The toner for developing electrostatic images is less likely to cause toner ejection and is excellent in printing durability. The toner includes colored resin particles and external additives. The external additives includes an external additive A and an external additive B; wherein the external additive A is silica particles being surface-hydrophobized with a specific hydrophobizing agent and having a specific number average particle diameter; and wherein the external additive B is silicone resin particles having a ratio (BS/TS) of a BET specific surface area (BS) to a theoretical specific surface area (TS) in a range of from 3.0 to 30.0, and having a specific number average particle diameter.

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.

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.

A toner having a toner particle including a toner base particle and an organosilicon polymer coating the toner base particle, wherein when S1 (μm.sup.2) is a total area of a non-coated part not coated with the organosilicon polymer on an outermost surface of the toner particle, S2 (μm.sup.2) is a total area of a coated part coated with the organosilicon polymer on the outermost surface of the toner particle, and SA1 (μm.sup.2) is a total of areas of non-coated part domains D1 with an area of not more than 0.10 μm.sup.2 in size in the non-coated part not coated with the organosilicon polymer, formulae (1) and (2) below are satisfied.
0.45≤[S2/(S1+S2)]≤0.65  (1)
(SA1/S1)≥0.50  (2)

A toner comprising a toner particle comprising a binder resin and an ester compound, wherein: the binder resin comprises a resin A comprising a specific amount of a long-chain acrylate unit and a styrene-based monomer unit, and a resin B comprising a specific monomer unit in a specific amount; the ester compound has an alkyl chain with a specific chain length, a content of the resin A in the chloroform-soluble portion of the toner particles is 60% by mass or more; and using SPm (J/cm.sup.3).sup.1/2 for a SP value of the long-chain acrylate unit and using SPw (J/cm.sup.3).sup.1/2 for a SP value of the ester compound, SPm is 18.00 to 19.00, and SPm and SPw satisfy formula (a).

|SPm−SPw|≤1.50  (a)

Provided is a process cartridge that is excellent in initial charge rising performance, and in charge uniformity of a halftone image throughout a long period of time from the start of use until after endurance. Specifically, provided is a process cartridge including: an electrophotographic photosensitive member; a toner; and a developing unit, wherein the toner contains toner particles and an external additive A, the external additive A, and wherein the electrophotographic photosensitive member includes an electroconductive support, a photosensitive layer, and a surface protective layer, wherein the surface protective layer contains electroconductive particles.

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.

A toner comprising a toner particle comprising a binder resin and a release agent, wherein the binder resin comprises a crystalline resin A, the crystalline resin A comprises a monomer unit derived from a monomer (a), the monomer (a) is at least one selected from the group consisting of (meth)acrylic acid esters having an alkyl group with 18 to 36 carbon atoms, the peak temperature and endothermic quantity at an endothermic peak derived from the crystalline resin A in DSC measurements using the toner satisfy specific relationships, and the release agent is at least one selected from the group consisting of hydrocarbon-based waxes and ester waxes.

A toner comprising a toner particle comprising a binder resin, wherein the binder resin has a side-chain crystalline polymer B having a monomer unit A made of at least one polymerizable monomer A selected from the group consisting of (meth)acrylic acid esters having a linear alkyl group having 18 to 36 carbon atoms, and the toner particle comprises boric acid.

A toner having: a toner particle containing a binder resin including a first resin that is a crystalline resin and a second resin that is an amorphous resin; and a fine particle on a surface of the toner particle, wherein the first resin contains a specific ratio of a specific monomer unit, an acid value of the first resin and an acid value of the second resin arc within specific ranges, a domain-matrix structure formed of a matrix containing the first resin and domains containing the second resin appears in cross -sectional observation of the toner, and the fine particle has on the surface a compound containing nitrogen atoms bound or adsorbed thereon.