Abstract: Provided is a charging member capable of suppressing the occurrence of an image defect due to the non-uniform abrasion of a photosensitive member and a stain, in a long-term use. The charging member includes an electro-conductive elastic layer as a surface layer. The electro-conductive elastic layer contains a binder and a bowl-shaped resin particle having an opening. The surface of the charging member has a concavity and a protrusion derived from the bowl-shaped resin particle. The relations represented by the following formulae are satisfied, 0.2 ? S = ? S ? ? 5 - S ? ? 1 ? S ? ? 1 ? 0.5 0.15 ? d = ? d ? ? 5 - d ? ? 1 ? d ? ? 1 ? 0.

Abstract: Provided is a charging member capable of suppressing the occurrence of an image defect due to the non-uniform abrasion of a photosensitive member and a stain, in a long-term use. The charging member includes an electro-conductive elastic layer as a surface layer. The electro-conductive elastic layer contains a binder and a bowl-shaped resin particle having an opening. The surface of the charging member has a concavity and a protrusion derived from the bowl-shaped resin particle. The relations represented by the following formulae are satisfied, 0.2 ? S = ? S ? ? 5 - S ? ? 1 ? S ? ? 1 ? 0.5 0.15 ? d = ? d ? ? 5 - d ? ? 1 ? d ? ? 1 ? 0.

Abstract: A roller for electrophotography including a mandrel and an elastic layer on the mandrel is provided. The elastic layer contains a hollow particle in a region from the surface of the elastic layer to a depth of 100 ?m. A cross-section of the hollow particle intersected by a first plane and a cross-section of the hollow particle intersected by a second plane each have a ratio of the length of the long axis to the length of the short axis of 1.2 or more and 1.9 or less.

Abstract: The present invention directs to provide a charging member having a protrusion to which smear is difficult to adhere even in a long-term used, and as a result being capable of exhibiting stable charging performance. The charging member has an electro-conductive substrate and an electro-conductive surface layer, wherein the surface layer includes a binder resin and a resin particle including a plurality of electro-conductive domains inside thereof, the surface layer has a protrusion derived from the resin particle, and the electro-conductive domains are localized in the vicinity of the surface of the resin particle.

Abstract: The electrophotographic member includes an electro-conductive substrate and an electro-conductive resin layer as the surface layer on the substrate. The electro-conductive resin layer contains a binder and a bowl-shaped resin particle; the surface of electrophotographic member has a concavity derived from the opening of the bowl-shaped resin particle, a protrusion derived from the edge portion of the opening and the electro-conductive resin layer; and when the surface of the member is observed using a scanning electron microscope at an accelerating voltage (1 kV) and a magnification (×2000) while applying a DC voltage (50 to 100 V) between an electrode disposed opposite to the electrophotographic member and the substrate, the brightness of the protrusion, K1, the brightness of the bottom of the concavity, K2, and the brightness of the exposed surface of the electro-conductive resin layer, K3, satisfy K2<K1, K3<K1 and 0.8?K2/K3?1.2.

Abstract: The electrophotographic member includes an electro-conductive substrate and an electro-conductive resin layer as the surface layer on the substrate. The electro-conductive resin layer contains a binder and a bowl-shaped resin particle; the surface of electrophotographic member has a concavity derived from the opening of the bowl-shaped resin particle, a protrusion derived from the edge portion of the opening and the electro-conductive resin layer; and when the surface of the member is observed using a scanning electron microscope at an accelerating voltage (1 kV) and a magnification (×2000) while applying a DC voltage (50 to 100 V) between an electrode disposed opposite to the electrophotographic member and the substrate, the brightness of the protrusion, K1, the brightness of the bottom of the concavity, K2, and the brightness of the exposed surface of the electro-conductive resin layer, K3, satisfy K2<K1, K3<K1 and 0.8?K2/K3?1.2.

Abstract: A roller for electrophotography including a mandrel and an elastic layer on the mandrel is provided. The elastic layer contains a hollow particle in a region from the surface of the elastic layer to a depth of 100 ?m. A cross-section of the hollow particle intersected by a first plane and a cross-section of the hollow particle intersected by a second plane each have a ratio of the length of the long axis to the length of the short axis of 1.2 or more and 1.9 or less.

Abstract: A charging member including an electro-conductive substrate, an electro-conductive elastic layer, and an electro-conductive surface layer, wherein the elastic layer includes a polymer having a unit derived from ethylene oxide and at least one particle selected from the group consisting of graphite particles and graphitized particles; wherein a particle-exposing portion where the particle is exposed is present on the surface of the elastic layer; the surface of the elastic layer including the particle-exposing portions is coated with the surface layer; the surface layer includes binder resin and resin particles dispersed in the binder resin and has a plurality of protrusions derived from the resin particles on the surface; when the resin particles in the surface layer are orthographically projected onto the surface of the elastic layer, areas other than projected areas of the resin particles on the surface of the elastic layer overlap the particle-exposing portion.

Abstract: There are provided an image forming apparatus in which the generation of lateral streak images due to a decrease in the in-nip discharge intensity is suppressed while at the same time the generation of spot-like images due to abnormal discharge caused by smudges on the surface of a charging member is suppressed, and a process cartridge. The image forming apparatus and the process cartridge each has: a charging member containing a resin particle having a plurality of pores inside thereof; and a toner in which the coverage ratio X1 of a surface of the toner with silica fine particles is 50.0 area % or more and 75.0 area % or less, and when a theoretical coverage ratio with the silica fine particles is X2, a diffusion index represented by formula 1 satisfies formula 2. diffusion index=X1/X2??(formula 1) diffusion index??0.0042×X1+0.

Abstract: A charging member includes an electro-conductive substrate and an electro-conductive resin layer. The electro-conductive resin layer contains a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles. The charging member has a surface having recesses due to openings of the bowl-shaped resin particles and protrusions due to edges of the openings of the bowl-shaped resin particles, where the positional relationship between one bowl-shaped resin particle and the hollow particles lying in the vicinity of the bowl-shaped resin particle is that the number of the hollow particles being in the space under the bowl-shaped resin particle in a predetermined depth is at least four in average.

Abstract: There are provided an image-forming apparatus that inhibit the occurrence of a longitudinal streak image attributed to a cleaning failure, and a process cartridge. The image-forming apparatus and the process cartridge each have a charging member with a surface having a concavities derived from an opening of the bowl-shaped resin particle, and a protrusions derived from an edge of the opening of the bowl-shaped resin particle, the coverage ratio X1 of a surface of the toner with the silica fine particles is 50.0 area % or more and 75.0 area % or less, and when a theoretical coverage ratio of the toner by the silica fine particles is X2, a diffusion index represented by the formula 1 satisfies the formula 2: diffusion index=X1/X2??(formula 1) diffusion index??0.0042×X1+0.

Abstract: A charging member includes an electro-conductive substrate and an electro-conductive resin layer. The electro-conductive resin layer contains a binder, a plurality of bowl-shaped resin particles, and a plurality of hollow particles. The charging member has a surface having recesses due to openings of the bowl-shaped resin particles and protrusions due to edges of the openings of the bowl-shaped resin particles, where the positional relationship between one bowl-shaped resin particle and the hollow particles lying in the vicinity of the bowl-shaped resin particle is that the number of the hollow particles being in the space under the bowl-shaped resin particle in a predetermined depth is at least four in average.

Abstract: Provided an electrophotographic image forming apparatus comprising an electrophotographic photosensitive member and a charging member. The electrophotographic photosensitive member includes a charge transport layer as a surface layer having a matrix-domain structure including specific resins. The charging member comprises an electro-conductive substrate, and an electro-conductive elastic layer. The electro-conductive elastic layer comprises a binder, and holding a bowl-shaped resin particle having an opening, so that at least a part of the bowl-shaped resin particle is exposed, and the charging member has a concavity derived from the opening of the bowl-shaped resin particle on the surface thereof, and a protrusion derived from an edge of the opening of the bowl-shaped resin particle on the surface thereof.

Abstract: Provided is an electrophotographic member for an electrophotographic apparatus, which suppresses the occurrence of a banding image caused by uneven charging. The electrophotographic member includes: an electroconductive substrate; and a surface layer, in which: the surface layer includes a binder resin and an aggregate of at least one crystal particle selected from the group consisting of a flaky crystal particle of magnesium carbonate and a flaky crystal particle of calcium carbonate; an edge face of a card house structure formed of the crystal particle is exposed at a surface of the aggregate; a surface of the surface layer includes a convex portion derived from the aggregate; and a surface of the convex portion has unevenness reflecting a shape of the edge face of the card house structure exposed at the surface of the aggregate.

Abstract: Provided a charging member including an electro-conductive substrate and a surface layer. The surface layer includes a binder resin, and a resin particle that roughens the surface layer. A surface of the charging member has a plurality of protrusions each derived from the resin particle. The resin particle has a pore inside thereof, has a porosity Vt of 1.5% by volume or more and 45.0% by volume or less, and has a first and second regions. The first region has a porosity V1, the second region thereof has a porosity V2, and V1 is larger than V2.

Abstract: Provided a charging member including an electro-conductive substrate and a surface layer. The surface layer includes a binder resin, and a resin particle that roughens the surface layer. A surface of the charging member has a plurality of protrusions each derived from the resin particle. The resin particle has a pore inside thereof, has a porosity Vt of 1.5% by volume or more and 45.0% by volume or less, and has a first and second regions. The first region has a porosity V1, the second region thereof has a porosity V2, and V1 is larger than V2.

Abstract: The present invention relates to a charging member. The charging member comprises an electro-conductive substrate and an electro-conductive surface layer, wherein the surface layer includes a binder resin, an electro-conductive particle dispersed in the binder resin, and a resin particle that roughens the surface of the surface layer; the surface layer has a plurality of protrusions each derived from the resin particle in the surface thereof; the resin particle that forms the protrusion has a pore inside thereof; has a porosity Vt of porosity is 2.5% by volume or less as a whole; and has a region whose porosity V11 is from 5% by volume to 20% by volume, wherein the region is farthest away from the electro-conductive substrate in the resin particle, and assuming that the resin particle is a solid particle having no pores, the region corresponds to a 11% by volume-occupying region of the solid particle.

Abstract: Provided an electrophotographic image forming apparatus comprising an electrophotographic photosensitive member and a charging member. The electrophotographic photosensitive member includes a charge transport layer as a surface layer having a matrix-domain structure including specific resins. The charging member comprises an electro-conductive substrate, and an electro-conductive elastic layer. The electro-conductive elastic layer comprises a binder, and holding a bowl-shaped resin particle having an opening, so that at least a part of the bowl-shaped resin particle is exposed, and the charging member has a concavity derived from the opening of the bowl-shaped resin particle on the surface thereof, and a protrusion derived from an edge of the opening of the bowl-shaped resin particle on the surface thereof.

Abstract: Provided is a charging member for suppressing the vibration of a charging roller which occurs owing to a difference in circumferential speed in a longitudinal direction when the roller is rotated to follow a photosensitive member, and suppressing a banding image caused by the vibration of the charging roller over a long period of time. The charging member includes a substrate and an elastic layer. The elastic layer contains a rubber having a polar group and hollow particles each having a shell containing a crystal of calcium carbonate.

Abstract: The present invention directs to provide a charging member having a protrusion to which smear is difficult to adhere even in a long-term used, and as a result being capable of exhibiting stable charging performance. The charging member has an electro-conductive substrate and an electro-conductive surface layer, wherein the surface layer includes a binder resin and a resin particle including a plurality of electro-conductive domains inside thereof, the surface layer has a protrusion derived from the resin particle, and the electro-conductive domains are localized in the vicinity of the surface of the resin particle.