Abstract: Provided is a toner including a toner particle containing a binder resin, and an external additive, wherein the external additive contains an external additive A and an external additive B, the external additive A is an organosilicon polymer fine particle, the number-average particle diameter of primary particles of the organosilicon polymer fine particle is from 30 to 300 nm, the external additive B is a silica fine particle, the number-average particle diameter of primary particles of the silica fine particle is from 100 to 300 nm, the fixing rate of the external additive A to the toner particle according to a water washing method is less than 30%, and the fixing rate of the external additive B to the toner particle according to the washing method is at least 30%.

Abstract: A toner including a toner particle containing a binder resin and an external additive, wherein the toner particle contains a polyvalent metal compound, the polyvalent metal compound is at least one selected from the group consisting of aluminum compounds, iron compounds and magnesium compounds, a content of a metal element derived from the polyvalent metal compound in the toner particle is from 0.080 to 20.000 ?mol/g, the external additive contains an organosilicon polymer particle having a hydroxyl group, a ratio of a number-average particle diameter of the organosilicon polymer particle to a number-average particle diameter of the toner particle is from 0.0160 to 0.0650, and a content of the organosilicon polymer particle is at least 0.10 mass parts per 100.00 mass parts of the toner particle.

Abstract: A toner comprising a toner particle that contains a binder resin and a wax; in a microcompression test under a maximum load condition of 1.1×10?3 N, a force applied to the toner particle when a percentage deformation of the toner particle with reference to a number-average particle diameter of the toner particle at 25° C. reaches 15% is 0.10 to 1.00 mN and the force applied to the toner particle when the percentage deformation at 45° C. reaches 15% is 0.10 to 0.40 mN; and when the force applied to the toner particle is a variable and the percentage deformation of the toner particle is from 15 to 30%, the rate of increase in the percentage deformation of the toner particle at 25° C. and the rate of increase in the percentage deformation of the toner particle at 45° C. satisfy specific formula.

Abstract: A developing device includes a developer carrying member, a developing frame, and a regulating member. The regulating member includes a curved surface portion contactable to a surface of the developer carrying member, and satisfies the following relationships: 200 MPa?HM?1100 MPa, and 0.08 mm?Rb?0.3 mm, where HM is a Martens hardness of toner contained in the developer under a maximum load of 2.0×10?4 N, and Rb is a radius of curvature of the curved surface portion.

Abstract: A toner having a toner particle including a binder resin and a wax, wherein the wax includes a specific diester compound; a proportion As of an area occupied by the wax in a region from a surface of the toner particle to 0.5 ?m is 15.0% or less; wax domains are observed in the cross section of the toner particle, and an average number of the domains per cross section of one toner particle is from 10 to 2000; when a mass concentration of a polyvalent metal element in the toner particle determined by fluorescent X-ray analysis is denoted by Mi (ppm), Mi is from 3.5 ppm to 1100 ppm; and when a mass concentration of a polyvalent metal element in the toner particle determined by X-ray photoelectron spectroscopy is denoted by Ms (ppm), Mi>Ms.

Abstract: An image forming apparatus including: an image bearing member; a developing member to supply a developer to the image bearing member; and a cleaning member to clean a peripheral surface of the image bearing member in contact with the peripheral surface, wherein a plurality of grooves extend in a circumferential direction on the peripheral surface, and have a width in a generatrix direction of the peripheral surface within a range of at least 0.5 ?m and not more than 40 ?m, and are formed to be side by side in the generatrix direction; the number of the grooves is at least 20 and not more than 1000 per a width of 1000 ?m in the generatrix direction of the peripheral surface; and an average depth (Rvk) of a valley of a projection under a core section of a roughness curve of the peripheral surface is 0.08 ?m or less.

Abstract: Provided is a process cartridge including: an electrophotographic photoreceptor; a charging unit configured to charge the electrophotographic photoreceptor through abutment against the electrophotographic photoreceptor; a developing unit configured to develop an electrostatic latent image formed on the electrophotographic photoreceptor with a toner to form a toner image; and a cleaning unit configured to remove the toner on the electrophotographic photoreceptor by bringing a blade into abutment against the electrophotographic photoreceptor, wherein the toner includes a toner base containing a coloring agent and a binder resin, and has a surface layer containing an organosilicon polymer having a specific sticking ratio to a toner base, and wherein the electrophotographic photoreceptor includes a supporting member and a surface layer, and the surface layer has a specific universal hardness value and a specific elastic deformation ratio (We).

Abstract: A charging member that contacts an image bearing member and charges the image bearing member has an electrically conductive support and an elastic layer in contact with the image bearing member. The elastic layer includes a semiconductive rubber composition including a matrix and domains having electric conductivity. The semiconductive rubber composition has a sea-island structure in which the domains form an island phase and the matrix forms a sea phase. The matrix has a higher volume resistivity than the domains. The developer includes a toner, and the toner has a Martens hardness of at least 200 MPa and not more than 1100 MPa when measured under a maximum load of 2.0×10?4 N.

Abstract: A toner including a toner particle containing a binder resin and an external additive, wherein the toner particle contains a polyvalent metal compound, the polyvalent metal compound is at least one selected from the group consisting of aluminum compounds, iron compounds and magnesium compounds, a content of a metal element derived from the polyvalent metal compound in the toner particle is from 0.080 to 20.000 ?mol/g, the external additive contains an organosilicon polymer particle having a hydroxyl group, a ratio of a number-average particle diameter of the organosilicon polymer particle to a number-average particle diameter of the toner particle is from 0.0160 to 0.0650, and a content of the organosilicon polymer particle is at least 0.10 mass parts per 100.00 mass parts of the toner particle.

Abstract: Provided is a toner including a toner particle containing a binder resin, and an external additive, wherein the external additive contains an external additive A and an external additive B, the external additive A is an organosilicon polymer fine particle, the number-average particle diameter of primary particles of the organosilicon polymer fine particle is from 30 to 300 nm, the external additive B is a silica fine particle, the number-average particle diameter of primary particles of the silica fine particle is from 100 to 300 nm, the fixing rate of the external additive A to the toner particle according to a water washing method is less than 30%, and the fixing rate of the external additive B to the toner particle according to the washing method is at least 30%.

Abstract: Provided is a toner including a toner particle and an external additive, wherein the external additive includes a composite particle including a hydrotalcite particle covered on the surface with an organosilicon polymer fine particle, a coverage ratio of the hydrotalcite particle surface by the organosilicon polymer fine particle is from 1% to 50%, and given A (nm) as the number-average particle diameter of the primary particles of the organosilicon polymer fine particle and B (nm) as the number-average particle diameter of the primary particles of the hydrotalcite particle, the toner satisfies the following formula (I) and formula (II): A<B??(I) 20?A?350??(II).

Abstract: A toner including a toner particle containing a binder resin, and an external additive, wherein the external additive contains an organosilicon polymer fine particle, the organosilicon polymer has a structure represented by at least one selected from the group consisting of RaSiO3/2 and Rb2SiO2/2 (wherein Ra and Rb represent organic groups), and in the number particle size distribution of the toner as measured within a particle size range of from 2 to 60 ?m, the number-average particle diameter T-D50n at which the accumulation from the smallest diameter is 50% is from 6 to 12 ?m, the number ratio of toner 4 ?m or less in size is from 2% to 5% of the total toner, and the number ratio of toner 3 ?m or less in size as a percentage of the total toner 4 ?m or less in size is from 25% to 50%.

Abstract: A toner containing: a toner particle that contains a binder resin and an external additive, wherein the external additive contains an organosilicon polymer fine particle, the binder resin contains an amorphous resin and a crystalline polyester resin, a content of the crystalline polyester resin in the binder resin is from 5 to 30 mass %, and the crystalline polyester resin contains from 5 to 25 mass % of a component having a molecular weight of not more than 2,500.

Abstract: A toner including a toner particle containing a binder resin and an external additive, wherein the external additive contains composite particles of an organosilicon polymer fine particle and a fatty acid metal salt.

Abstract: A charging member 2 that charges an image bearing member 1 has an electrically conductive support and an elastic layer in contact with the image bearing member 1. The elastic layer includes a semi-conductive rubber composition having a matrix-domain structure including a matrix and domains having electric conductivity. The matrix has a higher volume resistivity than the domain. The developer includes a toner having toner particles. The toner particles each have a surface layer including an organosilicon polymer. The organosilicon polymer has a structure represented by R—SiO3/2 (R is a hydrocarbon group having at least 1 and not more than 6 carbon atoms). The adhesion ratio of the organosilicon polymer on the surface of the toner particle is 90% or more.

Abstract: A charging member that contacts an image bearing member and charges the image bearing member has an electrically conductive support and an elastic layer in contact with the image bearing member. The elastic layer includes a semiconductive rubber composition including a matrix and domains having electric conductivity. The semiconductive rubber composition has a sea-island structure in which the domains form an island phase and the matrix forms a sea phase. The matrix has a higher volume resistivity than the domains. The developer includes a toner, and the toner has a Martens hardness of at least 200 MPa and not more than 1100 MPa when measured under a maximum load of 2.0×10?4 N.

Abstract: A developing device includes a developer carrying member, a developing frame, and a regulating member. The regulating member includes a curved surface portion contactable to a surface of the developer carrying member, and satisfies the following relationships: 200 MPa?HM?1100 MPa, and 0.08 mm?Rb?0.3 mm, where HM is a Martens hardness of toner contained in the developer under a maximum load of 2.0×10?4 N, and Rb is a radius of curvature of the curved surface portion.

Abstract: An image forming apparatus including: an image bearing member; a developing member to supply a developer to the image bearing member; and a cleaning member to clean a peripheral surface of the image bearing member in contact with the peripheral surface, wherein a plurality of grooves extend in a circumferential direction on the peripheral surface, and have a width in a generatrix direction of the peripheral surface within a range of at least 0.5 ?m and not more than 40 ?m, and are formed to be side by side in the generatrix direction; the number of the grooves is at least 20 and not more than 1000 per a width of 1000 ?m in the generatrix direction of the peripheral surface; and an average depth (Rvk) of a valley of a projection under a core section of a roughness curve of the peripheral surface is 0.08 ?m or less.

Abstract: A toner having a toner particle including a binder resin and a wax, wherein the wax includes a specific diester compound; a proportion As of an area occupied by the wax in a region from a surface of the toner particle to 0.5 ?m is 15.0% or less; wax domains are observed in the cross section of the toner particle, and an average number of the domains per cross section of one toner particle is from 10 to 2000; when a mass concentration of a polyvalent metal element in the toner particle determined by fluorescent X-ray analysis is denoted by Mi (ppm), Mi is from 3.5 ppm to 1100 ppm; and when a mass concentration of a polyvalent metal element in the toner particle determined by X-ray photoelectron spectroscopy is denoted by Ms (ppm), Mi>Ms.

Abstract: A toner comprising a toner particle that contains a binder resin and a wax; in a microcompression test under a maximum load condition of 1.1×10?3 N, a force applied to the toner particle when a percentage deformation of the toner particle with reference to a number-average particle diameter of the toner particle at 25° C. reaches 15% is 0.10 to 1.00 mN and the force applied to the toner particle when the percentage deformation at 45° C. reaches 15% is 0.10 to 0.40 mN; and when the force applied to the toner particle is a variable and the percentage deformation of the toner particle is from 15 to 30%, the rate of increase in the percentage deformation of the toner particle at 25° C. and the rate of increase in the percentage deformation of the toner particle at 45° C. satisfy specific formula.