A toner comprises a toner particle comprising a core particle comprising a resin component, a shell coating the surface of the core particle, and a polyvalent metal. The resin component comprises a polyester resin, and the shell comprises an amino resin; in an electron image of a cross section of the toner acquired using a transmission electron microscope, a polyvalent metal content P(M) obtained by energy-dispersive x-ray analysis at the core/shell interface and in the vicinity of this interface is 0.0010 to 2.00 atomic %; and the surface storage elastic modulus of the toner at a load of 30 μN at 25° C., according to nanoindentation measurement of the toner, is from 6.50 GPa to 12.00 GPa.

A toner comprising a toner particle comprising a binder resin, a hydrocarbon wax A, and an ester wax B, wherein assuming that a ratio of a peak intensity attributed to the hydrocarbon wax A to a peak intensity attributed to the binder resin in heating IR measurement in which the toner is held at 100° C. for 10 min is I, where an initial peak intensity ratio upon heating to 100° C. is denoted by I(ini) and a peak intensity ratio upon heating to 100° C. and holding for 10 min is denoted by I(10 min), the I(ini) and the I(10 min) satisfy a following formula (1):

I(ini)/I(10 min)≤0.95  (1).

The present disclosure provides a fine particle containing silicon, wherein the fine particle has a number-average particle diameter of a primary particle of 0.05 μm or more and 0.20 μm or less, wherein the fine particle contains a silicon atom at a ratio of 20% or more with respect to all elements in measurement by X-ray fluorescence.

Disclosed herein is a toner composition, developer and additive for a toner composition. The toner composition includes toner particles including at least one resin, an optional colorant, an optional wax, and a polymeric toner additive on at least a portion of an external surface of the toner particles. The polymeric toner additive includes a polymeric resin including a fluorinated monomer, wherein the polymeric resin is less than 10% by weight crosslinked, and optionally a charge control agent comprising nitrogen containing group at 0.1 wt % to 1.5 wt % of the polymeric resin.

Disclosed herein is a toner composition, developer and additive for a toner composition. The toner composition includes toner particles including at least one resin, an optional colorant, an optional wax, and a polymeric toner additive on at least a portion of an external surface of the toner particles. The polymeric toner additive includes a polymeric resin including a fluorinated acrylic monomer, a cross-linkable monomer containing two or more vinyl groups at 8 wt % to 40 wt % of the polymeric resin, and optionally a charge control agent comprised of a nitrogen containing group at 0.1 wt % to 1.5 wt % of the polymeric resin.

An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit has a conductive member contactable with the electrophotographic photosensitive member, and a conductive layer of the conductive member has a matrix-domain structure; at least some of the domains are exposed at the outer surface; a volume resistivity R1 of the matrix and a volume resistivity R2 of the domains satisfy specific relationship; Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy relationship G1<G2; the surface roughness Ra of the conductive member is not more than 2.00 μm; the toner has an external additive having a shape factor SF-1 of not more than 115; and A<Dms is satisfied where A is the number-average diameter of the external additive and Dms is a distance between adjacent walls between the domains.

A toner includes: a crystalline polyester resin; and a partially hydrogenated petroleum resin. A hydrogenation rate of the partially hydrogenated petroleum resin is from 30% through 70%. An amount of the partially hydrogenated petroleum resin relative to the toner is from 1% by mass through 15% by mass.

A toner including inorganic particles, wherein the inorganic particles include a fluorine-containing alumina, and the toner satisfies both Formula (1) below and Formula (2) below: 2.7≤X1/X2≤5.5 . . . Formula (1); and 2.1≤X1≤3.0 . . . Formula (2) where X1 denotes a concentration of aluminum in the toner and X2 denotes a concentration of fluorine in the toner, and the concentration of aluminum and the concentration of fluorine are determined through an X-ray photoelectron spectroscopic analysis method.

An external additive particle includes a sulfur-containing polymer. The polymer includes a vinyl polymer moiety and a siloxane moiety. The proportion of the number of silicon atoms to the sum of the number of carbon atoms, the number of oxygen atoms, and the number of silicon atoms in the external additive particle is 4.0% or more and 25.0% or less, and sulfur atoms are contained in the surface of the external additive particle as detected by X-ray photoelectron spectroscopy.

A toner comprising a toner particle comprising a binder resin, wherein the toner particle comprises a condensation product of an organosilicon compound, in time-of-flight secondary ion mass spectrometry of the toner particle, a normalized intensity of silicon ions derived from the condensation product of the organosilicon compound is from 7.00×10.sup.−4 to 3.00×10.sup.−2, a normalized intensity of silicon ions after sputtering the toner particle under a specific condition is 6.99×10.sup.−4 or lower, the toner comprises a fine particle on the surface of the toner particle, and the fine particle has at least one selected from the group consisting of a specific fine particle of a polyhydric acid metal salt, a strontium titanate fine particle, a titanium oxide fine particle and an aluminum oxide fine particles.