Canon Kabushiki Kaisha

Atsushi Uematsu

Takeshi Murakami

Yuki Yamamoto

Masahiro Watanabe

Taichi Sato

Tomohito Taniguchi

Noboru Miyagawa

Takehiko Aoyama

Yoshitaka Suzumura

Toshiro Suzuki

Kenichi Yazawa

Takeshi Yoshidome

Mototeru Goto

Katsuya Kodama

Harunobu Ogaki

Daisuke Miura

Yuichi Kikuchi

Takumi Furukawa

Takashi Anezaki

Akihiro Maruyama

Hidekazu Matsuda

Takashi Hiramatsu

Masataka Kodama

Hirofumi Kumoi

Masaki Tsunoda

Nao Higuchi

Masatsugu Hongo

An electroconductive member for electrophotography including a support having electro-conductivity and an electroconductive layer on the outer surface of the support, the electroconductive layer including a matrix containing a crosslinked product of a first rubber and first electroconductive particles and domains each containing a crosslinked product of a second rubber and second electroconductive particles, wherein at least part of the first electroconductive particles are present as a primary particle in the crosslinked product of the first rubber, wherein, the first electroconductive particles of the matrix observed in a specific observation region have d1 of 200 nm or more, the second electroconductive particles in the domains observed therein have d2 of 50 nm or less, and 80 number % or more of the domains satisfy specific conditions.

Electroconductive member, process cartridge, and electrophotographic image forming apparatus

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as Xl, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6&#xd7;(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do&#x2212;DX1)/2 and Z2=(DX1&#x2212;DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)&#x3c;1.931&#xd7;(Z1/L1).

Electrophotographic roller, process cartridge and electrophotographic image forming apparatus

An electrophotographic roller includes: a mandrel and an elastic layer on the mandrel, and having a crown shape in which a diameter decreases from a central position O in a longitudinal direction of the mandrel toward an end portion. When a position of the end portion in the longitudinal direction of the elastic layer is defined as X2, a position between the O and the X2 is defined as X1, a distance between the O and the X1 is defined as L1, and a distance between the X1 and the X2 is defined as L2, L1=0.6&#xd7;(L1+L2). When outer diameters of the electrophotographic roller at O, X1 and X2 are defined as Do, DX1 and DX2, respectively, and Z1=(Do&#x2212;DX1)/2 and Z2=(DX1&#x2212;DX2)/2 are defined, Z1, Z2, L1 and L2 satisfy (Z2/L2)&#x3c;1.931&#xd7;(Z1/L1).

The electro-conductive member has an electro-conductive support, and an electro-conductive layer, in which the electro-conductive layer has a matrix including a first rubber cross-linked product and domains dispersed in the matrix, each of the domains includes a second rubber cross-linked product and electro-conductive particles, an outer surface of the electro-conductive member has concave portions, a surface of at least a part of the domains is exposed to the outer surface of the electro-conductive member at bottom portions of the concave portions, a volume resistivity of the matrix is greater than 1&#xd7;10&#x3a9;cm, a volume resistivity of the electro-conductive layer is 1&#xd7;10&#x3a9;cm to 1&#xd7;10&#x3a9;cm, and A2 is 20 times or more of A1.

Electro-conductive member, manufacturing method thereof, process cartridge, and electrophotographic image forming apparatus

The electrophotographic roller has a surface layer comprising an electro-conductive elastic layer on an electro-conductive substrate. The opening of a bowl-shaped resin particle is exposed on the surface of the electrophotographic roller. The number of contact portions of the convex portion with the glass plate in a square region where a length of a nip in a direction along the circumferential direction of the electrophotographic roller of a nip formed by pressing the roller on the glass plate with a specific load applied as the length of one side and is located at any position in the nip is 8 or more. The average value of the areas of the contact portions is 10 &#x3bc;mto 111 &#x3bc;m. The variation coefficient of the areas of the contact portions and the variation coefficient D of the areas of a plurality of Voronoi regions each including a contact portion satisfy specific relationships.

Electrophotographic roller, process cartridge and electrophotographic apparatus

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, wherein, when the charging member is pressed onto a glass plate with 100 (g) load, S1 is the average value of contact areas, d1 is the average value of heights of spaces formed in a contact region; and when the load is changed to 500 (g), S5 is the average value of contact areas, d5 is the average value of heights of spaces.

Charging member with electro-conductive elastic layer having exposed bowl-shaped resin particles, process cartridge and electrophotographic apparatus

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 &#x3bc;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.

Roller for electrophotography, process cartridge, and image-forming apparatus

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 (&#xd7;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, K, the brightness of the bottom of the concavity, K, and the brightness of the exposed surface of the electro-conductive resin layer, K, satisfy K&#x3c;K, K&#x3c;Kand 0.8&#x2266;K/K&#x2266;1.2.

Electrophotographic member having bow-shaped resin particles defining concavity and protrusion at surface thereof

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.

Charging member, process cartridge and electrophotographic apparatus

A process cartridge that can suppress production of a banding image attributed to contact rotation of an electrophotographic photosensitive member and a charging member and output a high-quality image is provided. The charging member includes an electro-conductive substrate and an electroconductive resin layer, the resin layer contains a binder, a conductive fine particle, and a bowl-shaped resin particle having an opening, and the surface of the charging member has a concavity derived from the opening of the bowl-shaped resin particle and a protrusion derived from the edge of the opening thereof. The electrophotographic photosensitive member includes a support and a photosensitive layer, and the surface layer in the photosensitive member contains a specific resin (&#x3b1;), a specific resin (&#x3b2;), and a specific compound (&#x3b3;).

Process cartridge and electrophotographic apparatus

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:

Image forming apparatus and process cartridge utilizing a porous charging member

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.

Charging member, process cartridge, and electrophotographic apparatus

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=&#x2003;&#x2003;(formula)diffusion index&#x2267;&#x2212;0.0042&#xd7;&#x2003;&#x2003;(formula)

Image-forming apparatus with electro-conductive resin layer having resin particles and process cartridge

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.

Electrophotographic image forming apparatus having charge transport layer with matrix-domain structure and charging member having concavity and protrusion

The roller member has a substrate and an electroconductive elastic layer. The elastic layer has a crown shape of which an outer diameter at the middle in the lengthwise direction is larger than those at its both ends. The elastic layer includes a bowl-shaped resin particle. The surface of the roller member has concavity derived from an opening of the bowl-shaped resin particle and a protrusion derived from an edge of the opening of the resin particle. The relation in the restoring rate for elastic deformation between at the middle of the roller member and at its both ends is such that: on the surface of the elastic layer the restoring rate is larger at both ends than that at the middle, and at the position of depth t &#x3bc;m from the elastic layer surface the restoring rate is larger at the middle than that at both ends.

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Fuji, Japan

Atsushi Uematsu