A carrier for developing an electrostatic image includes a magnetic particle and a resin layer with which the magnetic particle is coated and which contains silica particles having an average particle diameter of 50 nm or more and 200 nm or less. In the carrier, a silicon element ratio Si1 in a region in which a distance from a surface of the resin layer in a direction toward an inside is 0.1 μm or more and 0.2 μm or less and a silicon element ratio Si2 in a region in which a distance from a surface of the magnetic particle in a direction toward the surface of the resin layer is 0.0 μm or more and 0.1 μm or less satisfy formula 1-1 and formula 2-1 below.

0.005≤Si1≤2  Formula 1-1

1≤Si1/Si2≤1000  Formula 2-1

The subject toner includes a toner particle containing a binding resin and an inorganic oxide particle, wherein the inorganic oxide particle is a particle of an oxide containing at least one element selected from the group consisting of: Si; Mg; Al; Ti; and Sr, wherein, when an area of the inorganic oxide particle is represented by Sm and a sectional area of the toner is represented by St in a cross-section of the toner observed with a transmission electron microscope, Sm/St is 4.0% or more, wherein an area Sm of the inorganic oxide particle that occupies each of four regions obtained by dividing the cross-section of the toner by a long diameter of the toner and a perpendicular bisector of the long diameter has a standard deviation of 0.40 or more in the observed cross-section, and wherein the toner has an average circularity of 0.950 or more.

A magnetic carrier comprises a magnetic carrier core and a coating resin layer coating a surface of the magnetic carrier core. The coating resin layer contains resin A and resin B at contents of 1% to 50% by mass and 50% to 90% by mass, respectively, based on resin components of the coating resin layer. The resin A has a first partial structure and a second partial structure, while the resin B has a third partial structure and a fourth partial structure. The mass X of the resin A, the total mass Ma of the first partial structure, and the total mass Mb of the second partial structure satisfy 0.50≤(Ma+Mb)/X≤1.00 and 0.10≤a/b≤30.0, and the SP value of the first partial structure SPa1 and the SP value of the third partial structure SPb3 satisfy 0≤|SPa1—SPb3|≤10.0.

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.

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.

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 a 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 higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.

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 a 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 higher than a volume resistivity of the second carrier, and a volume average particle diameter of the first carrier is more than a volume average particle diameter of the second carrier.

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.

The subject toner includes a toner particle containing a binding resin and an inorganic oxide particle, wherein the inorganic oxide particle is a particle of an oxide containing at least one element selected from the group consisting of: Si; Mg; Al; Ti; and Sr, wherein, when an area of the inorganic oxide particle is represented by Sm and a sectional area of the toner is represented by St in a cross-section of the toner observed with a transmission electron microscope, Sm/St is 4.0% or more, wherein an area Sm of the inorganic oxide particle that occupies each of four regions obtained by dividing the cross-section of the toner by a long diameter of the toner and a perpendicular bisector of the long diameter has a standard deviation of 0.40 or more in the observed cross-section, and wherein the toner has an average circularity of 0.950 or more.