JP2006017912A - Developer carrier and development method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer carrier which prevents the occurrence of the degradation in image density particularly in an initial period of image production, a sleeve ghost, image density unevenness, and image defects like a blotch etc., and with which high-grade stable images can be stably obtained even in a different environmental condition. <P>SOLUTION: The amount of the developer carried into the developer carrier is regulated by a developer layer thickness regulation member and the developer carrier is arranged to face an electrostatic latent image carrier on which an electrostatic latent image is carried. The developer carrier carries and conveys the developer to a development region in the section facing the electrostatic latent image carrier. The developer carrier on whose surface at least the particles stuck and fixed with particulates having electric conductivity are carried is used as the developer carrier used for a development method for developing and visualizing the electrostatic latent image on the electrostatic latent image carrier by the developer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

  Conventionally, a number of methods are known as electrophotography, but generally an electro latent image is formed on an electrostatic latent image carrier (photosensitive drum) by using a photoconductive substance by various means. Then, the electrostatic latent image is developed with a developer (toner) to be a visible image, and the toner image is transferred onto a transfer material such as paper as necessary, and then the toner image is formed on the transfer material by heat and pressure. Is fixed to obtain a copy.

  The development method in electrophotography is mainly divided into a one-component development method and a two-component development method. 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, the one-component development method is used. The used developing device is often used. Since the one-component development method does not require the use of carrier particles such as iron powder unlike the two-component development method, the development device itself can be reduced in size and weight. In addition, since the two-component development method needs to keep the toner concentration in the developer constant, a device for detecting the toner concentration and supplying a necessary amount of toner is required. Therefore, the developing device is also large and heavy here. In the one-component development method, since such an apparatus is not necessary, it can be reduced in size and weight, which is preferable.

  The following are known as developing devices using the one-component developing method. First, an electrostatic latent image is formed on the surface of a photosensitive drum as an electrostatic latent image carrier, and the friction between the developer carrier (developing sleeve) and the toner and / or the toner coat amount on the developing sleeve are regulated. The developer layer thickness regulating member (developing blade) of the toner and the toner give a positive or negative charge to the toner. The charged toner is thinly applied on the developing sleeve, and the photosensitive drum is rotated to convey the toner to a developing area where the photosensitive drum and the developing sleeve face each other. Then, development is performed by causing toner to fly and adhere to the electrostatic latent image on the surface of the photosensitive drum in the development region, and the electrostatic latent image is visualized as a toner image.

  When such a one-component development system is used, it is difficult to adjust the charged state of the toner, and various attempts have been made to improve the toner composition and physical properties. Problems related to durability and stability have not been completely solved. In particular, while the developing sleeve is repeatedly rotated, the charge amount of the toner coated on the developing sleeve becomes too high due to contact with the developing sleeve, and the toner is attracted by the reflection force on the developing sleeve surface and developed. A so-called charge-up phenomenon is likely to occur, particularly under low humidity, where the sleeve surface does not move and does not move from the developing sleeve to the latent image on the photosensitive drum. 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, which causes problems such as thin line images and thin image density of solid images.

  In addition, a toner that is not properly charged due to charge-up is poorly regulated and flows out onto the sleeve, causing a so-called blotch phenomenon in which spots and wavy unevenness occur on the image. Furthermore, the toner layer formation state changes between the image portion (toner consumption portion) and the non-image portion, and the toner charging state differs. For this reason, for example, if a position where a solid image having a high image density is once developed on the developing sleeve comes to a developing position at the next rotation of the developing sleeve and a halftone image is developed, a solid image trace appears on the image. The so-called sleeve ghost phenomenon is likely to occur.

  As a method for solving such a phenomenon, a method is proposed in which a developing sleeve in which 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 is used in a developing device. (For example, see Patent Documents 1 and 2). 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-mentioned conductive fine powder is added, it is favorable for improving charge-up and sleeve ghost, but the ability to impart proper charge to the toner is insufficient, It is difficult to obtain a sufficient image density in a high temperature and high humidity environment. Further, when a large amount of the above conductive fine powder is added, the coating layer becomes brittle and becomes easy to be scraped and the surface shape becomes non-uniform. The composition changes, and 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.

  Further, there has been proposed a developing sleeve in which a conductive coating layer formed by dispersing conductive fine powders such as crystalline graphite and carbon and spherical particles in a resin is provided on a metal substrate (see, for example, Patent Document 3). ). In this developing sleeve, the wear resistance of the coating layer is improved to some extent, the shape of the surface of the coating layer is made uniform, and the change in surface roughness due to durable use is relatively small. The toner charge can be stabilized and uniformized to some extent. For this reason, there is no problem in sleeve ghost, image density, image density unevenness, etc., and the image quality tends to be stabilized. However, this developing sleeve is also insufficient for rapid and uniform charge control to the toner and stabilization of an appropriate charge imparting ability to the toner.

  A developing sleeve having a conductive coating layer in which spherical particles having low specific gravity and conductive properties are dispersed has also been proposed (for example, see Patent Document 4). By using such spherical particles, it is possible to uniformly disperse the conductive spherical particles in the conductive coating layer, so that the wear resistance of the coating layer and the shape of the coating layer surface are made uniform, so that it is uniform to the toner. The charge imparting property is improved, and toner contamination and toner fusion can be 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.

  On the other hand, as a method for thinly applying the toner used in the above-described one-component development method onto the developing sleeve, the developing blade is brought into contact with the developing sleeve in the counter direction with respect to the rotation direction of the developing sleeve, and the developing blade There is a method of regulating the toner application amount on the developing sleeve by the contact pressure of the developing sleeve and the contact portion (nip portion) between the developing blade and the developing sleeve. As the developing blade, a hard material, for example, a member in which an elastic body such as silicone rubber or urethane rubber is fixed to a holding member of metal or synthetic resin is often used.

  In the apparatus having the above configuration, when the toner seal is not opened, that is, when the toner is sealed in the storage container and the toner is not on the developing sleeve, the developing blade contacts the surface of the developing sleeve. When the developing sleeve is rotated while the developing sleeve is rotated, the developing blade is turned over, which causes a problem that uniform toner application cannot be performed on the developing sleeve. In order to prevent these problems, a method of applying a powder lubricant dispersed in a volatile liquid on the surface of the developing blade has been used (see, for example, Patent Document 5).

Since such a lubricant is insulative, it is easily triboelectrically charged from a developing sleeve, a developing blade, or the like, and the charging of the lubricant may affect the charging of the toner. In particular, since a large amount of lubricant is present on the sleeve at the initial stage of image output, the influence on the charging of the toner becomes significant. If the charge series of the lubricant has a polarity opposite to that of the toner and the charge is too high, the lubricant acts as a frictional charge imparting member and extremely raises the charge of the toner, and the toner is reflected on the surface of the developing sleeve. It attracts by force 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 waves are uneven. On the other hand, when the charge series of the lubricant is the same polarity as the toner, if the charge of the lubricant is too high, the tribo is not sufficiently applied to the toner, resulting in uneven image density and low image density due to uneven toner coat. May occur.

  Therefore, as the lubricant, the toner is coated on the developing sleeve, the initial development characteristics when the development process is started, the appropriate shape and charging characteristics, etc., so as not to cause image defects due to uneven application of the lubricant It is necessary to use a lubricant having For example, by defining the average particle size and circularity of the lubricant and setting the lubricant itself to an appropriate range, the toner charge non-uniformity and charge-up can be reduced. A developing device that can prevent image defects such as the above-described sleeve ghost has been proposed (see, for example, Patent Document 6).

  On the other hand, LED and LBP printers have become the mainstream in the recent market, and the direction of technology is higher resolution, that is, the conventional 300, 400 dpi has become 600, 800, 1200 dpi. Along with this, a higher-definition development method has been demanded. Also, copying machines are becoming more sophisticated, and therefore are moving toward digitalization. In this trend, the copier mainly uses a method of forming an electrostatic charge image with a laser, so it is also moving in the direction of high resolution. Here, as with printers, high-resolution and high-definition development methods are also used. For this reason, countermeasures have been taken by reducing the particle size of the toner and making it finer.

  Such a toner having a small particle size has a large surface area per unit mass, so that the surface charge tends to increase 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. Here, a container for storing toner is inevitably required to be small in size, so that it is possible to print out a large number of sheets with a small amount, that is, a low consumption amount that can cover the same image with a smaller amount of toner. Toner is needed. As such a toner, a toner having a shape close to a sphere by a method of spheroidizing the toner itself by a mechanical impact force or a manufacturing method such as a spray granulation method, a solution dissolution method, or a polymerization method has been used.

  Such a spherical toner has a smoother surface than a conventional pulverized toner, and the magnetic material is easily encapsulated, so that the charging of the toner tends to be unstable. Along with this, image defects such as the sleeve ghost, blotch phenomenon, and density unevenness as described above tend to occur.

Therefore, by adding a quaternary ammonium salt compound that is positively charged to the iron powder in the resin, excessive charging such as charge-up is performed on the spheroidized toner or the negative toner manufactured by the polymerization method. There has been proposed a method using a developing sleeve for preventing the above (see, for example, Patent Documents 7 and 8). When such a method is used, although the effect of preventing the charge-up phenomenon and improving the charging imparting uniformity is recognized, the charging stability with respect to the toner is still insufficient.

In this way, as the particle size and spheroidization of the toner progresses to improve the performance of the electrophotographic apparatus, the charging of the toner tends to become unstable and non-uniform. Is noticeable. Although the above-mentioned prior art has a temporary effect in stabilizing and uniformizing the frictional charge to the toner, an image caused by unstable or uneven 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 of improving defects. Therefore, it is a problem to prevent further charge-up phenomenon, improve charging uniformity, and improve image defects such as sleeve ghost phenomenon and density unevenness caused by them.
Japanese Patent Laid-Open No. 2-105181 JP-A-3-36570 Japanese Patent Laid-Open No. 3-200986 JP-A-8-240981 JP-A-2-298971 JP 11-119551 A JP 2003-57951 A JP 2002-31636 A

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. Developer charge-up that occurs in the initial stage of image output, image density reduction that occurs due to non-uniform or unstable frictional charging, and image density It is an object of the present invention to provide a developer carrying member and a developing method capable of stably obtaining a high-quality image having a high image density without causing problems such as unevenness, image streaks, sleeve ghosts, and blotches. .

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

  In addition, the present invention does not cause problems such as density reduction, image density unevenness, image streaks, sleeve ghosts, and blotches, and the image density does not occur even under different environmental conditions, regardless of whether the image is initially printed or used endurancely. It is an object of the present invention to provide a developer carrier and a development method capable of stably obtaining a high-quality image.

  Furthermore, the present invention improves the uneven charging of the developer, which is likely to appear when an image is formed using a toner having a small particle diameter or a developer having a high sphericity, and provides an appropriate charge to the developer. It is an object of the present invention to provide a developer carrying member and a developing method capable of obtaining stable image quality without causing charge-up by performing application quickly.

  The present inventors have made it possible to prevent image defects caused by charge-up of a developer that is likely to occur at the initial stage of image formation, by supporting particles on which the conductive fine particles are adhered or fixed on the surface of the developer carrier. The inventors have found that the formation of a good image can be prevented from the initial stage by preventing the occurrence, and the present invention has been completed.

That is, the present invention is as follows.
(I) A developer carrying member for carrying a developer and transporting the developer to an electrostatic latent image carrying member carrying an electrostatic latent image,
The amount of developer carried on the developer carrier is regulated by the developer layer thickness regulating member,
The developer carrier is disposed opposite to the electrostatic latent image carrier on which the electrostatic latent image is carried. The developer is carried and conveyed to a developing area at a portion facing the electrostatic latent image carrier. It is used in a developing method for developing and visualizing an electrostatic latent image on an electrostatic latent image carrier with an agent,
The developer carrier is characterized in that at least particles having conductive fine particles attached or fixed thereon are carried on the surface of the developer carrier.
(II) The developer carrying member has at least a substrate and a coating layer formed on the surface of the substrate, and particles on which conductive fine particles are adhered or fixed are supported on the surface of the coating layer. The developer carrying member according to (I), wherein:
(III) The developer carrying member according to (II), wherein the coating layer has conductivity.
(IV) The developer carrying member according to (II) or (III), wherein the coating layer is a plating layer or a resin layer containing a conductive powder.
(V) A developer is carried on a developer carrying body disposed opposite to the electrostatic latent image carrying body carrying an electrostatic latent image, and the developer on the developer carrying body is formed by a developer layer thickness regulating member. The developer is carried and transported from the developer carrier to the development area of the opposite portion between the developer carrier and the electrostatic latent image carrier, and the electrostatic on the electrostatic latent image carrier is conveyed by the developer. A development method for developing and visualizing a latent image,
Prior to the developer carrying member carrying the developer, at least particles having conductive fine particles attached or fixed thereon are carried on the surface of the developer carrying member in the absence of the developer on the developer carrying member. And developing the electrostatic development on the electrostatic latent image carrier by carrying the developer on the developer carrier.
(VI) The developer carrier has at least a substrate and a coating layer formed on the surface of the substrate, and particles having conductive fine particles attached or fixed thereon are supported on the surface of the coating layer. (V) the developing method.
(VII) The developing method according to (VI), wherein the coating layer has conductivity.
(VIII) The developing method according to (VI) or (VII), wherein the coating layer is a plating layer or a resin layer containing conductive powder.

  According to the present invention, at least in the initial stage of image formation, the charge amount of the developer is made non-uniform and charged up by supporting at least the particles having conductive fine particles adhered or fixed on the surface of the developer carrier. The occurrence of image defects such as image density reduction, image density unevenness, and sleeve ghost due to the above can be suppressed, and favorable image formation can be performed from the initial stage over a long period under various environments.

  As a result of intensive studies, the present inventors have found that the above-described problems can be solved by using a developer carrying body carrying particles having conductive fine particles attached or fixed thereon. . As described in the background art, when the particles applied as the lubricant are insulative, the lubricant itself is likely to be triboelectrically charged by the developing sleeve, the developing blade, etc., and may affect the charging of the toner. is there. In the present invention, since the particles supported on the surface of the developer carrier have conductive fine particles attached or fixed to the surface of the particles, the particles themselves are electrically conductive while having a charge imparting property to the developer. It has sex. For this reason, it is possible to prevent the developer from being charged excessively, and the charge amount of the developer becomes a uniform and appropriate value, so that the charge-up and uneven charging of the developer can be reduced. Furthermore, since the charge-up of the particles themselves can be suppressed, it is possible to prevent the particles from agglomerating or firmly adhering to the surface of the developer carrying member. Therefore, it is possible to prevent the occurrence of image defects such as image density reduction, image density unevenness, blotch, and sleeve ghost due to developer charge-up and charging unevenness.

Next, the particles carried on the surface of the developer carrying member used in the present invention (hereinafter also referred to as “carrying particles”) will be described in more detail.
The supported particles used in the present invention are composed of mother particles and fine particles having conductivity (hereinafter also referred to as “conductive fine particles”) attached or fixed to the surface of the mother particles. The base particles may be silicone resin, PMMA (polymethyl), depending on the developer used on the developer carrier and the material of the friction carrier member such as the developer carrier or developer layer thickness regulating member. (Methacrylate) resin, urethane resin, acrylic resin, polystyrene resin, melamine-formaldehyde resin, phenol resin, poly-4 fluoroethylene, poly-3 fluoroethylene, polyvinylidene fluoride, and the like; boron nitride, disulfide Examples thereof include inorganic particles such as molybdenum, strontium titanate, silica, and talc.

  The mother particle preferably has at least a primary average particle size of 0.1 to 30 μm, and more preferably 1 to 20 μm. When the primary average particle diameter of the mother particles is less than 0.1 μm, the conductive particles are likely to be insufficiently adhered / fixed to the mother particles, and the conductivity of the carrier particles may be impaired, or the conductive particles may be free. In some cases, the charging of the developer is likely to be hindered, which may cause a reduction in image density. When the primary average particle diameter of the mother particles exceeds 30 μm, it becomes difficult to make the carrier particles uniformly exist on the surface of the developer carrier, and as a result, image defects such as image streaks and unevenness may be caused.

  Examples of the conductive fine particles that adhere to or adhere to the surface of the mother particles include, for example, carbon black such as furnace black, lamp black, thermal black, acetylene black, and channel black; titanium oxide, tin oxide, zinc oxide, molybdenum oxide, Examples thereof include metal oxides such as potassium titanate, antimony oxide and indium oxide; metals such as aluminum, copper, silver and nickel; inorganic fillers such as graphite, metal fibers and carbon fibers.

  The conductive fine particles preferably have a particle size smaller than at least the mother particle, and preferably have a primary average particle size of 1 μm or less. If the average primary particle size exceeds 1 μm, the adhesion of the conductive fine particles to the mother particles may be reduced, and the supported particles may not obtain the desired conductivity.

  Examples of the method for adhering or fixing the conductive fine particles to the surface of the mother particles include a method of mixing and stirring the mother particles and the conductive fine particles by mechanical means, and mechanical thermal energy mainly composed of impact force as necessary. The method of giving is adopted. A commercially available mixer or a high-speed fluidized agitator (for example, a chemical mixer, a super mixer, a Henschel mixer, a ball mill, etc.) can be used for the mixing and stirring. In the present invention, if there are many conductive fine particles released from the mother particles during the development process, the conductivity of the supported particles may be lowered and the above-described effects may be reduced. Desirable results can be obtained by fixing. Examples of a method for fixing the conductive fine particles more firmly include a method in which treatment is performed using a mechanofusion system, a hybridization system, a fluidized drying furnace, a hot air treatment apparatus, or the like.

The supported particles used in the present invention can be suitably used if the volume resistance value is 10 ⁸ Ω · cm or less, more preferably particles having a volume resistance value of 10 ⁶ Ω · cm or less. When the volume resistance value of the supported particles exceeds 10 ⁸ Ω · cm, the effect of suppressing the toner charge-up and the occurrence of uneven charging may be impaired.

In the present invention, “supported particles are supported on the surface of the developer carrier” means a state in which the supported particles are electrostatically attached to the surface of the developer carrier. That is, the carrier particles used in the present invention are those firmly fixed on the surface of the developer carrier (so that they are not detached even if the development process is performed) or those contained in the material of the developer carrier surface. Rather, it gradually desorbs from the developer carrying member as the development process proceeds (increase in the number of images printed).

As a method for supporting the carrier particles on the surface of the developer carrier, as shown in FIG. 1, a sponge roller is impregnated with the carrier particles and applied to the developer carrier, or a volatile liquid that does not attack the particles. A known method such as dispersing, brushing, dipping, or spraying is used, and the method is not particularly limited. Hereinafter, an example of a preferred method for applying the carrier particles to the developing sleeve will be described with reference to FIG. The particle coating apparatus is mainly composed of a coating container 28 that is a casing, and a sponge roller 26 and carrier particles 29 that are housed in the coating container 28. The sponge roller 26 is composed of a cylindrical cored bar 26a having a rotation axis orthogonal to the paper surface in the figure, and a sponge 26b covering the periphery of the cored bar 26a. One end of the cored bar 26a of the sponge roller 26 is rotatably supported by a bearing (not shown), and the other end is connected to a rotating shaft of a motor (not shown) via a gear.

  The sponge roller 26 is driven by a motor (not shown) and rotates in the direction of arrow F in the figure. Further, the rotation speed can be adjusted. In the coating container 28, the support particles 29 are filled so that the sponge of the sponge roller 26 is uniformly filled in the longitudinal direction (axial direction). The sponge roller 26 holds the carrier particles on the sponge surface, and conveys the carrier particles 29 to the developing sleeve 27 by rotation.

  The developing sleeve 27 is installed in the coating container 28 with its axis parallel to the rotational axis of the sponge roller 26. The developing sleeve 27 is installed so that both end portions in the longitudinal direction are pressed by a rotatable bearing (not shown) from the direction of arrow G in the drawing so that a certain amount enters the surface of the sponge roller 26. At this time, the intrusion amount of the developing sleeve 27 into the sponge roller 26 is held to be uniform in the longitudinal direction. The developing sleeve 27 has a gear flange (not shown) at one end thereof, 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 each other, and the carrier particles are applied so that the carrier particles on the sponge roller 26 are rubbed onto the developing sleeve 27. The coating amount of the carrier particles on the developing sleeve 27 is determined by the penetration amount of the developing sleeve with respect to the sponge roller, the rotational speed and relative speed of the developing sleeve / sponge roller, and the absolute amount of the carrier particles in the coating container.

  In addition to the above-described method, for example, a developer may be used when the carrier particles are applied to the developer carrier used in the development method in which a developer layer thickness regulating member such as an elastic blade is brought into contact with the developer carrier. After assembling the developing part (developing device) by applying the carrier particles on the layer thickness regulating member, the developer carrier is rotated for a certain period of time in a state where the toner is not coated on the developer carrier. A method of coating the developer carrying member with the carrier particles on the agent layer thickness regulating member can also be suitably used. In this case, any known method may be used as a method for applying the developer layer thickness regulating member.

Next, the configuration of the developer carrier used in the present invention will be described in more detail.
The developer carrying member is composed of a substrate and, if necessary, a coating layer provided on the substrate. The base of the developer carrier includes a cylindrical member, a columnar member, a belt-like member, etc. In a developing method that is not in contact with the electrostatic latent image carrier, a rigid cylindrical tube or solid such as a metal is used. A rod is preferably used. As such a substrate, a non-magnetic metal or alloy such as aluminum, stainless steel, or brass, which is molded into a cylindrical or columnar shape, polished, ground, 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 (axial direction of the cylinder or column) is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. The gap between the developer carrier and the electrostatic latent image carrier, for example, the gap between the vertical surface when the developer carrier is rotated by abutting the vertical surface with a uniform spacer is also preferable. Is 30 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less. As the base of the developer carrying member, aluminum is preferably used because of material cost and ease of processing.

  The substrate of the developer carrying member may be subjected to a blasting process on the surface thereof in order to improve the developer transportability. Specifically, by using an apparatus as shown in FIG. 2, a blast material such as spherical glass beads is sprayed from the blast nozzle at a predetermined pressure for a predetermined time on the surface of the substrate, thereby forming a number of depressions on the surface of the developer carrier. The method of forming is mentioned. However, the present invention is not limited to this method, and an arbitrary method can be used.

  The developer carrier used in the present invention is preferably provided with a coating layer made of metal plating, resin or the like on the surface of the substrate so as to control the chargeability of the developer together with the carrier particles. By providing such a coating layer on the surface of the developer carrying member, it is possible to suitably impart charge to the developer. Therefore, in the case where the carrying particles are not present due to the durable use of the developer carrying member. However, it is possible to always apply high and uniform frictional charging to the developer. Therefore, by using the carrier particles in a developer carrier having such a coating layer, it is possible to suppress the occurrence of a decrease in image density, uneven image density, etc. from the initial to long-term use, and obtain a high-quality image. Is possible.

  As a method for forming a metal plating layer as a coating layer on the surface of the developer carrying member, electrolytic plating 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 or alloy or metal compound selected from the group consisting of nickel, chromium, molybdenum, and palladium, such as electroless Ni-P plating, Examples thereof include electroless Ni-B plating, electroless Pd plating, electroless Pd-P plating, electroless Cr plating, electrolytic Mo plating, or electroless Mo plating. When the developer carrying body has a magnet roll inside, it is preferable that at least the surface of the developer carrying body is nonmagnetic. The thickness of the plating layer is preferably 0.5 to 20 μm, and more preferably 3 to 15 μm. 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, and when the thickness of the plating layer exceeds 20 μm, it exists on the substrate surface. It becomes difficult to keep the thickness of the plating layer uniform in the longitudinal direction of the developer carrier.

  In addition, regarding Ni-P plating, Ni is a ferromagnetic substance by itself, but in electroless plating, it becomes amorphous by reacting with phosphorus or boron, and magnetism is weakened. Is preferable. Also in the case of electroless Cr plating, if the plating layer is 20 μm or less, it can be used sufficiently because it does not actually disturb the magnetic field of the internal magnet.

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

In the present invention, in order to prevent the fixing of the developer on the developer carrier due to charge-up and the poor charging of the developer from the surface of the developer carrier caused by the charge-up of the developer, the developer The resin coating layer on the surface of the carrier is more preferably a conductive layer. Moreover, the volume resistance value of the resin coating layer is preferably 10 ⁴ Ω · cm or less, more preferably 10 ³ Ω · cm or less. By providing a conductive resin coating layer having a resistance value in the above range on the substrate, particularly when image formation is performed using a developer having a small particle size or a developer having a high sphericity. It is possible to more reliably suppress the occurrence of uneven charging and charge-up of the initial developer, which are likely to appear, and to stably apply frictional charging to the toner even in different environments. In addition, even when the number of images to be printed is increased and the developer tribo is raised during durable use, it is possible to obtain a stable and high-quality image from start to finish without charging the toner. If the volume resistance value of the resin coating layer exceeds 10 ⁴ Ω · cm, poor charge application to the developer is likely to occur, and as a result, blotch may occur.

  In the present invention, in order to adjust the resistance value of the resin coating layer to the above value, it is preferable that the coating layer contains a powder made of the following conductive material, that is, a conductive powder. Examples of the conductive material used at this time include metal powders such as aluminum, copper, nickel, and silver, metal oxides such as antimony oxide, indium oxide, and tin oxide, carbon fiber, carbon black, and graphite. Examples include carbon materials. In the present invention, among these, carbon black, in particular, conductive amorphous carbon, is particularly excellent in electrical conductivity, and it can be filled with a polymer material to impart electrical conductivity, and the addition amount can be controlled. It is preferably used because it can obtain an arbitrary conductivity to some extent. Moreover, it is preferable to make the addition amount of these electroconductive substances suitable in this invention into the range of 1-100 mass parts with respect to 100 mass parts of binder resin.

  Further, in the present invention, in order to make the surface roughness in the resin coating layer uniform and maintain an appropriate surface roughness, a more preferable result is obtained by adding solid particles for forming irregularities to the resin coating layer. Is obtained. As the solid particles for forming irregularities used in the present invention, spherical particles are preferable. By using spherical particles, a desired surface roughness can be obtained with a smaller addition amount than that of amorphous particles, and a surface shape having uniform irregularities 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 toner layer thickness on the developer carrier is less likely to occur, so the charging of the toner is made uniform and the sleeve ghost is good. The effects of preventing the occurrence of streaks and unevenness, and preventing the occurrence of sleeve contamination and fusion with toner on the developer carrying member can be exhibited over a long period of time.

  The number average particle diameter of the spherical particles used in the present invention is 0.3 to 30 μm, preferably 2 to 20 μm. When the number average particle diameter of the spherical particles is less than 0.3 μm, there is little effect of imparting a uniform surface roughness to the surface of the coating layer, the toner is charged up due to the wear of the coating layer, the sleeve is contaminated and fused by the toner. Therefore, image deterioration and image density reduction due to sleeve ghost may occur. When the number average particle diameter exceeds 30 μm, the surface roughness of the coating layer becomes too large, and the amount of toner transport increases, so the toner coat on the surface of the developing sleeve becomes non-uniform and the toner is uniformly charged. It becomes difficult to be broken. Further, the protrusion of coarse particles may cause white spots and black spots due to image streaks and bias leaks. Furthermore, the mechanical strength of the coating layer may be reduced.

The spherical shape in the spherical particles used in the present invention means a particle having a major axis / minor axis ratio of about 1.0 to 1.5. In the present invention, the major axis / minor axis ratio is preferably Particles of 1.0 to 1.2 are used, particularly preferably spherical particles. The ratio of major axis / minor axis of spherical particles is 1.5
In the case of exceeding the above, since the dispersibility of the spherical particles in the coating layer is reduced, or addition of multiple particles is necessary to obtain a desired surface roughness, the surface shape of the uniform coating layer is It becomes difficult to obtain. Therefore, there is a case where the toner is uniformly charged and the strength of the coating layer is insufficient.

  As the spherical particles used in the present invention, any conventionally known spherical particles can be used as long as their number average particle diameter is 0.3 to 30 μm. Examples include spherical resin particles, spherical metal oxide particles, and spherical carbonized particles. Among these, spherical resin particles are preferable because when they are added to the coating layer, a suitable surface roughness can be obtained with a smaller addition amount and a uniform surface shape can be easily obtained. The spherical resin particles that can be used in the present invention can be easily obtained, for example, by suspension polymerization, dispersion polymerization, or the like. Of course, particles obtained by spheroidizing resin particles obtained by a pulverization method by thermal or physical spheronization treatment may be used.

  Specific examples of the spherical resin particles suitable for the present invention include acrylic resin particles such as polyacrylate and polymethacrylate, polyamide resin particles such as nylon, polyolefin resin particles such as polyethylene and polypropylene, and silicone resin particles. And spherical particles produced by generally known resins such as phenol resin particles, polyurethane resin particles, styrene resin particles, and benzoguanamine resin particles.

  In addition, the spherical particles used in the present invention may have inorganic fine powder adhered or fixed on the surface thereof. For example, by treating the spherical resin particle surface with inorganic fine powder as described below, the dispersibility of the spherical particles in the coating layer is improved, the uniformity of the surface of the coating layer formed, It is possible to improve the stain resistance, the charge imparting property to the toner, the wear resistance of the coating layer, and the like.

Examples of the inorganic fine powder used at this time include oxides such as SiO ₂ , SrTiO ₃ , CeO ₂ , CrO, Al ₂ O ₃ , ZnO and MgO; nitrides such as Si ₃ N ₄ ; carbides such as SiC; CaSO ₄ , sulfates and carbonates such as BaSO ₄ and CaCO ₃ . These inorganic fine powders may be used after being treated with a coupling agent. For the purpose of improving the adhesion between the spherical particles and the binder resin, or for the purpose of imparting hydrophobicity to the spherical particles, an inorganic fine powder treated with a coupling agent can be particularly preferably used.

  Examples of the coupling agent used at this time include a silane coupling agent, a titanium coupling agent, a zircoaluminate coupling agent, and the like. More specifically, for example, as silane coupling agents, hexamethyldisilazane, trimethylsilane, trimethylchlorosilane, trimethylethoxysilane, dimethyldichlorosilane, methyltrichlorosilane, allyldimethylchlorosilane, allylphenyldichlorosilane , Benzyldimethylchlorosilane, bromomethyldimethylchlorosilane, α-chloroethyltrichlorosilane, β-chloroethyltrichlorosilane, chloromethyldimethylchlorosilane, triorganosilylmercaptan, trimethylsilylmercaptan, triorganosilylacrylate, vinyldimethylacetoxysilane, Dimethyldiethoxysilane, dimethyldimethoxysilane, diphenylethoxysilane, hexamethyldisiloxane, 1,3-divinyltet Lamethyldisiloxane, 1,3-diphenyltetramethyldisiloxane, and 2-12 siloxane units per molecule, each containing a hydroxyl group bonded to a corresponding silicon atom in the terminal unit And dimethylpolysiloxane.

True density of the spherical particles used in the present invention, 3 g / cm ³ or less, preferably 2.7 g / cm ³ or less, more preferably be a 0.9~2.5g / cm ^3. When the true density of the spherical particles exceeds ³ g / cm ³ , it is necessary to add a large amount of particles in order to impart an appropriate surface roughness to the resin coating layer. In addition, since the density difference between the spherical particles and the binder resin is too large, the dispersibility of the spherical particles in the coating layer becomes insufficient, and it becomes difficult to impart a uniform roughness to the surface of the coating layer. It becomes difficult to give.

  Furthermore, in the present invention, it is preferable to use conductive particles as spherical particles. By imparting conductivity to the spherical particles, it is possible to make it difficult to accumulate charges on the particle surface as compared to the insulating particles. Therefore, the inclusion of such conductive spherical particles in the coating layer has the effect of uniforming the surface roughness of the developer carrier through durable use, and also reduces the adhesion of toner to the spherical particles. This has the effect of further suppressing the source of contamination of the developer carrier by the toner and the source of fusion of the toner to the developer carrier. Therefore, it is possible to obtain the effect of further improving the chargeability to the toner and further improving the developability.

The conductivity of the conductive spherical particles used in the present invention refers to those having a volume resistance of 10 ⁶ Ω · cm or less, and preferably a volume resistance of 10 ⁶ Ω · cm to 10 ⁻³ Ω. Use cm particles. When the volume resistivity of the conductive spherical particles exceeds 10 ⁶ Ω · cm, the effect of making the particles conductive, that is, the contamination of the sleeve with toner using the spherical particles exposed on the surface of the conductive coating layer due to abrasion as the nucleus. And the effect of suppressing fusion is impaired.

  The method for obtaining the conductive spherical particles used in the present invention is preferably the method described below, but is not necessarily limited thereto. For example, a method of carbonizing and / or graphitizing resin-based spherical particles or mesocarbon microbeads to obtain low-concentration and highly conductive spherical carbon particles as conductive spherical particles is preferable. Examples of the resin used for the resin-based spherical particles include phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, and polyacrylonitrile. In addition, mesocarbon microbeads can be usually produced by washing spherical crystals formed in the process of heating and firing the medium pitch with a large amount of a solvent such as tar, medium oil, and quinoline.

  As a more preferable method for obtaining conductive spherical particles, the surface of spherical particles such as phenol resin, naphthalene resin, furan resin, xylene resin, divinylbenzene polymer, styrene-divinylbenzene copolymer, polyacrylonitrile, etc. is applied by mechanochemical method. Examples thereof include a method in which bulk mesophase pitch is coated, and the coated particles are heat-treated in an oxidizing atmosphere and then calcined to be carbonized and / or graphitized to obtain conductive spherical carbon particles as conductive spherical particles.

The conductive spherical carbon particles obtained by the method described above can be controlled to some extent by changing the firing conditions in any method, and are preferably used in the present invention. Is done. In addition, in some cases, the spherical carbon particles obtained by the above-described method may have a conductive metal and / or an amount within a range in which the true density of the conductive spherical particles does not exceed ³ g / cm ³ in order to further increase the conductivity. Alternatively, metal oxide plating may be applied.

  As another method for obtaining the conductive spherical particles used in the present invention, conductive fine particles smaller than the particle size of the core particles are mechanically mixed with the core particles made of spherical resin particles at an appropriate blending ratio. After the conductive fine particles are uniformly attached around the core particles by the action of van der Waals force and electrostatic force, for example, the surface of the core particles is increased by a local temperature rise caused by applying a mechanical impact force. And a spherical resin particle obtained by conducting a conductive treatment by forming conductive fine particles on the surface of the core particle.

For the core particles of the conductive spherical particles, it is preferable to use spherical resin particles having a small true density made of an organic compound. Examples of the resin include PMMA, acrylic resin, polybutadiene resin, polystyrene resin, polyethylene, polypropylene, Polybutadiene or copolymers thereof, benzoguanamine resin, phenol resin, polyamide resin, nylon,
Fluorine resin, silicone resin, epoxy resin, and polyester resin can be used. As the conductive fine particles (small particles) used when forming a film on the surface of the core particles (mother particles), the particle size of the small particles is the same as the particle size of the mother particles in order to provide a conductive fine particle coating uniformly. It is preferable to use 1/8 or less.

  Still another method for obtaining the conductive spherical particles used in the present invention is to obtain conductive spherical particles in which the conductive fine particles are dispersed by uniformly dispersing the conductive fine particles in the spherical resin particles. It is done. As a method for uniformly dispersing the conductive fine particles in the spherical resin particles, for example, the binder resin and the conductive fine particles are kneaded to disperse the conductive fine particles, then cooled and solidified, and pulverized to a predetermined particle size. A method of obtaining spherical conductive particles by mechanical treatment and thermal treatment; or adding a polymerization initiator, conductive fine particles and other additives to the polymerizable monomer, and uniformly using a dispersing machine. The dispersed monomer composition is suspended in an aqueous phase containing a dispersion stabilizer with a stirrer so as to have a predetermined particle size, and polymerization is performed to obtain spherical particles in which conductive fine particles are dispersed. The method of obtaining is mentioned.

  Even in the conductive spherical particles in which the conductive fine particles obtained by these methods are dispersed, they are further mechanically mixed with the conductive fine particles having a particle diameter smaller than that of the core particles at an appropriate blending ratio to obtain van der Waals. After the conductive fine particles are uniformly deposited around the conductive spherical particles by the action of force and electrostatic force, the surface of the conductive spherical particles is softened by a local temperature rise caused by applying a mechanical impact force, for example. Alternatively, conductive fine particles may be formed on the surface to further increase the conductivity.

  As described above, the spherical particles dispersed in the coating layer constituting the developer carrying member of the present invention optimize the surface roughness of the developing sleeve surface, and further uniformize the surface shape, so that the toner layer on the sleeve By making the conveyance force uniform and suppressing the change in surface roughness when wear occurs, the change in developer conveyance force due to durable use is suppressed, and the toner can be charged quickly and uniformly. Charge control, that is, the effect of preventing charge-up and preventing sleeve ghost, and the effect of preventing sleeve contamination and fusion by toner can be exhibited over a long period of time even by durable use. Among these, spherical carbon particles are particularly preferably used because they do not impair the conductivity of the coating layer and can prevent toner adhesion / fusion with the particles as nuclei.

  In the coating layer constituting the developer carrying member of the present invention, it is preferable to disperse a solid lubricant in combination with conductive spherical particles because the effect of the present invention is further promoted. Examples of the solid lubricant include crystalline graphite, molybdenum disulfide, boron nitride, mica, graphite fluoride, silver-niobium selenide, calcium chloride-graphite, talc, and fatty acid metal salts such as zinc stearate. Etc. Among them, crystalline graphite is particularly preferably used because it does not impair the conductivity of the conductive coating layer even when used in combination with conductive spherical particles.

  The solid lubricant preferably has a number average particle diameter of preferably about 0.2 to 20 μm, more preferably 1 to 15 μm. When the number average particle size of the solid lubricant is less than 0.2 μm, it is not preferable because sufficient lubricity may not be imparted. If the number average particle size exceeds 20 μm, the surface roughness of the coating layer (developer carrier) is greatly affected, and the surface roughness tends to change due to scraping due to durable use. Is unstable, and therefore, the developer coating on the developer carrier and the charged state of the developer may become unstable.

In the present invention, a charge control agent may be contained in the resin coating layer in order to adjust the chargeability of the developer carrying member. 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 and dicyclohexyltin oxide; diorganotins such as thibutyltin borate, dioctyltin borate and dicyclohexyltin borate Rate acids; guanidines, imidazole compounds.

  Among these charge control agents, in the case of using a negative toner having a particularly high sphericity as a developer, the resin coating layer contains a quaternary ammonium salt compound that is positively charged with respect to iron powder as the charge control agent. It is preferable to improve the charging property of the toner of the present invention. At this time, it is more preferable that the resin coating layer has at least one of an amino group, ═NH group, and —NH— bond in the resin structure.

  By providing a resin coating layer combining the above-mentioned quaternary ammonium salt compound and a specific binder resin on the developer carrying member, it works to prevent excessive charging of the negative toner having a high degree of spheroidization. The application of triboelectric charge can be controlled. This prevents toner charge-up on the developer carrying member, prevents toner fusion on the surface of the resin coating layer, and maintains high charging stability of the toner, resulting in environmental stability and long-term stability. It becomes possible to provide a high-definition image.

  The reason for this is not clear, but is presumed as follows. A quaternary ammonium salt compound which is preferably used in the present invention and is positively charged with respect to iron powder itself, when added, has at least one of an amino group, ═NH or —NH— in the structure. The binder resin composition containing the above compound has a negative chargeability because the binder resin is uniformly dispersed in the binder resin and further incorporated into the binder resin structure when the coating layer is formed. It is thought to become. Therefore, for negatively chargeable toners, the toner acts in a direction that prevents the toner from having an excessive negative charge amount, and as a result, the negative charge amount can be appropriately controlled.

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

（式中のＲ_１、Ｒ_２、Ｒ_３及びＲ_４は、それぞれ置換基を有してもよいアルキル基、置換基を有してもよいアリール基、又はアルアルキル基を表し、Ｒ_１〜Ｒ_４は同一でも異なっていても良い。Ｘ⁻は酸の陰イオンを表す。）

_{(R 1, R 2, R} 3 and R ₄ in the formula are each an optionally substituted alkyl group, an optionally substituted aryl group, or an aralkyl group, R ₁ ~ R ₄ may be the same or different, and X ⁻ represents an anion of an acid.)

In the above general formula, X ^- Specific examples of the acid ions, organic sulfate ions, organic sulfonate ions, organic phosphate ions, molybdate ions, tungstate ions, such as heteropoly acid containing molybdenum atoms or tungsten atoms are preferred Used.

  Specific examples of the quaternary ammonium salt compound which is preferably used in the present invention and is positively charged with respect to iron powder include the following, but are not limited thereto. is not.

  Further, as a preferred resin containing at least one of an amino group, = NH or -NH- in the structure, used in combination with the quaternary ammonium salt compound, it is produced using a nitrogen-containing compound as a catalyst in the production process. And phenol resins, polyamide resins, epoxy resins using polyamide as a curing agent, urethane resins, or copolymers partially containing these resins. By using the quaternary ammonium salt compound together with the binder resin containing these resins, the quaternary ammonium salt compound is easily taken into the structure of the binder resin when the coating layer is formed.

In the present invention, as the nitrogen-containing compound used as a catalyst in the production process of a phenol resin that can be suitably used in combination with the quaternary ammonium salt compound, examples of the acidic catalyst include ammonium sulfate, ammonium phosphate, and sulfamic acid. Examples thereof include ammonium salts and amine salts such as ammonium, ammonium carbonate, ammonium acetate, and ammonium maleate. Basic catalysts include ammonia, dimethylamine, diethylamine, diisopropylamine, diisobutylamine, diamylamine, trimethylamine, triethylamine, tri-n-butylamine, triamylamine, dimethylbenzylamine, diethylbenzylamine, dimethylaniline, diethylaniline, N , N-di-n-butylaniline, N, N-diamilaniline, N, N-di-t-amylaniline, N-methylethanolamine, N-ethylethanolamine, diethanolamine, triethanolamine, dimethylethanolamine , Diethylethanolamine, ethyldiethanolamine, n-butyldiethanolamine, di-n-butylethanolamine, triisopropanolamine, ethylenediamine, hexamethyl Amino compounds such as lentetramine; pyridine and derivatives thereof such as pyridine, α-picoline, β-picoline, γ-picoline, 2,4-lutidine, 2,6-lutidine; quinoline compounds, imidazole, 2-methylimidazole, 2 , 4-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, imidazole such as 2-heptadecylimidazole, and nitrogen-containing heterocyclic compounds such as derivatives thereof. Can be mentioned.

  In addition, examples of the polyamide resin constituting the binder resin that is preferably used together with the quaternary ammonium salt compound in the present invention include nylon 6, 66, 610, 11, 12, 9, 13, Q2 nylon, and the like. Nylon copolymers containing these as main components, N-alkyl-modified nylon, N-alkoxylalkyl-modified nylon and the like can be preferably used. Furthermore, various resins modified with polyamide, such as polyamide-modified phenolic resin, or epoxy resins using polyamide resin as a curing agent, and any resin containing a polyamide resin component Can be used.

  Moreover, as a urethane resin which comprises the binder resin suitably used by the combination with the said quaternary ammonium salt compound by this invention, as long as it is resin containing a urethane bond, all can be used. This urethane bond is obtained by polymerization addition reaction of polyisocyanate and polyol. Polyisocyanates that are the main raw materials for this polyurethane resin include TDI (tolylene diisocyanate), pure MDI (diphenylmethane diisocyanate), polymeric MDI (polymethylene polyphenyl polyisocyanate), TODI (tolidine diisocyanate), NDI (naphthalene diisocyanate), and the like. Aromatic polyisocyanates such as: HMDI (hexamethylene diisocyanate), IPDI (isophorone diisocyanate), XDI (xylylene diisocyanate), hydrogenated XDI (hydrogenated xylylene diisocyanate), aliphatic MDI (dicyclohexylmethane diisocyanate), etc. And polyisocyanates.

  Polyols that are the main raw materials for this polyurethane resin include polyether polyols such as PPG (polyoxypropylene glycol), polymer polyols, and polytetramethylene glycol (PTMG); polyesters such as adipate, polycaprolactone, and polycarbonate polyols. Polyols: polyether-based modified polyols such as PHD polyols and polyether ester polyols; other epoxy-modified polyols; partially saponified polyols of ethylene-vinyl acetate copolymers (saponified EVA); flame retardant polyols and the like.

Next, the specific configuration of the developer carrying member of the present invention will be described in more detail with reference to preferred embodiments. FIG. 3 is a partial cross-sectional view showing an example of a basic configuration of the developer carrying member of the present invention and its periphery. In FIG. 3, a member having elasticity such as urethane rubber is used as the developer layer thickness regulating member 301 in contact with the developing sleeve 300 as the developer carrying member. A regulating blade or the like may be used. A developing sleeve 300 as a developer carrier includes a metal cylindrical tube (base) 302, a coating layer 312 mainly including a binder resin 309 that covers the surface of the cylindrical tube 302, and supported particles supported on the surface of the coating layer. 310. The coating layer 312 includes a conductive substance 308, unevenness imparting particles 306, and a solid lubricant 307 dispersed in a binder resin 309. Further, the supported particles 310 supported on the surface of the coating layer 312 include the mother particles 304 and the conductive fine particles 305 attached or fixed to the surfaces of the mother particles 304.

  The supported particles are supported on the surface of the developing sleeve 300 before image use (before image formation), for example, by a method using a coating apparatus as shown in FIG. Since the developer does not exist on the developing sleeve before image use is used, the carrier particles 310 adhere to the developer regulating member 301 at the portion where the developing sleeve 300 and the developer layer thickness regulating member 301 are in contact with each other. . For this reason, the developing sleeve 300 and the developer regulating member 301 are not in direct contact with each other even before the image formation in which the developer is not carried on the surface of the developing sleeve 300, and the developing sleeve 300 is damaged by the developer regulating member 301. It is prevented.

  At the time of image use (during image formation), the developer 311 is conveyed so as to contact the surface of the coating layer 312 on the developing sleeve 300 and the carrier particles 310 attached on the developer layer thickness regulating member 301. At that time, the carrier particles 310 are controlled so that the amount of triboelectric charge held by the developer is appropriate, so that the charge-up phenomenon of the developer can be mitigated. As a result, images such as sleeve ghosts and blotches Defects can be eliminated. Further, as the number of images to be printed increases, the carrier particles 310 are consumed together with the developer, so that the amount of the carrier particles 310 on the developing sleeve 300 decreases, but the coating layer 312 provided on the developing sleeve 300. As a result, a good charged state of the developer 311 is maintained, so that a good image formation can be achieved over a long period of time without the charge amount of the developer 311 being insufficient or charging up.

  FIG. 4 is a schematic cross-sectional view showing a preferred example of a developing device using the developer carrying member of the present invention. Hereinafter, the developing method using the developer carrying member of the present invention will be described with reference to FIG. In FIG. 4, reference numeral 1 denotes an electrostatic 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. In the developing device used in the present invention, a developing sleeve 8 as a developer carrying member has a metal cylindrical tube (base) 6 and a resin coating layer 7 covering the surface thereof, and is disposed to face the photosensitive drum 1. ing. The developing sleeve 8 rotates in the direction of arrow A in FIG. 1 about an axis parallel to the rotation axis of the photosensitive drum 1. As described above, the support particles are supported on the surface of the developing sleeve 8 in advance. Further, the developing device has a hopper 3 for containing magnetic toner 4 as a magnetic one-component developer as a developer, and the hopper 3 is provided with a stirring blade 10 for stirring the magnetic toner 4. Further, a layer thickness regulating blade 11 as a developer layer thickness regulating member is provided in a state where one end is fixed in the developing device and the other free end is in contact with the surface of the developing sleeve 8.

  The developing sleeve 8 is arranged in the developing device in a state where a part of its circumferential surface is accommodated in the hopper 3, and is in contact with the magnetic toner 4 in a portion accommodated in the hopper 3. Here, the magnetic toner 4 supplied from the hopper 3 to the developing sleeve 8 is carried on the developing sleeve 8, and the developing sleeve 8 rotates in the direction of the arrow A, so that the developing sleeve 8 and the photosensitive drum 1 are opposed to each other. The magnetic toner 4 is carried and conveyed to the development area D. At this time, the amount of the magnetic toner 4 on the developing sleeve 8 is regulated by the layer thickness regulating blade 11 to form a thin layer having a constant thickness. A magnet 5 for magnetically attracting and holding the magnetic toner 4 on the developing sleeve 8 is disposed in the developing sleeve 8. The magnetic toner 4 obtains a triboelectric charge that enables development of the electrostatic latent image on the photosensitive drum 1 by friction with the developing sleeve 8 and / or the layer thickness regulating blade 11.

In the developing device of the present invention, the thickness of the thin layer of the magnetic toner 4 formed on the developing sleeve 8 by the layer thickness regulating blade 11 is more than the minimum gap between the developing sleeve 8 and the photosensitive drum 1 in the developing unit. It is preferable that it is thin. In other words, the developing method of the present invention is particularly effective for a method using 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 is applied to the developing sleeve 8 by a power source 9 in order to cause the magnetic toner 4 that is a one-component magnetic developer carried on the developing sleeve 8 to fly to the photosensitive drum 1. When a DC voltage is used as the developing bias, 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 sleeve. 8 is preferably applied. On the other hand, in order to increase the density of the developed image or improve the gradation of the developed image, an alternating bias may be applied to the developing sleeve 8 to form an oscillating electric field whose direction is alternately reversed in the developing portion. Good. 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 image portion potential and the background portion potential is superimposed.

  In the so-called regular development, where toner is attached to the high potential part of an electrostatic latent image having a high potential part and a low potential part, the toner is charged with a polarity opposite to that of the electrostatic latent image. On the other hand, in the so-called reversal development in which toner is attached to the low potential portion of the electrostatic latent image for visualization, a toner charged with the same polarity as that of the electrostatic latent image is used. Note that high potential and low potential are expressed in absolute values. In any case, the magnetic toner 4 is charged to a polarity necessary for developing the electrostatic latent image by friction with the developing sleeve 8.

  FIG. 5 is a schematic cross-sectional view showing another preferred example of a developing device using the developer carrying member of the present invention. In this example, a magnetic regulation blade 2 made of a ferromagnetic metal is used as a developer layer thickness regulating member for regulating the layer thickness of the developer 4 conveyed to the development area D. The other configuration is shown in FIG. This is the same as the developing device. The magnetic regulating blade 2 is suspended from the hopper 3 so as to face the developing sleeve 8 with a gap width of about 50 to 500 μm from the surface of the developing sleeve 8. A magnetic force line from the magnetic pole N1 of the magnet roller 5 concentrates on the magnetic regulation blade 2, whereby a thin layer of the developer 4 corresponding to the gap width is formed on the developing sleeve 8.

  4 and 5 are merely schematic illustrations of the developing device used in the present invention, and the shape of the hopper 3, the presence or absence of the stirring blade 10, the shape of the developer layer thickness regulating member 11 or 2, the magnet 5 Needless to say, there are various forms of the arrangement of magnetic poles and the like.

  Next, the developer used in the present invention will be described. The developer is mainly a binder resin, a release agent, a charge control agent, a colorant, etc., melted and kneaded, solidified and then pulverized, and then classified, etc. An external additive is externally mixed with the toner particles as necessary. As the binder resin used for the developer, generally known resins can be used.

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

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

  In order to use the developer as a magnetic toner that is a one-component magnetic developer, magnetic powder may be contained in the developer. As such magnetic powder, a substance that is magnetized in a magnetic field is used, and powders of ferromagnetic metals such as iron, cobalt, and nickel; or alloys and compounds such as magnetite, hematite, and ferrite are exemplified. One type or two or more types are appropriately selected and used. The content of the magnetic powder is preferably 15 to 70% by mass of the magnetic toner.

  Further, the developer may contain a wax for the purpose of improving releasability from the fixing member at the time of fixing and improving fixability. Such waxes include paraffin wax and derivatives thereof, microcrystalline wax and derivatives thereof, Fischer-Tropsch wax and derivatives thereof, polyolefin wax and derivatives thereof, carnauba wax and derivatives thereof, etc. , Block copolymers with vinyl monomers, and graft modified products. In addition, alcohols, fatty acids, acid amides, esters, ketones, hydrogenated castor oil and derivatives thereof, plant waxes, animal waxes, mineral waxes, petrolactams, and the like can also be used.

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

  Further, the following are examples of positive charge control agents for controlling the developer to be positively charged. Modified products with nigrosine and fatty acid metal salts, quaternary ammonium salts such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate, and phosphonium salts that are analogs thereof Onium salts and lake pigments (Lake agents include phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.); higher fatty acid metals Salts; diorganotin oxides such as dibutyltin oxide, dioctyltin oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate, dioctyltin borate and dicyclohexyltin borate; guani Emissions compounds, imidazole compounds and the like.

  The developer in the present invention is used by being externally added and mixed with toner particles, using powder such as inorganic fine powder as an external additive for the purpose of improving fluidity, if necessary. Examples of such fine powder include silica fine powder, metal oxides such as alumina, titania, germanium oxide, and zirconium oxide; carbides such as silicon carbide and titanium carbide; and inorganic fine particles such as nitrides such as silicon nitride and germanium nitride. Powder is used.

  The developer used in the present invention is preferably subjected to a spheroidizing treatment or a surface smoothing treatment by various methods because transferability is improved. As such a method, a device having a stirring blade or a blade and a liner and a casing is used, and the toner particles are passed through a minute gap between the blade and the liner, and at that time, the mechanical force of the toner particles is reduced. There are a method of smoothing or spheroidizing the surface; a method of suspending toner in warm water to spheroidize; a method of spheroidizing by exposing toner in a hot air stream, and the like.

  FIG. 6 shows an example of a schematic cross-sectional view of a surface modification apparatus that can be suitably used in the present invention as an example. FIG. 7 is a top view of the dispersion rotor 36 of FIG. The surface modification apparatus shown in FIG. 6 includes a casing 30; a jacket (not shown) through which cooling water or antifreeze liquid can be passed; an upper surface that is attached to the central rotating shaft in the casing 30 as surface modification means. Dispersion rotor 36, which is a rotating body on a disk rotating at high speed, having a plurality of square discs or cylindrical pins 40; arranged on the outer periphery of the dispersion rotor 36 at regular intervals, and provided with a number of grooves on the surface Liner 34 (there is no need to have a groove on the liner surface); classification rotor 31 which is a means for classifying the surface-modified raw material into a predetermined particle size; cold air inlet for introducing cold air 35; Raw material supply port 33 for introducing the raw material to be treated; Discharge valve 38 that is openable and closable so that the surface modification time can be freely adjusted; Powder discharge for discharging the powder after treatment The space between the classification rotor 31 as the classification means and the dispersion rotor 36-liner 34 as the surface modification means, and the first space 41 before being introduced into the classification means, and the fine powder by the classification means Is formed of a cylindrical guide ring 39 which is a guide means for partitioning into a second space 42 for introducing the classified particles into the surface treatment means. A gap portion between the dispersion rotor 36 and the liner 34 is a surface modification zone, and a classification rotor 4 and a rotor peripheral portion are classification zones. The classifying rotor 31 may be installed vertically or horizontally as shown in FIG. Further, the number of classification rotors 31 may be singular as shown in FIG. 6 or plural.

  In the surface reforming apparatus configured as described above, when a finely pulverized product is introduced from the raw material supply port 33 with the discharge valve 38 closed, the introduced finely pulverized product is firstly fed by a blower (not shown). Suctioned and classified by the classification rotor 31. At that time, the classified fine powder having a predetermined particle diameter or less is continuously discharged out of the apparatus, and the coarse powder having a predetermined particle diameter or more is removed by centrifugal force from the inner periphery (second space 42) of the guide ring (guide plate) 39. ) Along the circulation flow generated by the dispersion rotor 36 and led to the surface modification zone. The raw material (coarse powder) guided to the surface modification zone is subjected to a surface modification treatment by receiving a mechanical impact force between the dispersion rotor 36 and the liner 34. The surface-modified particles having undergone surface modification ride on the cold air passing through the inside of the machine, are guided again to the classification zone along the outer periphery (first space 41) of the guide ring 39, and are classified into the classification rotor 4. Thus, the fine powder is again discharged out of the machine. The coarse powder rides on the circulating flow and returns again to the surface modification zone, and repeatedly undergoes surface modification. After a certain period of time, the discharge valve 38 is opened and the surface modified particles are recovered from the discharge port 37.

  In addition, as a method for producing spherical toner particles, there is a method in which a mixture containing a monomer as a binder resin for toner particles as a main component is suspended in water and polymerized to form toner particles. Generally, a monomer composition is prepared by uniformly dissolving or dispersing a polymerizable monomer, a colorant, a polymerization initiator, and, if necessary, a crosslinking agent, a charge control agent, a release agent, and other additives. Then, the monomer composition is dispersed in a continuous layer containing a dispersion stabilizer (for example, in an aqueous phase) with an appropriate stirrer and further subjected to a polymerization reaction. Then, toner particles having a desired particle diameter are obtained.

The physical property measurement method according to the present invention will be described below.
(1) Particle size measurement of toner particles and carrier particle base particles As a measuring device, Coulter Counter TA-II, Coulter Multisizer II or Coulter Multisizer III (both manufactured by Beckman Coulter, Inc.) are used. As the electrolytic solution, an approximately 1% NaCl aqueous solution prepared using primary sodium chloride is used. As such an electrolytic solution, for example, ISOTON-II (manufactured by Beckman Coulter, Inc.) can be used. The measuring method is as follows. As a dispersant, 0.1 to 5 ml of a surfactant, preferably an alkylbenzene sulfonate, is added to 100 to 150 ml of the electrolytic solution, and 2 to 20 mg of a sample to be measured is further added. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes. By using the 100 μm aperture or the 30 μm aperture as the aperture, the volume and the number of the samples subjected to the dispersion treatment are measured by the above measuring apparatus to calculate the volume distribution and the number distribution. From this result, the weight-based weight average particle diameter (D4) obtained from the volume distribution (the median value of each channel is used as a representative value for each channel) is obtained.

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

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

  Next, 1 to 25 mg of a measurement sample is added to 50 ml of IPA. A sample solution is obtained by dispersing the sample suspension in an ultrasonic disperser for about 1 to 3 minutes. The sample solution was gradually added to the measurement system of the measurement device, the measurement was performed by adjusting the sample concentration in the measurement system so that the PIDS on the screen of the device was 45 to 55%, and the number distribution was calculated. The number average particle diameter is determined.

(4) Measurement of particle diameter of fine particles having a particle diameter of less than 1 μm For fine particles having a particle diameter of less than 1 μm, such as carbon black, the particle diameter is measured using an electron microscope. The shooting magnification is 60,000 times, but if it is difficult, the photograph may be enlarged and printed so as to be 60,000 times after shooting at a low magnification. The particle size of the primary particles is measured on the obtained photograph. At this time, the lengths of the major axis and the minor axis are measured, and the average value is defined as the particle size. This is measured for 100 samples, and the 50% value is taken as the average particle size.

(5) Measurement of the volume resistance of the supported particles Put the supported particles in a 40 mmφ aluminum ring, press mold at 2500 N, and use a 4-terminal probe with a resistivity meter Loresta AP (Mitsubishi Chemical) in the low resistance region. In the high resistance region, the volume resistance value is measured using a ring electrode probe with Hiresta IP (Mitsubishi Chemical). The measurement environment is 20 to 25 ° C. and 50 to 60% RH.

(6) Average circularity of toner particles Measurement is performed under an environment of 23 ° C./60% RH using a flow type particle image analyzer FPIA-2100 manufactured by Sysmex Corporation. Measure the particles in the range of equivalent circle diameter of 0.60 to 400 μm, and determine the circularity of the particles measured there by the following formula. The value divided by the number is defined as the average circularity.
Circularity a = L ₀ / L
(In the formula, L ₀ indicates the circumference of a circle having the same area as the particle projection image, and L is the particle projection when image processing is performed at an image processing resolution of 512 × 512 (pixels of 0.3 μm × 0.3 μm). Indicates the perimeter of the image.)

  The circularity used in the present invention is an index of the degree of unevenness of the toner particles, and indicates 1.00 when the toner is perfectly spherical, and the circularity becomes smaller as the surface shape becomes more complicated. As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkylbenzene sulfonate, is added as a dispersant in 200 to 300 ml of water from which impurities in the container have been removed in advance. Add about 1-0.5g. The suspension in which the sample is dispersed is dispersed for 2 minutes by an ultrasonic oscillator, and the circularity distribution of the particles is measured by setting the dispersion concentration to 0.2 to 1 million particles / μl. As the ultrasonic oscillator, for example, the following apparatus is used, and the following dispersion conditions are used.

apparatus:
UH-150 (manufactured by SMT Corporation)
Dispersion condition:
OUTPUT level: 5
Constant mode

  The outline of the measurement is as follows. The sample dispersion is passed through a flow channel (expanded along the flow direction) of a flat and flat flow cell (thickness: about 200 μm). A strobe and a CCD camera are mounted on opposite sides of the flow cell so as to form an optical path that passes across 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. Taken as a dimensional image. From the area of each particle on the obtained captured image, 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 area of the projected image and the perimeter of the two-dimensional image of each particle using the above circularity calculation formula.

  Hereinafter, the present invention will be described more specifically with reference to production examples and examples, but these do not limit the present invention in any way.

<Production Example 1 of Supported Particles>
100 parts by mass of PMMA resin particles having a number average particle diameter of 4.6 μm as mother particles are mixed with 3 parts by mass of carbon black fine particles (primary average particle diameter of 30 nm) as conductive fine particles using a Henschel mixer. The carbon black fine particles were fixed to the surface of the PMMA resin particles by uniformly adhering to the surface of the PMMA resin particles and applying a mechanical impact force using a hybridizer to obtain supported particles R1.

<Comparative Production Example 1 of Supported Particles>
The PMMA resin particles (in which carbon black is not fixed) used in Production Example 1 of the supported particles were designated as supported particles R2.

<Production Examples 2 and 3 of supported particles>
For 100 parts by mass of melamine-formaldehyde resin particles having a number average particle size of 4.1 μm as mother particles, 4 parts by mass of carbon black fine particles (primary average particle size of 30 nm) as conductive fine particles were mixed with a Henschel mixer. By uniformly adhering to the surface of the mother particles, supported particles R3 were obtained. Further, by applying a mechanical impact force to the supported particles R3 using a hybridizer, carbon black fine particles were fixed to the surface of the melamine-formaldehyde resin particles to obtain supported particles R4.

<Production Example 4 of Supported Particles>
For 100 parts by mass of the melamine-formaldehyde resin particles used in Production Example 2 of supported particles, 5 parts by mass of conductive tin oxide fine particles (primary average particle size of 70 nm) as conductive fine particles were mixed with a Henschel mixer to form a mother. By uniformly adhering to the surface of the particles and applying a mechanical impact force using a hybridizer, the conductive tin oxide fine particles were fixed to the surface of the melamine-formaldehyde resin particles to obtain supported particles R5.

<Comparative Production Example 2 of Supported Particles>
The melamine-formaldehyde resin particles used in Production Example 4 of supported particles (those that do not fix conductive tin oxide fine particles) were used as supported particles R6.

<Production Example 5 of Supported Particles>
100 parts by mass of boron nitride particles having a number average particle diameter of 5.8 μm as mother particles are mixed with 3 parts by mass of carbon black fine particles (primary average particle diameter of 30 nm) as conductive fine particles using a Henschel mixer to form mother particles. The carbon black fine particles were fixed to the surface of the boron nitride particles by uniformly adhering to the surface of the particles and applying a mechanical impact force using a hybridizer to obtain supported particles R7.

<Production Example 6 of Supported Particles>
3 parts by mass of carbon black fine particles (primary average particle size 30 nm) as conductive fine particles are used for 100 parts by mass of silicone resin particles having a number average particle size of 7.1 μm surface-treated with an aminosilane coupling agent as mother particles. The mixture was uniformly attached to the surface of the mother particles by mixing with a Henschel mixer. Further, by applying a mechanical impact force to the surface using a hybridizer, carbon black fine particles were fixed to the surface of the silicone resin particles to obtain supported particles R8.

<Production Example 7 of Supported Particle>
10 parts by mass of conductive titanium oxide fine particles (primary average particle size 35 nm) as conductive fine particles are mixed with 100 parts by mass of the silicone resin particles used in Production Example 6 of the supported particles by using a Henschel mixer. By uniformly adhering to the surface and applying a mechanical impact force using a hybridizer, the conductive titanium oxide fine particles were fixed to the surface of the silicone resin particles to obtain supported particles R9.

<Production Example 8 of Supported Particle>
100 parts by mass of polyvinylidene fluoride (PVDF) resin particles having a number average particle size of 5.3 μm as mother particles are mixed with 4 parts by mass of carbon black fine particles (primary average particle size of 30 nm) as conductive fine particles using a Henschel mixer. By doing so, it was made to adhere uniformly to the surface of the mother particle. Further, by applying a mechanical impact force to the PVDF resin particles by using a hybridizer, carbon black fine particles were fixed to the surface of the PVDF resin particles to obtain supported particles R10.
Table 1 shows the composition and volume resistivity of the obtained supported particles.

<Developer Production Example 1>
Styrene-butyl acrylate resin 100 parts by weight Magnetite 100 parts by weight Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts by weight Low molecular weight polypropylene 5 parts by weight After sufficiently mixing the above materials in a Henschel mixer, The mixture was melt kneaded and dispersed with a shaft extruder to obtain a kneaded product. After cooling this, coarse pulverization is performed with a cutter mill, followed by pulverization using a jet type pulverizer, followed by classification using a multi-division type classifier, and the weight average particle diameter (D4) is 5 A fine powder (toner particles) having a diameter of 0.9 μm and a circularity of 0.926 was obtained. One part magnetic developer T1 was obtained by adding 1.0 part by weight of hydrophobic colloidal silica to 100 parts by weight of the fine powder, and mixing and dispersing with a Henschel mixer.

<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 sufficiently mixing the above materials with a Henschel mixer, biaxial A kneaded product was obtained by melt-kneading and dispersing with a type extruder. After cooling this, coarse pulverization is performed with a cutter mill, and then pulverization is performed using a jet type pulverizer, followed by classification using a multi-division type classifier, and a weight average particle diameter (D4) of 6 is obtained. A fine powder of 6 μm was obtained. Using the surface modification apparatus shown in FIG. 6, the fine powder was spheroidized and fine powder was removed. Through the above steps, a fine powder (toner particle) having a weight average particle diameter (D4) of 6.9 μm and a circularity of 0.949 was obtained. One-component magnetic developer T2 was obtained by adding 1.0 part by weight of hydrophobic colloidal silica to 100 parts by weight of the fine powder and mixing and dispersing the mixture with a Henschel mixer.

<Developer Production Example 3>
Polyester resin 100 parts by weight Magnetite 90 parts by weight Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts by weight Fischer-Tropsch wax 4 parts by weight After premixing the above materials with a Henschel mixer, using a biaxial extruder A kneaded product was obtained by melt-kneading and dispersing. After cooling, coarse pulverization was performed with a cutter mill to obtain a coarsely pulverized toner. The obtained coarsely pulverized product is finely pulverized by mechanical pulverization using a mechanical pulverizer turbo mill (manufactured by Turbo Kogyo Co., Ltd .; the rotor and stator surfaces are coated with chromium alloy plating containing chromium carbide). The finely pulverized product obtained by pulverization was classified using a multi-division classifier to obtain a fine powder having a weight average particle diameter (D4) of 6.4 μm and a circularity of 0.937. . To 100 parts by mass of the fine powder, 1.5 parts by mass of hydrophobic colloidal silica treated with hexamethyldisilazane and dimethylsilicone oil and 0.5 parts by mass of strontium titanate are added and mixed and dispersed by a Henschel mixer. As a result, a one-component magnetic developer T3 was obtained.

<Developer Production Example 4>
Polyester resin 100 parts by weight Magnetite 95 parts by weight Azo-based iron complex compound (negatively chargeable charge control agent) 2 parts by weight Polyethylene wax 3 parts by weight After thoroughly mixing the above materials with a Henschel mixer, a biaxial type A kneaded product was obtained by melt-kneading and dispersing with a router. After cooling this, coarse pulverization is performed with a cutter mill, and then pulverization is performed using a jet type pulverizer, followed by classification using a multi-division type classifier, and the weight average particle diameter (D4) is 7 A fine powder having a diameter of 0.1 μm and a circularity of 0.925 was obtained. One part of magnetic developer T4 was obtained by adding 1.0 part by weight of hydrophobic colloidal silica to 100 parts by weight of the fine powder, and mixing and dispersing it with a Henschel mixer.

<Developer Production Example 5>
Styrene-butyl acrylate resin 100 parts by weight Magnetite 95 parts by weight Imidazole compound (positively chargeable charge control agent) 3 parts by weight Polyethylene-based wax 4 parts by weight A kneaded product was obtained by melt-kneading and dispersing with a router. After cooling this, coarse pulverization is performed with a cutter mill, and then pulverization is performed using a jet type pulverizer, followed by classification using a multi-division type classifier, and a weight average particle diameter (D4) of 6 is obtained. A fine powder having a diameter of 0.4 μm and a circularity of 0.924 was obtained. To 100 parts by mass of the fine powder, 1.2 parts by mass of colloidal silica treated with an aminosilane coupling agent and amino-modified silicone oil, and 2.5 parts by mass of strontium titanate fine powder were added. By mixing and dispersing, a one-component magnetic developer T5 was obtained.

<Example 1>
[Production of developer carrier A1]
A coating solution for a resin coating layer provided on the surface of the developing sleeve was prepared at the following blending ratio.
Resol type phenol resin produced using ammonia as a catalyst (50% methanol solution; Mw = 1700) 440 parts by weight Crystalline graphite (number average particle size 5.4 μm) 80 parts by weight Conductive carbon black 20 parts by weight Conductive spherical particles P-1 20 parts by mass Isopropyl alcohol 430 parts by mass

In addition, the said conductive spherical particle P-1 is manufactured by the following method. 100 parts of spherical phenol resin particles having a number average particle diameter of 5.8 μm were uniformly coated with 14 parts of a coal-based bulk mesophase pitch powder having a number average particle diameter of 2 μm or less using a Reika machine (automatic mortar, manufactured by Ishikawa Factory). This was heat-stabilized at 280 ° C. in air, then graphitized by firing at 2000 ° C. in a nitrogen atmosphere, and further classified to obtain spherical conductive carbon particles having a number average particle size of 6.0 μm (conductive Spherical particles P-1) were obtained.

  The material for the coating solution was dispersed in a sand mill using glass beads by the following method to obtain a coating solution. A resol type phenolic resin solution (containing 50% methanol) was diluted with a part of isopropyl alcohol. Conductive carbon black and crystalline graphite were added to this diluted solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles P-1 dispersed in the remaining isopropyl alcohol were further added thereto, and further sand mill dispersion was performed to obtain a coating liquid.

  By applying the above coating solution using a spray method, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 16 mmφ, followed by heating in a hot air drying oven at 160 ° C. for 20 minutes to conduct electricity. The developer carrying member was produced by curing the conductive coating layer. This was designated as “developer carrier A3”. When the surface roughness (arithmetic mean roughness) of this developer carrying member A3 was measured, Ra = 1.07 μm.

  Next, using the particle coating apparatus shown in FIG. 1, the carrier particles R1 were applied onto the conductive coating layer of the developer carrier A3 to obtain a developer carrier A1.

[Evaluation]
The developer carrier A1 was evaluated as follows. In the evaluation, a commercially available laser beam printer LBP1760 (manufactured by Canon Inc.) with an EP-52 cartridge developing blade modified to a urethane regulated blade specification was used. A magnet and a flange were attached to the developer carrier A1 so that the developer carrier A1 can be attached to the cartridge, and attached to the EP-52 modified cartridge. The developer T1 was filled in the hopper of the process cartridge, and image formation (image output) was performed with an LBP 1760 machine, and image evaluation shown below was performed. Evaluation is as follows: 15 ° C./10% RH low temperature / low humidity environment (L / L), 23 ° C./50% RH normal temperature / normal humidity environment (N / N), and 30 ° C./85% RH high temperature / Each durable environment under a high humidity environment (H / H) was conducted. In addition, the following evaluations were performed at the time of outputting 10, 100, 500, 1,000, 2,000, and 10,000 sheets in each of the above environments.

(1) Image density of 5mm square (■) or 5mm circle (●) Outputs a 5mm square square solid black image (■) at each position of the character pattern (or character chart), and at a predetermined place The image density at 10 locations was measured, and the average value was defined as a 5 mm square image density. Alternatively, instead of the above 5 mm square image, a 5 mm diameter round solid black image (●) was output to obtain a 5 mm round image density. The image density was measured using a reflection densitometer RD918 (manufactured by Macbeth).

(2) Solid Black Image Density Solid black was output, and the image density at 10 predetermined locations was measured in the same manner as in (1) above, and the average value was taken as the solid black image density. Similarly, a reflection densitometer RD918 (manufactured by Macbeth) was used for the measurement. Even if the image density of 5 mm square (■) or 5 mm round (●) is excellent, the developer to be developed depends on the state of the developer carried on the developer carrier (friction charge amount, developer carrying amount). May be insufficient, and the density of a solid black image may be smaller than the image density of a 5 mm square or 5 mm circle.

(3) Ghost In the output image of the printer (image chart in the case of a copier), a solid black image (■, ●, etc.) is placed at equal intervals on a white background in the area corresponding to one round of the sleeve at the top of the image. Then, using the other portions as halftones, ranking of how the ghosts of the above-mentioned hieroglyph images appear on the halftones was performed according to the following evaluation criteria. (Positive ghost indicates a ghost having a higher image density than halftone, and negative ghost indicates a ghost having a lower image density than halftone.)

(Evaluation criteria)
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. Practical level is not possible.
E: A ghost appears over two or more sleeves.

(4) Image Unevenness A halftone image and a solid black image were output, and the presence or absence of the occurrence of linear and belt-like streaks (thickness differences) running in the image formation progression direction was evaluated according to the following evaluation criteria. Note that image density unevenness due to ghost and blotch factors was excluded and evaluated.

(Evaluation criteria)
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.

(5) Blotch A solid black image and a halftone image were output, and a blotch (spotted, rippled, or carpet-like) image that was likely to be generated due to excessive charging of the toner in each image was visually observed. Further, at the time of outputting the image, the surface of the developer carrying member (developing sleeve) coated with the developer was also observed. These observation results were evaluated according to the following evaluation criteria.

(Evaluation criteria)
A: No blotch is observed on the image or on the sleeve.
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. Practical level is not possible.
E: Blotch appears almost on the entire surface.

  Table 2 shows the constitution of developer carrier A1 and the types of developers used for evaluation. Moreover, the result of each said evaluation in each environment is shown to Tables 3-5.

In addition, a measurement relating to the charge amount of the developer was also performed. Comparison was made at the time of the 100th sheet from the start of image printing using a new developer carrier under the L / L environment and the H / H environment. In order to eliminate the influence of the supported particles, a solid black image is created on the photosensitive member, and the developer is sucked and collected by a metal cylindrical tube and a cylindrical filter. At that time, the charge amount Q stored in the capacitor through the metal cylindrical tube, The charge amount Q / M (mC / kg) per unit weight was calculated from the collected mass M of the developer and the area S where the toner was sucked, and used as the charge amount of the developer. Further, the developer transport amount M / S (dg / m ² ) was also calculated. These results are shown in Table 6.

<Comparative example 1>
The developer carrier A2 was obtained by applying the carrier particles R2 instead of the carrier particles R1 on the developer carrier A3 used in Example 1. The obtained developer carrying member A2 was evaluated in the same manner as in Example 1. Table 2 shows the configuration and the like of developer carrier A2, and Tables 3 to 6 show the evaluation results.

<Comparative example 2>
The developer carrying member A3 used in Example 1 was mounted on the above-described modified EP-52 cartridge (without coating the carrying particles), and the same evaluation as in Example 1 was performed. Table 2 shows the configuration of the developer carrier A3 and Tables 3 to 6 show the evaluation results.

  In Example 1 using the developer carrier A1, the image density did not decrease in any environment in the initial stage of image output, and neither image unevenness nor ghost occurred. On the other hand, in Comparative Example 1 using the developer carrier A2, image density reduction, image unevenness, and ghost images occurred in the L / L environment. Also in the H / H environment, a solid black image density drop and image unevenness occurred at the initial stage of image output. In Comparative Example 2 using the developer carrier A3, ghosts were observed in both environments at the initial stage of image output, and a decrease in density was also observed. However, in any of the developer carriers A1 to A3, the defect of the image was improved as the number of durable images was increased, and a good image was obtained at the time of 2000 images.

Further, from the measurement results of the developer charge amount and developer transport amount shown in Table 6, the developer carrier A1 having a good image evaluation result has an appropriate toner charge amount and toner transport amount. I understand. This is because the support particles have conductivity and the base particles of the support particles are weakly positively chargeable PMMA particles, so that sufficient initial and proper tribo can be applied to the developer. It is estimated that. On the other hand, in the developer carriers A2 and A3, it is considered that a charge-up phenomenon occurs in the L / L environment. In both cases, although M / S is high, M / S is low. The following can be considered about this. In the developer carriers A2 and A3, the lower layer portion of the developer existing on the sleeve has a high charge amount, so that it is strongly attracted by the reflection force on the sleeve, and the upper layer developer is difficult to have a charge. It has become. Therefore, it is considered that the upper layer developer is difficult to be developed on the photoconductor, and thus the M / S on the photoconductor is reduced. In particular, in the developer carrier A2, the PMMA resin particles as the carrier particles are weakly positively charged, but the insulating property causes excessive and uneven charging of the developer at the initial stage of image formation. As a result, image defects such as a reduction in initial image density, image unevenness, and blotch as described above are prominent.

  Further, in the H / H environment, there is a slight decrease in the triboelectric chargeability of the developer. In particular, in the developer carrier A3, it is considered that sufficient developability is not obtained because the initial triboelectric chargeability is insufficient. As the durability test proceeds, frictional charging is repeatedly performed by stirring the developer, and as a result, an appropriate amount of frictional charge can be maintained.

  Further, when the evaluation using the developer carriers A1 to A3 was performed up to 2000 images, the developer was sucked and observed from the developing sleeve, and almost no supported particles were observed in the developer. It was. Observation was also made on the developing sleeve after the developer was collected by suction. Similarly, almost no supported particles adhered.

<Example 2>
A spherical glass bead of # 150 was used for an aluminum cylindrical tube having an outer diameter of 16 mmφ, and blasting was performed using a sand blasting apparatus shown in FIG. The surface roughness Ra after blasting was 1.01 μm. This was designated as “developer carrier B2”. The carrier particles R1 were adhered by applying the carrier particles R1 on the developer carrier B2 in the same manner as in Example 1. The obtained developer carrying member was designated as B1.

  The developer carrier B1 is mounted on the EP-52 cartridge, and the image density of 5 mm square and the evaluation of blotches are evaluated as 10 sheets, 100 sheets, 500 sheets, 1000 sheets by the same method as in Example 1. Sometimes went. The evaluation environment was 23 ° C./50% RH (N / N). Table 2 shows the configuration of the developer carrier B1 and Table 7 shows the evaluation results.

<Comparative Example 3>
The developer carrying member B2 used in Example 2 was mounted on the above-described modified EP-52 cartridge (without coating the carrying particles), and the same evaluation as in Example 2 was performed. Table 2 shows the configuration of the developer carrier B2, and Table 7 shows the evaluation results.

The developer carriers B1 and B2 are both samples in which a conductive coating layer is not provided on the substrate. In Comparative Example 3 using the developer carrier B2 in which the carrier particles were not adhered and the aluminum cylindrical tube as the substrate was just blasted, ripples of ripples were generated from the beginning, and the image density was low. On the other hand, in Example 2 using the developer carrier B1 coated with the carrier particles R1, the image density was high at the initial stage and no blotch was observed. However, the image density gradually decreased as the durability test progressed. As with the developer carrier A1 and the like, the developer was sucked and observed from the developing sleeve, and almost no carrier particles were found in it. Observation was also made on the developing sleeve after the developer was collected by suction. Similarly, almost no supported particles adhered.

  When these results are compared with Example 1, the results of Example 1 are considered as follows. That is, in Example 1, the initial image output characteristics are improved by the presence of the support particles R1. In Example 1, since the developer carrying member A1 has a conductive resin coating layer on the surface of the developing sleeve, a good image can be obtained even in the middle and second half of the durability test in which the developer has been charged. It will be.

<Example 3>
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at the following blending ratio.
Resol type phenol resin produced using ammonia as a catalyst (50% methanol solution; Mw = 1700) 400 parts by weight Crystalline graphite (number average particle size 5.4 μm) 80 parts by weight Conductive carbon black 20 parts by weight Conductive spherical particles P-2 20 mass parts Quaternary ammonium salt compound represented by the above formula (1) 10 mass parts Methanol 250 mass parts

  The conductive spherical particles P-2 are manufactured by the following method. 100 parts of spherical phenolic resin particles having a number average particle size of 12.2 μm were uniformly coated with 14 parts of a coal-based bulk mesophase pitch powder having a number average particle size of 2 μm or less using a Reika machine (automatic mortar, manufactured by Ishikawa Factory). This was heat-stabilized at 280 ° C. in air, then graphitized by firing at 2000 ° C. in a nitrogen atmosphere, and further classified to obtain spherical conductive carbon particles having a number average particle diameter of 12.5 μm (conductive Spherical particles P-2) were obtained.

  The material for the coating solution was dispersed in a sand mill using glass beads by the following method to obtain a coating solution. A resol type phenolic resin solution (containing 50% methanol) was diluted with a part of methanol. Conductive carbon black and crystalline graphite were added to this diluted solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles P-2 and quaternary ammonium salt compound (1) dispersed in the remaining methanol were further added thereto, and further sand mill dispersion was performed to obtain a coating solution.

  By applying the coating liquid using a spray method, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 20 mmφ, and then heated at 160 ° C. for 20 minutes in a hot air drying furnace to conduct electricity. The developer carrying member was produced by curing the conductive coating layer. This was designated as “developer carrier C5”. When the surface roughness (arithmetic mean roughness) of this developer carrying member C5 was measured, it was Ra = 1.44 μm. On this developer carrier C5, the carrier particles R3 were adhered by applying the carrier particles R3 in the same manner as in Example 1. The obtained developer carrying member was designated as C1.

The developer carrier C1 was evaluated. In the evaluation, a process cartridge for a commercially available printer LaserJet 9000 (manufactured by Hewlett-Packard) was used. A magnet and a flange were attached to the developer carrier C1 so that the developer carrier C1 can be attached to the cartridge, and the developer carrier C1 was attached to the cartridge. The developer T2 is filled in the hopper of this process cartridge, and image output is performed by a LaserJet 9000 machine. Evaluations similar to those in Example 1 are 10 sheets, 100 sheets, 500 sheets, 1,000 sheets, 3,000 sheets, and This was done when 30,000 sheets were printed. Table 2 shows the configuration of the developer carrier C1 and Tables 8 to 10 show the evaluation results.

<Examples 4 and 5>
On the developer carrier C5 used in Example 3, the carrier particles R4 and R5 were applied in place of the carrier particles R3 to obtain developer carriers C2 and C3. The obtained developer carriers C2 and C3 were evaluated in the same manner as in Example 3. The structures and the like of developer carriers C2 and C3 are shown in Table 2, and the evaluation results are shown in Tables 8 to 10, respectively.

<Comparative example 4>
A developer carrier C4 was obtained by applying the carrier particles R6 instead of the carrier particles R3 on the developer carrier C5 used in Example 3. The obtained developer carrying member C4 was evaluated in the same manner as in Example 3. The configuration and the like of developer carrier C4 are shown in Table 2, and the evaluation results are shown in Tables 8 to 10, respectively.

<Comparative Example 5>
The developer carrier C5 used in Example 3 was mounted on the process cartridge (without applying the carrier particles), and the same evaluation as in Example 3 was performed. The structure and the like of developer carrier C5 are shown in Table 2, and the evaluation results are shown in Tables 8 to 10, respectively.

  The toner particles that have been spheroidized have a smoother surface than the pulverized toner particles, and it is observed that the magnetic material is likely to be encapsulated. With this effect, it is possible to suppress the consumption of the developer. However, the charge amount of the developer may become too high, resulting in charge-up. Therefore, the charge of the developer may be locally increased, and the charge distribution may be non-uniform. As a result, image defects such as density unevenness are likely to occur.

  In Examples 3 to 5, in order to compensate for this disadvantage, for the purpose of suppressing the application of triboelectric charge to the developer to some extent, a coating material in which a quaternary ammonium salt compound is mixed with a phenol resin is applied as a developer carrier. A cured resin-coated sleeve was used. Due to the effect of the resin-coated sleeve, problems such as a charge-up phenomenon due to a durability test can be dealt with. However, even in this system, the initial triboelectric charge tends to become unstable, and as a result, the ghost and image unevenness at the initial stage of image generation as seen in Comparative Example 5 or 6 occur.

For example, in Comparative Example 4 using the developer carrier C4, although the triboelectric charge is sufficiently imparted to the developer, the resistance of the carrier particle R6 itself is high, which is caused by the charge-up phenomenon particularly in the L / L environment. Image density reduction, image unevenness, sleeve ghost, and blotch were observed. In Comparative Example 5 using the developer carrier C5, image unevenness and sleeve ghosting occurred in both L / L and H / H environments because the initial triboelectric charging was unstable. .

  However, as in Examples 3 to 5 using developer carriers C1 to C3, particles having conductive fine particles attached or fixed to positively charged melamine-formaldehyde resin particles are supported on the surface of the developer carrier. Accordingly, it is possible to appropriately impart negative chargeability to the developer while ensuring conductivity at the initial stage of image output. In each of the above examples, the result using the developer carrying member C2 was the best, and the image density did not decrease in both environments at the initial stage of image output, and neither image unevenness nor ghost occurred. In the developer carrier C1, since the adhesion state of the carbon black fine particles on the surface of the mother particle in the carrier particle R3 is weaker than that of the carrier particle R4, the carrier particle R4 is used more than the case where the carrier particle R4 is used due to the progress of image formation. Some ghost was noticeable in the H / H environment because the carbon black was slightly liberated and the conductivity was lowered. Further, in the developer carrier C3, the volume resistance of the particles itself in the supported particles R5 is higher than that in R4, and some image unevenness and ghosting were observed in the L / L environment.

<Example 6>
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at the following blending ratio.
Resol type phenol resin produced using ammonia as a catalyst (50% methanol solution; Mw = 1700) 460 parts by weight Crystalline graphite (number average particle size 5.4 μm) 80 parts by weight Conductive carbon black 20 parts by weight Conductive spherical particles P-1 20 mass parts Quaternary ammonium salt compound represented by the above formula (2) 5 mass parts Methanol 250 mass parts

  The above materials were dispersed in a sand mill using glass beads by the following method to obtain a coating solution. A resol type phenolic resin solution (containing 50% methanol) was diluted with a part of methanol. Conductive carbon black and crystalline graphite were added to this diluted solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles P-1 dispersed in the remaining methanol were further added thereto, and further sand mill dispersion was performed to obtain a coating solution.

  By applying the coating liquid using a spray method, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 20 mmφ, and then heated at 160 ° C. for 20 minutes in a hot air drying furnace to conduct electricity. The developer carrying member was produced by curing the conductive coating layer. This was designated as “developer carrier D2”. When the surface roughness (arithmetic mean roughness) of this developer carrying member D2 was measured, Ra = 1.08 μm. On this developer carrier D2, the carrier particles R7 were applied by the same method as in Example 1 to adhere the carrier particles R7. The obtained developer carrying member was designated as D1.

  The developer carrier D1 was evaluated. In the evaluation, a process cartridge for a commercially available printer Lesser Jet 4200 (manufactured by Hewlett Packard) was used. A magnet and a flange were attached to the developer carrier D1 so that the developer carrier D1 can be attached to the cartridge, and the developer carrier D1 was attached to the cartridge. The developer T3 of the process cartridge is filled with the developer T3, and image formation is performed using a Lesser Jet 4200 machine. Evaluations similar to those in Example 1 are 10 sheets, 100 sheets, 500 sheets, 1,000 sheets, 3,000 sheets, and This was done when 12,000 images were printed. The configuration and the like of the developer carrier D1 are shown in Table 2, and the evaluation results are shown in Tables 11 to 13, respectively.

<Comparative Example 6>
The developer carrier D2 used in Example 6 was mounted on the process cartridge cartridge (without applying the carrier particles), and the same evaluation as in Example 6 was performed. The configuration and the like of the developer carrier D2 are shown in Table 2, and the evaluation results are shown in Tables 11 to 13, respectively.

<Example 7>
A spherical glass bead of # 150 was used for an aluminum cylindrical tube having an outer diameter of 20 mmφ, and blasting was performed by a sand blasting apparatus shown in FIG. The surface roughness Ra after blasting was 1.15 μm.

  Next, the cylindrical tube was washed and then plated. As a pretreatment, zincate was attached to the surface of the cylindrical tube by attaching zinc. For this zincate treatment, a commercially available zincate treatment agent (Schuma K-102; manufactured by Nippon Kanisen Co., Ltd.) was used. The treated cylindrical tube was immersed in a molybdic acid solution to form a molybdenum layer having a thickness of 6 μm. This was designated as “developer carrier E2”. The surface roughness of this developer carrying member E2 was Ra = 1.12 μm. On this developer carrier E2, the carrier particles R8 were applied by the same method as in Example 1 to adhere the carrier particles R8. The obtained developer carrying member was designated E1.

  A magnet and a flange were attached to the developer carrier E1 in the same manner as in Example 6 and mounted on a process cartridge, and the same evaluation as in Example 6 was performed. The configuration and the like of the developer carrier E1 are shown in Table 2, and the evaluation results are shown in Tables 11 to 13, respectively.

<Comparative Example 7>
The developer carrier E2 used in Example 7 was mounted on the process cartridge cartridge (without applying the carrier particles), and the same evaluation as in Example 6 was performed. The structure and the like of developer carrier E2 are shown in Table 2, and the evaluation results are shown in Tables 11 to 13, respectively.

  Toner particles produced using a mechanical pulverizer are not as spheroidized as toner particles, but are slightly spheroidized compared to toner particles produced using an airflow pulverizer. Since the toner particles are close to the toner particles, charge-up is likely to occur. As described above, also in Examples 6 and 7 and Comparative Examples 6 and 7, a resin-coated sleeve obtained by applying a coating solution obtained by mixing a quaternary ammonium salt compound to a phenol resin and thermally curing it was used. However, problems such as the charge-up phenomenon due to the durability test can be dealt with, but even in this system, the triboelectric charge at the initial stage of image formation tends to become unstable, and as a result, in Comparative Example 6 using the developer carrier D2. The ghost and image unevenness at the initial stage of image output as seen can occur. On the other hand, in Example 6 using the developer carrier D1, such a problem at the initial stage of image output did not occur.

  In addition, the molybdenum plating sleeve can adjust the triboelectric chargeability of the developer and suppress the occurrence of charge-up, but the triboelectric chargeability at the initial stage of image output is insufficient particularly in an H / H environment. . In Example 7, since the triboelectric chargeability of the supported particles R8 at H / H was good, it was possible to compensate for the deterioration in image performance at the initial stage of image output.

<Example 8>
A coating liquid for a resin coating layer provided on the surface of the developing sleeve was prepared at the following blending ratio.
Resol type phenol resin produced using ammonia as a catalyst (50% methanol solution; Mw = 1700) 500 parts by weight Crystalline graphite (number average particle size 5.4 μm) 80 parts by weight Conductive carbon black 20 parts by weight Conductive spherical particles P-1 10 parts by mass Isopropyl alcohol 250 parts by mass

  The above materials were dispersed in a sand mill using glass beads by the following method to obtain a coating solution. A resol type phenolic resin solution (containing 50% methanol) was diluted with a part of isopropyl alcohol. Conductive carbon black and crystalline graphite were added to this diluted solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles P-1 dispersed in the remaining isopropyl alcohol were further added thereto, and further sand mill dispersion was performed to obtain a coating solution.

  By applying the coating liquid using a spray method, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 24.5 mmφ, followed by heating at 160 ° C. for 20 minutes in a hot air drying furnace. Then, the developer carrying member was prepared by curing the conductive coating layer. This was designated as “developer carrier F2”. When the surface roughness (arithmetic average roughness) of this developer carrying member F2 was measured, Ra = 0.67 μm. On this developer carrier F2, the carrier particles R9 were applied by the same method as in Example 1 to adhere the carrier particles R9. The obtained developer carrying member was designated as F1.

  The developer carrier sample F1 was evaluated. In the evaluation, a magnet and a flange are attached to the developer carrier F1 so that the developer carrier F1 can be attached to the development device for the digital copying machine IR-6000 manufactured by Canon Inc., and development for IR-6000 is performed. Attached to the device. The developer T4 is filled in the hopper of this developing device, and image formation is performed by IR-6000. Evaluations similar to those in Example 1 are 10 sheets, 100 sheets, 1,000 sheets, 3,000 sheets, and 30, This was done when 000 images were printed. Table 2 shows the configuration of the developer carrier F1, and Tables 14 to 16 show the evaluation results.

<Comparative Example 8>
The developer carrying member F2 used in Example 8 was attached to the developing device (without coating the carrying particles), and the same evaluation as in Example 8 was performed. Table 2 shows the configuration of the developer carrier F2, and Tables 14 to 16 show the evaluation results.

<Example 9>
A spherical glass bead of # 200 was used for an aluminum cylindrical tube having an outer diameter of 24.5 mmφ, and blasting was performed using a sand blasting apparatus shown in FIG. The surface roughness after blasting was Ra = 0.71 μm.

  Next, the cylindrical tube was washed and then plated. As a pretreatment, zincate was attached to the surface of the cylindrical tube to deposit it. For this zincate treatment, a commercially available zincate treatment agent (Schuma K-102; manufactured by Nippon Kanisen Co., Ltd.) was used. The treated cylindrical tube was immersed in a Ni—P solution to form an electroless Ni—P layer having a thickness of 6 μm. The P concentration in the Ni—P plating layer was 10.3 mass%. As the electroless Ni—P plating solution, a commercially available plating solution (S-754; manufactured by Nippon Kanisen Co., Ltd.) was used. The obtained developer carrying member was designated as H2. The surface roughness of the developer carrier G2 was Ra = 0.62 μm. The carrier particles R8 were adhered to the developer carrier G2 by applying the carrier particles R8 in the same manner as in Example 1. The obtained developer carrying member was designated as G1.

  A magnet and a flange were attached to the developer carrier G1 in the same manner as in Example 8 and attached to the developing device, and the same evaluation as in Example 8 was performed. Table 2 shows the configuration of the developer carrier G1 and Tables 14 to 16 show the evaluation results.

<Comparative Example 9>
The developer carrying member G2 used in Example 9 was attached to the developing device (without coating the carrying particles), and the same evaluation as in Example 8 was performed. Table 2 shows the configuration of the developer carrier G2, and Tables 14 to 16 show the evaluation results.

  As shown in FIG. 5, the developing device for IR-6000 used in Examples 8 and 9 and Comparative Examples 8 and 9 is provided with magnetic regulation blades spaced apart from the developer carrier by a fixed interval. This is a type of developing device that regulates the layer thickness of the developer. Even in such a developing device, an image defect may occur due to charge-up in the early stage of image output. In Comparative Example 8 using the developer carrier F2, some blotches were initially generated. In addition, a developer carrier having a Ni—P plating coating layer is excellent in durability, but has a tendency to easily charge up at the initial stage of image output. In the developer carrying member G2, the occurrence of blotch was remarkable at the initial stage of image printing in the L / L environment, and the image density was also lowered. On the other hand, in Examples 8 and 9 using the developer carriers F1 and G1 coated with carrier particles, no defects were observed in the initial images.

<Example 10>
A coating solution for a resin coating layer provided on the surface of the developing sleeve was prepared at the following blending ratio.
Resol type phenol resin produced using ammonia as a catalyst (50% methanol solution; Mw = 1700) 500 parts by weight Crystalline graphite (volume average particle size 5.8 μm) 80 parts by weight Conductive carbon black 20 parts by weight Conductive spherical particles P-1 70 mass parts Quaternary ammonium salt compound represented by the above formula (1) 70 mass parts Methanol 250 mass parts

  The above materials were dispersed in a sand mill using glass beads by the following method to obtain a coating solution. A resol type phenolic resin solution (containing 50% methanol) was diluted with a part of methanol. Conductive carbon black and crystalline graphite were added to this diluted solution, and dispersed in a sand mill using glass beads having a diameter of 1 mm as media particles. The conductive spherical particles P-1 dispersed in the remaining methanol were further added thereto, and further sand mill dispersion was performed to obtain a coating solution.

  By applying the coating liquid using a spray method, a conductive coating layer is formed on an aluminum cylindrical tube having an outer diameter of 32 mmφ, followed by heating at 160 ° C. for 20 minutes in a hot air drying furnace to conduct electricity. The developer carrying member was produced by curing the conductive coating layer. This was designated as “developer carrier H2.” When the surface roughness (arithmetic mean roughness) of this developer carrying member H2 was measured, Ra = 0.67 μm. On the developer carrier H2, the carrier particles R10 were applied by the same method as in Example 1 to adhere the carrier particles R8. The obtained developer carrying member was designated as H1.

  A magnet and a flange were attached to the developer carrier H1 so that the developer carrier H1 can be attached to the development device for the Canon digital copying machine GP-605, and attached to the GP-605 developer. The developer T5 is filled in the hopper of this developing device, and image output is performed by GP-605. Evaluations similar to those in Example 1 are 10 sheets, 100 sheets, 1,000 sheets, 3,000 sheets, and 30, This was done when 000 images were printed. The configuration and the like of the developer carrier H1 are shown in Table 2, and the evaluation results are shown in Tables 17 to 19, respectively.

<Comparative Example 10>
The developer carrier H2 used in Example 10 was mounted on the developing device (without applying the carrier particles), and the same evaluation as in Example 10 was performed. Table 2 shows the configuration of the developer carrier H2, and Tables 17 to 19 show the evaluation results.

  Usually, a positively chargeable developer is a material that can be positively charged only by a positively chargeable charge control agent (charge control resin) and / or a positively chargeable external additive among the materials forming the developer. In many cases, it is not used, and ghosts and blotches due to charge-up are unlikely to occur. For this reason, in Example 10 above, for the purpose of increasing the triboelectric charge amount of the positively chargeable developer, a resin coating layer formed by adding a quaternary ammonium salt compound to a phenol resin using ammonia as a catalyst is used. It was set as the structure which self-negatively charged by the effect | action of a phenol resin. In the developer carrier having such a resin coating layer, in some cases, the conductive crystalline graphite is present on the surface in the unused state, but in part, the crystalline graphite is covered with the binder resin. ing. Therefore, even if an attempt is made to increase the triboelectric charge amount of the positively chargeable developer by adding a quaternary ammonium salt to the resin coating layer, if the developer carrier has insufficient conductivity, the developer is sufficient. May not be able to hold a positive charge.

  In Comparative Example 10 using the developer carrier H2, since the rise of the image density at the initial stage of image output was slow, streaks were generated in the halftone or solid black image, and in addition, ghost was also observed. This is because the triboelectric charge amount of the positively chargeable developer is insufficient. On the other hand, as in Example 10 using the developer carrier H1, the carrier particles R10 in which conductive carbon black is fixed to the negatively charged PVDF resin particles are coated on the surface of the developer carrier. It was possible to suppress the above phenomenon by imparting positive chargeability to the developer via the carrier particles R10 while ensuring conductivity at the initial stage of dispensing. Usually, in the resin coating layer, the resin on the surface is worn by durable use, and the probability of existence of crystalline graphite on the surface of the developer carrier increases, so that conductivity is ensured and sufficient image performance can be obtained.

Typical sectional drawing of an example of the particle | grain coating apparatus used suitably in order to apply | coat a support particle to a developing agent carrier. Schematic diagram of an example of a blasting device used in the present invention Partial sectional view showing an example of a basic configuration of the developer carrying member of the present invention and its periphery Schematic sectional view showing a preferred example of a developing apparatus using the developer carrying member of the present invention. Schematic sectional view showing a preferred example of a developing apparatus using the developer carrying member of the present invention. Schematic cross-sectional view of an example of a surface modification device used in a toner particle surface modification process Schematic top view of the dispersion rotor of FIG.

Explanation of symbols

1 Image carrier (photosensitive drum)
2 Developer layer thickness regulating agent (magnetic blade)
3 Hopper 4 Magnetic toner 5 Magnet roller 6 Metal cylindrical tube (base)
7 Resin coating layer 8 Developer carrier (developing sleeve)
9 Power supply 10 Stirring blade 11 Developer layer thickness regulating agent (elastic blade)
101 Blast nozzle 102 Nozzle holder (support)
103 Injection nozzle (injection means)
104 Abrasive inlet (Abrasive inflow means)
105 Screw 106 Abrasive grain (abrasive)
107 Masking jig 108 Developer carrier (developing sleeve)
DESCRIPTION OF SYMBOLS 109 Ball screw 110 Fixing base 301 Developer layer thickness control part 302 Base body 303 Magnet roller 304 Base particle 305 Conductive fine particle 306 Concavity and convexity imparting particle 307 Lubricant particle 308 Conductive agent 309 Binder resin 310 Carrier particle 311 Developer

Claims (8)

A developer carrying member for carrying the developer and transporting the developer to an electrostatic latent image carrying member carrying an electrostatic latent image,
The amount of developer carried on the developer carrier is regulated by the developer layer thickness regulating member,
The developer carrier is disposed opposite to the electrostatic latent image carrier on which the electrostatic latent image is carried. The developer is carried and conveyed to a developing area at a portion facing the electrostatic latent image carrier. It is used in a developing method for developing and visualizing an electrostatic latent image on an electrostatic latent image carrier with an agent,
The developer carrier is characterized in that at least particles having conductive fine particles attached or fixed thereon are carried on the surface of the developer carrier. The developer carrying member has at least a substrate and a coating layer formed on the surface of the substrate, and further, particles on which conductive fine particles are adhered or fixed are supported on the surface of the coating layer. The developer carrying member according to claim 1. The developer carrying member according to claim 2, wherein the coating layer has conductivity. 4. The developer carrying member according to claim 2, wherein the coating layer is a plating layer or a resin layer containing conductive powder. A developer is carried on a developer carrying body disposed opposite to the electrostatic latent image carrying body carrying an electrostatic latent image, and the amount of developer on the developer carrying body is controlled by a developer layer thickness regulating member. The developer is carried and transported from the developer carrier to the development area opposite to the developer carrier and the electrostatic latent image carrier, and the electrostatic latent image on the electrostatic latent image carrier is transferred by the developer. A development method for developing and visualizing,
Prior to the developer carrying member carrying the developer, at least particles having conductive fine particles attached or fixed thereon are carried on the surface of the developer carrying member in the absence of the developer on the developer carrying member. And developing the electrostatic development on the electrostatic latent image carrier by carrying the developer on the developer carrier. The developer carrying member has at least a substrate and a coating layer formed on the surface of the substrate, and particles having conductive fine particles attached or fixed thereon are supported on the surface of the coating layer. The developing method according to claim 5. The developing method according to claim 6, wherein the coating layer has conductivity. 8. The developing method according to claim 6, wherein the coating layer is a plating layer or a resin layer containing conductive powder.

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