[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 is an electrostatic charge image developing toner containing at least toner particles, wherein the toner particles contain an amorphous vinyl resin, an amorphous polyester resin, a crystalline polyester resin, and an ester wax; the crystalline polyester resin is a crystalline polyester resin obtained by polycondensation of a dicarboxylic acid having a number of carbon atoms in the range of 9 to 14 and a dialcohol having a number of carbon atoms in the range of 9 to 14; the amorphous polyester resin is an amorphous polyester resin containing a constituent unit derived from a dicarboxylic acid having a number of carbon atoms in the range of 9 to 14 or a dialcohol having a number of carbon atoms in the range of 9 to 14; and a sum of the number of carbon atoms of the dicarboxylic acid and the dialcohol is in the range of 18 to 24.

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 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.

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.

A toner is provided, which has a toner particle containing a binder resin including a first resin and a second resin, wherein the first resin is a crystalline resin, the second resin is an amorphous resin, the first resin contains a specific amount of a first monomer unit having a specific structure, an acid value of the first resin and an acid value of the second resin are 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, the toner particle contains a multivalent metal element, the multivalent metal element is at least one metal element selected from the group consisting of Mg, Ca, Al, Fe and Zn, and a total content of the multivalent metal element is within a specific range.

According to one embodiment, a toner contains a toner mother particle and an external additive. The toner mother particle contains a crystalline polyester resin and a specific ester wax. The external additive contains silica A having a D.sub.50 of 10 nm to 14 nm and monodispersed silica B having a D.sub.50 of 90 nm to 150 nm. The following conditions are satisfied. Content of silica A: 0.1 parts by mass to 0.8 parts by mass with respect to 100 parts by mass of the toner mother particle. Content of silica B: 0.3 parts by mass to 1.2 parts by mass with respect to 100 parts by mass of the toner mother particle. Ratio (content of silica B/content of silica A): 1.0 to 5.0. Residual ratio X of silica A: 70% or more. Residual ratio Y of silica B: 30% or more. Ratio (residual ratio X/residual ratio Y): 1.0 to 3.0.

An electrostatic charge image developing toner has toner particles and silica particles that are added to an exterior of the toner particles, contain a nitrogen element-containing compound, have a ratio C/D of 0.10 or more and 0.75 or less where C represents an integral value of signals observed in a range of chemical shift of −50 ppm or more and −75 ppm or less in a .sup.29Si solid-state nuclear magnetic resonance (NMR) spectrum obtained by a cross-polarization/magic angle spinning (CP/MAS) method and D represents an integral value of signals observed in a range of chemical shift of −90 ppm or more and −120 ppm or less in the same spectrum, have an extraction amount X of the nitrogen element-containing compound by a mixed solution of ammonia/methanol of 0.1% by mass or more, and satisfy Expression: Y/X<0.3 where X represents an extraction amount of the nitrogen element-containing compound by a mixed solution of ammonia/methanol and Y represents an extraction amount of the nitrogen element-containing compound by water.

An electrostatic charge image developing toner has toner particles that contain a binder resin, a release agent, and resin particles, in which a loss coefficient tan δ (1%) of the resin particles at a melting temperature Tw of the release agent and a strain of 1% and a loss coefficient tan δ (100%) of the resin particles at the melting temperature Tw of the release agent and a strain of 100% satisfy the following Expression (1) and the following Expression (2).

0.02≤tan δ(1%)≤0.5  Expression (1):

0.4≤tan δ(100%)−tan δ(1%)≤2.0  Expression (2):

An electrostatic charge image developing toner has toner particles and silica particles that are added to an exterior of the toner particles and contain a nitrogen element-containing compound, in which in a case where A represents a pore volume of pores of the silica particles having a diameter of 1 nm or more and 50 nm or less determined from a pore size distribution curve obtained by a nitrogen adsorption method before baking at 350° C., and B represents a pore volume of pores of the silica particles having a diameter of 1 nm or more and 50 nm or less determined from a pore size distribution curve obtained by a nitrogen adsorption method after baking at 350° C., B/A is 1.2 or more and 5 or less, and B is 0.2 cm.sup.3/g or more and 3 cm.sup.3/g or less.