A toner having: a toner particle containing a binder resin including a first resin and a second resin; and an inorganic fine particle on a surface of the toner particle, wherein the first resin has a specific content ratio of a specific monomer unit, acid values of the first unit and second unit are within specific ranges, a domain matrix structure including a matrix containing the first resin and domains containing the second resin appears in cross-sectional observation of the toner, a compound having an alkyl group is present on a surface of the inorganic fine particle, and a volume resistivity of the inorganic fine particle is 1.0×10.sup.5 Ω.Math.cm to 1.0×10.sup.13 Ω.Math.cm.

A toner comprising a toner particle comprising a resin A, and an external additive A, wherein the resin A is a resin represented by formula (1) below, the resin A is present at the surface of the toner particle, the external additive A is a fine particle containing silicon, the average value of the shape factor SF-1 of the external additive A is from 105 to 120, the average value of the shape factor SF-2 of the external additive A is from 100 to 130. ##STR00001##

An electrostatic image developing toner includes an amorphous polyester resin and a crystalline polyester resin, wherein a Net intensity N.sub.Na of a Na element and a Net intensity N.sub.Cl of a Cl element, the Net intensities N.sub.Na and N.sub.Cl being determined by X-ray fluorescence analysis, satisfy 2.5≤N.sub.Cl/N.sub.Na≤260.0.

A toner comprising a toner particle comprising a toner core particle and a shell covering the toner core particle, wherein the shell comprises an organosilicon polymer, the shell encapsulates a domain of a release agent, and in cross-sectional observation of the toner particle by a transmission electron microscope, a ratio of domains of the release agent that are not in contact with the toner core particle to a total number of the observed domains of the release agent is 85% by number or more.

A toner contains mother toner particles each containing a binder resin, a releasing agent, and a charge control agent and an external additive containing hydrophobized polymethylsilsesquioxane particles with an average particle diameter of from 0.050 to 0.150 μm, wherein the mother toner particles have an average circularity of 0.95 or less.

A core-shell particle includes a core, and a shell on a surface of the core. The core includes a crystalline release agent. A value of a sum of a number-average value of Feret diameter of the core-shell particle and a standard deviation of the Feret diameter of the core-shell particle is 20 to 500 nm. The shell comprises an organosilicon polymer. In a differential scanning calorimetric measurement of the core-shell particle, a maximum endothermic peak is present when a temperature is raised from 30° C. to 120° C. at 10.0° C./min, a maximum exothermic peak is present when the temperature is lowered from 120° C. to 30° C. at 10.0° C./min, and Tc (° C.) is at least 5° C. lower than Tm (° C.) where Tm is a peak temperature of the maximum endothermic peak and Tc is a peak temperature of the maximum exothermic peak.

A toner composition having improved toner usage efficiency, wherein toner particles having an average size range of 1-25 μm may be mixed with an extra particulate additive package including a first small silica surface treated with both a silane and an aminosilane having a primary particle size of about 5 nm-20 nm, a second fumed silica having a primary particle size of 30 nm-60 nm, a third silica having a primary particle size of about 70 nm-120 nm, an electro-conductive titania having a primary particle size of 30 nm-60 nm and an acicular titania having a size of about 1.6 μm to 1.7 μm in length and about 130 nm in diameter. An alternative embodiment of the extra particulate additive package does not include a third silica having a primary particle size of about 70 nm-120 nm.

Toner comprising toner particles, wherein the toner contains gold nanorods, and wherein in a case where an aspect ratio distribution of the gold nanorods contained in the toner is measured, an average value μ in the aspect ratio distribution is in a range of 6.0 to 13.0 and a standard deviation σ in the aspect ratio distribution is in a range of 0.5 to 4.5.

According to one embodiment, a toner which has excellent low-temperature fixability, and also has excellent heat resistance even when the toner is reused, sufficiently maintains an electric charge amount, and hardly decreases an image density is provided. Also provided are a toner cartridge and an image forming apparatus, in each of which the toner is stored. A toner according to an embodiment contains toner base particles and an external additive. The external additive contains silica particles A, B, and C having a particle diameter of 10 to 14 nm, 40 to 70 nm, and 90 to 150 nm, respectively.

A toner composition having improved toner usage efficiency, wherein toner particles having an average size range of 1-25 μm may be mixed with an extra particulate additive package including a first small silica surface treated with both a silane and an aminosilane having a primary particle size of about 5 nm-20 nm, a second fumed silica having a primary particle size of 30 nm-60 nm, a third silica having a primary particle size of about 70 nm-120 nm, an electro-conductive titania having a primary particle size of 30 nm-60 nm and an acicular titania having a size of about 1.6 μm to 1.7 μm in length and about 130 nm in diameter. An alternative embodiment of the extra particulate additive package does not include a third silica having a primary particle size of about 70 nm-120 nm.