Abstract: Carrier includes a mixture of carrier particles. The mixture may contain first carrier particles containing carrier cores that are coated with a polymer coating, the coating containing polymer and conductive particles, and second carrier particles containing carrier cores that are not coated with a polymer coating. The mixture may contain carrier particles having a conductivity of at least about 5×10?8 (ohm-cm)?1 and carrier particles having a conductivity of less than about 1×10?8 (ohm-cm)?1.

Abstract: In the image forming apparatus by: visualizing an electrostatic latent image formed on an electrostatic charge carrying member; transferring a toner image, which is thus visualized, to a recording medium, or to a recording medium through an intermediate transfer material; and fixing the toner image, which is thus transferred to the recording medium, to obtain a recorded image, the toner includes at least a fixing resin, a colorant, a releasing agent, and an external additive, the toner has an average particle diameter in a range of from 4 to 12 ?m and including no particle having a diameter of 45 ?m or more, a ratio of a toner adhesion amount in a character part to a toner adhesion amount in a solid image part upon printing is more than 0.5 and less than 4, and the toner adhesion amount in a character part is 1.6 mg/cm2 or less.

Abstract: A carrier for an electrophotographic developer which is used as an electrophotographic developer in a mixture with a toner and which secures sufficiently the image density and can maintain high-quality images for a long period, and an electrophotographic developer using the carrier, are provided. A resin-filled ferrite carrier for electrophotographic developer obtained by filling, with a resin, avoid of a porous ferrite core whose void continues from the surface to reach the interior of the core, the carrier comprising a plurality of three-dimensional laminate structures in which resin layers and ferrite layers are alternately present, and an electrophotographic developer including the carrier and a toner, are employed.

Abstract: A carrier core material containing at least one metal oxide (MLO) having a melting point of not higher than 1000° C. and at least one metal oxide (MHO) having a melting point of not lower than 1800° C., wherein the metal (MH) for constituting the metal oxide (MHO) has an electrical resistivity of not less than 10?5 ?·cm. Also disclosed is a two-component developing agent comprising a coated carrier, which comprises the carrier core material coated with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed on a photosensitive member with the two-component developing agent using an alternating electric field. The carrier core material and the coated carrier have high magnetization and are free from occurrence of leakage of electric charge over a wide range of electric field from low electric field to high electric field. According to the two-component developing agent, an excellent image can be formed.

Abstract: A spherical resin-coated ferrite carrier for an electrophotographic developer which can maintain a stable resistance and chargeability, a favorable charge rising property because of an excellent fluidity, and has a suitable durability, its production method which is excellent in economic efficiency and production stability, and an electrophotographic developer using the resin-coated ferrite carrier, are provided. A resin-coated ferrite carrier for an electrophotographic developer which is a spherical resin-coated ferrite carrier, wherein a carrier core material thereof has an irregular surface to improve the adhesive strength to a resin coat, and wherein the irregularity of the surface takes a finely streaked wrinkle pattern, its production method, and an electrophotographic developer using the resin-coated ferrite carrier, are employed.

Abstract: A resin-coated ferrite carrier having a uniform resin coating and emitting no offensive odors, etc., its production method, and an electrophotographic developer which comprises the resin-coated ferrite carrier, is excellent in the charge stability and image quality stability over a long period, causes less fogging of image or carrier adhesion, is favorable in the image density and environmental dependency, and can fully respond to high-speed and full-color imaging, are provided. The resin-coated ferrite carrier for the electrophotographic developer is characterized in that the surface of ferrite particles is coated with a mixed resin of a tetrafluoroethylene-hexafluoropropylene copolymer or a tetrafluoroethylene-perfluoroalkylvinyl ether copolymer and a polyamideimide resin, and that the mixed resin contains a silicon oxide.

Abstract: The present invention is to provide a carrier and a developer, which have fewer occurrences of carrier adhesion and background smear, excellent granularity and longer durability. The carrier comprises the core material particles having magnetism and resin coating layer covering the core material particles, and wherein the weight average particle diameters is in the range of 22 m to 32 m, the proportion of the weight average particle diameters relative to the number average particle diameter is in the range of 1.00 to 1.20, the content of particles having a diameter of 20 m or smaller is 7% by mass, the content of carrier particles having a diameter of 36 m or smaller is in the range of 90% by mass to 100% by mass, and the proportion of the particle density of the core material particles is in the range of 85% to 100% of the true density of the core material particles.

Abstract: To provide a resin-coated carrier for an electrophotographic developer capable of providing an image with excellent image quality; and a two-component developer and a replenishing developer each of which contains the resin-coated carrier as a constituent.

Abstract: A carrier for electrophotographic developer comprises a resin carrier core comprising a binder resin and magnetic powder dispersed in the binder resin, and a coating layer comprising a coating resin on a surface of the core, the binder resin being a silicone resin obtained by curing of a polysiloxane compound (A) having an epoxy group and a polysiloxane compound (B) having a group capable of reacting with the epoxy group, due to a ring-opening addition reaction; the binder resin containing a functional group which is an epoxy group and/or a group capable of reacting with an epoxy group; the coating resin containing a functional group capable of reacting with the functional group of the binder resin; the functional group of the coating resin and the function group of the binder resin forming a chemical bond.

Abstract: The present invention is a carrier for electrophotography in which a surface of at least a core material is coated with a resin, in which the coating resin contains a fluorine modified silicone resin and an aminosilane coupling agent, and in which the carrier charges a toner negatively. Consequently, a carrier with a high durability and a long lifetime for electrophotography is provided, in which the charge amount does not decrease at high temperature or high humidity nor extremely increase at low temperature or low humidity, in which a deterioration of a developing agent caused by stripping of a coating layer is prevented, and in which a deterioration caused by formation of spent toner of a toner is not caused.

Abstract: A carrier excellent in durability and environmental stability and a two-component developing agent is provided. In the carrier, a core material is coated with a resin, and the coating resin is formed on the core material such that the coating resin comes to be in an amount of 5% by weight to 20% by weight on the basis of a weight of the core material, thereby enhancing durability. Further, the coating resin contains fine particles of titanium oxide, thereby enhancing environmental stability.

Abstract: A carrier comprised of a core and a polymer generated from a mixture of two latexes, and wherein the first latex enables a polymer with a high molecular weight, and the second latex enables a polymer with a low molecular weight, and wherein high represents a weight average molecular weight of from about 1,000,000 to about 8,000,000, and said low represents a weight average molecular weight of from about 500,000 to about 750,000.

Abstract: A ferrite carrier for the electrophotographic developer containing 40 to 500 ppm of zirconium; a method for preparing a ferrite carrier for the electrophotographic developer, comprising the steps for weighing, mixing, and pulverizing ferrite raw materials, and for granulating, drying, and firing the obtained slurry; wherein a zirconium raw material is added so that the zirconium content after firing becomes 40 to 500 ppm; and an electrophotographic developer using the ferrite carrier.

Abstract: Employed are a resin-coated ferrite carrier for an electrophotographic developer including a ferrite carrier core material having a BET specific surface area of 900 to 5,000 cm2/g and an apparent density of 2.30 to 2.80 g/cm3, and the electrophotographic developer using this resin-coated ferrite carrier.

Abstract: A carrier containing a core, a polymer coating, mixtures of polymers, or a plurality of polymers thereover, and wherein at least one of, and more specifically, one of the coating polymers, includes graphite.

Abstract: A carrier containing a core material and a resin coating layer located overlying the surface of the core material. The resin coating layer contains resin and electroconductive particles having an oil absorption amount of from 10 to 300 ml/100 g. The electroconductive particle contains a base material particle and an electroconductive coating layer located overlying the surface of the base material particle. The electroconductive coating layer contains an underlayer containing tin dioxide and an upper layer containing indium oxide and tin dioxide, located overlying the underlayer.

Abstract: A carrier composition having magnetite with a diameter of from about 80 microns to about 150 microns, and wherein the carrier has a conductivity of from about 10?8 to about 10?11 (ohms-cm)?1 and a carrier breakdown voltage of from about 20 to about 200 volts, and a developer composition with toner and this carrier composition, and also including a developer housing apparatus and an electrostatographic apparatus comprising the developer housing apparatus.

Abstract: An objective is to provide a carrier exhibiting stable charge providing ability in which sufficient charge can be provided to toner having a small particle diameter, and no image contamination such as fog caused by toner scattering via lack of electrification is generated. Another objective is to provide a carrier capable of maintaining a charging level of no interference for image formation even under the image forming condition at which a charging level for printing a number of prints continuously is difficult to be maintained. Disclosed is a carrier comprising a core particle made of ferrite possessing Mg and coated thereon, a resin, wherein the core particle has a ratio of the number of irregular-shaped core particles of at most 5%, based on the total number of core particles, and a surface of the core particle has grains having a maximum grain diameter of 2-5 ?m.

Abstract: A ferrite carrier for an electrophotographic developer having a compression breaking strength of 150 MPa or more, a rate of compressive change of 15.0% or more and a shape factor SF-1 of 100 to 125, a method for producing the same, and an electrophotographic developer containing the ferrite carrier.

Abstract: A carrier for electrostatic development contains a core particle and a coating layer covering the core particle, and the core particle is a ferrite particle containing at least one of Zr in an amount of 0.005% by mass to 5% by mass and Bi in an amount of 0.001% by mass to 1% by mass. The carrier shows a sufficient resistance, is stably charged over a long period of time, can avoid roughness and irregular density in halftone images, prevents deposition of the carrier particles on a photoconductor, can satisfactorily reproduce character images and can produce high-quality images over a long period of time. The carrier is usable for constituting a developer, a container housing the developer, an image forming apparatus and process, and process cartridge using the developer.

Abstract: Carrier comprised of a core, a polymer coating, and wherein said coating contains a conductive polypyrrole contained in a carbon black matrix; or a polyaniline contained in a carbon black matrix.

Abstract: A carrier including a manganese ferrite core material having a layer on its surface such that 0.1?K?30, where K=(S/M)×100, S and M represent the standard deviation and average of M2/(M1+M2), respectively, M ranging from 0.05 to 0.45, and M1 and M2 represent the content of iron and manganese, respectively, in a carrier particle. The carrier has a magnetization ranging from 45 to 75 emu/g at 1,000 Oe, a mass-averaged particle diameter, D4, ranging from 25 to 65 ?m and carrier particles having a particle diameter not greater than 12 ?m are included in an amount not greater than 0.3% by weight, and a ratio, D4/D1, ranging from 1 to 1.3, where D1 is a number-averaged particle diameter of the carrier.

Abstract: A carrier for electrostatic development contains a core particle and a coating layer covering the core particle, and the core particle is a ferrite particle containing at least one of Zr in an amount of 0.005% by mass to 5% by mass and Bi in an amount of 0.001% by mass to 1% by mass. The carrier shows a sufficient resistance, is stably charged over a long period of time, can avoid roughness and irregular density in halftone images, prevents deposition of the carrier particles on a photoconductor, can satisfactorily reproduce character images and can produce high-quality images over a long period of time. The carrier is usable for constituting a developer, a container housing the developer, an image forming apparatus and process, and process cartridge using the developer.

Abstract: A resin-coated carrier for an electrophotographic developer and a process of producing the carrier. The carrier comprises a ferrite core mainly comprising iron oxide, primarily having a spinel structure, and having a volume average particle size of 20 to 45 ?m and a resin coat, wherein the carrier has a magnetization of 65 to 80 emu/g in a magnetic field of 1 KOe, the core has an electric current value of 50 to 150 ?A and a surface smoothness uniformity of 75% or higher, and the amount of the resin coat is 0.1 to 5.0% by weight based on the core.

Abstract: Carrier comprised of a mixture of a first carrier and a second carrier, and wherein the first carrier is comprised of a steel core and the second carrier is comprised of a magnetite.

Abstract: An image-forming apparatus which includes an image developer configured to develop a latent electrostatic image and to have a developer, a developer bearing member which has a magnet therein, has the developer on a surface thereof, and rotates with carrying the developer, and a developer limiting member which faces the developer bearing member, and controls an amount of the developer, and a latent electrostatic image support configured to contain a filler in its outermost layer. In the image-forming apparatus, the developer is a double-component developer which contains a magnetic carrier and a toner, the magnetic carrier has a coating layer which is formed of a binder resin having particles retained on a surface of the magnetic carrier, and a ratio of a particle diameter D1 of the particles to a film thickness h1 of the binder resin satisfies a relation of: 1<D1/h1<10.

Abstract: A carrier including a magnetic core material and a layer located on a surface of the magnetic core material, wherein the carrier satisfies the following relationships (1) to (3): 0.90≦(&sgr;a/&sgr;b)<1.00 (1); 200≦(&sgr;b·&rgr;c)≦400 (2); 10≦(&sgr;b/&rgr;c)≦20 (3), wherein &sgr;b represents a magnetization of the carrier at 1,000 Oe, &sgr;a represents a magnetization of the carrier after frictionized with a cylindrical sleeve under a specific condition and &rgr;c represents a true specific gravity of the carrier, wherein the carrier has a weight-average particle diameter of about 25 to about 65 &mgr;m and includes carrier particles having a weight-average particle diameter not greater than about 12 &mgr;m in an amount of not greater than about 0.3% by weight, wherein a ratio between the weight-average particle diameter and a number-average particle diameter of the carrier is about 1 to about 1.3, and wherein an electric resistance is from about 1.0×109 to about 1.

Abstract: A carrier for electrophotographic developer comprising carrier particles, each carrier particle having at least one surface-coating layer by resin material, wherein the surface-coating layer containing an acrylic resin and a silicone resin, the acrylic resin is in an amount ranging 10 to 90 wt. % based on the total amount of resin coating ingredients. The carrier shows no accumulation of toner-spents, therefore can obtain a stable electric charge, and has no layer scraping in binder resin layer, therefore can obtain a stable electric resistance, hence occurs no deterioration of images reproduced, by using acrylic resin having high anti-abrasive and high surface energy, whereas it has strong adhesiveness and high fragility, in combination use of silicone resin having poor anti-abrasive and small adhesiveness but has low fragility, thus is hard to cause a toner spent and hard to integrate the spent constituents due to its low surface energy.

Abstract: A carrier core material containing at least one metal oxide (MLO) having a melting point of not higher than 1000° C. and at least one metal oxide (MHO) having a melting point of not lower than 1800° C., wherein the metal (MH) for constituting the metal oxide (MHO) has an electrical resistivity of not less than 10−5 &OHgr;·cm. Also disclosed is a two-component developing agent comprising a coated carrier, which comprises the carrier core material coated with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed on a photosensitive member with the two-component developing agent using an alternating electric field. The carrier core material and the coated carrier have high magnetization and are free from occurrence of leakage of electric charge over a wide range of electric field from low electric field to high electric field.

Abstract: Carrier comprised of a mixture of a first carrier and a second carrier, and wherein the first carrier is comprised of a steel core and the second carrier is comprised of a magnetite.

Abstract: A carrier comprised of a core and thereover a polymer coating, and which coating is generated by the emulsion polymerization of one or more monomers and a surfactant, and wherein said polymer coating is of a diameter of equal to or less than about 100 nanometers.

Abstract: A carrier is composed of carrier particles, each carrier particle having a core particle containing at least a magnetic material and a surface coating layer provided on the core particle containing at least a resin, the surface coating layer being constituted of a plurality of regions, the regions being separately formed and joined together to form a complex configuration, and having different phase lags when the surface coating layer is subjected to scanning by phase imaging measurement using a scanning probe microscope in a tapping mode, wherein a region having a phase lag over the average phase lag obtained from Eavg=&Sgr;(E(i)·S(i))/&Sgr;S(i) has an area SO, and SO and &Sgr;S(i) are in a relationship of 10%≦SO/&Sgr;S(i)×100≦90% when each region comprises a component A(i) having an area S(i) and a phase lag E(i), in which i represents the number of regions with different phase lags. A two-component developer employs the above-mentioned carrier.

Abstract: Methods for development of an electrostatic image are disclosed that utilize developer compositions with hard magnetic carrier compositions which can provide improved development efficiencies and reduced amounts of image carrier pick-up. The methods utilize hard magnetic carrier particles that are modified to have specific levels of resistivity, such as, for example, of from about 1×105 ohm-cm to about 1×1010 ohm-cm, and a carrier charge-to-mass of greater than about 1.0 &mgr;C/g, which carriers can provide greater development speeds without unacceptable levels of image carrier pick-up. In embodiments, the hard magnetic materials are doped, i.e., bulk substituted, with multi-valent metals to adjust resistivity, while in other embodiments, the hard magnetic materials are coated with at least one multi-valent metal oxide.

Abstract: A resin-coated carrier to be mixed with a polymer toner obtained by suspension polymerization or emulsion polymerization to provide an electrophotographic developer, which exposes 2 to 20% of the surface area of the core thereof, the average exposed area ratio per exposed part of the core being 0.03% or less.

Abstract: A carrier for a two-component developer for developing a latent electrostatic image is composed of carrier particles, each of the carrier particles having a core particle and a coating layer provided on the surface of the core particle, with the coating layer containing an amino-group-containing modified silicone resin. A two-component developer is composed of a toner and the above-mentioned carrier.

Abstract: A carrier comprised of a core and thereover a polymer coating, and which coating is generated by the emulsion polymerization of one or more monomers and a surfactant, and wherein said polymer coating is of a diameter of equal to or less than about 100 nanometers.

Abstract: The present invention provides a carrier for electrophotography, which is capable of charging the toner in the developer very rapidly to a target electrostatic charge and at the same time, is capable of maintaining the target electrostatic charge during printing, so that the chemical fogging related to the slow charging rate can be eliminated and the image density related to the maintenance of the electrostatic charge can be preserved during printing. The charging rate and the charge maintenance of the electrophotographic carrier can be preserved if the carrier composed of magnetic core particles and the resin coat satisfies the following equation (B)>[(−19.4)×(A)+31], wherein (A) represents a carbon content (weight %) of the carrier and (B) represents a ratio of the square root of the number of emitted photoelectrons ((CPS)½) and the photon energy (eV).

Abstract: A resin-coated carrier for an electrophotographic developer and a process of producing the carrier. The carrier comprises a ferrite core mainly comprising iron oxide, primarily having a spinel structure, and having a volume average particle size of 20 to 45 &mgr;m and a resin coat, wherein the carrier has a magnetization of 65 to 80 emu/g in a magnetic field of 1 KOe, the core has an electric current value of 50 to 150 &mgr;A and a surface smoothness uniformity of 75% or higher, and the amount of the resin coat is 0.1 to 5.0% by weight based on the core.

Abstract: A carrier for electrophotographic developer comprising carrier particles, each carrier particle having at least one surface-coating layer by resin material, wherein the surface-coating layer containing an acrylic resin and a silicone resin, the acrylic resin is in an amount ranging 10 to 90 wt. % based on the total amount of resin coating ingredients. The carrier shows no accumulation of toner-spents, therefore can obtain a stable electric charge, and has no layer scraping in binder resin layer, therefore can obtain a stable electric resistance, hence occurs no deterioration of images reproduced, by using acrylic resin having high anti-abrasive and high surface energy, whereas it has strong adhesiveness and high fragility, in combination use of silicone resin having poor anti-abrasive and small adhesiveness but has low fragility, thus is hard to cause a toner spent and hard to integrate the spent constituents due to its low surface energy.

Abstract: A carrier for an electrophotographic developer which has a flowability index F1, represented by formula (1), of 63 to 75 sec/(50·cm3) and a flowability index F2, represented by formula (2), of 30 to 100 Oe·g/cm3: F1=AD×FR  (1) F2=AD×Hc  (2) wherein AD is an apparent density (g/cm3); FR is a flow rate (sec/50 g); and Hc is a coercive force (Oe).

Abstract: There is provided a carrier, for an electrcostatographic developer, comprising particles of a hard magnetic ferrite material as the core, the core having a coating of a polymer resin, said resin in turn having a coating of an organic conductive material. The organic conductive material can be a charge control agent and can be present in very small amounts. The developer compositions have no need for preconditioning since they have stable charging characteristics. Further, they exhibit low levels of “dusting”.

Abstract: A developer for a trickle developing method is used in formation of a full color image and is made of a mixture of a toner and a carrier. The toner contains inorganic fine particles as an internal additive and an external additive, a volume average particle diameter D50v of the toner is between 5.0 and 9.0 &mgr;m, a true specific gravity of the carrier is between 3.00 and 4.60, a volume average particle diameter of the carrier is between 15 and 60 &mgr;m, and the ratio of the volume average particle diameter of the carrier to the volume average particle diameter of the toner is between 3.00 and 7.00, and an image forming method using the developer.

Abstract: A carrier is composed of carrier particles, each carrier particle having a core particle containing at least a magnetic material and a surface coating layer provided on the core particle containing at least a resin, the surface coating layer being constituted of a plurality of regions, the regions being separately formed and joined together to form a complex configuration, and having different phase lags when the surface coating layer is subjected to scanning by phase imaging measurement using a scanning probe microscope in a tapping mode, wherein a region having a phase lag over the average phase lag obtained from Eavg=&Sgr;(E(i)·S(i))/&Sgr;S(i) has an area SO, and SO and &Sgr;S(i) are in a relationship of 10%≦SO/&Sgr;S(i)×100≦90% when each region comprises a component A(i) having an area S(i) and a phase lag E(i), in which i represents the number of regions with different phase lags. A two-component developer employs the above-mentioned carrier.

Abstract: Carrier comprised of a core, a number of the pores thereof containing a polymer, and thereover a coating.

Abstract: An electrostatic latent image developer is provided which has an improved durability and a longer life-time by preventing the toner spent. The electrostatic latent image developer comprises a resin-coated magnetic carrier and a toner. Said resin-coated magnetic carrier consists of a magnetic ferrite carrier core and a coating layer formed thereon by polymerizing a high molecular weight polyethylene resin directly on the surface of said carrier core. Said toner does not contain polyethylene wax but polypropylene wax and/or polyester wax having an average molecular weight of 10,000 as the wax component or components in an amount of from 0.1 to 20 wt. %.

Abstract: An electrophotographic image formation method for developing a latent electrostatic image formed on a latent image bearing member with toner to a toner image, using a two-component developer including a carrier and a toner. The zoner is held on a developer bearing member, with a gap between the facing surfaces of the latent image bearing member and the developer bearing member being set in a range of 0.1 mm to 0.5 mm. The carrier includes carrier particles, each carrier particle including a core material and a coating material which is coated on the surface of the core material The coating material includes a polysiloxane resin including at least an oxygen atom (O) and a silicon atom as constituent elements therefor, with an atomic ratio of the constituent elements, O/Si, being in a range of 2.1 to 4.0, and the carrier having a specific resistivity of 109 to 1016 &OHgr;·cm.

Abstract: A carrier for use in electrophotography provided by the present invention satisfies such conditions that when (i) the porosity of the surface of a core particle is A %(A≦40) and (ii) the resin-coated rate of the porous part of the surface the core particle is B %, (iii) A×B/100 is 15 or more and further (ix) the resin-coated rate of the smooth part, besides the porous part, is 20% or less.

Abstract: Carrier comprised of a core, a number of the pores thereof containing a polymer, and thereover a coating.

Abstract: An electrostatic charge regulator capable of holding an electric charge in a stable state and superior in environmental stability, as well as a method for making the electrostatic charger regulator and an image forming method using the electrostatic charge regulator, are disclosed. The electrostatic charge regulator has a surface layer containing a non-linear resistor on a base member such as a carrier, a developer sleeve, a developer blade, or a transfer belt. The electrostatic charge regulator is obtained by forming on the base member a surface layer by using a thin film of a composite metal oxide or by using dispersion of powder of the composite metal oxide in a high molecular compound, the composite metal oxide being prepared using at least one metal selected from Group A metals (Zn, Ti, Si, Al, Zr) and at least one metal selected from Group B metals (Bi, Sb, C, Y, La, Pr, Sc, Ce, Sn, Pb). The image forming method uses the above electrostatic charge regulator to form an image.

Abstract: A magnetic carrier exhibiting excellent durability against mechanical impact as exerted by vibration and capable of exhibiting a stable charging performance in electrophotography is provided.