide. Added. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.6 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and washing was repeated until the electrical conductivity of the supernatant liquid reached 50 μS / cm.

0.97-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, and the mixture was placed in a SUS reaction vessel and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.6 mol / liter in terms of SrTiO ₃ . The slurry was heated to 60 ° C. at a rate of 10 ° C./hour in a nitrogen atmosphere, and reacted for 7 hours after reaching 60 ° C. After the reaction, the reaction mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.

  Furthermore, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 6.5% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to the surface of the perovskite crystal. Zinc acid was precipitated.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with zinc stearate. The obtained strontium titanate had an approximately cubic or rectangular particle shape, an average primary particle diameter of 40 nm, and an aggregate content of 600 nm or more was 0.70% by number. This strontium titanate is used as inorganic particles B. Table 1 shows the physical properties of the inorganic particles B.

<Inorganic particle production example C>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.9 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and washing was repeated until the electrical conductivity of the supernatant became 80 μS / cm.

A 0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.5 mol / liter in terms of SrTiO ₃ . The slurry was heated to 85 ° C. at 35 ° C./hour in a nitrogen atmosphere, and reacted for 5 hours after reaching 85 ° C. After the reaction, the reaction mixture was cooled to room temperature, the supernatant was removed, and washing was repeated with pure water.

  Furthermore, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 6.5% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to the surface of the perovskite crystal. Zinc acid was precipitated.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with zinc stearate. The obtained strontium titanate had a substantially cubic or cuboid particle shape, an average primary particle diameter of 270 nm, and an aggregate content of 600 nm or more was 1.30% by number. This strontium titanate is used as inorganic particles C. Table 1 shows the physical properties of the inorganic particles C.

<Inorganic particle production example D>
Except having been surface-treated with 2% by mass of lauric acid (12 carbon atoms) aluminum, surface treated strontium titanate fine particles not subjected to a sintering step were obtained in the same manner as in Production Example A of inorganic particles. The strontium titanate fine particles are referred to as inorganic particles D. Table 1 shows the physical properties of the inorganic particles D.

<Inorganic particle production example E>
Except having been surface-treated with 2% by mass of sorbic acid (6 carbon atoms) calcium, surface-treated strontium titanate fine particles not subjected to a sintering step were obtained in the same manner as in Production Example A of inorganic particles. The strontium titanate fine particles are referred to as inorganic particles E. Table 1 shows the physical properties of the inorganic particles E.

<Inorganic particle production example F>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 0.7 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion to adjust the pH of the dispersion to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 70 μS / cm.

A 0.98-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.5 mol / liter in terms of SrTiO ₃ . The slurry was heated to 80 ° C. at a rate of 7 ° C./hour in a nitrogen atmosphere, and reacted for 6 hours after reaching 80 ° C. After the reaction, the reaction solution was cooled to room temperature, and the supernatant was removed. Then, the washing was repeated with pure water, and then filtered with Nutsche. The obtained cake was dried to obtain strontium titanate fine particles not passing through the sintering step. The strontium titanate fine particles were designated as inorganic particles F. Table 1 shows the physical properties of the inorganic particles F.

<Inorganic particle production example G>
The hydrous titanium oxide slurry obtained by hydrolyzing the aqueous titanyl sulfate solution was washed with an alkaline aqueous solution. Next, hydrochloric acid was added to the hydrous titanium oxide slurry to adjust the pH to 1.1 to obtain a titania sol dispersion. NaOH was added to the titania sol dispersion, the pH of the dispersion was adjusted to 5.0, and washing was repeated until the electrical conductivity of the supernatant reached 100 μS / cm.

A 1.00-fold molar amount of Sr (OH) ₂ .8H ₂ O was added to the hydrous titanium oxide, placed in a SUS reaction vessel, and purged with nitrogen gas. Furthermore, distilled water was added so as to be 0.3 mol / liter in terms of SrTiO ₃ . The slurry was heated to 90 ° C. at 70 ° C./hour in a nitrogen atmosphere, and reacted for 5 hours after reaching 90 ° C. After the reaction, the reaction solution is cooled to room temperature, the supernatant is removed, and washing is repeated with pure water.

  Furthermore, in a nitrogen atmosphere, the slurry is placed in an aqueous solution in which 6.5% by mass of sodium stearate is dissolved with respect to the solid content of the slurry, and while stirring, an aqueous zinc sulfate solution is added dropwise to the surface of the perovskite crystal. Zinc acid was precipitated.

  The slurry was washed repeatedly with pure water and then filtered with Nutsche, and the resulting cake was dried to obtain strontium titanate surface-treated with zinc stearate. The obtained strontium titanate had a substantially cubic or cuboid particle shape, an average primary particle diameter of 390 nm, and an aggregate content of 600 nm or more was 2.20% by number. This strontium titanate is used as inorganic particles G.

<Inorganic particle production example H>
The inorganic particles B were sintered at 1000 ° C. and then crushed to obtain strontium titanate fine particles via a sintering process. The inorganic particles H were strontium titanate fine particles having an average primary particle size of 510 nm and an irregular particle shape. Table 1 shows the physical properties of the comparative inorganic particles H.

<Developer Production Example 1>
An aqueous solution containing ferrous hydroxide was prepared by mixing 1.0 equivalent of a caustic soda solution with respect to iron ions in an aqueous ferrous sulfate solution. Air was blown in while maintaining the pH of the aqueous solution at around 9, and an oxidation reaction was performed in 90 seconds to prepare a slurry liquid for generating seed crystals. Subsequently, the ferrous sulfate aqueous solution was added to this slurry liquid so that it might become 1.0 equivalent with respect to the original alkali amount (sodium component of caustic soda). Thereafter, the slurry liquid was maintained at pH 8, and the oxidation reaction was promoted while blowing air. The magnetic particles generated after the oxidation reaction were washed, filtered, and once taken out. At this time, a small amount of water-containing sample was collected and the water content was measured. Next, this water-containing sample was redispersed in another aqueous medium without drying, and then the pH of the redispersed liquid was adjusted to about 6. 2 parts by mass of the silane coupling agent (n-C ₉ H ₁₇ Si (OCH ₃ ) ₃ ) with respect to 100 parts by mass of magnetic iron oxide with sufficient stirring (the amount of the magnetic material is a value obtained by subtracting the water content from the water-containing sample) (Calculated) was added and the coupling process was performed. The produced magnetic particles are washed, filtered and dried by a conventional method, and then the slightly agglomerated particles are crushed to obtain a surface-treated magnetic material-1 having an average particle size of 0.20 μm and a hydrophobicity of 83 Got.

next,
Styrene 78 parts by mass n-butyl acrylate 22 parts by mass divinylbenzene 0.5 parts by mass saturated polyester resin (acid value 8, peak molecular weight (Mp) 12000) 2 parts by mass negatively chargeable charge control agent (Hodogaya Chemical Co., Ltd.) , Trade name: T-77) 1 part by mass surface-treated magnetic material-1 88 parts by mass The above formulation was uniformly dispersed and mixed using an attritor (Mitsui Miike Chemical Co., Ltd.). This monomer composition was heated to 60 ° C., and 7 parts by mass of ester wax (maximum endothermic peak 72 ° C. in DSC) was added and dissolved therein. In this, 3 parts by mass of a polymerization initiator 2,2-azobis (2,4-dimethylvaleronitrile) was dissolved.

On the other hand, after adding 451 parts by mass of 0.1 M Na ₃ PO ₄ aqueous solution to 709 parts by mass of ion-exchanged water and heating to 60 ° C., 67.7 parts by mass of 1.0 M CaCl ₂ aqueous solution was added and Ca ₃ was added. An aqueous medium containing (PO ₄ ) ₂ was obtained. Into this aqueous medium, the polymerizable monomer composition was charged, and stirred at 10,000 rpm for 15 minutes in a TK homomixer (Special Machine Industries Co., Ltd.) at 60 ° C. in an N ₂ atmosphere. Granulated. Thereafter, the mixture was reacted at 70 ° C. for 5 hours while stirring with a paddle stirring blade. Thereafter, the liquid temperature was maintained at 80 ° C., and stirring was further continued for 4 hours. After completion of the reaction, distillation is further performed at 80 ° C. for 2 hours, after which the suspension is cooled, hydrochloric acid is added to dissolve the dispersant, and the mixture is filtered, washed with water and dried to obtain black particles having a weight average particle diameter of 7.5 μm. Got.

100 parts by mass of the black particles and silica having a primary particle diameter of 12 nm are treated with hexamethyldisilazane and then treated with silicone oil, and 1.2 parts by mass of hydrophobic silica particles having a BET value of 120 m ² / g after the treatment. Was mixed using a Henschel mixer (Mitsui Miike Chemical Co., Ltd.). Thus, magnetic developer T-1 having a weight average particle diameter of 7.4 μm and an average circularity of 0.989 was prepared.

<Developer Production Example 2>
Styrene-butyl acrylate resin 100 parts by weight Magnetite 95 parts by weight Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts by weight Paraffin wax 4 parts by weight After premixing the above materials with a Henschel mixer, a biaxial extruder And kneaded and dispersed to obtain a kneaded product. This was cooled and then coarsely pulverized by a cutter mill to obtain a coarsely pulverized toner. The obtained coarsely pulverized product was mechanically pulverized and finely pulverized using a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; coated with chromium alloy plating containing chromium carbide on the rotor and stator surfaces). . The obtained finely pulverized product was classified using a multi-division classifier, and particles having a weight average particle diameter (D4) of 5.1 μm were obtained. The particles were subjected to spheronization and fine powder removal using a surface modification apparatus shown in FIG. In FIG. 4, 30 is a casing, 31 is a classification rotor, 32 is fine powder collection, 33 is a raw material supply port, 34 is a liner (fixed body), 35 is a cold air inlet, 36 is a dispersion rotor (rotary body), and 37 is a product. A discharge port, 38 is a discharge valve, and 39 is a guide ring (guide means). 41 is a first space and 42 is a second space.

Through the above steps, a toner T2 having a weight average particle diameter (D ₄ ) of 5.2 μm and a circularity of 0.965 measured by a Coulter counter method was obtained. One-component magnetic developer T-2 was obtained by adding 1.0 part by weight of hydrophobic colloidal silica to 100 parts by weight of the toner, and mixing and dispersing with a Henschel mixer.

[Example 1]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenol resin (ammonia catalyst used, methanol 40% contained, manufactured by Dainippon Ink & Chemicals, Inc., trade name: J325) 350 parts by mass of graphitized particles A 80 parts by mass of conductive carbon black (produced by Columbia Carbon Co., Ltd., trade name: Conductex 975)
20 parts by mass of conductive spherical particles (Nippon Carbon Co., Ltd., trade name: Nikabeads PC0520) 5 parts by mass of isopropyl alcohol 400 parts by mass As graphitized particles A, β-resin was extracted from coal tar pitch by solvent fractionation, After the addition and heavy treatment, a mesophase pitch was obtained by removing the solvent-soluble component with toluene. The mesophase pitch powder is finely pulverized, oxidized in air at about 300 ° C., and then heat-treated at 2600 ° C. in a nitrogen atmosphere. After classification, the volume average particle size is 3.4 μm, and the graphitization degree is p. Graphitized particles A having (002) of 0.55 were obtained.

  The above material was dispersed in a sand mill using glass beads. As a dispersion method, a resol type phenol resin solution is diluted with a part of isopropyl alcohol. Conductive carbon black and crystalline graphite were added and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles dispersed in the remaining isopropyl alcohol were further added thereto, and the sand mill dispersion was further advanced to obtain a coating solution. The volume average particle diameter of the particles contained in this coating liquid was 1.98 μm.

  A conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 12 mmφ by the spray method using the above coating solution, and then the conductive coating layer is cured by heating at 160 ° C. for 20 minutes in a hot air drying furnace. Developer carrier a was prepared. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 0.88 μm and B / A = 5.4. Table 2 shows the surface shape of the developer carrier.

  Next, the inorganic particles A were applied onto the resin layer of the developer carrier a using the lubricant application device shown in FIG. The sponge roller 26 is composed of a core metal 26b and a sponge 26a formed of urethane foam. The core metal diameter is φ5, the sponge roller diameter is φ16, the thickness of the sponge is 5.5 mm, and the average foaming number is The thing of 5 pieces / mm was used. The coated particles were applied to the sponge roller 26 and brought into contact with the developer carrier 27 to apply the inorganic particles A. This sample is referred to as a developer carrier A-1. Table 3 shows the adhesion state of the inorganic particles for the developer carrier A-1.

  In evaluating the developer carrier A-1, a cartridge for a laser printer (trade name: Lesser Jet 3030; manufactured by Hewlett-Packard Company) was used. A magnet and a flange are attached so that the developer carrier A-1 can be attached to the cartridge, the cartridge is attached to the cartridge, the developer T-1 is filled, and image evaluation to be described later is performed by a Lesser Jet 3030 machine.

[Examples 2 to 4]
Samples obtained by applying the inorganic particles B, C, and D to the developer carrier a of Example 1 in the same manner as in Example 1 are referred to as developer carriers A-2 to A-4. These were subjected to image evaluation in the same manner as in Example 1.

[Example 5]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol-type phenolic resin (using ammonia catalyst, containing 40% methanol, manufactured by Dainippon Ink & Chemicals, Inc., trade name: J325) 350 parts by mass of crystalline graphite (made by Nippon Graphite Co., Ltd., trade name: CP) 50 parts by weight of conductive carbon Black (product name: Conductex 975, manufactured by Columbia Carbon)
50 parts by mass of conductive spherical particles (manufactured by Nippon Carbon Co., Ltd., trade name: Nikabeads PC0520) 15 parts by mass of isopropyl alcohol 450 parts by mass The above materials were dispersed in the same manner as in Example 1 to obtain a coating solution. The volume average particle diameter of the particles contained in this coating solution was 6.42 μm. Using this coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 12 mmφ by spraying, followed by heating in a hot air drying oven at 160 ° C. for 20 minutes to cure the conductive coating layer. Developer carrier b was produced. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 0.95 μm and B / A = 6.4.

  Next, in the same manner as in Example 1, the inorganic particles A were applied on the resin layer of the developer carrier b. This sample is referred to as a developer carrier A-5. This was subjected to image evaluation in the same manner as in Example 1.

[Example 6]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenolic resin (using ammonia catalyst, containing 40% methanol, manufactured by Dainippon Ink & Chemicals, Inc., trade name: J325) 350 parts by mass of crystalline graphite (trade name: UF-G5, manufactured by Showa Denko KK) Carbon black (trade name: Conductex 975, manufactured by Columbia Carbon Co., Ltd.)
90 parts by mass of conductive spherical particles (manufactured by Nippon Carbon Co., Ltd., trade name: Nikabeads PC0520) 15 parts by mass of isopropyl alcohol 500 parts by mass The above materials were dispersed in the same manner as in Example 1 to obtain a coating solution. The volume average particle diameter of the particles contained in this coating liquid was 1.08 μm. Using this coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 12 mmφ by spraying, followed by heating in a hot air drying oven at 160 ° C. for 20 minutes to cure the conductive coating layer. A developer carrier c was produced. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 0.82 μm and B / A = 4.6.

  Next, in the same manner as in Example 1, the inorganic particles A were applied on the resin layer of the developer carrier c. This sample is referred to as a developer carrier A-6. This was subjected to image evaluation in the same manner as in Example 1.

[Example 7]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenolic resin (using ammonia catalyst, containing 40% methanol, manufactured by Dainippon Ink & Chemicals, trade name: J325) 350 parts by weight crystalline graphite (made by Nippon Graphite, trade name: CP) 80 parts by weight conductive carbon Black (product name: Conductex 975, manufactured by Columbia Carbon)
20 parts by mass of conductive spherical particles (manufactured by Nippon Carbon Co., Ltd., trade name: Nikabeads PC0520) 15 parts by mass of isopropyl alcohol 400 parts by mass The above materials were dispersed in the same manner as in Example 1 to obtain a coating solution. The volume average particle diameter of the particles contained in this coating liquid was 9.35 μm. Using this coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 12 mmφ by a spray method, followed by heating at 160 ° C. for 20 minutes in a hot air drying furnace to cure the conductive coating layer. Developer carrier d was prepared. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 1.02 μm and B / A = 9.8.

  Next, in the same manner as in Example 1, the inorganic particles A were applied on the resin layer of the developer carrier d. This sample is referred to as a developer carrier A-7. This was subjected to image evaluation in the same manner as in Example 1.

[Example 8]
A spherical glass bead of # 200 was used for an aluminum cylindrical tube having an outer diameter of 12 mmφ, and blasting was performed using a sand blasting apparatus. The surface roughness after blasting was Ra = 0.97 μm.

  Next, the cylindrical tube was washed and then plated. As a pretreatment, the surface of the cylindrical tube was subjected to a zincate treatment to deposit zinc on the surface. For this zincate treatment, a commercially available zincate treatment agent (Schuma K-102; manufactured by Nippon Kanisen Co., Ltd.) was used. This treatment sleeve was immersed in a Ni-P solution (S-754; manufactured by Nippon Kanisen Co., Ltd.) having a P concentration of 12.0% by mass to form an electroless Ni-P layer having a thickness of 6 μm. The sample after the Ni-P plating was used as a developer carrier e. The surface roughness was Ra = 0.93 μm and B / A = 10.4.

  Next, coating was performed in the same manner as in Example 1 using the inorganic particles A. This sample was designated as developer carrier A-8. This was subjected to image evaluation in the same manner as in Example 1.

[Example 9]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenol resin (ammonia catalyst used, containing 40% methanol, manufactured by Dainippon Ink & Chemicals, trade name: J325) 350 parts by mass of conductive carbon black (produced by Columbia Carbon Co., trade name: Conductex 975)
100 parts by mass of conductive spherical particles (manufactured by Nippon Carbon Co., Ltd., trade name: Nikabeads PC0520) 15 parts by mass of isopropyl alcohol 400 parts by mass The above materials were dispersed in the same manner as in Example 1 to obtain a coating solution. The volume average particle diameter of the particles contained in this coating liquid was 0.33 μm. Using this coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 12 mmφ by spraying, followed by heating in a hot air drying oven at 160 ° C. for 20 minutes to cure the conductive coating layer. A developer carrier f was prepared. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 0.76 μm and B / A = 2.9.

  Next, in the same manner as in Example 1, the inorganic particles A were applied onto the resin layer of the developer carrier f. This sample is referred to as a developer carrier A-9. This was subjected to image evaluation in the same manner as in Example 1.

[Comparative Example 1]
Using the developer carrier a prepared in Example 1, image evaluation was performed in the same manner as in Example 1.

[Comparative Examples 2 and 3]
Similarly to Example 1, the samples in which the inorganic particles F and G are applied to the developer carrier a are referred to as developer carriers g and h, respectively. These were subjected to image evaluation in the same manner as in Example 1.

[Comparative Example 4]
As the inorganic particles I, zinc stearate was used. In the same manner as in Example 1, a sample obtained by applying inorganic particles I to developer carrier a was designated as developer carrier i, and image evaluation was performed in the same manner as in Example 1.

[Example 10]
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at a blending ratio shown below.
Resol type phenol resin (ammonia catalyst used, methanol 40% contained, manufactured by Dainippon Ink & Chemicals, Inc., trade name: J325) 350 parts by mass of graphitized particles A 80 parts by mass of conductive carbon black (produced by Columbia Carbon Co., Ltd., trade name: Conductex 975)
20 parts by mass of conductive spherical particles (manufactured by Nippon Carbon Co., Ltd., trade name: Nikabeads PC1020) 15 parts by mass of isopropyl alcohol 400 parts by mass The above materials were dispersed in the same manner as in Example 1 to obtain a coating solution. The volume average particle diameter of the particles contained in this coating liquid was 2.25 μm. Using the above coating solution, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 20 mmφ by a spray method, followed by heating at 160 ° C. for 20 minutes in a hot air drying oven to cure the conductive coating layer. Developer carrier j was prepared. When the surface roughness (arithmetic average roughness) at this time was measured, Ra = 1.15 μm and B / A = 5.6.

  Next, the inorganic particles A were added to methanol so as to have a concentration of 5.0% by mass, and a solution suspended with a commercially available homogenizer was applied to the developer carrier j by a spray method. After coating, the sample after drying at room temperature was designated as developer carrier A-10.

  In evaluating the developer carrier A-10, a commercially available cartridge for a laser beam printer Lesser Jet 4350 (manufactured by Hewlett Packard) was used. A magnet and a flange were attached so that the developer carrier sample could be attached to the cartridge, and this developer was attached to the cartridge, filled with the developer T-2, and image evaluation was performed with a Lesser Jet 4350 machine. These results are shown in Tables 6-8.

[Example 11]
A sample obtained by applying the inorganic particles E to the developer carrying member j of Example 10 in the same manner as in Example 9 is referred to as Developer Carrier A-11, and image evaluation is performed in the same manner as in Example 10. It was.

[Example 12]
A solution in which inorganic particles A were added to methanol so as to have a concentration of 2.0% by mass and suspended with a commercially available homogenizer was applied to developer carrier j by a spray method. After coating, the sample after drying at room temperature was used as developer carrier A-12, and image evaluation was performed in the same manner as in Example 10.

[Example 13]
A solution in which inorganic particles A were added to methanol so as to have a concentration of 10.0% by mass and suspended with a commercially available homogenizer was applied to the developer carrier j by a spray method. After coating, the sample after drying at room temperature was used as developer carrier A-13, and image evaluation was performed in the same manner as in Example 10.

[Example 14]
A solution in which inorganic particles A were added to methanol so as to have a concentration of 20.0% by mass and suspended with a commercially available homogenizer was applied to the developer carrier j by the dipping method. After coating, the sample after drying overnight at room temperature was designated as developer carrier A-14, and image evaluation was performed in the same manner as in Example 10.

[Example 15]
A solution in which inorganic particles A were added to methanol so as to have a concentration of 0.5% by mass and suspended with a commercially available homogenizer was applied to the developer carrier j by a dipping method. After coating, the sample after drying overnight at room temperature was designated as developer carrier A-15, and image evaluation was performed in the same manner as in Example 10.

[Comparative Example 5]
Image evaluation was performed in the same manner as in Example 10 using the developer carrying member j prepared in Example 10.

[Comparative Examples 6 and 7]
Similarly to Example 10, the samples in which the inorganic particles F and H are applied to the developer carrier j are referred to as developer carriers k and l, respectively. These were subjected to image evaluation in the same manner as in Example 10.

[Comparative Example 8]
As the inorganic particles I, zinc stearate was used. In the same manner as in Example 10, the sample in which the inorganic particles I were applied to the developer carrier j was designated as a developer carrier m, and image evaluation was performed in the same manner as in Example 10.

<Image evaluation>
As the evaluation environment, a low temperature / low humidity environment (L / L) of 15 ° C./10% RH and a durable environment under a high temperature / high humidity environment (H / H) of 30 ° C./85% RH were performed.

(1) Image density A solid image was output in the image output test at the initial stage and at the end of durability evaluation, and the density was measured for evaluation. The image density was measured using a “Macbeth reflection densitometer RD918” (manufactured by Macbeth Co., Ltd.) to measure the relative density with respect to an image of a white background portion having a document density of 0.00.
A: Very good 1.40 or more B: Good 1.35 or more, less than 1.40 C: No practical problem 1.00 or more, less than 1.35 D: Practical problem Less than 1.00

(2) Ghost In the output image of the printer (image chart in the case of a copier), images of solid black images (square and circle) on a white background with an area corresponding to one round of the sleeve at the tip of the image at regular intervals Arranged and the other part was halftone. Ranking was based on how the ghost of the hieroglyph image appeared on the halftone (a positive ghost is a ghost with a higher image density than the halftone, and a negative ghost is a ghost with a lower image density than the halftone. Is shown.)
A: No difference in shading is observed.
B: A slight shade difference can be confirmed depending on the viewing angle.
C: A ghost is clearly confirmed visually. Practical level lower limit.
D: Ghost appears clearly as light and shade. The density difference can be measured with a reflection densitometer. There are practical problems.
E: A ghost appears over two or more sleeves.

(3) Image Unevenness A linear or belt-like streak (shading difference) that outputs halftone and solid black and runs in the image traveling direction was evaluated according to the following criteria. Image density unevenness due to ghost and blotch factors was excluded and evaluated.
A: Neither image nor sleeve can be confirmed at all.
B: A slight density difference can be confirmed on the halftone image, but there is no problem on the solid black image.
C: Although the density difference is slight on the solid black image, a streak or band in which the density difference can be visually confirmed is confirmed on the halftone image. Practical level lower limit.
D: A density difference that can be clearly measured with a reflection densitometer appears as a streak or a band on the halftone image. A density difference can be visually confirmed even on a solid black image. Levels that are problematic for graphic images.
E: Level at which a solid black image appears quite clearly.

(4) Blotch A solid black image and a halftone image are output, and a blotch (spotted, rippled, or carpet-like) image that is likely to be generated due to excessive charging of the toner in each image is visually observed. Indicated by indicators.
A: No blotch is observed on the image and on the sleeve (observation of the state where the toner is coated).
B: Slight blotch is confirmed on the sleeve, but there is no effect on the image.
C: Level at which a blotch image appears slightly on a part of a halftone image. Practical level lower limit.
D: A clear blotch appears on a part of a halftone image or a solid black image. There are practical problems.
E: Blotch appears almost on the entire surface.

(5) Fog Measure the reflectance of the solid white image in the appropriate image, and further measure the reflectance of the unused transfer paper. (Worst value of the reflectance of the solid white image-Average reflectance of the unused transfer paper) Value) is fog density, and the evaluation results are shown by the following indices. However, the reflectance was measured at 10 points at random. The reflectance was measured with TC-6DS (manufactured by Tokyo Denshoku).
A: Less than 1.0% (Fog is not recognized visually)
B: 1.0% or more and less than 2.0% (fogging is not allowed unless watched)
C: 2.0% or more and less than 3.0% (although there is fog, there is no practical problem)
D: 3.0% or more (fogging is conspicuous NG level)

  The results of image evaluation of the above Examples and Comparative Examples are shown in Tables 4-1 to 4-3 and Tables 5-1 to 5-3 below.

It is a schematic diagram of the example of the application means of the support | carrier particle | grains used by this invention. FIG. 6 is a schematic diagram showing a state of the vicinity of a developer carrying member and a developer layer thickness regulating member used in the developing method of the present invention. It is a schematic diagram which shows an example of the image development apparatus used for the image development method of this invention. 1 is a schematic cross-sectional view of an example of a surface modification apparatus used in a surface modification process for toner particles used in the present invention.

Explanation of symbols

1 Image carrier (photosensitive drum)
3 ... Hopper 4 ... Magnetic toner 5 ... Magnet roller 6 ... Metal cylindrical tube (base)
7 ... Coating layer 8 ... Developer carrier (developing sleeve)
9 ... Power supply 10 ... Agitating blade 11 ... Developer layer thickness regulating agent (elastic blade)
26 .. Sponge roller 27 .. Developer carrier (developing sleeve)
28 ·· Application container 29 · · Inorganic particles 30 · · Casing 31 · · Classification rotor 32 · · Fine powder recovery 33 · · Raw material supply port 34 · · Liner (fixed body)
35 .. Cold air inlet 36 .. Distributed rotor (rotating body)
37..Product discharge port 38..Drain valve 39..Guide ring (guide means)
41 ·· First space 42 · · Second space 301 · Developer layer thickness regulating member 302 · Substrate 303 · Magnet roller 306 · Concavity and convexity imparting particles 307 · Lubricating particles 308 · Conductive agent 309 · Binder resin 310・ Supported particles 311 ・ Developer

Claims (7)

A developer carrier having at least a substrate and a conductive coating layer as a surface layer;
The conductive coating layer is characterized by carrying inorganic particles made of perovskite-type crystals having a rectangular parallelepiped particle shape, on which at least one selected from fatty acids and fatty acid metal salts is present on the surface. A developer carrier.   The developer carrying member according to claim 1, wherein the primary particles of the inorganic particles have an average particle size of 0.03 μm or more and 0.30 μm or less.   3. The developer carrier according to claim 1, wherein the inorganic particles have a content of aggregates having a particle size of 0.60 μm or more of 1% by number or less.   The developer carrier according to claim 1, wherein the inorganic particles are strontium titanate. The surface of the conductive coating layer has a relationship of 0.03 ≦ M / R ≦ 0.30 with respect to the area M (mm ² ) on which the inorganic particles are supported in a certain area R (mm ² ) of the surface. The developer carrying member according to claim 1, wherein:   The conductive coating layer contains at least rough particles, and the surface shape of the conductive coating layer measured by using a focus optical laser is constant in a minute uneven region in which no convex portion is formed by the rough particles. The developer carrying member according to any one of claims 1 to 5, wherein a volume B of the shape of the minute uneven portion measured by area A satisfies a relationship of 4.5 ≦ B / A ≦ 6.5.   A developer is carried on the developer carrying member according to any one of claims 1 to 6, and the developer is applied to a developing region of the electrostatic latent image carrying member arranged to face the developer carrying member. A developing method comprising a step of transporting and developing the electrostatic latent image on the electrostatic latent image carrier with the developer.