Abstract: The present invention provides a toner that can maintain excellent transferability even when a transfer bias is low. The toner includes a toner particle that includes a toner base particle and a plurality of convex portions X existing on a surface of the toner base particle, wherein the convex portion X contains an organic silicon polymer; when a cross-section of the toner is observed with a scanning transmission electron microscope (STEM), and the convex portions X comprise a plurality of convex portions Y each having a convex height H of 40 nm or higher, a number ratio P (H/w) of the a number of the convex portions Y2 in which a ratio (H/w) of the convex height H to the convex width w is 0.33 or larger and 0.80 or smaller is 70% by number or more with respect to a total number of the convex portions Y.

Abstract: A developing device comprising a developing roller in which a vicinity of an outer surface of a surface layer is hardened, a toner supply roller, and a toner, wherein the developing roller has fine particles comprising an organosilicon compound and having a substantially hemispherical shape on the outer surface, a particle diameter of the fine particles is within a specific range, and the toner comprises silica particles as an external additive and a adhesion rate of the silica particles is 50% or more.

Abstract: A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied: A?90??(I) 100?B?1000??(II).

Abstract: The process cartridge is a process cartridge to be removably mounted onto a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member; a toner; and a developing member, wherein the electrophotographic photosensitive member includes a surface layer that is a polymerized film of a composition containing at least one kind of monofunctional (meth)acrylic compound selected from the group consisting of: a monofunctional (meth)acrylic monomer; and a monofunctional (meth)acrylic oligomer, and at least one kind of tri- or higher functional (meth)acrylic compound selected from the group consisting of: a tri- or higher functional (meth)acrylic monomer; and a tri- or higher functional (meth)acrylic oligomer, wherein the toner contains a toner particle and a hydrotalcite particle as an external additive, and wherein the hydrotalcite particle contains fluorine in filter fitting analysis of STEM-EDS analysis.

Abstract: Provided is a process cartridge removably mountable onto a main body of an electrophotographic apparatus, the process cartridge comprising an electrophotographic photosensitive member, a toner, and a developing member configured to supply the toner to the electrophotographic photosensitive member, wherein, in filter fitting analysis in STEM-EDS analysis, a hydrotalcite particle comprises fluorine, and wherein, when a number-average primary particle diameter of a particle A is represented by “m” [nm], a content ratio of the particle A with respect to the surface layer is represented by “p” [vol %], and a number-average primary particle diameter of the hydrotalcite particle is represented by “h” [nm], the “m”, the “p”, and the “h” satisfy the following expressions, respectively: 5?m?300??Expression (1); 5?p?40??Expression (2); and 60?h?1,000??Expression (3).

Abstract: A process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including an electrophotographic photosensitive member, a toner, and a developing member that feeds the toner to the electrophotographic photosensitive member, wherein the electrophotographic photosensitive member includes a surface layer containing a (meth)acrylic resin having a urethane structure, the toner includes a toner particle and a hydrotalcite particle as an external additive, and the hydrotalcite particle contains fluorine in filter fitting analysis in STEM-EDS analysis.

Abstract: The subject toner includes a toner particle containing a binding resin and an inorganic oxide particle, wherein the inorganic oxide particle is a particle of an oxide containing at least one element selected from the group consisting of: Si; Mg; Al; Ti; and Sr, wherein, when an area of the inorganic oxide particle is represented by Sm and a sectional area of the toner is represented by St in a cross-section of the toner observed with a transmission electron microscope, Sm/St is 4.0% or more, wherein an area Sm of the inorganic oxide particle that occupies each of four regions obtained by dividing the cross-section of the toner by a long diameter of the toner and a perpendicular bisector of the long diameter has a standard deviation of 0.40 or more in the observed cross-section, and wherein the toner has an average circularity of 0.950 or more.

Abstract: A toner set capable of eliminating unclearness in a color boundary of an image in which a color image and a black image are printed side by side. The toner set includes at least: a black toner for forming a black image; and a color toner for forming a color toner image. The black toner is a toner comprising a black toner particle containing a black colorant formed of carbon black or iron oxide, a binder resin, and a releasing agent, and an external additive. The color toner is a toner comprising a color toner particle containing a color organic colorant, a binder resin, and a releasing agent. A ratio in surface roughness (Sa) between the toners is 1.30? surface roughness Sa(C) of color toner/surface roughness Sa(Bk) of black toner ?4.00. The surface roughness Sa(C) of the color toner is 10 nm to 30 nm.

Abstract: A toner comprising: a toner particle comprising a binder resin; and an external additive at the surface of the toner particle, wherein, in a wettability test of the toner in a mixed methanol/water solvent, the methanol concentration at which the transmittance of light having a wavelength of 780 nm is 50% is 5 to 35 vol %, the external additive comprises a fluorine-containing particle, and the fluorine-containing particle is at least one selected from the group consisting of a fluorine-containing titania particle, a fluorine-containing silica particle, a fluorine-containing alumina particle, a fluorine-containing titanium composite oxide particle and a fluorine-containing hydrotalcite particle.

Abstract: A toner comprising a toner particle and an external additive, wherein the toner particle comprises a core comprising a resin A and a shell comprising a resin B on the surface of the core, the external additive comprises a hydrotalcite particle A, fluorine and aluminum are present in an inner part of the hydrotalcite particle A in line analysis in STEM-EDS mapping analysis of the toner, and a concentration ratio of the number of fluorine atoms relative to aluminum atoms (F/Al) in the hydrotalcite particle A, as determined by primary component mapping of the hydrotalcite particle A in the STEM-EDS mapping analysis of the toner, is 0.01 to 0.60.

Abstract: The present disclosure provides a toner excellent in low-temperature fixability and excellent in durability under harsh environments of high-temperature and high-humidity, and a method for producing the toner. The toner can contain: a toner particle containing a binder resin, wax, and an inorganic oxide particle; and an external additive, wherein the inorganic oxide particle contains, as a main component, an oxide of at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; when a thin piece obtained by cutting the toner with a microtome is observed with a transmission electron microscope (TEM), the major axis A of the inorganic oxide particle is 0.10 to 3.00 ?m; and in a wettability test of the toner with respect to a methanol/water mixed solvent, a methanol concentration at a transmittance of light having a wavelength of 780 nm of 50% is 5.0 to 30.0% by volume.

Abstract: A toner comprising: a toner particle comprising a binder resin; and an external additive on a surface of the toner particle, wherein the binder resin comprises a resin having an ester bond, a peak corresponding to boric acid is detected in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal, and when a dispersed solution obtained by dispersing the toner in an aqueous solution containing a surfactant is subjected to a detachment treatment A including shaking for 300 seconds using a shaker, and when an external additive detached from the toner by the detachment treatment A is denoted as external additive A, a charge amount of the external additive A using a standard carrier (F81) is ?0.5 ?C/g or less.

Abstract: A toner comprising: a toner particle comprising a binder resin and boric acid; and an external additive A having a primary particle major diameter of 80 to 200 nm, wherein in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal, a peak corresponding to boric acid is detected, the average value of a shape factor SF-1 of the external additive A is 105 to 250, and the average value of a shape factor SF-2 of the external additive A is 102 to 250.

Abstract: 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/mm2 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.

Abstract: 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/mm2 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.

Abstract: A toner comprising a toner particle comprising a binder resin, a crystalline material A, and a crystalline material B, wherein the binder resin contains a resin M in an amount of 70 mass % or more relative to the binder resin, the crystalline material A has a melting point of 50.0° C. to 100.0° C., and when, the difference between the SP value of the resin M and material A is designated as ?SPAM, the difference between the SP value of the resin M and crystalline material B is designated as ?SPBM, the difference between the SP value of the crystalline material A and crystalline material B is designated as ?SPAB, the peak molecular weight of the crystalline material A and crystalline material B is designated as MpA and MpB each, the formulae (1) to (3) are satisfied: 50?MpB×?SPBM2?MpA×?SPAM2?450??(1) MpA×?SPAM2?800??(2) ?SPAB?0.

Abstract: A toner including: a toner particle containing a binder resin and a colorant; and a fine particle on a surface of the toner particle, wherein the fine particle is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, and wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm. An external additive for a toner that is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm. A fine particle that is a solid and substantially hemispherical shape, and has a substantially flat surface and a curved surface, wherein a number-average value of a longest diameter “w” of the substantially flat surface is 10 to 400 nm.

Abstract: The present invention provides a toner that can maintain excellent transferability even when a transfer bias is low. The toner includes a toner particle that includes a toner base particle and a plurality of convex portions X existing on a surface of the toner base particle, wherein the convex portion X contains an organic silicon polymer; when a cross-section of the toner is observed with a scanning transmission electron microscope (STEM), and the convex portions X comprise a plurality of convex portions Y each having a convex height H of 40 nm or higher, a number ratio P (H/w) of the a number of the convex portions Y2 in which a ratio (H/w) of the convex height H to the convex width w is 0.33 or larger and 0.80 or smaller is 70% by number or more with respect to a total number of the convex portions Y.

Abstract: A toner including a toner particle including a binder resin, wherein fine particles A and B are present on a surface of the toner particle; the fine particles A are a fatty acid metal salt; the fine particles B have a specific volume resistivity; an average theoretical surface area of the toner particle, an amount of the fine particles A, and a coverage ratio of the toner particle surface by the fine particles A satisfy a specific relationship; the amount of the fine particles B is in a specific range; and a proportion F of an area occupied by a part of the fine particles B embedded in a surface vicinity region of the toner in a total area occupied by the fine particles B present in a cross section of one particle of the toner is 50% by area or more.

Abstract: A toner comprising a toner particle and an external additive, wherein the external additive comprises a composite particle comprising an organosilicon polymer fine particle covering a surface of an alumina particle, a coverage ratio of the surface of the alumina particle with the organosilicon polymer fine particle is 1 to 50 area %, and given A (nm) as a number-average particle diameter of primary particles of the organosilicon polymer fine particle and B (nm) as a number-average particle diameter of primary particles of the alumina particle, following formulae (I) and (II) are satisfied: A?90??(I) 100?B?1000??(II).