Provided is a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: a developing unit including a toner; and an electrophotographic photosensitive member, wherein the toner includes a toner particle, the toner particle has a surface containing a polyvalent acid metal salt particle, and a surface layer of the electrophotographic photosensitive member contains at least one metal oxide particle among an aluminum oxide particle, a silicon dioxide particle, and a tin oxide particle.

An electrostatic charge image developing toner includes toner particles, and an external additive that contains particles A containing a perovskite-type compound and having an equivalent circle diameter of 15 nm or greater and 90 nm or less and particles B containing a perovskite-type compound and having an equivalent circle diameter of 1.0 μm or greater and 3.0 μm or less, in which the particles B occupy 0.3% by number or greater and 3.5% by number or less of an entirety of the toner particles.

An electrostatic charge image developing toner includes a toner particle containing a binder resin, a release agent, a divalent metal, and a trivalent metal, in which the release agent has a domain diameter of 0.5 μm or greater and 1.5 μm or less.

An electrostatic image developer includes a toner containing toner particles, a carrier, and an external additive containing titanium dioxide particles of two types having different refractive indexes, fatty acid metal salt particles, and an abrasive.

A fine particle of a silicon polymer, wherein the fine particle has pores; the total pore volume of the fine particle is 0.35 to 1.00 cm.sup.3/g; a number-average primary particle diameter of the fine particle is 0.05 to 0.30 μm; the silicon polymer has a siloxane bond and an Si—R.sup.1 bond; R.sup.1 represents an alkyl group having 1 to 6 carbon atoms; and designating, with reference to a chart obtained by .sup.29Si-NMR measurement of the fine particle, A as a total peak area corresponding to the silicon polymer, and B as a peak area corresponding to Si—R.sup.1, A and B satisfy a following formula (1):

10.0≤B/A×100≤45.0   (1).

A white toner includes a toner particle that contains a binder resin, a release agent, and titanium oxide, at least a part of the titanium oxide being present in a release agent domain, in which in observation of a cross section of the toner particle, an average major axis length Dt of the toner particle, an average major axis length Dw of the release agent domain, and an average major axis length Dp of the titanium oxide in the release agent domain satisfy Expressions (1) and (2).

2×Dp≤Dw≤10×Dp  Expression (1):

0.1×Dt≤Dw≤0.5×Dt  Expression (2):

A toner for developing an electrostatic charge image incorporates toner particles that contain binder resins, in which: the binder resins include amorphous resins and at least one crystalline resin, the amorphous resins including amorphous resin a1 and amorphous resin a2, the crystalline resin including crystalline resin cl; and

10,000≤Mw(a2)−Mw(a1)≤150,000  (1), and

|SP(a1)−SP(c1)|/|SP(a2)−SP(c1)|≤0.9  (2),

where Mw (al) is the weight-average molecular weight of amorphous resin a1, Mw (a2) is that of amorphous resin a2, SP (a1) is the solubility parameter (SP) of amorphous resin a1, SP (a2) is that of amorphous resin a2, and SP (c1) is that of crystalline resin c1.

A toner includes toner base particles. Each of the toner base particles includes a binder resin, a colorant, and inorganic filler. An atomic concentration % of Al in the toner base particles as measured by XRF is 0.35 or greater but 0.85 or less. The toner satisfies 0.8<(M1/M2)/(M3/M4)<1.2. M1 is an atomic concentration % of Al in the toner base particles as measured by XPS, M2 is the atomic concentration % of Al in the toner base particles as measured by XRF, and M3 is an atomic concentration % of Al in particles as measured by XPS, and M4 is an atomic concentration % of Al in the particles as measured by XRF. The particles are particles obtained by classifying the toner base particles into 6/5 Dv, and Dv is a volume average particle diameter of the toner base particles.

A toner comprising a toner particle, wherein the toner particle includes a toner base particle containing a binder resin and includes a protruded portion on a surface of the toner base particle; the protruded portion comprises an organosilicon polymer and a polyhydric acid metal salt; and the polyhydric acid metal salt is present on a surface of the protruded portion.

A toner comprising a toner particle that contains a binder resin and a wax, wherein the toner particle contains an organosilicon polymer as given by formula (1) below;
R.sup.1—SiO.sub.3/2  (1),
in formula (1), R.sup.1 is an alkyl group having from 1 to 4 carbons; in a cross section of the toner particle observed using a transmission electron microscope, in terms of a distance A from the centroid of the cross section of the toner particle to a contour of the cross section, the organosilicon polymer is present in a region that is not more than 80% of the distance A from the centroid; and an absolute value of a difference between an SP value of the organosilicon polymer and an SP value of the wax is not more than 0.70 (cal/cm.sup.3).sup.1/2.