A toner containing a toner particle, wherein, when a dielectric loss tangent measured at a frequency of 10 kHz in an impedance measurement on the toner in an environment having a temperature of 50 C. and a relative humidity of 50% RH is designated by tan 50 C.(1), and a dielectric loss tangent measured at a frequency of 10 kHz in an impedance measurement on the toner in an environment having a temperature of 30 C. and a relative humidity of 50% RH after the impedance measurement on the toner in an environment having a temperature of 50 C. and a relative humidity of 50% RH is designated by tan 30 C.(2), tan 50 C.(1) is from 0.015 to 0.050, the relationship tan 50 C.(1)>tan 30 C.(2) is satisfied, and tan 30 C.(2)/tan 50 C.(1) is from 0.25 to 0.66.

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.

A toner comprising a toner particle, wherein the toner particle includes a binder resin, where a volume resistivity .Math.cm of an unfixed solid image on a recording material on which the solid image has been formed using the toner at a toner laid-on level of 0.4 mg/cm.sup.2 is denoted by Tv, and a volume resistivity .Math.cm of the solid image after fixing by applying heat and pressure to the recording material is denoted by Fv, Tv/Fv8 is satisfied.

A toner set includes a plurality of toners, wherein the toner set includes a first toner containing a yellow colorant and a second toner containing a cyan colorant, the first toner and the second toner each contain a binder resin containing a vinyl-based resin and a crystalline resin, and a release agent containing a hydrocarbon wax, a content of the vinyl-based resin with respect to a total mass of the binder resin is 50% by mass or more, the first toner contains the crystalline resin having a moiety having a crystal structure and a crystal nucleating agent moiety having a crystal nucleating agent, and the second toner contains the cyan colorant that is a compound represented by general formula (1). ##STR00001##

Provided are a process cartridge and an electrophotographic apparatus each of which is reduced in fogging for reducing a toner consumption. Specifically, provided is a process cartridge, which is removably mounted onto a main body of an electrophotographic apparatus, the process cartridge including: a developing unit containing a toner; and an electrophotographic photosensitive member, wherein the toner is a toner including a toner particle, and has a polyvalent acid metal salt on at least part of a surface of the toner particle, wherein the polyvalent acid metal salt includes at least one kind of metal element selected from metal elements belonging to from Group 3 to Group 13, and wherein a surface layer of the electrophotographic photosensitive member contains a resin including a siloxane segment.

The present disclosure provides a process cartridge and an electrophotographic apparatus in which fogging is reduced so as to reduce an amount of toner consumed. A process cartridge configured to be detachably attachable to a main body of an electrophotographic apparatus includes a developing unit containing a toner, and an electrophotographic photosensitive member, wherein the toner is a toner that has a toner particle, and has a metal salt of a polyvalent acid at least on a part of a surface of the toner particle; wherein the metal salt of the polyvalent acid includes at least one kind of metal element selected from metal elements belonging to from Group 3 to Group 13, and a surface layer of the electrophotographic photosensitive member contains an acrylic resin or a methacrylic resin.

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 positively-chargeable toner for developing electrostatic images excellent in printing durability, charge stability, and conveyance amount stability. The toner comprises colored resin particles comprising a binder resin and a colorant, and an external additive, wherein the external additive comprises spherical silica particles with a number average particle diameter of 70 to 200 nm. wherein the external additive has a particle size distribution in which a percentage of a number of particles having a particle diameter of 50 nm or more is 75% or more, which is calculated based on a SEM image.

A toner for developing electrostatic images, comprising colored resin particles that contain a binder resin, a colorant and a charge control agent, and external additives, wherein the external additives contain at least an external additive A and an external additive B; wherein the external additive A is metal oxide particles charged to the same polarity as a polarity of the colored resin particles, with a specific charge amount per unit surface area and a specific number average particle diameter; wherein the external additive B is resin particles charged to the opposite polarity to the polarity of the colored resin particles, with a specific number average particle diameter; and wherein a content of the external additive A and a content of the external additive B are in specific ranges.

A toner for developing electrostatic images, comprising colored resin particles that contain a binder resin, a colorant and a charge control agent, and external additives, wherein the external additives contain at least an external additive A and an external additive B; wherein the external additive A is metal oxide particles charged to the same polarity as a polarity of the colored resin particles, with a specific charge amount per unit surface area and a specific number average particle diameter; wherein the external additive B is resin particles charged to the opposite polarity to the polarity of the colored resin particles, with a specific number average particle diameter; and wherein a content of the external additive A and a content of the external additive B are in specific ranges.