A magnetic core material for electrophotographic developer, satisfying a value of Expression (1): a+b10+c+d+e+f, being from 300 to 1,300, when an amount of fluorine ion is denoted by a (ppm), an amount of chlorine ion is denoted by b (ppm), an amount of bromide ion is denoted by c (ppm), an amount of nitrite ion is denoted by d (ppm), an amount of nitrate ion is denoted by e (ppm), and an amount of sulfate ion is denoted by f (ppm), which are measured by combustion ion chromatography, and having a BET specific surface area being from 0.06 to 0.25 m.sup.2/g.

An electrostatic image developer includes: a toner A to which silica particles (A) containing an elemental nitrogen-containing compound containing elemental molybdenum are externally added; and a carrier B including a core material and a coating resin layer that covers the core material and contains inorganic particles. In the silica particles (A), the ratio N.sub.Mo/N.sub.Si of a Net intensity N.sub.Mo of elemental molybdenum that is measured by X-ray fluorescence analysis to a Net intensity N.sub.Si of elemental silicon that is measured by the X-ray fluorescence analysis is from 0.035 to 0.45 inclusive.

An electrostatic charge image developer includes: a toner A incorporating toner particles and silica particles (A) as an external additive, the toner particles containing a binder resin and resin particles, and the silica particles (A) containing a nitrogen-containing compound containing the element molybdenum; and a carrier B incorporating a core and a coating resin layer, the coating resin layer covering the core and containing inorganic particles, and the ratio N.sub.Mo/N.sub.Si is 0.035 or greater and 0.45 or less, where N.sub.Mo and N.sub.Si are measured net intensities for the element molybdenum and the element silicon, respectively, in the silica particles (A) in x-ray fluorescence analysis.

An electrostatic image developer includes a toner including toner particles that include a binder resin and a release agent and have an exposure ratio of the release agent of 15% or more and 30% or less, and a carrier including magnetic particles and resin cover layers covering the magnetic particles and including inorganic particles, wherein the inorganic particles have an arithmetic average particle size of 5 nm or more and 90 nm or less, the resin cover layers have an average thickness of 0.6 ?m or more and 1.4 ?m or less, and a fine-irregularity-structure surface roughness of surfaces of the carrier three-dimensionally analyzed has, in an analysis region, a ratio B/A of an irregularity-surface area B to a plan-view area A of 1.020 or more and 1.100 or less.

A carrier is provided including a core particle and a resin layer coating the surface of the core particle. The resin layer includes fine metal particles, and a detected metal element amount A obtained by X-ray photoelectron spectrometry of the surface of the carrier is in a range of 4.0 atomic %A20.0 atomic % and an average major-axis length B of the fine metal particle exposing from the resin layer is in a range of 100 nmB800 nm.

The electrostatic charge image developing toner of the present invention is an electrostatic charge image developing toner including a toner mother particle including at least a binding resin, and an external additive attached onto a surface of the toner mother particle, wherein a median size on a volume basis of the toner mother particle is in the range from 3.0 to 5.0 m, the binding resin contains at least an amorphous polyester resin as a main component, and a spherical silica particle (1) having a number average particle size in the range from 20 to 55 nm is included as the external additive.

Provided is a magnetic carrier comprising a magnetic carrier particle having a magnetic body-dispersed resin carrier core material and a resin coating layer; the core material includes magnetic particles A and B having number average primary particle diameter of ra and rb (m), respectively, satisfying rarb; the particles A each include an oxide of at least one nonferrous metal of Mn, Al, Mg, Ti, and Ni; and an iron oxide; M1 represents total content of the nonferrous metal and F1 represents content of an iron of the magnetic carrier particle measured by XRF diffraction, M1/F1 is 0.010 to 0.100; M2 represents total content of the nonferrous metal and F2 represents content of an iron is F2 of the magnetic carrier particle measured by XPS, M2/F2 is 1.0 to 10.0.

An electrophotographic image forming carrier includes core particles and a coating layer coating a surface of the core particles. The coating layer contains antimony-containing particles comprising inorganic fine particles A and antimony-doped tin oxide disposed on a surface of the inorganic fine particles A. The electrophotographic image forming carrier has an apparent density of 2.0 g/cm.sup.3 or more and 2.5 g/cm.sup.3 or less.

An image forming apparatus includes: a first image forming unit that includes a first image holding member and a first developing unit, the first developing unit accommodating a first developer that includes a first toner and a first carrier; a first transfer unit; a second image forming unit that is disposed downstream of the first image forming unit in a traveling direction of the transfer medium and includes a second image holding member and a second developing unit, the second developing unit accommodating a second developer that includes a second toner and a second carrier; and a second transfer unit, in which a volume resistivity of the first carrier is lower than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is less than a volume average particle diameter of the second carrier.

A developer set includes a first developer and a second developer. The first developer includes a first toner and a first carrier. The second developer includes a second toner and a second carrier. The second toner is a toner that includes a flaky brilliant pigment, a toner that includes a white pigment, or a transparent toner. The second carrier has a higher volume resistivity than the first carrier and has a larger volume average particle diameter than the first carrier.