Abstract: A core material of a ferrite carrier for an electrophotographic developer, the core material being composed of a ferrite particle containing at least one or more temperature compensation-type dielectric components selected from Mg2TiO4, MgTiO3 and MgTi2O4, a ferrite carrier for an electrophotographic developer, the ferrite carrier being prepared by coating a surface of the carrier core material with a resin, and an electrophotographic developer using the ferrite carrier.

Abstract: There are adopted an electrophotographic resin-coated ferrite carrier having a carrier core coated with a resin, wherein a product of an apparent density ? (g/cm3), average particle size d (?m) and BET specific surface area S (m2/g) of the carrier core satisfies the following condition, a method for producing the same, and an electrophotographic developer. 4.5??×d×S?8.

Abstract: The present invention relates to a toner composition for forming a masking pattern for use e.g. in connection with a method of building up a three-dimensional body from a large number of mutually connected layers of powder particles that are bonded to each other using radiant heat. The toner composition consists of powder particles that arc able to withstand a temperature of at least 200° C. without sticking together. It also relates to a developer that comprises the toner composition and carrier particles and a method in connection with the production of a volume body by using a toner composition or a developer according to the invention.

Abstract: The present disclosure provides carriers for use with toner compositions. In embodiments, a carrier may include a core, having a dry powder polymer coating. The polymer coating possesses a carbon to oxygen from about 3:1 to about 8:1. In embodiments, the coating may also include a colorant, such as carbon black. Processes for coating such carriers with the dry powder polymer coatings are also provided.

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 core material for an electrophotographic developer containing Li ferrite, maghemite, and Fe3O4, wherein a part thereof is substituted with Mn, a Li content is 1 to 2.5% by weight, a Mn content is 2 to 7.5% by weight, and a silicon content is 25 to 10,000 ppm, a compression breaking strength is 130 MPa or more, an SF-1 is 125 to 145, respective cumulative strengths of respective spinel crystal structure faces in X-ray diffraction satisfy a certain equation, a vacuum resistivity R500 across a 2 mm gap when a measurement voltage of 500 V is applied is 1×106 to 5×109 ?, and a vacuum resistivity R1000 across a 6.5 mm gap when a measurement voltage of 1,000 V is applied is 5×107 to 1×1010 ?.

Abstract: A method of forming fixed images, including the step of applying a two-component developer containing a carrier and a toner containing a wax and a resin binder containing a crystalline polyester to a two-component development device with a linear speed of from 500 to 5,000 mm/sec, to develop the toner, wherein the crystalline polyester is contained in an amount of from 3 to 40% by weight and the wax in an amount of from 2.5 to 10% by weight, of the toner, and wherein the two-component development device comprises at least three magnet rollers which are arranged closely to each other along the perimeter of a photoconductor, wherein one magnet roller arranged on the uppermost side in the rotational direction of the photoconductor rotates in a direction opposite to the rotational direction of the photoconductor at the point therebetween, and the other magnet rollers rotate in the same direction as the photoconductor at the point therebetween.

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: An image forming apparatus includes a photosensitive drum to which an electrostatic image is formed and a developing sleeve carrying a developer including toner carrier. An alternating voltage is applied to the sleeve to form an alternating electric field between the sleeve and the drum to develop the electrostatic image with the developer. A relation |K1|<|K2| is satisfied, where K1: a slope at an electric field intensity Ed=|(Vp2?VL)/D|, K2: a slope at an electric field intensity Eb=|(Vp1?VL)/D|, VL: a potential [V] of the electrostatic image at which a maximum density is obtained, Vp1: a peak potential [V] that provides a potential difference to move the toner toward the drum, Vp2: a peak potential [V] that provides a potential difference to move the toner toward the sleeve, and D: a closest distance [m] between the drum and the sleeve.

Abstract: An electrostatic image developing carrier includes a ferrite particle that contains from about 1.0% by weight to about 14.0% by weight of elemental magnesium, wherein an average distribution ratio D of the elemental magnesium in the ferrite particle is from about 1.1 to about 2.0, wherein the average distribution ratio D is defined as an average value of D? of at least 50 ferrite particles, wherein D? is defined as W1/W2, wherein W1 is a weight ratio of elemental magnesium content Mg to elemental iron content Fe, Me/Fe, in a whole cross-section of the ferrite particle, and W2 is a weight ratio of elemental magnesium content Mg to elemental iron content Fe, Me/Fe, in a square, the two opposite vertices of which are located at two points on a diameter of a circle circumscribing the cross-section, each being half a radius distant from the center of the circumscribing circle.

Abstract: Employment of a carrier core material for an electrophotographic developer containing 0.8 to 5% by weight of Mg, 0.1 to 1.5% by weight of Ti, 60 to 70% by weight of Fe and 0.2 to 2.5% by weight of Sr and having an amount of Sr dissolved with a pH4 standard solution of 80 to 1000 ppm, a carrier using the core material and a process for producing them, and an electrophotographic developer using the carrier.

Abstract: A carrier includes at least one magnetic material and a conductive material. The conductive material is at least one carbon nanotube. A developer includes a toner and the carrier.

Abstract: In a method for recycling a double component developer that contains a carrier and a toner used for an image forming device such as office automation equipment, an economic value of recycling is increased, thereby allowing a company to carry out an active and sustainable environmental activity. Material components of a carrier are completely utilized, so that a process of removing and disposing part of components of the carrier, which is present in the conventional technology of a carrier recycling, is omitted from a recycling system, and in consequence, a cost of recycling is minimized. Furthermore, as well as a subject of the recycling, i.e. a carrier itself, a more valuable material, i.e. a platinum group metal, is utilized for the recycling.

Abstract: To provide a carrier for two-component electrophotographic developer not only having excellent fluidity but also having proper surface irregularities necessary for imparting electric charge, without generating cracks/chipping of particles even under an influence of stirring stress over a long period of time. A particle surface has raised parts of striped pattern extending almost continuously in a plurality of directions while being superposed on one another, with a surface formed with raised parts of striped pattern occupying 80% or more of the whole surface of a particle. Depths of grooves between the adjacent raised parts are 0.05 ?m or more and 0.2 ?m or less, average surface roughness Ra is 0.1 ?m or more and 0.3 ?m or less, roundness is 0.90 or more, and average particle size is 151 ?m or more and 100 ?m or less, and a carrier core material thus constituted is coated with resin. Thus, the carrier for two-component electrophotographic developer is prepared.

Abstract: A resin-filled carrier for an electrophotographic developer which carrier is obtained by filling a resin in the voids of a porous ferrite core material, wherein the Cl concentration of the porous ferrite core material, measured by an elution method, is 10 to 280 ppm and the resin contains an amine compound, and an electrophotographic developer using the resin-filled carrier.

Abstract: The use of electrographic printing to prepare prints which have a desired tactile feel or raised information in a controlled manner by utilizing a developer having toner particle size larger than 50 microns volume average diameter and carrier particles larger than the toner particle size such that the volume average distribution overlap between the toner distribution curve and carrier particle distribution curve is less than 35% and the carrier and toner particles have a volume average diameter size differential equal to or greater than 5 microns or the ratio of carrier-to-toner volume average diameter exceeds 1.25.

Abstract: The present invention provides a carrier core material for use in the production of an electrophotographic developer which, even when applied, for example, to MFPs (multifunction printers), can realize stable, high-quality and high-speed development, and has a prolonged replacing life of magnetic carriers, and a method of manufacturing the same, a magnetic carrier including the carrier core material, and an electrophotographic developer manufactured from the magnetic carrier. An electrophotographic development carrier is prepared by adding resin particles, a binder, a dispersant, a wetting agent, and water to a raw material powder, wet pulverizing the mixture, drying the pulverized product to give granulated powder, calcinatng the granulated powder, and then sintering the granulated powder to prepare a carrier core material having an internally hollow structure, and coating the carrier core material with a resin.

Abstract: It is contemplated to provide irregular shaped ferrite carrier which has a lower resistance, a high specific surface area, a low specific gravity and a longer operational life, and an electrophotographic developer comprising the ferrite carrier which prevents the toner scattering, has a high image density, and is responsive to high-speed and color imaging. The irregular shaped ferrite carrier is characterized in that the carrier particles are irregular shaped, and 40 percent by number or more of the particles have a rock candy sugar shape and/or an oyster shell shape, and that the shape factor (SF-1=R2/S×?/4×100, wherein R is a maximum length and S is a projected area.) is 140 to 250, and the distribution width (?) is 60 or less.

Abstract: An object of the present invention is to suppress the adhesion of a carrier to an image bearing member and the generation of a flaw in the surface layer of the image bearing member, and to improve the dot reproducibility of an electrostatic latent image, and so on. The object is achieved by a two-component developer containing a magnetic carrier, which contains resin-containing magnetic particles, in which the packed bulk density ?1 is 0.80 to 2.40 and ?1/?2 (?2 represents true density) is 0.20 to 0.42 of the porous magnetic core particles, and a specific resistance of the porous magnetic core particles, an average breaking strength of the magnetic carrier and a toner surface tension constant in a 45-vol % aqueous solution of methanol measured by a capillary suction time method fall into the specific range, respectively.

Abstract: A carrier core material for an electrophotographic developer including Li ferrite, maghemite, and Fe3O4, wherein a part thereof is substituted with Mn, Li content is 1 to 2.5% by weight, Mn content is 2 to 7.5% by weight, and silicon content is 25 to 10,000 ppm, the following equation (1) is satisfied when respective integrated strengths of spinel crystal structure (110), (210), (211), and (311) faces in X-ray diffraction are respectively I110, I210, I211, and I311, a resistivity R50 of 50 V across a 6.5 mm gap is 5×107 to 7×108?, and a resistivity R1000 of V across a 6.5 mm gap is 1×107 to 8×108?.

Abstract: A resin-filled carrier for an electrophotographic developer obtained by filling resin into voids of a porous ferrite core material, wherein the porous ferrite core material has a pore volume of 0.04 to 0.16 mL/g and a peak pore size of 0.9 to 2.0 ?m, and wherein microparticles are included in the resin to be filled, and an electrophotographic developer using this resin-filled carrier.

Abstract: The object of the present invention is to provide a carrier for electrophotography which includes a core material and a coating layer comprising particles on a surface of the core material, in which the carrier for electrophotography comprises indium (In) in an amount of 0.0001% by mass to 0.5% by mass. The present invention also provides a developer using the carrier, a developer container, an image forming method, an image forming apparatus, and a process cartridge in each of which the carrier is used.

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 resin-filled carrier for an electrophotographic developer obtained by filling resin into voids of a porous ferrite core material, wherein the porous ferrite core material has a pore volume of 0.055 to 0.16 mL/g and a peak pore size of 0.20 to 0.7 ?m, and an electrophotographic developer using this resin-filled carrier.

Abstract: A carrier contains a core; and a cover layer located overlying the core, wherein the cover layer comprises a binder resin, a first particulate material and a second particulate material, wherein the following relationships are satisfied: 1<(D1/h)<10, and 0.001<(D2/h)<1, wherein D1(?m) represents a volume average particle diameter of the first particulate material, D2(?m) represents a volume average particle diameter of the second particulate material, and h (?m) represents a thickness of the cover layer, and wherein the second particulate material has a volume resistivity of not greater than 1.0×1012 ?·cm.

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: This invention provides an Mg-based ferrite having a high dielectric breakdown voltage and a saturation magnetization suitable for electrophotographic development, a carrier containing the ferrite, and an electrophotographic developer containing the carrier. The Mg-based ferrite material of this invention comprises Li, Na, K, Rb, Cs, Ca, Sr, Ba, Y, La, Ti, Zr, Hf, V, Nb, Ta, Al, Ga, Si, Ge, P, Sb, Bi or a combination thereof. The Mg-based ferrite material has a saturation magnetization of 30 to 80 emu/g, and a dielectric breakdown voltage of 1.5 to 5.0 kV. The Mg-based ferrite material can realize high image quality, and be in compliance with environmental regulations.

Abstract: Hard magnetic core particles for use in the development of electrostatic latent images are produced by combining ferric oxide, a strontium oxide precursor, an oxygenated boron compound and a binder to form a mixture, wherein the strontium oxide precursor is preferably present in an amount that provides SrO in a molar amount that is in excess of a stoichiometric amount that provides a ratio of Fe2O3 to SrO of 6/1. The mixture can be formed into green beads and the green beads can be fired to form the hard magnetic core particles.

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: A resin-filled ferrite carrier for an electrophotographic developer filled with a silicone resin in voids of a porous ferrite core material which continuously extend from a surface to a core interior, wherein the resin-filled ferrite carrier has an average particle size of 20 to 50 ?m, and (Si/Fe)×100 as determined from X-ray fluorescence elemental analysis is 2.0 to 7.0, and the particle size and (Si/Fe)×100 are correlated, and wherein in the correlation relationship between [(Si/Fe)×100] and the particle size, a gradient (a) in a correlation equation thereof is ?0.50?a?0.15.

Abstract: Disclosed are a ferrite carrier for electrophotographic developer and an electrophotographic developer using the ferrite carrier, wherein: the ferrite carrier is a composite ferrite composed of Li and Mg; when the composition of the ferrite is calculated as a mixture of a Li ferrite having a stoichiometric composition and a Mg ferrite having a stoichiometric composition, the excessive amount of Fe2O3 is less than 5 mol %, or the total excessive amount of Li2O and MgO is less than 1 mol %; the content of the elements other than Li, Mg, Fe and O is 2% by weight or less; and further, the content of Mn in terms of element is 1000 to 9000 ppm.

Abstract: Provided are a carrier for electrophotography developers prepared by generating a slight amount of byproducts such as water, alcohol, etc, which carrier is free from release of a magnetic powder, has excellent mechanical strength and durability, and good environmental stability, and further can restrain occurrence of toner spent condition and has favorable fluidity and excellent capability of imparting charging to a toner, a two-component developer comprising the carrier and a method for forming an image using the developer. The carrier for electrophotography developers comprises a magnetic powder dispersed binder resin, the binder resin material comprises (A) a polysiloxane compound having an epoxy group as a functional group and (B) a polysiloxane compound having a group capable of ring-opening addition reaction with the epoxy group of the polysiloxane compound (A), and the binder resin is a silicone resin prepared by curing with ring-opening addition reaction of the epoxy resin.

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 carrier core material for an electrophotographic developing agent, which comprises 100 parts by weight of a ferrite component represented by a formula (A) and 0.1 to 5.0 parts by weight of ZrO2 that is present in the ferrite component without forming a solid solution, and which has a magnetization, at 1000(103/4?·A/m), of 65 to 85 Am2/kg and an electrical resistance, at an applied voltage of 1000 V, of 105 to 109 ?. (MnO)x(MgO)y(Fe2O3)z??(A) wherein x, y and z are each expressed in % by mol and are numbers satisfying the conditions of 40?x?60, 0.1?y?10 and x+y+z=100. Also disclosed is a two-component developing agent comprising a coated carrier, which is obtained by coating the above carrier core material with a resin, and toner particles. Further disclosed is an image forming method comprising developing an electrostatic latent image formed by the use of an alternating electric field, with the two-component developing agent.

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: The present invention provides a toner: comprising a binder resin comprising a polyester unit, a colorant, a releasing agent, and inorganic fine particles; has a weight average particle diameter of 3.0–6.5 ?m; has an average circularity of particles in the toner each having a circle-equivalent diameter of 2 ?m or more of 0.920–0.945; has a BET specific surface area of 2.1–3.5 m2/g; and has a permeability of light of a wavelength of 600 nm in a liquid having dispersed the toner in a 45 vol % methanol aq. of 30–80%. The present invention also provides a two-component developer: comprising the toner and a magnetic carrier comprising magnetic core particles coated by a coating layer; and has a number average particle diameter of 15–80 ?m. Using the toner and the two-component developer enables a high-quality image to be formed at a high speed even in an oilless fixing system.

Abstract: Development systems and methods for developing using magnetic toner are disclosed. The present invention further discloses developers used in development systems as well as the toner used in developer for magnetic ink character recognition printing. With respect to the development system, a development system is disclosed which includes a supply of dry developer mixture which contains magnetic toner particles and hard magnetic carrier particles. The development system further includes a non-magnetic, cylindrical shell for transporting the developer between the supply and the development zone, wherein the shell can be rotatable or stationary. A rotating magnetic core of a pre-selected magnetic field strength and means for rotating at least the magnetic core to provide for the transport of the toner particles from the shell to an electrostatic image also provided as part of the development system.

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 electrostatic latent image on an image-bearing member is developed with a two-component developer comprising a toner and a carrier stored in a developer vessel while supplying as required a replenishing developer to the developer vessel. The replenishing developer comprises 1 wt. part of a carrier and 2-50 wt. parts of a toner, wherein the carrier is a magnetic fine particle-dispersed resin carrier comprising at least inorganic compound particles and a carrier binder resin, and the toner has a weight-average particle size of 3 to 10 ?m and contains 1 to 40 wt. % of solid wax.

Abstract: A dry two-component developer for electrophotography comprising a carrier particle and a toner particle, wherein a toner water adsorption ratio (T) obtained by a following equation (1) for the toner particle ranges from 1.0 to 7.0 and a carrier water adsorption ratio (C) obtained by a following equation (2) is 20.0 or less, and a water adsorption ratio (T/C) expressed in a following equation (3) representing a relationship between the toner water adsorption ratio (T) and the carrier water adsorption ratio (C) is 5.0 or less; a toner water adsorption ratio (T)=a water adsorption amount (TH) of the toner particle/an N2 adsorption amount (TN) of the toner particle (1), a carrier water adsorption ratio (C)=a water adsorption amount (CH) of the carrier particle/an N2 adsorption amount (CN) of the carrier particle (2), and a water adsorption ratio (T/C)=a toner water adsorption ratio (T)/a carrier water adsorption ratio (C) (3).

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: The present invention provides a dry two-component type developer for electrophotography comprising a carrier particle and a toner particle, wherein a toner water adsorption ratio (T) obtained by a following equation (1) for the toner particle ranges from 1.0 to 7.0 and a carrier water adsorption ratio (C) obtained by a following equation (2) is 20.0 or less, and a water adsorption ratio (T/C) expressed in a following equation (3) representing a relationship between the toner water adsorption ratio (T) and the carrier water adsorption ratio (C) is 5.

Abstract: A carrier core material having a voltage breakdown of at least 300V, essentially consisting of a magnetite base powder, the particles of which are surrounded by an electrically insulating coating essentially free from organic material.

Abstract: An electrographic, two-component dry developer composition including charged toner particles and oppositely charged carrier particles which (a) includes: an combination of a soft magnetic material exhibiting a coercivity of at least 300 gauss when magnetically saturated, exhibit an induced magnetic moment of less than 20 EMU/gm of carrier when in an applied field of 1000 gauss and (b) a hard magnetic material exhibiting a coercivity of at least 300 gauss when magnetically saturated, exhibit an induced magnetic moment of at least 20 EMU/gm of carrier when in an applied field of 1000 gauss.

Abstract: A positively chargeable toner for two-component development comprising a resin binder; a colorant; a releasing agent comprising a wax having a melting point of 50° to 120° C.; and an external additive comprising a positively chargeable silica, the positively chargeable silica having an absolute deviation of an error of 0.1 or less, against an approximate straight line showing an adhesion state of silicon atoms to carbon atoms, and a free ratio of 5% or less, wherein the positively chargeable toner is usable together with a ferrite carrier having a saturation magnetization of from 40 to 100 Am2/kg. This positively chargeable toner is used for development of an electrostatic latent image formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.

Abstract: An electrographic, two-component dry developer composition comprising charged toner particles and oppositely charged carrier particles which (a) includes: a soft magnetic material exhibiting a coercivity of less than 300 gauss when magnetically saturated and (b) exhibit an induced magnetic moment of less than 20 EMU/gm of carrier when in an applied field of 1000 gauss; and a hard magnetic material exhibiting a coercivity of at least 300 gauss when magnetically saturated and (b) exhibit an induced magnetic moment of at least 20 EMU/gm of carrier when in an applied field of 1000 gauss.

Abstract: Disclosed are methods and apparatus for electrographic development which utilize a rotating magnetic core, a toner shell disposed around the rotating magnetic core, and developer compositions disposed on the toner shell which include a hard magnetic material, such as a strontium ferrite. The shell in embodiments has an outer surface with a surface roughness Ra of less than 32 microinches. The methods and apparatus do not require special manufacturing steps to place surface roughness or irregularities on the shell, and, thus, can provide the same or better image quality with relatively less complex manufacturing steps and at reduced cost.

Abstract: The invention concerns a new carrier core material having high voltage breakdown. The new material comprises a particulate ferrite base material having a substantially spherical particle shape, wherein the powder particles are coated with an inorganic, electrically insulating coating having a resistivity higher than that of the ferrite base material.

Abstract: The inventions concerns a new carrier core material consisting of particles of essentially pure, spherical magnetite. These particles are electrically insulated by an inorganic phosphorus containing coating.

Abstract: A ferrite carrier for electrophotographic developers which comprises ferrite particles with irregular, non-spherical configuration capable of forming a conductive magnetic chain, said carrier having the general formula