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%.

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.

An image forming apparatus includes an image holding member; a charging unit; an electrostatic image forming unit; a developing unit that includes an electrostatic image developer including a toner and develops the electrostatic image formed on the surface of the image holding member with the electrostatic image developer to form a toner image; a transfer unit; and a cleaning unit that removes toner particles present on the surface of the image holding member. The cleaning unit includes a cleaning blade arranged to contact with the surface of the image holding member. The cleaning unit includes a cleaning blade A containing a contacting portion having a JIS-A hardness of 90 or more, or the cleaning unit includes a control unit B that controls a load with which the cleaning blade contacts with the image holding member, the control unit B controlling the load in a constant load mode. The toner includes toner particles; and silica particles having a number average particle size of 110 nm to 130 nm, a large-diameter-side number particle size distribution index (upper GSDp) of less than 1.080, and an average circularity of 0.94 to 0.98, wherein 80 number % or more of the silica particles have a circularity of 0.92 or more.

A toner includes toner particles. The toner particles each include a toner mother particle. The toner mother particles contain a binder resin, a magnetic powder, and a charge control agent. The binder resin includes a block polymer. The block polymer has a polyester portion and a vinyl polymer portion. The charge control agent includes a styrene-acrylic resin having a quaternary ammonium group. A content percentage of the charge control agent in the toner mother particles is at least 1.5% by mass and no greater than 12.0% by mass.

An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging device and a developing device, wherein the charging device comprises a conductive member arranged to be capable of contacting the electrophotographic photosensitive member, the conductive layer at the outer surface of the conductive member comprises a matrix and a plurality of domains dispersed in the matrix, at least some of the domains are exposed at the outer surface of the conductive member, the matrix has a volume resistivity R1 of larger than 1.0010.sup.12 .Math.cm, the volume resistivity R1 of the matrix is 1.010.sup.5 times or more a volume resistivity R2 of the domains, the developing device comprises the toner comprising a toner particle and a silica fine particle, and a coverage ratio of the toner surface with the silica fine particles is from 62.0% by area to 100.0% by area as determined by X-ray photoelectron spectroscopy.

An electrophotographic apparatus including an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit includes a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer of the conductive member has a matrix-domain structure, at least some of the domains are exposed at the outer surface of the conductive member, the volume resistivity RI of the matrix is greater than 1.0010.sup.12 .Math.cm and not greater than 1.0010.sup.17 .Math.cm, the matrix volume resistivity R1 is at least 1.010.sup.5-times the domain volume resistivity R2, and the developing unit includes a toner, the toner includes a binder resin-containing toner particle and an external additive, and the external additive contains fine particles of a hydrotalcite compound.

An electrophotographic apparatus comprising an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit has a conductive member contactable with the electrophotographic photosensitive member, and a conductive layer of the conductive member has a matrix-domain structure; at least some of the domains are exposed at the outer surface; a volume resistivity R1 of the matrix and a volume resistivity R2 of the domains satisfy specific relationship; Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy relationship G1<G2; the surface roughness Ra of the conductive member is not more than 2.00 m; the toner has an external additive having a shape factor SF-1 of not more than 115; and A<Dms is satisfied where A is the number-average diameter of the external additive and Dms is a distance between adjacent walls between the domains.

A toner comprising a toner particle comprising a magnetic body, and a silica fine particle on a surface of the toner particle, wherein fragment ions corresponding to a D unit structure are observed in a specific measurement; when the silica fine particle is dispersed in a mixed solution of ethanol and aqueous solution of NaCl, followed by a titration operation using sodium hydroxide, a titer is within a specific range; in a chemical shift obtained by a specific measurement, with D as an area of a peak having a peak top present in a range from 25 to 15 ppm, and with D1 as an area of a peak having a peak top present in a range of more than 19 ppm and 17 ppm or less, D and D1 are in a specific ratio; and the magnetic body is present on the surface of the toner particle.

A toner including a polyester resin-including toner particle and a silica fine particle, wherein fragment ions corresponding to a D unit structure are observed in TOF-SIMS measurement of the silica fine particle, where the silica fine particle is dispersed in a specific mixed liquid and a titration operation using sodium hydroxide is performed, the titer is within a specific range, where an area of a peak having a peak top within the range from 25 to 15 ppm in .sup.29Si-NMR measurement of the silica fine particle is denoted by D and an area of a peak having a peak top within the range from more than 19 ppm to 17 ppm or less is denoted by D1, the specific surface area of the silica fine particle, D and D1 satisfy specific relationships, and the polyester resin is present on the surface of the toner particle.

A toner which has a toner particle and silica fine particle A on a surface of the toner particle, wherein a weight average particle diameter of the toner is 4.0 to 15.0 m, a carbon loss ratio when the silica fine particle A is washed with hexane is 5 to 70%, and a temperature at which a differential coefficient of a nine-point moving average of integrated values integrated from 35 C. reaches 4000 or more for an intensity of an obtained ion having a mass number (M/z) of 207 is 270 C. or higher, when mass spectrometry is carried out at a sampling interval of 0.4 seconds while heating the silica fine particle A under specific conditions.