A developing device including: a developer; and a developing member configured to carry the developer on a surface thereof, the developing roller including an electro-conductive substrate and a single-layer elastic layer serving as a surface layer on the substrate, the surface layer comprising a binder resin, and the binder resin contains a crosslinked urethane resin and a crosslinked acrylic resin, the crosslinked urethane resin and the crosslinked acrylic resin form an interpenetrating polymer network structure in a first region from an outer surface of the surface layer to a position at a depth of 0.1 μm from the outer surface, wherein the developer contains developer particles each containing at least a binder resin and a magnetic substance.

A toner for developing an electrostatic charge image contains toner particles containing at least one binder resin; the Mg element in an amount such that the net intensity of x-ray fluorescence from the Mg element in the toner is 0.10 kcps or more and 1.20 kcps or less; and at least one external additive including particles of a metal salt of a fatty acid.

A toner for developing an electrostatic charge image contains toner particles containing at least one binder resin; the Mg element in an amount such that in an x-ray fluorescence analysis of the toner, the net intensity of the peak for the Mg element is 0.10 kcps or more and 1.20 kcps or less; and at least one external additive including particles of at least one compound represented by formula (1),

MTiO.sub.3  (1)

where M represents at least one selected from the group consisting of Ca, Sr, and Ba.

A toner comprising: a toner particle containing a resin component and a wax; and an inorganic fine particle on the surface of the toner particle, wherein, in a cross section of the toner particle, domains containing the wax are observed, and when among the domains, domains having a major diameter of 10-300 nm are defined as domains S, an occupation area percentage of which a ratio of a total sum of areas occupied by the domains S in a region from a surface of the toner particle to a depth of 600 nm in the cross section with respect to an area of the region, is 3.0-15.0%, and wherein the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×10.sup.3 to 3.0×10.sup.5 Ω.Math.cm, and having a relative permittivity εr of 100 or more.

A toner comprising: a toner particle containing a resin component and a wax; and an inorganic fine particle on the surface of the toner particle, wherein, in a cross section of the toner particle, domains containing the wax are observed, and when among the domains, domains having a major diameter of 10-300 nm are defined as domains S, an occupation area percentage of which a ratio of a total sum of areas occupied by the domains S in a region from a surface of the toner particle to a depth of 600 nm in the cross section with respect to an area of the region, is 3.0-15.0%, and wherein the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×10.sup.3 to 3.0×10.sup.5 Ω.Math.cm, and having a relative permittivity εr of 100 or more.

A carrier for developing an electrostatic charge image has magnetic particles and a resin coating that covers the magnetic particles and contains at least one lubricant. The resin coating has a dispersed phase of the lubricant and meets requirement (1). Requirement (1): the lubricant content in a top layer>the lubricant content in a middle layer>the lubricant content in a bottom layer The top, middle, and bottom layers are of the resin coating divided into three in the direction of thickness, and the lubricant content is the percentage area of the dispersed phase of the lubricant in a cross-section of the layer taken along the thickness thereof.

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein in cross-sectional observation of the magnetic toner particle using a transmission electron microscope, a variation coefficient CV3 of an occupied area ratio of the magnetic body when a cross section of the magnetic toner particle is divided by a square grid having a side of 0.8 μm is from 40.0% to 80.0%, and assuming that a storage elastic modulus at 40° C. is taken as E′(40) [Pa] and a storage elastic modulus at 85° C. is taken as E′(85) [Pa], the storage elastic moduli being obtained in a powder dynamic viscoelasticity measurement of the magnetic toner, the following formulas (1) and (2) are satisfied.

E′(85)≤2.0×10.sup.9  (1)

[E′(40)−E′(85)]×100/E′(40)≥70  (2)

A toner comprising: a toner particle containing a resin component and a wax; and an inorganic fine particle on the surface of the toner particle, wherein, in a cross section of the toner particle, domains containing the wax are observed, and when among the domains, domains having a major diameter of 10-300 nm are defined as domains S, an occupation area percentage of which a ratio of a total sum of areas occupied by the domains S in a region from a surface of the toner particle to a depth of 600 nm in the cross section with respect to an area of the region, is 3.0-15.0%, and wherein the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×10.sup.3 to 3.0×10.sup.5 Ω.Math.cm, and having a relative permittivity εr of 100 or more.

A toner comprising: a toner particle containing a resin component and a wax; and an inorganic fine particle on the surface of the toner particle, wherein, in a cross section of the toner particle, domains containing the wax are observed, and when among the domains, domains having a major diameter of 10-300 nm are defined as domains S, an occupation area percentage of which a ratio of a total sum of areas occupied by the domains S in a region from a surface of the toner particle to a depth of 600 nm in the cross section with respect to an area of the region, is 3.0-15.0%, and wherein the inorganic fine particle contains a fine particle A having a volume resistivity of 1.0×10.sup.3 to 3.0×10.sup.5 Ω.Math.cm, and having a relative permittivity εr of 100 or more.

A toner including a toner particle that contains a binder resin, and an inorganic fine particle, wherein the inorganic fine particle contains aggregated particles; the aggregated particles contain primary particles of at least one metal salt selected from the group consisting of titanate metal salts and zirconate metal salts; the primary particles have a number-average particle diameter of from 15 nm to 55 nm; the aggregated particles have an aggregation diameter of from 80 nm to 300 nm, the aggregated particles have a volume resistivity of from 2×10.sup.9 Ω.Math.cm to 2×10.sup.13 Ω.Math.cm; and the aggregated particles cover a surface of the toner particle, and a coverage ratio of the aggregated particles with respect to the surface of the toner particle is from 0.3 area % to 10.0 area %.