Abstract: A toner comprising a toner particle, the toner particle comprising: a binder resin and a wax; wherein the toner particle has a toner core particle and a protrusion present on the surface of the toner core particle, the protrusion comprises an organosilicon polymer, where in cross-sectional observation of the toner particle, a line segment connecting both ends of an interface between the toner core particle and the protrusion is defined as a reference line, and the length of the reference line is denoted by W (nm), and a maximum length of the protrusion in the toner core particle direction from the reference line in the normal direction of the reference line is defined as a maximum penetration depth I (nm), W and I satisfy I/W?0.050, and Young's modulus of the protrusion E1 is 1.00 to 3.90 GPa.

Abstract: A toner comprising a toner particle, wherein the toner particle comprises a binder resin and wax, and where with respect to a slope X of a straight line obtained by performing a micro-compression test on the toner, obtaining a relationship of a deformation amount (?m) to a load (mN), calculating a percentage deformation (%), which is a ratio of the deformation amount to a particle diameter of the particle measured, plotting a load (mN)?percentage deformation (%) plot, and then using all the points plotted within the range in which the percentage deformation was 15% or less of the particle diameter of the particle for approximation by a least squares method, the slope X measured at 30° C. is denoted by X30 and the slope X measured at 45° C. is denoted by X45, the X30 is 25 to 300, and the X45 is 400 to 1000.

Abstract: Provided are a process cartridge and an electrophotographic apparatus each capable of suppressing an image defect (coarseness in a halftone image) caused by toner scattering in association with a charging failure that occurs when the process speed of the electrophotographic apparatus is further increased. The process cartridge includes: an electrophotographic photosensitive member; and a developing unit, which includes a toner storing portion that stores a toner, and which supplies the toner to a surface of the electrophotographic photosensitive member. The electrophotographic photosensitive member includes a surface protective layer containing an electroconductive particle in an appropriate amount, and the volume resistivity of the surface protective layer is controlled. As the toner, there is used a toner in which an organosilicon polymer is present on the surface of a toner particle, a silanol group is present in part of the organosilicon polymer, and the amount of the silanol group is controlled.

Abstract: Provided is a process cartridge that is excellent in initial charge rising performance, and in charge uniformity of a halftone image throughout a long period of time from the start of use until after endurance. Specifically, provided is a process cartridge including: an electrophotographic photosensitive member; a toner; and a developing unit, wherein the toner contains toner particles and an external additive A, the external additive A, and wherein the electrophotographic photosensitive member includes an electroconductive support, a photosensitive layer, and a surface protective layer, wherein the surface protective layer contains electroconductive particles.

Abstract: A toner comprising a toner particle comprising a binder resin and an ester compound, wherein: the binder resin comprises a resin A comprising a specific amount of a long-chain acrylate unit and a styrene-based monomer unit, and a resin B comprising a specific monomer unit in a specific amount; the ester compound has an alkyl chain with a specific chain length, a content of the resin A in the chloroform-soluble portion of the toner particles is 60% by mass or more; and using SPm (J/cm3)1/2 for a SP value of the long-chain acrylate unit and using SPw (J/cm3)1/2 for a SP value of the ester compound, SPm is 18.00 to 19.00, and SPm and SPw satisfy formula (a). |SPm?SPw|?1.

Abstract: Provided are a process cartridge and an electrophotographic apparatus each capable of suppressing an image defect (coarseness in a halftone image) caused by toner scattering in association with a charging failure that occurs when the process speed of the electrophotographic apparatus is further increased. The process cartridge includes: an electrophotographic photosensitive member; and a developing unit, which includes a toner storing portion that stores a toner, and which supplies the toner to a surface of the electrophotographic photosensitive member. The electrophotographic photosensitive member includes a surface protective layer containing an electroconductive particle in an appropriate amount, and the volume resistivity of the surface protective layer is controlled. As the toner, there is used a toner in which an organosilicon polymer is present on the surface of a toner particle, a silanol group is present in part of the organosilicon polymer, and the amount of the silanol group is controlled.

Abstract: A process cartridge that is detachable from a main body of an electrophotographic apparatus, in which a surface protective layer of an electrophotographic photosensitive member contains an electroconductive particle; the content of the electroconductive particle is 20.0 to 70.0% by volume of the surface protective layer; the surface protective layer has a volume resistivity of 1.0×109 to 1.0×1014 ?·cm; a toner particle has at least one multivalent metal element selected from the group consisting of aluminum, magnesium, calcium, and iron; and a total content of the multivalent metal elements in the toner particle, as measured by coupled induction plasma atomic emission spectrometry (ICP-AES), is 0.10 to 1.25 ?mol/g.

Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer at the surface of the conductive member has a matrix-domain structure, at least a portion of the domains is exposed at the outer surface of the conductive member, the outer surface of the conductive member is constituted at least of the matrix and these domains, a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm, a volume resistivity R2 of the domains is less than R1, Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy a prescribed relationship, and an onset temperature T(A) for a storage elastic modulus E? of the toner is not more than 80.0° C.

Abstract: The present disclosure provides a toner that achieves both high image gloss and high image loadability. The toner includes a toner particle that includes: a styrene-acrylic resin having a unit represented by the formula (1); and an ester compound A, wherein the ester compound A is an ester compound represented by the formula (2) or the formula (3): and an absolute value of a difference between SPb (J/cm3)1/2 that is an SP value of the styrene-acrylic resin and SPw1 (J/cm3)1/2 that is an SP value of the ester compound A is 1.00 or larger and 2.00 or smaller.

Abstract: A toner including a toner particle containing a binder resin and an ester compound, wherein the binder resin contains a styrene-acrylic-based resin, the styrene-acrylic-based resin contains a specific unit, the ester compound has a specific structure, and a molar ratio of the specific unit to the ester compound is 0.5 to 1.5.

Abstract: A toner comprising a toner particle comprising a binder resin, a hydrocarbon wax A, and an ester wax B, wherein assuming that a ratio of a peak intensity attributed to the hydrocarbon wax A to a peak intensity attributed to the binder resin in heating IR measurement in which the toner is held at 100° C. for 10 min is I, where an initial peak intensity ratio upon heating to 100° C. is denoted by I(ini) and a peak intensity ratio upon heating to 100° C. and holding for 10 min is denoted by I(10 min), the I(ini) and the I(10 min) satisfy a following formula (1): I(ini)/I(10 min)?0.95??(1).

Abstract: A toner comprising a toner particle comprising a binder resin, and an ester wax A having a specific structure, wherein in a diffraction spectrum obtained by an X-ray diffractometer after the toner has been allowed to stand at 120° C. for 5 minutes and then at 60° C. for 5 minutes, assuming that a spectrum having a maximum peak in a range where 2? is from 5.45° to 5.95° is P1 and an integrated intensity of the P1 is S1, and a spectrum having a maximum peak in a range where 2? is from 21.45° to 21.95° is P2 and an integrated intensity of the P2 is S2, relationships of formulas (2) and (3) below are satisfied. S1/S2?0.

Abstract: A toner comprising a toner particle including a binder resin and a colorant and an external additive, wherein the external additive contains an external additive A having a Feret diameter of 60 to 200 nm, the external additive A is inorganic fine particles or organic-inorganic composite fine particles, adhesion index of the external additive A to the toner is 0.00 to 3.00, and penetration depth b and protrusion height c satisfy Relational expressions (1) and (2) below, where b (nm) denotes penetration depth of the external additive A, at a portion of the external additive A penetrating into the toner particle interior from the surface thereof, and c (nm) denotes a protrusion height of the external additive A at that portion, in an observation of an image resulting from image processing of a cross section of the toner using TEM; 60?b+c?200??(1), 0.15?b/(b+c)?0.30??(2).

Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer at the surface of the conductive member has a matrix-domain structure, at least a portion of the domains is exposed at the outer surface of the conductive member, the outer surface of the conductive member is constituted at least of the matrix and these domains, a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm, a volume resistivity R2 of the domains is less than R1, Martens hardness G1 of the matrix and Martens hardness G2 of the domains satisfy a prescribed relationship, and an onset temperature T(A) for a storage elastic modulus E? of the toner is not more than 80.0° C.

Abstract: An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00×1012 ?·cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

Abstract: A toner comprising: a toner particle that contains a binder resin and a colorant: and an external additive, wherein (1) the average circularity of the toner is at least 0.960; (2) the fixing ratio of the external additive on the toner particle is from 75% to 100%; and (3) in a differential curve obtained by the differentiation, by load, of a load-displacement curve where the horizontal axis is load (mN) and the vertical axis is displacement (?m), the load-displacement curve being provided by measurement of the strength of the toner by a nanoindentation procedure, a load A that provides a maximum value in the differential curve in a load region from 0.20 mN to 2.30 mN is from 1.15 mN to 1.50 mN.

Abstract: Provided is a toner containing a toner particle including a binder resin, a wax, and a colorant. The softening point of the toner is at least 80° C. and not more than 140° C. The average circularity of the toner is at least 0.940. The integrated value of stress in the toner at 150° C. which is measured by using a tackiness tester is at least 78 g·m/sec.

Abstract: A toner comprising a toner particle including a binder resin and a colorant and an external additive, wherein the external additive contains an external additive A having a Feret diameter of 60 to 200 nm, the external additive A is inorganic fine particles or organic-inorganic composite fine particles, adhesion index of the external additive A to the toner is 0.00 to 3.00, and penetration depth b and protrusion height c satisfy Relational expressions (1) and (2) below, where b (nm) denotes penetration depth of the external additive A, at a portion of the external additive A penetrating into the toner particle interior from the surface thereof, and c (nm) denotes a protrusion height of the external additive A at that portion, in an observation of an image resulting from image processing of a cross section of the toner using TEM; 60?b+c?200??(1), 0.15?b/(b+c)?0.30??(2).

Abstract: A toner comprising a toner particle that contains a binder resin and a colorant, wherein (1) an average circularity of the toner is at least 0.960, (2) an onset temperature T? (° C.) of a storage elastic modulus E? of the toner, as determined by a powder dynamic viscoelastic measurement, is from 50° C. to 70° C., and (3) in a differential curve obtained by differentiation, by load, of a load-displacement curve provided by measurement of the strength of the toner by a nanoindentation procedure, with the horizontal axis being load (mN) and the vertical axis being displacement (?m), the load X that provides the maximum value in the differential curve in the load region from 0.20 mN to 2.30 mN is from 1.00 mN to 1.50 mN.