Abstract: A toner composition includes resin core particles having outer surfaces, and surface treatment, wherein the surface treatment includes at least first metal oxide particles having a surface area equivalent average particle diameter of greater than 25 nm and a surface energy of less than 28 erg/cm2, as determined by methanol wettability midpoint at 22° C., tacked to the outer surfaces of the resin core particles, at a concentration to provide a total projected area of the first metal oxide particles sufficient to cover at least 10% of the resin core particle outer surfaces area, and wherein the toner composition comprises less than 0.013 g non-tacked surface treatment per square meter of resin core particles outer surface. A developer for developing electrostatic images includes magnetic carrier particles and toner as described above, wherein the developer comprises less than 0.

Abstract: A coated carrier that peeling and wearing of a coating layer are hard to be generated and a method of manufacturing the coated carrier are provided. The coated carrier includes a core particle including a magnetic body, a first resin layer coating the core particle, a resin particle layer including a resin particle fixed to the first resin layer as a single layer, and a second resin layer. The first resin layer includes a first resin having a first reactive group. The resin particle layer is formed of resin particles including a cross-linking resin having a second reactive group which can undergo a cross-linking reaction with the first reactive group. The second resin layer is provided so as to fill gaps between the resin particles.

Abstract: The present disclosure relates to a process for preparing a polyester-based magnetic toner composition. The toner composition includes one or more polyester amorphous binder resins, optionally a crystalline polyester resin, and spherical barium iron oxide particles. In embodiments, the toner is prepared from barium iron oxide particles that are in a dispersion including water and a dispersant. In yet other embodiments, the process may be conducted under an inert gas such as argon to avoid oxidation of the ferromagnetic particles during toner preparation.

Abstract: A magnetic toner which has superior charging stability and charging uniformity, maintains stable developing performance without any dependence on service environments and may less cause any decrease in image density and any image defects such as fog and ghost, the magnetic toner has magnetic toner particles, each of the magnetic toner particles has magnetic toner base particle containing a binder resin and a magnetic material, and an inorganic fine powder, (a) the magnetic toner having, at a frequency of 100 kHz and a temperature of 30° C., a dielectric loss factor (??) of 2.5×10?1 pF/m or more and 7.0×10?1 pF/m or less and a dielectric dissipation factor (tan ?L) of 3.0×10?2 or less, (b) the magnetic toner having, in a dielectric dissipation factor (tan ?) thereof at a frequency of 100 kHz, a maximum value (tan ?H) within the temperature range of 60° C. to 140° C.; and the tan ?H and the tan ?L satisfying (tan ?H?tan ?L)?3.0×10?2.

Abstract: An anisotropic magnetic material-dispersed resin carrier including: fine magnetic particles; and a binder resin in which at least the fine magnetic particles are dispersed, wherein the anisotropic magnetic material-dispersed resin carrier has a magnetic anisotropy where magnetic fields of the fine magnetic particles are orientated in the same direction, and wherein the anisotropic magnetic material-dispersed resin carrier has a saturation magnetization of 16 emu/g to 30 emu/g, a coercive force of 15 kA/m to 40 kA/m, and a number average particle diameter of 15 ?m or more but less than 100 ?m.

Abstract: Provided is a magnetic toner capable of preventing electrostatic offset while attaining a high image quality by a high speed machine. The magnetic toner comprises magnetic toner particles, each of which contains a binder resin and a magnetic material, and a fine inorganic powder, in which the binder resin contains a polyester unit, and the magnetic toner has a dielectric loss factor at 40° C. and 100 kHz of 0.40 pF/m or more but 1.00 pF/m or less and a dielectric loss factor at 150° C. and 100 kHz of 0.50 pF/m or more but 4.00 pF/m or less.

Abstract: A toner for electrophotography comprising a charge control agent comprising a specified iron-azo complex or a specified metal compound of a benzilic acid derivative, a colorant, and a resin binder comprising a polyester, the polyester being a polyester obtained by polycondensing an alcohol component containing a propylene oxide adduct of bisphenol A and a carboxylic acid component, wherein the propylene oxide adduct of bisphenol A has an average mole of propylene oxide added of from 2.4 to 4.0, and wherein an adduct with 2 mol of propylene oxide is contained in an amount of 60% by mol or less, and an adduct with 4 mol of propylene oxide is contained in an amount of 10% by mol or more, of the propylene oxide adduct of bisphenol A, and wherein the propylene oxide adduct of bisphenol A has a content ratio of primary hydroxyl groups of 10% by mol or less of the entire hydroxyl groups.

Abstract: To provide a toner excellent in low-temperature fixability, releasing performance, and development stability in long-term use under a high-temperature and high-humidity environment, provided is a magnetic toner including: magnetic toner particles each containing at least a binder resin and a magnetic particles; and an inorganic fine powder, in which: the magnetic particles is a treated magnetic particles treated with a silane compound; the treated magnetic particles has a water adsorption per unit area based on a BET specific surface area of 0.300 mg/m2 or less; portion of styrene extractables constitutes 25 mass % or less among the silane compound in the treated magnetic particles; and the silane compound with which the treated magnetic particles is treated contains a compound having a hydrocarbon group having 2 or more and 4 or less carbon atoms as a main component.

Abstract: The present invention relates to a magnetic carrier for an electrophotographic developer comprising spherical composite particles comprising spherical composite core particles comprising at least ferromagnetic iron oxide fine particles and a cured phenol resin and having an average particle diameter of 1 to 100 ?m, and a melamine resin coating layer formed on the respective core particles, wherein a ratio of R100 to R300 (R100/R300) in which R100 is an electric resistance value as measured when applying a voltage of 100 V to the magnetic carrier; and R300 is an electric resistance value as measured when applying a voltage of 300 V to the magnetic carrier, is controlled to lie within the range of 1 to 50.

Abstract: The present disclosure relates to a magnetic toner composition. The toner composition includes one or more resins, and spherical ferromagnetic nanoparticles. Also provided is a process for preparing these toners including ferromagnetic nanoparticles. In embodiments, the aggregation of the toner is conducted at a pH greater than about 7, without the use of a coagulant. Additionally, in embodiments, freezing (stopping particle growth) and coalescence of the toner particles may be conducted at a pH greater than about 9. In yet other embodiments, the process may be conducted under an inert gas such as argon to avoid oxidation of the ferromagnetic nanoparticles during toner preparation.

Abstract: A toner including stabilized magnetic single-crystal nanoparticles, wherein the value of the magnetic anisotropy of the magnetic nanoparticles is greater than or equal to 2×104 J/m3. The magnetic nanoparticle may be a ferromagnetic nanoparticle, such as FePt. The toner includes a magnetic material that minimizes the size of the particle, resulting in excellent magnetic pigment dispersion and dispersion stability, particularly in emulsion/aggregation toner processes. The smaller sized magnetic particles of the toner also maintains excellent magnetic properties, thereby reducing the amount of magnetic particle loading required in the toner.

Abstract: The present invention relates to magnetic composite particles comprising at least magnetic fine particles and a bio-based polymer, wherein the magnetic composite particles have an average particle diameter of 10 to 100 ?m, and a content of the magnetic fine particles in the magnetic composite particles is 50 to 99.9% by weight; a magnetic carrier; and a developer. The magnetic composite particles, magnetic carrier and developer according to the present invention are effective for reduction of environmental burden such as saving of underground sources and prevention of global warming, have a high safety for human bodies and a high durability, and are capable of forming developed images with a high quality.

Abstract: A carrier including a magnetic core particle and a resin layer covering a surface of the magnetic core particle. The magnetic core particle is a ferrite particle including strontium in an amount of 0.005 to 3% by mass, measured by fluorescent X-ray spectroscopy. The resin layer comprises a resin obtained by heating a copolymer comprising a silicon-containing unit A and another silicon-containing specific unit B.

Abstract: The object of the present invention is to provide a magnetic toner enabling an image with high image density and excellent image reproducibility to be obtained, which is excellent in fluidity, charging stability, and charging uniformity, even for long-term use, and also enabling an image whose fogging, ghost, and scattering are suppressed to be obtained. The magnetic toner has at least a binder resin and a magnetic material, where, the magnetic material is an magnetic iron oxide whose dielectric breakdown voltage of the magnetic material is 160 to 1600 V/cm, and the dielectric loss tangent (tan ?) of the magnetic toner at 100 kHz and 40° C. is 2.0×10?3 to 1.0×10?2.

Abstract: A magnetic toner is provided that exhibits an excellent dot reproducibility and developing performance after being allowed to stand in a high temperature and high humidity environment and an excellent low-temperature fixability. The magnetic toner has an inorganic fine powder and a magnetic toner particle containing a binder resin, a magnetic body, and a release agent, wherein in a stress relaxation measurement using a rotating plate rheometer, the magnetic toner exhibits a yield value A at 25° C. of at least 3×106 (sec), and the magnetic toner that has been heated to 80° C. and then cooled to 25° C. exhibits a yield value B at 25° C. of not more than 1×105 (sec).

Abstract: An electrophotographic developer including: magnetic particles, and a toner containing toner particles charged with the magnetic particles and having a particle diameter distribution, wherein the toner exhibits cumulative toner weight distributions of both square of charge amount q2 [C2] and attachment force F [N] per particle with respect to a representative toner particle diameter in the particle diameter distribution, giving a linear approximation of plots of the attachment force F [N] versus the square of charge amount q2 [C2] per particle at a plurality of corresponding cumulative toner weight ratios, and the linear approximation satisfies a slope of the linear approximation of from 5×1020 to 3×1022 and a squared multiple correlation coefficient (R2) of 0.6 or more. As a result, the developer allows good control of transferability under the control of an electric field and allows a reduction in transfer residual amount of the toner.

Abstract: A method and system for printing documents with one or more embedded security features is provided. Security features are embedded in the document by co-printing magnetic and non-magnetic toner on a receiver before fixation by a fixing station. The combination of magnetic and non-magnetic toners in the image results in image elements that easily show alteration or are undetectable by visual means.

Abstract: The invention provides a color toner for flash fusing containing at least: a binder resin, a colorant, a leuco dye, a developer and a decolorizer. An absorbance of the color toner after photoirradiation at a wavelength of about 900 nm is smaller than an absorbance of the color toner before the photoirradiation at the wavelength of about 900 nm. The invention further provides a method for producing the color toner, a electrostatic image developer comprising the color toner, a process cartridge comprising a developer bearing body which accommodates the electrostatic image developer, and an image forming apparatus to form a toner image by the electrostatic image developer.

Abstract: Nano-sized particles for use in making emulsion aggregation toner particles have a core portion and a shell portion, wherein the core portion of the nano-sized particles includes crystalline resin and the shell portion includes amorphous resin and is substantially to completely free of the crystalline resin.

Abstract: When being blended particularly in a color toner, a barium titanate external additive for toner enhances the toner fluidity, electrical properties, and other relevant performance; concurrently achieves high image density and reduced background fog in a color printer using the toner; and further retains high image quality even under a high-temperature high-humidity environment and a low-temperature low-humidity environment. An industrially advantageous producing method of the barium titanate external additive for toner is also provided. The external additive for toner of the present invention includes spherical barium titanate having undergone coating treatment with a hydrophobicizing agent.

Abstract: A toner which can efficiently induce high-frequency magnetic induction heating by Neel relaxation and/or Brown relaxation is provided. A toner including a core particle containing a thermoplastic polymer material and superparamagnetic ferrite fine particles having a particle diameter of less than 100 nm which adhere to the surfaces of the core particle is manufactured by directly forming the superparamagnetic ferrite fine particles having a particle diameter of less than 100 nm on the surfaces of the core particle so that the superparamagnetic ferrite fine particles having a particle diameter of less than 100 nm are not in contact with each other. As a result, the toner is prevented from being scattered due to the influence of a magnetic field, so that a high quality image is formed.

Abstract: An electrophotographic developer is provided which includes: a toner that includes toner base particles and an external additive attached to a surface of the toner base particles and has an amount of Al on the surface of the toner base particles of from about 0.002 to about 0.02 atm %; and a carrier that includes magnetic particles and a coating resin layer that coats the magnetic particles, the coating resin layer including particles with a volume-average particle diameter of from about 80 to about 800 nm, such as organic particles or inorganic particles having an organic layer on a surface of the inorganic particles, the carrier satisfying any one of the following formulas, where SP1, SP2 and SP3 represent a solubility parameter of resin of the coating resin layer, the organic particles, and the organic layer respectively: about 10>|SP1?SP2|>about 4??(1); and about 10>|SP1?SP3|>about 4??(2).

Abstract: The present invention provides an electrostatic latent image developing toner including a binding resin having an acidic polar group, a magnetic powder, and a carboxylic acid group-containing compound, the toner having a shape factor (SF1) of 110 to 140, wherein the carboxylic acid group-containing compound has a weight-average molecular weight of 1800 to 50,000 and an acid value of 150 to 600 mg KOH/g.

Abstract: In a magnetic toner which has magnetic toner base particles containing at least a binder resin and a magnetic material, and an inorganic fine powder, (i) the magnetic toner has an average circularity of from 0.950 or more to 1.000 or less, (ii) the magnetic toner has a compressibility of 30 or less, and (iii) the magnetic toner contains boron nitride particles having a median diameter (D50) of from 0.5 ?m or more to 8.0 ?m or less, as the inorganic fine powder in an amount of from 0.05 part by mass or more to 1.00 part by mass or less based on 100 parts by mass of the magnetic toner base particles. This provides a magnetic toner with which stable image density can be achieved without regard to service environment and which do not cause any image defects such as fog.

Abstract: A magnetic toner is disclosed including magnetic toner particles containing at least a binder resin and a magnetic powder. The magnetic powder contains a specific amount of phosphorus elements, and a specific amount of silicon elements, based on the iron element, with the ratio of the phosphorous element to the silicon elements being in a specific range, and has a specific volume-average particle diameter, a specific saturation magnetization in a specific magnetic field, and a specific residual magnetization. The magnetic toner can realize high image density and reduce fog and spots around line images regardless of environmental variation, and is superior in durability, and besides, can achieve small toner consumption.

Abstract: The present invention provides a toner for developing an electrostatic latent image comprising at least a core layer including at least a coloring agent and a first binder resin, and a shell layer for covering the core layer and including a second binder resin, wherein two local maximum values of the tangent loss (tan ?) of the dynamic visco-elasticity are present in a temperature range of 90° C. or less, with one of the local maximum values present in a range of less than 60° C., and the other local maximum value present in a range of 60° C. or more and 90° C. or less. Moreover, a production method for the toner for developing an electrostatic latent image, a developer for developing an electrostatic latent image, using the toner, and an image forming method are provided.

Abstract: To provide a toner which allows low temperature fixation irrespective of the configuration of a fuser, which is excellent in offset resistance, and which provides high image quality at high and low humidities in a stable manner without causing any image defect over time. A toner containing: a binder resin and a colorant; in which the toner contains a THF-soluble component to be dissolved in tetrahydrofuran (THF); the binder resin component contained in the THF-soluble component contains: a vinyl resin unit (I) formed by at least a carboxyl group-containing vinyl resin and an epoxy group-containing vinyl resin and having an epoxy value of 0.001 to 1.

Abstract: A method for producing a low density resin-coated carrier having a small resin amount to a carrier core material and having a uniform resin coating layer formed on the carrier core material is provided. A resin-coated carrier has a carrier core material and a resin coating layer formed on the surface of the carrier core material. The carrier core material has pores and an apparent density of 1.6 g/cm3 to 2.0 g/cm3 and a remanent magnetization of 10 emu/g of less. The resin coating layer is formed by a dry process of adhering resin particles to a surface of the carrier core material and applying heat and impact force to the resin particles. A volume average particle size of the resin particles is less than 1 ?m. A two-component developer containing the resin-coated carrier is charged in a developing device in an image forming apparatus, and an image is formed.

Abstract: Provided is magnetic toner including capsule type toner particles each having a surface layer (B) on a surface of a toner base particle (A) containing at least a binder resin (a) mainly formed of a polyester, a magnetic substance, and a wax, in which, the surface layer (B) includes a resin (b), and the resin (b) includes a resin selected from the group consisting of a polyester resin (b1), a vinyl resin (b2), and a urethane resin (b3); a glass transition temperature Tg(a) of the binder resin (a) and a glass transition temperature Tg(b) of the resin (b) satisfy a relationship of Tg(a)<Tg(b); a magnetization (?t) in an external magnetic field of 79.6 kA/m of the magnetic toner is 12 Am2/kg or more and 30 Am2/kg or less; and an average circularity of the toner is 0.960 or more and 1.000 or less.

Abstract: A developing apparatus is provided which can suppress a fluctuation in image density in a discontinuous printing mode provided with a pause period. The developing apparatus includes a developer for developing an electrostatic latent image on a photosensitive drum, a developer bearing member for carrying and conveying the developer and a developer layer thickness-regulating unit placed close to the developer bearing member for regulating the amount of the developer carried and conveyed by the developer bearing member, the developer layer thickness-regulating unit being. As the developer, a negatively chargeable, one-component, magnetic toner is used having magnetic toner particles containing a binder resin and a magnetic iron oxide particle, and has a specific saturation magnetization, specific weight-average particle diameter and specific composition.

Abstract: The invention provides a developer for developing an electrostatic latent image, the developer having at least: a transparent toner; and a carrier. The carrier contains at least: a magnetic particle; and a resin coating layer. The resin coating layer coats the surface of the magnetic particle and has cyan color. The invention further provides a developer cartridge storing the developer. The invention further provides a process cartridge storing the developer. The invention further provides an image formation apparatus having at least a color toner image-forming unit, a transparent toner image-forming unit that uses the developer to form a transparent toner image, and a fixing unit.

Abstract: The invention relates to an image forming media composition including an infrared reflecting pigment. The infrared reflecting pigment may be one that substantially absorbs light in the visible spectrum of about 400-700 nanometers and reflects greater than about 5.0% of light within the wavelength of about 700-2500 nanometers. The infrared reflecting pigment may therefore be combined with pigments such as carbon black in a toner formulation and provide the ability to control toner thickness level within a device such as a toner patch sensor.

Abstract: The present invention relates to black magnetic iron oxide particles having an average particle diameter of 0.05 to 2.0 ?m and an electric resistance value at an applied voltage of 100 V of not less than 1×108 ?·m; and a magnetic carrier for electrophotographic developer comprising spherical magnetic composite particles obtained by dispersing black magnetic iron oxide particles in a binder resin, wherein the magnetic carrier has an electric resistance value R100 at an applied voltage of 100 V of 1×108 to 1×1014 ?·m, and an electric resistance value R300 at an applied voltage of 300 V which satisfies the relationship represented by the formula: 0.1?R300/R100?1.

Abstract: The present invention provides a magnetic mono-component toner which can suppress a selection development on a latent image carrier and can maintain favorable image properties for a long period by using a toner having the coarse powder distribution (S) within a given range in a jumping developing method and an image forming method which uses the toner. In the toner used in the jumping developing method which develops an electrostatic latent image formed on a latent image carrier using a developer carrier, the toner includes toner particles which contain at least a binding resin and a magnetic powder, and the coarse powder distribution (S) of the toner particles satisfies a following formula (1). Coarse powder distribution (S)=(50?A)/2?17 (volume %/?m)??(1) (wherein, A is a volume % of the coarse powder having particle sizes larger than D50 based on volume by 2 ?m or more).

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: Magnetic toner involves magnetic powder 1 having the particle shape of an octahedron 2 that is a convex polyhedron surrounded by eight triangles as a basis, each of the vertexes and edges of the octahedron being in a curved surface shape, and having a portion 3 that can be taken as a straight line on the outer periphery of its projected image. Therefore, the magnetic toner is superior in both two contradictory properties, that is the property of making it easy for a charging amount to quickly rise as well as improving the charging amount and the property of making it difficult for charge-up to occur, thereby making it possible to form a good image under a wide environment. In an image forming method, an electrostatic latent image is developed into a toner image by a magnetic one-component jumping developing method using the magnetic toner.

Abstract: The object is to provide a magnetic toner with which toner scattering, toner spent to carrier, development of scratch streaks by the magnetic brush on the photoreceptor drum can be prevented for a prolonged period and a good image characteristic (in image density and background fogging) can be maintained for a prolonged period, and an image forming method using the magnetic toner. A two-component developer comprising carriers and toner which contains magnetic particle at least in a binder resin thereof, the magnetic particle being of basically polyhedral shaped shape, vertexes and edges of said polyhedral shape being curved surfaces, said shape having peripheral parts taken as straight lines in a projected image thereof, saturation magnetization of said toner in a magnetic field of 79.6 kA/m being 4.0 to 15.

Abstract: The toner of the present invention is characterized in that the charges rise up rapidly, the charge quantity is not insufficient nor excessive, the photoreceptor contamination is minimized and the toner is endurable under harsh conditions and against the high stress usage. The magnetic particle contained in the toner is of average particle size 0.01 ?m through 0.50 ?m, is of octahedron shape that is a convex polyhedron surrounded by eight triangles as a basis, each of vertexes and edges of the octahedron being in a curved surface shape and having a portion that can be taken as a straight line on the outer periphery of a projected image of said octahedron. The sphericity of the toner is 0.94 through 0.98. Here, the sphericity is defined by C2/C1, where C1 is a circumferential length of an image projected on a plane and C2 is a circumferential length of an assumed circle area as same as that of the projected image. Further, a number content of the toner of particle size 0.6 ?m through 2.

Abstract: The present invention provides a toner for electrostatic charge development comprising an amorphous polyester resin, a releasing agent, and magnetic metal particles covered with a resin the main component of which is a crystalline polyester resin.

Abstract: The present invention relates to a magnetic mono-component toner composition with positive charge comprising i) a magnetic toner particle containing a charge control agent with positive charge; ii) a hydrophobic silica with negative charge; iii) a fluorinated organic fine powder; and iv) a metal oxide fine powder containing 20 to 80 wt % of tin oxide. The toner has an advantageous in the extended life of the drum, reduction of the background contamination, and improvement of long-term reliability, and thus can be used effectively for image forming apparatus.

Abstract: In a magnetic toner which has magnetic toner base particles containing at least a binder resin and a magnetic material, and an inorganic fine powder, (i) the magnetic toner has an average circularity of from 0.950 or more to 1.000 or less, (ii) the magnetic toner has a compressibility of 30 or less, and (iii) the magnetic toner contains boron nitride particles having a median diameter (D50) of from 0.5 ?m or more to 8.0 ?m or less, as the inorganic fine powder in an amount of from 0.05 part by mass or more to 1.00 part by mass or less based on 100 parts by mass of the magnetic toner base particles. This provides a magnetic toner with which stable image density can be achieved without regard to service environment and which do not cause any image defects such as fog.

Abstract: Provided is a developer for replenishment capable of forming a high-quality image even upon duration. The developer for replenishment includes at least a toner and a magnetic carrier, and in the developer for replenishment, 1 part by mass of the magnetic carrier is blended with 2 to 50 parts by mass of the toner, and the magnetic carrier contains a ferrite core and a resin component, has a true specific gravity of 2.5 to 4.2 g/cm3, has a 50% particle diameter on a volume basis (D50) of 15 to 70 ?m, and has an average circularity of 0.850 to 0.950, the average circularity having a coefficient of variation of 1.0 to 10.0%.

Abstract: An image-forming method is provided which can provide stable image density irrespective of use environments and does not cause image defects such as fogging, tailing, or transfer voids, even when being applied to a developing sleeve with a reduced diameter. In the image-forming method, a latent image bearing member and a toner bearing member bearing a magnetic toner on its surface and having inside a unit for generating a magnetic field are placed with a predetermined interval, and an alternating field is applied between the latent image bearing member and the toner bearing member, and an electrostatic latent image borne by the latent image bearing member is developed with the magnetic toner. The toner bearing member has a specific diameter, and the magnetic toner has a specific circularity and a specific compressibility. The total energy of the toner measured with a powder flowability measuring apparatus satisfies a specific value.

Abstract: According to the present invention, a magnetic toner comprising magnetic toner particles including at least a binder resin and magnetic particles is provided, wherein an isoelectric point of the magnetic particles is pH 4.0 or less, in order to provide a magnetic toner stably having an optimum charged amount regardless of environments so that a high-quality image having high blackness can be formed without causing any ghost phenomenon.

Abstract: The present invention provides a magnetic mono-component toner which can suppress a selection development on a latent image carrier and can maintain favorable image properties for a long period by using a toner having the coarse powder distribution (S) within a given range in a jumping developing method and an image forming method which uses the toner. In the toner used in the jumping developing method which develops an electrostatic latent image formed on a latent image carrier using a developer carrier, the toner includes toner particles which contain at least a binding resin and a magnetic powder, and the coarse powder distribution (S) of the toner particles satisfies a following formula (1).

Abstract: A magnetic one-component toner of the invention contains at least a binding resin and a magnetic powder, and has a volume average particle size of 6.0 to 9.0 ?m, a compressibility of 15 to 50%, and a mean roundness of 0.950 to 0.960. The magnetic powder has at its surface a phosphorus element of 0.10 to 0.50% by weight. This toner is suitable for use in an image forming apparatus provided with a developer carrier made of stainless steel, or an image forming apparatus provided with an amorphous silicon photosensitive material. This toner has high transfer efficiency and less fog, thereby enabling to maintain image density for a long period of time, and form high image-quality image.

Abstract: To provide a magnetic toner which is excellent in durability and developability even in the case of being applied to high-speed developing process or being used in a large-capacity process cartridge amount of toner in which is increased, and which has high degree of blackness. Provided is a magnetic toner having magnetic toner particles containing at least a binder resin and magnetic material particles each comprising a predetermined amount of a titanium compound, characterized in that: 1) the magnetic material particles have a predetermined amount of adsorbed moisture at a relative vapor pressure of 50%; and 2) a difference between the amount of moisture adsorbed to the magnetic material particles in an adsorbing process for increasing a relative vapor pressure and the amount of moisture adsorbed to the magnetic material particles in a desorbing process for reducing a relative vapor pressure is reduced.

Abstract: The present invention provides a one-component magnetic toner for developing an electrostatic charge image, which do not cause an image defect by toner aggregation or fusion even though a device is miniaturized and the processing speed of the device is accelerated, and which allows easy recycling of a toner cartridge. The one-component magnetic toner for developing an electrostatic charge image of the present invention is one comprising: toner particles comprising fine magnetic particles (A) and a binder resin; and fine magnetic particles (B) externally added to the toner particles, in which the maximum permeability (?mA) of the fine magnetic particles (A) contained in the toner particles and the maximum permeability (?mB) of the fine magnetic particles (B) externally added to the toner particles satisfy a relationship represented by the following formula (1) ?mB/?mA?1.8 .

Abstract: An electrostatic developing toner which can effectively suppress image fogging*1 by setting a ratio (d/D) of the average particle diameter D of the toner and the average particle diameter d of iron oxide particles contained in the toner as a colorant to within a predetermined range, and by setting the value of a ratio (?r/?s) between the residual magnetization ?r and saturation magnetization ?s of the iron oxide particles to a predetermined value or less, is provided. The value of the ratio (d/D) of the average particle diameter D of the toner and the average particle diameter d of iron oxide particles contained in the toner as a colorant is set to within the range of 0.01-0.03, and the value of the ratio (?r/?s) between the residual magnetization ?r and saturation magnetization ?s of the iron oxide particles is set to 0.3 or less.

Abstract: In a toner comprising toner particles which comprise toner base particles containing at least a binder resin and a magnetic material, and inorganic fine particles, the toner base particles have been obtained through a pulverization step; and, the toner base particles having a circle-equivalent diameter of from 3 ?m or more to 400 ?m or less as measured with a flow type particle image analyzer have an average circularity of from 0.935 or more to less than 0.970; and the toner base particles have an average surface roughness of from 5.0 nm or more to less than 35.0 nm as measured with a scanning probe microscope. The toner can enjoy less toner consumption per sheet of images, can achieve a long lifetime in a smaller quantity of toner, and has superior developing performance in any environment.