Abstract: The magnetic toner contains: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles comprise strontium titanate fine particles and metal oxide fine particles, and the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles. In addition, the magnetic toner has a characteristic state of coverage, by the inorganic fine particles, of the magnetic toner particle surface, and the ratio [D4/D1] of the weight-average particle diameter (D4) to the number-average particle diameter (D1) is in a prescribed range.

Abstract: A magnetic toner includes: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles that are present on the surface of the magnetic toner particles and are not a magnetic iron oxide and magnetic iron oxide particles that are present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles; when a coverage ratio A (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles th

Abstract: A magnetic toner is provided that exhibits an excellent electrostatic offset resistance both initially and after long-term use. The magnetic toner contains: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain a prescribed metal oxide fine particle in a prescribed proportion; the magnetic toner has prescribed numerical value ranges for a coverage ratio A of the magnetic toner particle surface covered by the inorganic fine particles and for a coverage ratio B by the inorganic fine particles that are fixed to the magnetic toner particle surface; the magnetic toner particle contains a crystalline polyester; and measurement of the magnetic toner with a differential scanning calorimeter provides a characteristic differential scanning calorimetric curve.

Abstract: The developing apparatus includes a toner, a developing container, a developing roller, and a toner layer thickness controlling member, wherein the toner contains toner particles containing a binder resin and a colorant, and silica fine particles; the covering rate X1 of the surface of each of the toner particles with the silica fine particles is 40.0 to 75.0 area %; and a diffusion index represented by X1/X2 satisfies a predetermined range where the theoretical covering rate with the silica fine particles is defined as X2, the developing roller includes a substrate, a base layer, and a coverage portion; and the volume resistivity of the coverage portion and the average thickness of the coverage portion are within predetermined ranges.

Abstract: Provided is a developing apparatus, including: a toner for developing an electrostatic latent image; a toner carrier for carrying the toner; and a regulating member for regulating a layer thickness of the toner carried by the toner carrier, in which: the toner includes a toner containing toner particles each containing a binder resin and a magnetic material, and inorganic fine particles present on surfaces of the toner particles; the toner has a dielectric loss factor (??) at a frequency of 100 kHz and a temperature of 30° C. of 0.03 pF/m or more and 0.30 pF/m or less; the toner carrier includes a substrate, an elastic layer, and a surface layer containing a urethane resin; and the urethane resin has a partial structure derived from a reaction between a compound represented by the structural formula (1) and a polyisocyanate.

Abstract: It is intended to provide toner that has favorable fixability, releasability and few negative effects on images. The present invention provides toner including toner particles each containing a binder resin, a colorant and an ester wax, and silica fine particles, wherein: the ester wax contains a plurality of esters represented by R1-COO—(CH2)x1—OOC—R2, or R3-OOC—(CH2)x2—COO—R4; (i) when an ester whose content is maximum is designated as “ester A”, a content of the ester A in the ester wax is 40-80%, and (ii) when the ester A has a molecular weight M1, a content of an ester having a molecular weight of M1×0.8-M1×1.2 in the ester wax is 90% or larger; a coverage ratio X1 of the surface of the toner particles with the silica fine particles is 40.0-75.0%; and when a theoretical coverage ratio is defined as X2, a diffusion index (X1/X2) satisfies the following: X1/X2??0.0042×X1+0.62.

Abstract: It is intended to provide magnetic toner that produces a stable image density in long-term use and can prevent ghosting under conditions of low-temperature and low-humidity. The present invention provides magnetic toner including magnetic toner particles each containing a binder resin, a magnetic material and a releasing agent, and silica fine particles, wherein the silica fine particles include silica fine particles A and B, the silica fine particles A have a number-average particle size of 5-20 nm as primary particles, the silica fine particles B are produced by a sol-gel method, and have a number-average particle size of 40-200 nm as primary particles, an abundance ratio of secondary particles of the silica fine particles B is 5-40% by number, and a coverage ratio X1 of the surface of the magnetic toner particles with the silica fine particles determined by ESCA is 40.0-75.0% by area.

Abstract: The present invention provides a developing apparatus including a toner, a toner carrying member and a regulating member, wherein the toner is a magnetic toner including a toner particle, a first fine silica particle having a number average primary particle diameter of 5 to 20 nm and a second fine silica particle having a number average primary particle diameter of 40 to 200 nm, the second fine silica particle is a fine silica particle produced by a sol-gel method, the toner has a total energy of 270 to 355 mJ/(g/ml), the toner carrying member has a substrate, an elastic layer and a surface layer including a urethane resin, and the urethane resin has a partial structure derived from a reaction of a particular amine type compound with a polyisocyanate.

Abstract: Provided is a developing apparatus, including toner for developing an electrostatic latent image, a toner carrier for carrying the toner, and a regulating member for regulating a layer thickness of the toner carried by the toner carrier. The toner carrier is placed to be brought into contact with the electrostatic latent image bearing member. The toner carrier includes a substrate, an elastic layer, and a surface layer containing a urethane resin. The urethane resin has a partial structure derived from a reaction between a compound represented by the structural formula (1) and a polyisocyanate. The toner contains toner particles each containing a binder resin and a magnetic material, and inorganic fine particles. The toner has a weight average particle diameter (D4) of from 9.5 ?m to 14.0 ?m. The toner has a porosity of 50 or more and 56 or less.

Abstract: A developing apparatus and a developing method that significantly suppress generation of fogging and form a high-quality electrophotographic images under any environments such as a high temperature and high humidity environment and a low temperature and low humidity environment are provided. A toner wherein a covering rate X1 of the surface of a toner particle with silica fine particles, which is determined by ESCA, is 40.0 to 75.0 area %, and the diffusion index represented by (Expression 1) diffusion index=X1/X2 satisfies (Expression 2) diffusion index??0.0042×X1+0.62 where in the theoretical covering rate with the silica fine particles is defined as X2; and a developing apparatus including a developing carrying member which is a surface layer formed of a urethane resin having a partial structure derived from a reaction of a polyisocyanate with a compound represented by Formula 1.

Abstract: A toner has toner particles including a binder resin, a colorant, an ester wax and a hydrocarbon wax; and inorganic fine particles. The ester wax includes an ester compound having a structure represented by formula (1): R1—CO—O—(CH2)x—O—OC—R2; or formula (2): R3—O—OC—(CH2)x—CO—O—R4. The ester wax includes an ester compound having a highest abundance rate in an amount of 40% to 80% by mass with respect to a total amount of the ester wax in a composition distribution. The ester wax has, in differential scanning calorimetry, a peak top temperature of an endothermic peak of 65° C. to 80° C. In differential scanning calorimetry, the toner has only one endothermic peak derived from the waxes. A relationship: 3.0?(Tw?Tt)?8.0 is satisfied.

Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body, and inorganic fine particles present on the surface of the magnetic toner particles, wherein a ratio of coverage of the magnetic toner particles' surface by the inorganic fine particles is in a prescribed range for the magnetic toner, the inorganic fine particles contain prescribed metal oxide fine particles, with at least 85 mass % of the metal oxide fine particles being silica fine particles, the coefficient of variation on the coverage ratio A is in a prescribed range, the binder resin contains a styrene resin, in a GPC measurement of a THF-soluble matter in the magnetic toner, a peak molecular weight (Mp) of a main peak is in a prescribed range, and a prescribed fatty acid ester compound is incorporated as a release agent.

Abstract: A magnetic toner includes: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles that are present on the surface of the magnetic toner particles and are not a magnetic iron oxide and magnetic iron oxide particles that are present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles; when a coverage ratio A (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particles' surface by the inorganic fine particles th

Abstract: The magnetic toner contains: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles comprise strontium titanate fine particles and metal oxide fine particles, and the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles. In addition, the magnetic toner has a characteristic state of coverage, by the inorganic fine particles, of the magnetic toner particle surface, and the ratio [D4/D1] of the weight-average particle diameter (D4) to the number-average particle diameter (D1) is in a prescribed range.

Abstract: A magnetic toner including: magnetic toner particles containing a binder resin, a magnetic body, and a release agent; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein the magnetic toner has a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles fixed to the magnetic toner particles' surface that reside in prescribed numerical value ranges; the binder resin contains a styrene resin; the re

Abstract: A magnetic toner is provided that exhibits an excellent electrostatic offset resistance both initially and after long-term use. The magnetic toner contains: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain a prescribed metal oxide fine particle in a prescribed proportion; the magnetic toner has prescribed numerical value ranges for a coverage ratio A of the magnetic toner particle surface covered by the inorganic fine particles and for a coverage ratio B by the inorganic fine particles that are fixed to the magnetic toner particle surface; the magnetic toner particle contains a crystalline polyester; and measurement of the magnetic toner with a differential scanning calorimeter provides a characteristic differential scanning calorimetric curve.

Abstract: An object of the present invention is to provide a developing apparatus which is less affected by usage environments, has high development efficiency for long term use and can provide a high quality image without image density non-uniformity. The present invention relates to a developing apparatus wherein a magnetic toner-carrying member has a work function value at the surface thereof within a specific range, a toner regulating member which regulates toner carried on the magnetic toner-carrying member is made of a specific material at a portion contacting the magnetic toner, the magnetic toner has an average circularity of 0.950 or more and the magnetic toner has a surface tension index within a specific range.

Abstract: A magnetic toner containing: magnetic toner particles containing a binder resin and a magnetic body; and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain silica fine particles and alumina fine particles and/or titania fine particles; a coverage ratio A of the magnetic toner particles' surface by the inorganic fine particles each of which has a particle diameter of from 5 nm to not more than 50 nm and a coverage ratio B of the magnetic toner particles' surface by the inorganic fine particles each of which has a particle diameter of from at least 5 nm to not more than 50 nm and is fixed to the magnetic toner particles' surface, have prescribed values and a prescribed relationship in the magnetic toner; and alumina fine particles and/or titania fine particles each of which has a particle diameter of from at least 100 nm to not more than 800 nm is present on the surface of the magnet

Abstract: A magnetic toner contains magnetic toner particles containing a binder resin, a release agent, and a magnetic body and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles contain metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, the coverage ratio of the magnetic toner particles' surface by the inorganic fine particles and the coverage ratio by the inorganic fine particles fixed to the magnetic toner particles' surface reside in a prescribed relationship, the binder resin contains a polyester resin, the release agent contains an ester compound, and an endothermic peak for the magnetic toner

Abstract: The magnetic toner includes magnetic toner particles comprising a binder resin and a magnetic body and inorganic fine particles present on the surface of the magnetic toner particles, wherein the inorganic fine particles present on the surface of the magnetic toner particles comprise metal oxide fine particles, the metal oxide fine particles containing silica fine particles, and optionally containing titania fine particles and alumina fine particles, and a content of the silica fine particles being at least 85 mass % with respect to a total mass of the silica fine particles, the titania fine particles and the alumina fine particles, wherein; when a coverage ratio A (%) is a coverage ratio of the magnetic toner particle's surface by the inorganic fine particles and a coverage ratio B (%) is a coverage ratio of the magnetic toner particle' surface by the inorganic fine particles that are fixed to the magnetic toner particle's surface, the magnetic toner has a coverage ratio A, a coefficient of variation on the