There is provided a carrier including a magnetic core material having a surface coated with a surfactant-containing resin mixture of an elemental fluorine-containing resin and a polyimide resin. The carrier has an elution amount of an eluted material into water in an elution test ranging from 180 ppm to 3,500 ppm.

According to the present invention, there is provided a carrier core material that is formed of ferrite particles in which 48 to 52 mass % of Fe, 16 to 22 mass % of Mn, 1.0 to 3.5 mass % of Mg and 0.05 to 0.5 mass % of Ca are included, and when an electrical resistance value with an applied voltage of 500 V in an environment (in an L/L environment) in which the temperature is 10° C. and the relative humidity is 35% is R.sub.L (Ω.Math.cm), and an electrical resistance value with an applied voltage of 500 V in an environment (in an H/H environment) in which the temperature is 30° C. and the relative humidity is 70% is R.sub.H (Ω.Math.cm), formula (1) below is satisfied.

0.1≤(log R.sub.L−log R.sub.H)≤0.3  (1)

A magnetic carrier including a magnetic carrier particle having a magnetic core particle and a coating layer of an organosilicon polymer on a surface of the magnetic core particle, wherein the organosilicon polymer has the structure given by formula (T3) below; in .sup.29Si-NMR measurement of the THF-insoluble matter of the organosilicon polymer, the ratio ST3 of the peak area for the structure given by formula (T3) to the total peak area for the organosilicon polymer is at least 0.05; and in the roughness curve measured on the magnetic carrier particle, the mean width (RSm) of the roughness curve elements of the magnetic carrier particle, and the ratio (/RSm) to this RSm of the standard deviation of the width of the region where one period of a protrusion and a recess occurs, are in prescribed ranges.

RSi(O.sub.1/2).sub.3(T3)

R in the formula represents a prescribed substituent.

To provide a magnetic core material for electrophotographic developer and carrier for electrophotographic developer which have small environmental dependence of the electric resistance, can suppress the carrier scattering, and can stably provide good images; a developer contains the carrier; a method for producing the magnetic core material for electrophotographic developer; a method for producing the carrier for electrophotographic developer, and a method for producing the developer.

The magnetic core material for electrophotographic developer, satisfying a value of Formula (1): a+b10+c+d+e+f, being from 20 to 150, when a fluoride ion amount is denoted by a (ppm), a chloride ion amount is denoted by b (ppm), a bromide ion amount is denoted by c (ppm), a nitrite ion amount is denoted by d (ppm), a nitrate ion amount is denoted by e (ppm), and a sulfate ion amount is denoted by f (ppm), which are measured by a combustion ion chromatography method.

A carrier for developing an electrostatic latent image includes a core material particle and a resin layer covering a surface of the core material particle. The resin layer includes a resin and at least one kind of a fine particle. At least one kind of the fine particles includes a chargeable fine particle. The chargeable fine particle has a long diameter of 400 to 900 nm. The chargeable fine particle has a shape factor SF-1 of 160 to 250.

A magnetic carrier comprising a magnetic carrier particle having a magnetic carrier particle having a magnetic carrier core particle and a resin coat layer formed on the magnetic carrier core particle surface, and inorganic fine particles A present on a surface of the magnetic carrier particle, wherein each of the inorganic fine particles A has a rectangular parallelepiped particle shape, the inorganic fine particles A have D1 of 10 to 60 nm, the inorganic fine particles A are inorganic particles which have been surface treated with a surface treatment agent or silane coupling agent-treated particles, SP1 of the resin coat layer and SP2 of the surface treatment agent satisfies SP1SP214.00, and the coverage ratio of the magnetic carrier surface by the inorganic fine particles A as measured by ESCA is 5.0 to 20.0 atom %: and a two-component developer comprising at least the magnetic carrier and a toner.

A carrier for electrostatic image development includes: a core material; and a coating resin layer that contains inorganic particles and covers the core material. The content of the inorganic particles is 10% by mass or more and 60% by mass or less based on the total mass of the coating resin layer. The volume average diameter D (m) of the inorganic particles and the thickness T (m) of the coating resin layer satisfy the following relational expression (1): 0.007D/T0.24.

A carrier includes carrier particles. The carrier particles include first carrier particles and second carrier particles. The first carrier particles each include a first carrier core and a first coat layer covering a surface of the first carrier core. The second carrier particles each include a second carrier core and a second coat layer covering a surface of the second carrier core. The first coat layers contain no fatty acid metal salt. The second coat layer contains a coat layer binder resin and a fatty acid metal salt. The second coat layers contain the fatty acid metal salt in a proportion of from 85 mass % to 95 mass % relative to a total mass of the second coat layers. The second carrier particles are contained in a proportion of from 7 mass % to 15 mass % relative to a total mass of the first carrier particles and the second carrier particles.

A magnetic carrier includes a magnetic carrier particle including a magnetic carrier core particle having an amino group on a surface thereof and a resin covering layer disposed on the surface of the magnetic carrier core particle, in which the resin covering layer contains a vinyl-based copolymer and a trialkoxyalkylsilane.

A magnetic carrier including a magnetic carrier particle having a magnetic carrier core and a resin coating layer formed on a surface of the magnetic carrier core, wherein the resin coating layer includes a resin component including a resin A and a resin B, the resin A is a copolymer of monomers including (a) a (meth)acrylic acid ester monomer having an alicyclic hydrocarbon group and (b) a specific macromonomer, the resin B is a copolymer of monomers including (c) a styrene-based monomer and (d) a specific (meth)acrylic acid ester monomer, and based on the resin components of the resin coating layer, the amount of the resin A is from 20% by mass to 99% by mass, and the amount of the resin B is from 1% by mass to 80% by mass.