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.

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, 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.

Provided is a toner including toner particles. Each of the toner particles includes a toner base particle including a binder resin and a release agent. The toner particles have an average circularity of 0.974 or greater and 0.985 or less. An arithmetic mean height Sa of surfaces of the toner particles is 45 nm or greater. The toner particles have a BET specific surface area of 1.3 m.sup.2/g or greater and 2.5 m.sup.2/g or less.

[Object] An object of the invention is to provide a toner that can both achieve a higher level of low temperature fixability and suppression of the toner scattering.

[Means of Achieving the Object]

The disclosure is to provide a toner, including base-particles, and an external-additive, wherein a glass-transition temperature obtained from a DSC-curve at a second-warming of a THF-insoluble component is −50° C. or higher and 10° C. or lower, wherein an average circularity of the toner is 0.975 or more and 0.985 or lower, wherein the toner satisfies the following formula:

1.5≤Bt−0.025−Ct≤3.0, wherein the Bt [m.sup.2/g] is a BET-specific-surface area of the toner-particles, and the Ct [%] is a coverage by the external-additive, and, at least a portion of a surface of the external-additive is coated with either an oxide of a metallic element, a hydroxide of the metallic element, or both.

Provided are a process cartridge and an electrophotographic apparatus each capable of suppressing an image defect (coarseness in a halftone image) caused by toner scattering in association with a charging failure that occurs when the process speed of the electrophotographic apparatus is further increased. The process cartridge includes: an electrophotographic photosensitive member; and a developing unit, which includes a toner storing portion that stores a toner, and which supplies the toner to a surface of the electrophotographic photosensitive member. The electrophotographic photosensitive member includes a surface protective layer containing an electroconductive particle in an appropriate amount, and the volume resistivity of the surface protective layer is controlled. As the toner, there is used a toner in which an organosilicon polymer is present on the surface of a toner particle, a silanol group is present in part of the organosilicon polymer, and the amount of the silanol group is controlled.

A process cartridge that is detachable from a main body of an electrophotographic apparatus, in which a surface protective layer of an electrophotographic photosensitive member contains an electroconductive particle; the content of the electroconductive particle is 20.0 to 70.0% by volume of the surface protective layer; the surface protective layer has a volume resistivity of 1.0×10.sup.9 to 1.0×10.sup.14 Ω.Math.cm; a toner particle has at least one multivalent metal element selected from the group consisting of aluminum, magnesium, calcium, and iron; and a total content of the multivalent metal elements in the toner particle, as measured by coupled induction plasma atomic emission spectrometry (ICP-AES), is 0.10 to 1.25 μmol/g.

The electrophotographic apparatus and process cartridge comprising an electrophotographic photosensitive member, a cleaning blade, and developing unit containing a toner, wherein the cleaning blade comprising a support member and an elastic member whose portion is abutting a surface of the electrophotographic photosensitive member; the elastic member has an elastic modulus of 15 to 470 MPa with coefficient of variation for the elastic modulus being not more than 7.0%, and the absolute value of a difference between Martens hardness values is not more than 0.30 N/mm.sup.2 as measured under prescribed conditions; the toner contains a toner particle and an external additive whose a number-average primary particle diameter is from 5 to 25 nm, when X1 is a coverage ratio of the toner particle by the external additive and X2 is a theoretical coverage ratio, X1 is 50 to 85 area %, and X1/X2≥−0.0042×X1+0.60 is satisfied.

A toner excellent in low-temperature fixing property and shelf stability. The toner comprising colored resin particles containing a binder resin, a colorant, a softening agent and a charge control agent, and an external additive, wherein a glass transition temperature (Tg) specified from a temperature dependence curve for a loss tangent (tan δ) of the toner, which is obtained by a dynamic viscoelastic measurement of the toner at a measurement frequency of 24 Hz, satisfies 45° C.<Tg(° C.)<100° C., and formula (I-1): 5.00×10.sup.−2<(tan δ(Tg)−tan δ(45° C.))/(Tg−45)<7.60×10.sup.−2 and formula (I-2): −3.0×10.sup.−3<(tan δ(130° C.)−tan δ(100° C.))/30<9.8×10.sup.−1 are satisfied, or formula (II-1): 5.00×10.sup.−2<(tan δ(Tg)−tan δ(45° C.))/(Tg−45)<7.60×10.sup.−2 and formula (II-2): 2.1×10.sup.−3<(tan δ(130° C.)−tan δ(100° C.))/30<4.4×10.sup.−2 are satisfied.