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.

Provided is a magnetic toner in which enhancement of initial transfer efficiency and transfer efficiency that is stable during a long-term use are achieved by simultaneously suppressing the friction force between the toner and a drum and the cohesion between toners, and further the degradation in chargeability and fluidity caused by the deterioration of the toner. The magnetic toner includes: a magnetic toner particle; a first external additive; and a second external additive. The first external additive includes an organic-inorganic composite fine particle, a plurality of convexes derived from an inorganic fine particle being present on a surface of the organic-inorganic composite fine particle, and has a number-average particle diameter of 50 nm or more and 500 nm or less. The second external additive includes a silica fine particle and has a number-average particle diameter of 5 nm or more and 30 nm or less. A shear load calculated from a rotation torque is 0.50 kPa or more and 2.00 kPa or less when a disc-shaped disc is pressed against a surface of a magnetic toner powder layer, the magnetic toner powder layer being produced by applying a vertical load of 9.0 kPa to the magnetic toner, under a vertical load of 5.0 kPa, and the disc which is being pressed is rotated, and an absolute value |(T)(A1)| of a difference between a zeta potential (T) of the magnetic toner particle dispersed in water and a zeta potential (A1) of the first external additive dispersed in water is 50 mV or less.

A compound that includes an aqueous dispersion, wherein the dispersion includes a thermoplastic resin and at least one stabilizing agent, and at least one selected from the group consisting of a colorant and a magnetic pigment, wherein the dispersion has an average volume diameter particle size from about 0.05 to about 10 microns is described.

Provided are magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.

An image forming apparatus is an image forming apparatus of a trickle development type, in which a two-component developer containing a toner and a carrier A is accommodated in a developing machine and a toner is supplied together with a supply carrier B in response to a toner consumed by development, in which the carrier A has a magnetic core material A and a resin coating layer A coating the magnetic core material A, where the resin coating layer A contains no metal oxide particles, and the supply carrier B has a magnetic core material B and a resin coating layer B coating the magnetic core material B, where the resin coating layer B contains metal oxide particles.

Magnetic particles (cobalt ferrite) having a micrometer-order average particle diameter and similar particle diameters. A cobalt ferrite precursor is heated in the presence of a sulfite, thereby obtaining intended cobalt ferrite magnetic particles.

A toner comprising a toner particle comprising a binder resin, a nonmagnetic inorganic oxide particle A, and a magnetic iron oxide particle B, wherein a softening point of a chloroform-soluble component of the toner particle is not greater than 90 C.; the nonmagnetic inorganic oxide particle A and the magnetic iron oxide particle B are internally added to the toner particle; the nonmagnetic inorganic oxide particle A comprises as its main component at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; a proportion of the inorganic oxide particles having a long diameter of specific length is in specific range; and a value of a ratio of a number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A, to a number-average particle diameter of the long diameter for the magnetic iron oxide particle B, is 5 to 30.

A toner includes toner particles individually containing a binder resin and a coloring agent, and strontium titanate fine particles. The strontium titanate fine particles have a work function of 5.65 eV to 7.00 eV.

Provided are cobalt ferrite particles having a micrometer-order average particle diameter and similar particle diameters. When a cobalt ferrite precursor is treated at a high temperature and a high pressure, an oxidation reaction is caused in the presence of a complexing agent, thereby obtaining intended cobalt ferrite magnetic particles.

Magnetic one-component toner has toner particles including: a toner base particle containing at least a binder resin and a magnetic powder; and an external additive attached to the surface of the toner base particle. The toner base particle contains a nigrosine dye. The external additive contains strontium titanate particles of which the surface is hydrophobically treated. The amount of nitrogen element in toner particles is 0.5 mass % or more but 5 mass % or less. The Abs value representing the amount of nigrosine dye that dissolves when toner particles are immersed in methanol as expressed in terms of light absorbance is 0.2 or more but 2.0 or less. The volume resistivity of strontium titanate particles is 1.0 E+7 [.Math.cm] or more but 1.0 E+10 [.Math.cm] or less.