An image forming apparatus includes a magnetic toner, an image bearing member, and a development device. The image bearing member is an amorphous silicon photosensitive drum. The magnetic toner includes toner particles. The toner particles each include a toner mother particle containing a binder resin and a magnetic powder and alumina particles attached to a surface of the toner mother particle. The alumina particles each include a core containing alumina and a conductive layer covering the core. The conductive layer contains antimony tin oxide. The alumina particles have a number average primary particle diameter of at least 0.15 ?m and no greater than 0.50 ?m. The alumina particles have a specific resistance of no greater than 250 ?.Math.cm. The alumina particles have an X-ray intensity ratio of at least 0.25 and no greater than 0.35.

There is provided a magnetic substance containing substituted -iron oxide particles applicable as a magnetic toner of one-component development system, and a technique related thereto, which is the magnetic substance containing substituted -iron oxide particles in which a part of -iron oxide is substituted with a metal element other than iron, and satisfying at least one of the following conditions: (Condition 1) A molar extinction coefficient of a magnetic substance dispersion liquid at a wavelength of 450 nm is less than 770 dm.sup.3 mol.sup.1 cm.sup.1. (Condition 2) A molar extinction coefficient of the magnetic substance dispersion liquid at a wavelength of 500 nm is less than 430 dm.sup.3 mol.sup.1 cm.sup.1.

There is provided a toner containing: a toner particle containing a binder resin, a releasing agent, and a colorant; and an iron oxide particle present on a surface of the toner particle, in which the iron oxide particle has a surface containing a compound having a specific structure.

A plurality of toner particles each include a toner core, a shell layer covering a surface of the toner core, and a plurality of magnetic particles penetrating the shell layer. Each of the magnetic particles has an embedded portion and a protrusion portion. The embedded portions are embedded in the surface of the toner core. The protrusion portions are located further outward than the embedded portions in a radial direction of the toner particle and protrude outward from a surface of the shell layer in the radial direction of the toner particle. An average Heywood diameter X of the magnetic particles, a shell layer thickness Y, and an average value Z of protrusion heights of the respective magnetic particles satisfy relation (1) and relation (2) shown below.
0<Z(X/2)(1)
10 nmY50 nm(2)

Provided is a toner having a toner particle that contains a binder resin and a magnetic particle, wherein the magnetic particle satisfies the following stipulations (i) to (iii): (i) the magnetic particle has a prescribed shape and has a protruded portion on a plane portion thereof, (ii) the magnetic particle has a core particle that contains magnetite and has a coating layer, and (iii) the coating layer contains an iron-containing oxide and at least one of a silicon-containing oxide and an aluminum-containing oxide. In a molecular weight distribution measured on the tetrahydrofuran-soluble matter of the toner, the ratio (Mw/Mn) of a weight-average molecular weight to a number-average molecular weight is at least 10.0.

A magnetic toner containing a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein when the inorganic fine particles are classified as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles in accordance with fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X of coverage of the magnetic toner surface by the third inorganic fine particles are in prescribed ranges.

The magnetic toner contains a magnetic toner particle having a binder resin and a magnetic body, and inorganic fine particles, wherein the average circularity of the magnetic toner is at least 0.955 and, when classifying the inorganic fine particles, in accordance with the fixing strength thereof to the magnetic toner particle and in the sequence of the weakness of the fixing strength, as first inorganic fine particles, second inorganic fine particles, and third inorganic fine particles, the content of the first inorganic fine particles, the ratio of the second inorganic fine particles to the first inorganic fine particles, and the coverage ratio X are in prescribed ranges.

A plurality of toner particles each include a toner core, a shell layer covering a surface of the toner core, and a plurality of magnetic particles penetrating the shell layer. Each of the magnetic particles has an embedded portion and a protrusion portion. The embedded portions are embedded in the surface of the toner core. The protrusion portions are located further outward than the embedded portions in a radial direction of the toner particle and protrude outward from a surface of the shell layer in the radial direction of the toner particle. An average Heywood diameter X of the magnetic particles, a shell layer thickness Y, and an average value Z of protrusion heights of the respective magnetic particles satisfy relation (1) and relation (2) shown below.

0<Z(X/2)(1)

10 nmY50 nm(2)

There is provided a toner containing: a toner particle containing a binder resin, a releasing agent, and a colorant; and an iron oxide particle present on a surface of the toner particle, in which the iron oxide particle has a surface containing a compound having a specific structure.

An electrostatic charge image developing carrier includes a magnetic particle and a coating resin layer that covers the magnetic particle and contains a silica particle, and a ratio of Si on a surface of the coating resin layer, determined by an X-ray photoelectron spectroscopy (XPS), is 6 atom % or more and 12 atom % or less.