Abstract: 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 1.00×1012 ?·cm, the volume resistivity R1 of the matrix is 1.0×105 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.

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 process cartridge includes an electrophotographic photosensitive member having a first support and a photosensitive layer; and a charging member. In the photosensitive member when an electric current is measured which flows when a voltage is applied to a surface while being varied, a gradient a1 of a low electric field region and a gradient a2 of a high electric field region satisfy a2/a1?1.50, in a graph. The charging member includes a second support having an electroconductive outer surface, and a second electroconductive layer including a matrix and a plurality of domains being dispersed in the matrix, at least a portion of the domain is exposed to an outer surface which includes at least the matrix and at least a portion of the domain, and a volume resistivity ?M of the matrix is 1.00×105 times or higher of a volume resistivity ?D of the domain.

Abstract: 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 1.00×1012 ?·cm and not greater than 1.00×1017 ?·cm, the matrix volume resistivity R1 is at least 1.0×105-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.

Abstract: There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including: an electrophotographic photosensitive member and a charging member, in which when average local potential differences of calculated lengths in the electrophotographic photosensitive member is calculated based on a specific method, a maximum value of the average local potential difference is 2 V or more, the charging member includes a support and an electro-conductive layer, the electro-conductive layer has a matrix and domains dispersed in the matrix, a volume resistivity ?M of the matrix is at least 1.00×105 times a volume resistivity ?D of the domain, and a specific calculated length SCP [?m] and a specific value relating a distance between the domains Dms [?m] satisfy SCP?3×Dms.

Abstract: 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.

Abstract: A process cartridge which allows any spot and stripe as image defects to be suppressed is provided. A process cartridge, in which an electroconductive layer of a charging member has a matrix including a first rubber, and domains dispersed in the matrix, the domains include a second rubber and an electron electroconductive agent, at least some of the domains are exposed on a surface of the charging member, when a volume resistivity of the matrix is 105 times or more a volume resistivity of the domains, a protective layer of an electrophotographic photosensitive member includes a metal oxide particle, and when a number average primary particle size of the metal oxide particle is defined as Sm and an average value of equivalent circle diameters of the domains is defined as Sd, the Sd/Sm satisfies the following expression (1): 0.5<Sd/Sm<100 . . . expression (1).

Abstract: Provided is a process cartridge in which lateral running is suppressed while satisfactory potential fluctuation is maintained. The process cartridge includes: an electrophotographic photosensitive member including a support, a lowermost layer, and a photosensitive layer; and a charging member including a support and a conductive layer. In a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the lowermost layer while changing the AC voltage, is represented by fOPC (Hz), and in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the charging member while changing the AC voltage, is represented by fC (Hz), the fOPC and the fC each have a value within a certain range.

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: There is provided a process cartridge detachably attachable to a main body of an electrophotographic apparatus, the process cartridge including an electrophotographic photosensitive member and a charging member, wherein an outer surface of the charging member is composed of at least a matrix and at least a part of domains, a volume resistivity of the matrix is 1.0×105 times or more of a volume resistivity of the domain, an average value Sd of circle equivalent diameters of the domains observed on the outer surface of the charging member is in a predetermined range, the electrophotographic photosensitive member contains a support, a photosensitive layer, and a protective layer in this order and when a surface roughness of the protective layer is measured, each of a protruding valley portion Rvk, a load length ratio Mr2, and Sd/Rvk is in a predetermined range.

Abstract: 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, a conductive layer on the conductive member outer surface comprises a matrix and a plurality of domains dispersed in the matrix, at least some of the domains are exposed at the conductive member outer surface, the matrix has a volume resistivity of larger than 1.00×1012 ?·cm and is 1.0×105 times or more one of the domains, the developing device comprises the toner comprising a toner particle, fine particles A and B, the fine particle A has a volume resistivity of 1.0×103 to 1.0×1010 ?·cm, and the fine particle B is silica fine particle and having a volume resistivity of 1.0×1011 to 1.0×1017 ?·cm.

Abstract: A process cartridge is provided, which is configured to recover, with a developing member, developer remaining on an image bearing member after transfer of a developer image to a transfer receiving member, wherein a charging member has a shaft that is conductive and an elastic layer supported on the shaft and being in contact with the image bearing member; the elastic layer has a matrix containing a first rubber, and a plurality of domains containing a second rubber and an electron-conductive agent and interspersed within the matrix. The electric resistance of the domains is lower than the electric resistance of the matrix. The matrix is exposed on an outer surface of the elastic layer and forms multiple depressed portions, and the domains include a domains exposed at a bottom section of the depressed portion.

Abstract: Provided is a polymer nanofiber sheet having high delamination resistance, a high mechanical strength, and a high specific surface area. Specifically, provided is a polymer nanofiber sheet, including polymer nanofibers, the polymer nanofibers being laminated and three-dimensionally entangled with each other, in which: at least part of the polymer nanofibers are crosslinked at a crosslinked part having crosslinking portions and a non-crosslinking portion; and the crosslinked part contains a low-molecular weight epoxy compound having a molecular weight of from 100 to 3,000.

Abstract: An electroconductive member for electrophotography has an electroconductive support and an electroconductive layer in the order mentioned. The electroconductive layer has a matrix including a crosslinked product of a first rubber, and a domain including a crosslinked product of a second rubber and an electroconductive particle. The impedance of the outer surface of the electroconductive member is 1.0×103 to 1.0×108 ?. 80% by number or more of domains observed at each of a total of nine 15-?m square observation regions, which are disposed at any three points in a thickness region from the outer surface to a specific depth on each of cross sections in the thickness direction at three points: the center of the electroconductive layer in the longitudinal direction and points at a specific distance from the both edges of the electroconductive layer toward the center, satisfy specific requirements.

Abstract: Provided is an electrophotographic electroconductive member including an electroconductive support and an electroconductive layer on the support, an electroconductive member is used, in which an electroconductive layer has a matrix comprising a first rubber, and domains dispersed in the matrix, the domains each comprising a second rubber and an electronic electroconductive agent, and for impedance measured by applying an AC voltage with an amplitude of 1 V to the electroconductive layer while varying frequencies between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, when a double logarithmic plot with a frequency on an abscissa and an impedance on an ordinate is obtained, a slope on a high frequency side is ?0.8 or more and ?0.3 or less, and the impedance a low frequency side is from 1.0×103 to 1.0×107?.

Abstract: An electrophotographic developing member includes an electro-conductive support and an electro-conductive layer provided on the support, wherein the electro-conductive layer has a matrix containing a first rubber and a plurality of domains dispersed in the matrix, and the domain contains a second rubber and an electronic conductive agent and when a frequency is log-log-plotted on a horizontal axis and an impedance is log-log-plotted on a vertical axis with respect to an impedance measured by applying an alternating current voltage having an amplitude of 1 V on the electro-conductive layer while changing a frequency between 1.0×10?2 Hz to 1.0×107 Hz under a specific environment, an inclination of an impedance on a high frequency side is ?0.8 or more and ?0.3 or less and an impedance on a low frequency side is 1.0×104? to 1.0×1011?.

Abstract: The present invention provides a silanol composition including a cyclic silanol (A1) represented by the following formula (1): wherein R1 to R4 are each independently fluorine, an aryl group, a vinyl group, an allyl group, a fluorine-substituted linear or branched alkyl group having 1 to 4 carbon atoms, or an unsubstituted linear or branched alkyl group having 1 to 4 carbon atoms; and a dehydration condensation product of the cyclic silanol (A2), and wherein the silanol composition has a haze of 10% or less at a thickness of 3 ?m.

Abstract: Provided is a rubber composition for producing a rubber molded article that is improved in fouling resistance while being reduced in tackiness and frictional force despite the presence of the rubber in its surface. The rubber composition includes: a rubber A; and a plastic B, in which: the rubber A includes a non-fluorine-based rubber material; a difference in elastic modulus between the rubber A and the plastic B is 50 MPa or more; a sea-island structure having a sea portion containing the rubber A and a plurality of island portions each containing the plastic B is formed; the plastic B is contained at a content of more than 0 vol % and 50 vol % or less with respect to a total amount of the rubber A and the plastic B; and 90% or more of the plurality of island portions each have a volume of 4,000 ?m3 or less.

Abstract: Provided an electro-conductive member that can be used as a charging member capable of preventing the emergence of a ghost image. The member comprises an electro-conductive support and an electro-conductive layer, the electro-conductive layer has a matrix including a first cross-linked rubber, and domains, the domains each includes a second cross-linked rubber and an electronically conductive agent, at least some of the domains are exposed to an outer surface of the member to constitute protrusions, the outer surface is constituted by the matrix and the exposed domains, and in a double logarithmic plot with a frequency on the abscissa and an impedance on the ordinate, a slope at a frequency of 1.0×105 Hz to 1.0×106 Hz is ?0.8 to ?0.3, and an impedance at a frequency of 1.0×10?2 Hz to 1.0×101 Hz is 1.0×103 to 1.0×107?.

Abstract: The electro-conductive member has an electro-conductive support, and an electro-conductive layer in this order, the electro-conductive layer including a matrix and domains, the matrix constituted by a first rubber composition containing a cross-linked product of a first rubber, the domains having electro-conductivity, and dispersed in the matrix, each of the domains constituted by a second rubber composition containing a cross-linked product of a second rubber and an electro-conductive particle, the first rubber and the second rubber being diene-based rubbers, the first rubber having at least one monomer unit, the second rubber having at least one monomer unit different from the monomer unit which the first rubber has; a difference of absolute values of SP values between the first rubber and the second rubber is 0.2 (J/cm3)0.5 to 4.0 (J/cm3)0.5; and a tan ?1/tan ?2 is 0.45 to 2.00.