Abstract: A toner comprising a toner particle comprising a resin A, and an external additive A, wherein the resin A is a resin represented by formula (1) below, the resin A is present at the surface of the toner particle, the external additive A is a fine particle containing silicon, the average value of the shape factor SF-1 of the external additive A is from 105 to 120, the average value of the shape factor SF-2 of the external additive A is from 100 to 130.

Abstract: A toner comprising a toner particle, wherein the toner particle includes a binder resin, where a volume resistivity ?·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/cm2 is denoted by Tv, and a volume resistivity ?·cm of the solid image after fixing by applying heat and pressure to the recording material is denoted by Fv, Tv/Fv?8 is satisfied.

Abstract: A toner including a toner particle, wherein the toner particle includes a toner base particle containing a binder resin, and a shell on the surface of the toner base particle; the shell contains a metal compound and an organosilicon polymer; the shell has at least an exposed portion of the metal compound and an exposed portion of the organosilicon polymer, on the surface of the toner particle; and in an analysis of a cross section of the toner particle by TEM-EDX, Ha (nm) and Hb (nm) which are average distances from the interface of the toner base particle and the shell up to the toner particle surface at the exposed portion of the metal compound and at the exposed portion of the organosilicon polymer, respectively, on the toner particle surface, satisfy Expression (1) below: Hb>Ha+20.0??(1).

Abstract: 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.

Abstract: 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.

Abstract: A toner comprising a toner particle, wherein the toner has G1 of from 5.0×10?13 to 1.0×10?10, and a ratio G2/G1 of G2 to G1 is from 0.10 to 0.60, when a conductivity of the toner measured at a frequency of 0.01 Hz under a pressure of 1,000 kPa is designated by G1 in S/m, and a conductivity of the toner measured at a frequency of 0.01 Hz under a pressure of 100 kPa is designated by G2 in S/m.

Abstract: A toner comprising a toner particle, wherein the toner particle includes a binder resin, where a volume resistivity ?·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/cm2 is denoted by Tv, and a volume resistivity ?·cm of the solid image after fixing by applying heat and pressure to the recording material is denoted by Fv, Tv/Fv?8 is satisfied.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A toner including a toner particle, wherein the toner particle includes a toner base particle containing a binder resin, and a shell on the surface of the toner base particle; the shell contains a metal compound and an organosilicon polymer; the shell has at least an exposed portion of the metal compound and an exposed portion of the organosilicon polymer, on the surface of the toner particle; and in an analysis of a cross section of the toner particle by TEM-EDX, Ha (nm) and Hb (nm) which are average distances from the interface of the toner base particle and the shell up to the toner particle surface at the exposed portion of the metal compound and at the exposed portion of the organosilicon polymer, respectively, on the toner particle surface, satisfy Expression (1) below:

Abstract: A toner comprising a toner particle having a binder resin and a colorant, and metal titanate fine particles, wherein the toner particle includes a polyvalent metal element having an electric resistivity of from 2.5×10?8 ?·m to 10.0×10?8 ?·m; the amount of the polyvalent metal element in the toner particle is from 0.080 ?mol/g to 20.000 ?mol/g; the metal titanate fine particles have a perovskite crystal structure; and the number average particle diameter of primary particles of the metal titanate fine particles is from 10 nm to 80 nm.

Abstract: A toner comprising a toner particle having a binder resin and a colorant, and metal titanate fine particles, wherein the toner particle includes a polyvalent metal element having an electric resistivity of from 2.5×10?8 ?·m to 10.0×10?8 ?·m; the amount of the polyvalent metal element in the toner particle is from 0.080 ?mol/g to 20.000 ?mol/g; the metal titanate fine particles have a perovskite crystal structure; and the number average particle diameter of primary particles of the metal titanate fine particles is from 10 nm to 80 nm.

Abstract: A toner including a toner particle that contains a binder resin, a polyester resin A and a wax, wherein the polyester resin A contains a specific amount of an isosorbide unit based on a total number of monomer units constituting the polyester resin A, the content of the polyester resin A is a specific amount, and when observing a cross-section of the toner, twenty toner particle cross-sections are selected that have a major axis R (?m) that satisfies a specific relationship with respect to the weight-average diameter D4 (?m) of the toner, each major axis r that have the largest major axis is measured for those domains composed of wax present in the selected toner particle cross-sections, and the arithmetic mean (r/R)st of the determined r/R satisfies a specific relationship.

Abstract: A toner including a toner particle that contains a binder resin, a polyester resin A and a wax, wherein the polyester resin A contains a specific amount of an isosorbide unit based on a total number of monomer units constituting the polyester resin A, the content of the polyester resin A is a specific amount, and when observing a cross-section of the toner, twenty toner particle cross-sections are selected that have a major axis R (?m) that satisfies a specific relationship with respect to the weight-average diameter D4 (?m) of the toner, each major axis r that have the largest major axis is measured for those domains composed of wax present in the selected toner particle cross-sections, and the arithmetic mean (r/R)st of the determined r/R satisfies a specific relationship.

Abstract: It is intended to provide an image forming method, a process cartridge and an electrophotographic apparatus which have favorable cleaning properties and can suppress reduction in image quality caused by the contamination of a charging member. A surface layer of an electrophotographic photosensitive member satisfies the condition (i) or (ii), and toner contains a resin having an isosorbide unit: (i) containing a fluorine resin particle and at lease one resin selected from the group consisting of a polyarylate resin and a polycarbonate resin, and (ii) containing at least one resin selected from the group consisting of a polyarylate resin and a polycarbonate resin each having a polysiloxane structure.

Abstract: A toner has a toner particle that contains a binder resin and a charge control resin, wherein the charge control resin is a polymer that contains a unit A and a unit B, the unit A is a unit derived from 2-acrylamido-2-methylpropanesulfonic acid, the unit B is a unit derived from an electron donor compound that has a polymerizable unsaturated group, and a molar ratio between the unit A and the unit B is from 1.0 to 10.0.

Abstract: Since a charge amount of a toner and a charge rise characteristic thereof are liable to be influenced by the change in temperature and humidity condition, the change in image density occurs in printing, and in particular, in high temperature and high humidity environment, inconveniences, such as image fogging, occur due to non-uniformity of the charge amount distribution. In a toner including toner particles obtained by dispersing a monomer composition containing a polymerizable monomer and a colorant in an aqueous medium to form droplets and polymerizing the polymerizable monomer in the droplets, the toner particles contain a polymer formed by a polymerization reaction of the polymerizable monomer and a metal compound having a vinyl group.

Abstract: A toner including a toner particle that contains a binder resin, a polyester resin A and a wax, wherein the polyester resin A contains a specific amount of an isosorbide unit based on a total number of monomer units constituting the polyester resin A, the content of the polyester resin A is a specific amount, and when observing a cross-section of the toner, twenty toner particle cross-sections are selected that have a major axis R (?m) that satisfies a specific relationship with respect to the weight-average diameter D4 (?m) of the toner, each major axis r that have the largest major axis is measured for those domains composed of wax present in the selected toner particle cross-sections, and the arithmetic mean (r/R)st of the determined r/R satisfies a specific relationship.

Abstract: A toner has a toner particle that contains a binder resin and a charge control resin, wherein the charge control resin is a polymer that contains a unit A and a unit B, the unit A is a unit derived from 2-acrylamido-2-methylpropanesulfonic acid, the unit B is a unit derived from an electron donor compound that has a polymerizable unsaturated group, and a molar ratio between the unit A and the unit B is from 1.0 to 10.0.