Canon Kabushiki Kaisha

Oki Semiconductor Co., Ltd.

Takayoshi Kihara

Hideaki Hasegawa

Norihito Naito

Motoki Adachi

Masataka Mochizuki

Taichi Sato

Takayuki Kanazawa

Masahito Kato

Shuhei Tokiwa

Takashi Kase

Kosuke Ikada

Nobuo Oshima

Shuhei Kawasaki

Bunro Noguchi

Shunsuke Matsushita

Go Shindo

Shinichi Agata

Kuniaki Tamagaki

Hiroyuki Seki

Yoshihiro Mitsui

Hisashi Taniguchi

Yuichiro Hirata

Yusaku Iwasawa

Taku Watanabe

Yasukazu Ikami

Takuya Oka

Shogo Satomura

Shota Nakamura

An image forming apparatus includes a rotatable image bearing member, a developing member, a transfer member, and a brush contacting a surface of the image bearing member in a contact portion downstream of a transfer portion and upstream of a developing portion with respect to a rotational direction of the image bearing member. The toner which is not transferred onto a toner image receiving member is collected by the developing member. In a charging series, the toner is positioned on the same side as a normal charge polarity of the toner relative to the brush. In the contact portion, a maximum value of a contact pressure of 0.7 gf/mmor more and 3.5 gf/mmor less, a maximum contact area ratio is 18% or more and 74% or less, and a Clark-Evans index of the brush is 1 or more.

Brush having a higher contact pressure with an image bearing member at an upstream end of the brush and image forming apparatus

An image forming apparatus includes a rotatable image bearing member, a charging member, a developing member, a transfer member, an exposure unit, and a controller. The controller executes a preparatory operation in which, before an image forming operation, rotation of the image bearing member is started and a charging voltage and a developing voltage are increased stepwisely. In the preparatory operation, the controller carries out control so as to start application of the charging voltage at a voltage value not less than a discharge start voltage of the charging member before a surface region of the image bearing member positioned in a developing portion at a time of a start of the rotation of the image bearing member reaches a charging portion in a state in which a surface of the image bearing member is exposed to light by the exposure unit.

Image forming apparatus

An image forming apparatus includes an image bearing member, a charging member for charging the image bearing member, an exposure unit for exposing the charged surface of the image bearing member, a developing apparatus that supplies a developer containing a toner particle and an external additive having an opposite charging polarity to the regular charging polarity of the toner particle to the image bearing member, a cleaning member for removing the developer from the image bearing member, a transfer member for transferring a developer image on the image bearing member onto a transfer subject material, and a voltage application unit for applying a voltage to the transfer member. During an image non-formation period as a lubrication operation to the cleaning member, (i) the developer is supplied to the image bearing member, and (ii) a voltage having an identical polarity to a voltage applied during the image formation operation is applied.

A unit includes: a conveying member that conveys developer; a frame that stores the developer and includes a first chamber storing the conveying member, a second chamber, a first opening connecting the first chamber and the second chamber, and through which the developer is passed, and a second opening connecting the interior of the second chamber and the exterior of the frame in an orthogonal direction that is orthogonal to a direction of a rotation axis line of the conveying member; and a filter that allows air to pass the second opening and restricts the developer from passing the second opening, and is fixed to the frame, wherein the frame is displaceable with respect to an apparatus main body in a state where the unit is attached to the apparatus main body, and the filter is displaced with respect to the apparatus main body by the displacement of the frame.

Unit having a developer conveying member and a filter for a chamber

A developer on a developer bearing member includes a toner having a toner particle including a binder resin and an inorganic particle present on the surface of the toner particle. A fixing ratio of the inorganic particle to the surface of the toner particle is 80% or more. The aspect ratio of the toner is 0.90 or more. Where a contact pressure of a regulating member, which regulates the developer on the developer bearing member, against the developer bearing member is denoted by N (gf/mm) and a contact pressure of the supplying member, which is in contact with the developer bearing member and supplies the developer to developer bearing member, against the developer bearing member is denoted by D (gf/mm), the following expressions are satisfied: D+2&#xd7;N&#x2212;6&#x2265;0, 1.5&#x2264;N&#x2264;4.0, and 2.0&#x2264;D&#x2264;3.5.

Developing device, process cartridge, and image forming apparatus

An image forming apparatus includes a control unit that controls an electric potential difference between a development roller and a supply roller in such a manner that force in a direction from the supply roller toward the development roller acts on toner in a section of an image forming region extending from a leading edge of a first image forming region toward a trailing edge thereof. The control unit controls the electric potential difference in such a manner that force acting on the toner becomes smaller in a section extending from a switching point, which is located at a position obtained by returning from a leading edge of a second image forming region to the first image forming region by a distance equal to or greater than a circumferential length of the development roller, to the trailing edge of the first image forming region.

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

A regulation member includes an opposed surface and a contact surface in a portion corresponding to an image forming area. The opposed surface is opposed to a developer bearing member. The contact surface protrudes from the opposed surface and has a height different from that of the opposed surface. An end seal seals a gap between a frame body, the developer bearing member, and the regulation member. The regulation member further includes an area not having the contact surface between the image forming area and a sealing area in which the regulation member and the end seal overlap. In the sealing area, a step between the opposed surface and the contact surface has a height of greater than or equal to 0 mm and not greater than 0.10 mm.

An image forming apparatus includes: a transfer member that secondarily transfers a developer image primarily transferred to a intermediate transfer medium, to a recording medium; a charging member that charges residual developer remaining on the intermediate transfer medium after the developer image is secondarily transferred from the intermediate transfer medium to the recording medium; and a storage portion that stores information on a image bearing member. A bias applied to the charging member is changed based on the information when the residual developer charged by the charging member is collected by being transferred from the intermediate transfer medium to the image bearing member.

Image forming apparatus that applies bias voltage according to stored image bearing member information

A developer container includes a stirring member that stirs a developer and a conductive resin sheet that comes into contact with the stirring member when the stirring member rotates. Wherein, the developer container detects developer quantity using capacitance from the conductive resin sheet.

Developer container, developing device, process cartridge, and image forming apparatus incorporating a developer quantity detection unit

A developing blade has a protrusion that protrudes toward a developing roller in an opposing portion facing the developing roller. The potential difference between a supply bias and a developing bias is denoted by &#x394;(V), a contact pressure of the developing blade with respect to the developing roller is denoted by X (gf/cm), a height of the protrusion from the opposing surface that faces the developing roller at a position further toward a tip side than the protrusion is denoted by H (mm), and a length of the opposing surface in the rotation direction of the developing roller is denoted by L (mm). When viewing a cross-section perpendicular to the rotation axis of the developing roller, 0.05&#x2264;H&#x2264;0.1, 0.15&#x2264;L&#x2264;1.0, and 15&#x2264;X&#x2264;60 are established, and at least &#x394;&#x2265;&#x2212;5*X&#x2212;125 is satisfied.

Developing device having developer regulating member, process cartridge, and image forming apparatus

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.

The present disclosure relates a developer container for accommodating a developer. The developer container includes a conductive path. The conductive path includes a resin.

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Mishima, Japan

Takayoshi Kihara