Canon Kabushiki Kaisha

Kosuke Ikada

Yoshihiro Mitsui

Shinichi Hagiwara

Yasukazu Ikami

Shinichi Agata

Norihito Naito

Kentaro Yamawaki

Takayoshi Kihara

Go Shindo

Keitaro Nakata

Yuichiro Hirata

Hisashi Yamauchi

Masamichi Sato

Toshiaki Takeuchi

Yuhei Terui

Tomonori Matsunaga

Katsuyuki Nonaka

Shuhei Kawasaki

Kodai Hayashi

Noriyoshi Umeda

Masahito Kato

Hideharu Shimozawa

Shunsuke Matsushita

Shohei Kototani

Kazunori Hashimoto

Katsuichi Abe

Katsuhiro Kojima

Akinobu Saito

A process cartridge using an image forming apparatus, including a rotatable image bearing member having a circumferential surface; a developing unit configured to supply a developing agent to the image bearing member; and a cleaning member that cleans the circumferential surface, wherein the developing agent contains a toner including toner particles and a metal soap, the image bearing member includes a plurality of grooves formed on the circumferential surface to extend in a circumferential direction of the circumferential surface and to be arranged side by side in a rotation axis direction, and the plurality of grooves and portions between the grooves form concave-convex portions on the circumferential surface. The circumferential surface of the image bearing member had surface roughness Rz of 0&#x3c;Rz&#x2264;0.70 &#x3bc;m and average interval Sm between concave-convex portions on the circumferential surface of 0&#x3c;Sm&#x2264;70.0 &#x3bc;m.

Process cartridge and image forming apparatus

An image forming apparatus that executes an image forming operation for forming a toner image on a recording material and an application operation of applying a metal soap to a surface of an image bearing member by supplying a toner stored in a toner storing unit to the surface of the image bearing member from the developing member. A surficial moving speed of the image bearing member during the application operation is lower than the surficial moving speed of the image bearing member during the image forming operation, and a speed difference between the surficial moving speed of the developing member and the surficial moving speed of the image bearing member during the application operation is larger than that during the image forming operation.

Image forming apparatus that suppresses occurrence of image smearing by maintaining a metal soap on a surface of a photoconductor

A process cartridge includes a seal member contacting an image bearing member upstream in the rotation direction of the image bearing member from a cleaning member and allowing the developer to move from upstream in the rotation direction from the contact part between the seal member and the image bearing to downstream from the contact part while regulating movement from downstream to upstream from the contact part. The developer has surface protrusions containing an organic silicon polymer, wherein either (i) the work function of the seal member is greater than the work function of the developer when the developer has a negative charging polarity and is smaller than the work function of the developer when the developer has a positive charging polarity, or (ii) the absolute value of the difference between the work function of the seal member and the work function of the developer is within a predetermined range.

Process cartridge, image forming apparatus and cleaning apparatus

A charging memberthat charges an image bearing memberhas an electrically conductive support and an elastic layer in contact with the image bearing member. The elastic layer includes a semi-conductive rubber composition having a matrix-domain structure including a matrix and domains having electric conductivity. The matrix has a higher volume resistivity than the domain. The developer includes a toner having toner particles. The toner particles each have a surface layer including an organosilicon polymer. The organosilicon polymer has a structure represented by R&#x2014;SiO(R is a hydrocarbon group having at least 1 and not more than 6 carbon atoms). The adhesion ratio of the organosilicon polymer on the surface of the toner particle is 90% or more.

A process cartridge includes a developing device that supplies developer to a photosensitive member and an elastic portion that cleans a peripheral surface of the photosensitive member. Multiple grooves are formed side by side in a generatrix direction on the peripheral surface. The developer contains a toner including a toner particle and an organosilicon polymer having a structure represented by R&#x2014;SiOcovering the toner particle surface, where R represents a hydrocarbon group having at least 1 and not more than 6 carbon atoms. When a penetration amount of the elastic portion with respect to the photosensitive member is set as &#x3b4; (mm), and a fixing rate of the organosilicon polymer on the surface of the toner particle is set as &#x3b1; (%), &#x3b4;&#x2264;0.02&#xd7;&#x3b1;&#x2212;0.4 is satisfied.

Process cartridge including photosensitive member having multiple grooves and image forming apparatus including the process cartridge

An image forming apparatus includes a regulating member that regulates a developing agent that a developing agent carrying member carries in order to develop an electrostatic image, and a regulatory bias application portion that applies a regulatory bias to the regulating member, wherein the developing agent includes a toner containing a toner particle, inorganic silicon fine particles present on the surface of the toner particle, and a metal soap, wherein the amount of water-washing migration of the inorganic silicon fine particles is 0.20 mass % or less, wherein a peripheral speed ratio, which is a ratio of a peripheral speed of the developing agent carrying member to a peripheral speed of an image bearing member, has a range of 120% to 300%, and a dark portion potential Vd on the surface of the image bearing member and a regulatory bias Vb satisfy the relationship of Vd&#x3c;Vb.

Image forming apparatus that regulates developing agent and applies regulatory bias

An image forming apparatus including: an image bearing member; a developing member to supply a developer to the image bearing member; and a cleaning member to clean a peripheral surface of the image bearing member in contact with the peripheral surface, wherein a plurality of grooves extend in a circumferential direction on the peripheral surface, and have a width in a generatrix direction of the peripheral surface within a range of at least 0.5 &#x3bc;m and not more than 40 &#x3bc;m, and are formed to be side by side in the generatrix direction; the number of the grooves is at least 20 and not more than 1000 per a width of 1000 &#x3bc;m in the generatrix direction of the peripheral surface; and an average depth (Rvk) of a valley of a projection under a core section of a roughness curve of the peripheral surface is 0.08 &#x3bc;m or less.

Image forming apparatus

A charging member that contacts an image bearing member and charges the image bearing member has an electrically conductive support and an elastic layer in contact with the image bearing member. The elastic layer includes a semiconductive rubber composition including a matrix and domains having electric conductivity. The semiconductive rubber composition has a sea-island structure in which the domains form an island phase and the matrix forms a sea phase. The matrix has a higher volume resistivity than the domains. The developer includes a toner, and the toner has a Martens hardness of at least 200 MPa and not more than 1100 MPa when measured under a maximum load of 2.0&#xd7;10N.

At least one partial measurement region is set in the longitudinal direction in a printable region of a photosensitive drum. After the photosensitive drum has been charged to a constant potential with a charging roller, different potentials are set in the partial measurement region and a region excluding the partial measurement region with a laser scanner, partial discharge information of the partial measurement region is detected by a discharge information detection unit, and a bias voltage in image formation that is applied to the charging roller is corrected on the basis of the value of the partial discharge information.

Process cartridge, image forming apparatus, image forming method

An image forming apparatus includes: an acquisition portion that acquires, based on a current value detected by a detection unit, a discharge start voltage value between a photosensitive body and a charging member, in a voltage value of a voltage applied to the charging member, the discharge start voltage value being acquired from at least one of a plurality of measurement regions set by dividing an image forming region of the photosensitive body, in which an electrostatic image is formed, into a plurality of regions in a longitudinal direction orthogonal to a recording material conveyance direction; and a control portion that performs unevenness suppression control to reduce unevenness, in the longitudinal direction, of density of a developer image transferred onto the recording material based on the discharge start voltage value.

An image forming apparatus includes a control unit configured to change, to a light quantity different from a plurality of reference light quantities, a light quantity per unit area of a surface of an electrical charge retention layer of a photosensitive member when an exposure unit exposes the surface in correspondence with a plurality of gradation levels, based on a plurality of exposure potentials corresponding to the plurality of gradation levels which is acquired by exposing with the exposure unit the surface with each of the plurality of reference light quantities corresponding to the plurality of gradation levels, and measuring with the measurement unit the plurality of exposure potentials of the photosensitive member which is formed by the exposure with the plurality of reference light quantities.

An image forming apparatus includes: a first exposing unit exposing a surface of a charged photosensitive member to form a latent image; a second exposing unit exposing the surface of the photosensitive member after the surface of the photosensitive member passes a transfer position at which a toner image obtained by causing toner to adhere to the latent image is transferred to a transferred body and before the surface of the photosensitive member reaches a charging position; and a control unit varying a length of a period from a timing at which a portion of the photosensitive member exposed by the second exposing unit is initially charged by the charging member to a timing at which the first exposing unit starts formation of the latent image when performing image formation based on a print signal, based on information related to a photosensitive layer thickness of the photosensitive member.

Image forming apparatus for preventing abnormally discharged image

An image forming apparatus includes an acquiring portion that acquires a duration of an overcharged state occurring in an area of an image bearing body charged by a charging member after the image bearing body is exposed by a preliminary exposing portion. Adjustment is made to an interval between a first timing when the preliminary exposing portion starts exposing the image bearing body before execution of an adjustment operation for setting a transfer voltage value and a second timing when a voltage applying portion starts, during the subsequent adjustment operation, applying a voltage with an adjustment voltage value to a transfer member such that the second timing is later than a third timing when the duration acquired by the acquiring portion ends.

Growing community of inventors

Machida, Japan

Kosuke Ikada