Canon Kabushiki Kaisha

Norihito Naito

Masataka Mochizuki

Hideaki Hasegawa

Takayoshi Kihara

Nobuo Oshima

Yasunao Otomo

Masahito Kato

Go Shindo

Kazumi Yamauchi

Hideki Matsumoto

Masao Uyama

Go Araki

Yuichiro Hirata

Kodai Hayashi

Daisuke Baba

Takashi Kase

Makoto Tokudome

Kosuke Ikada

Satoru Izawa

Keisuke Mochizuki

Hisashi Yamauchi

Yuko Tanaka

Yoshihiro Ogawa

Masahiro Goto

Akihiko Uchiyama

Takayuki Namiki

Tomonori Matsunaga

Satoru Inami

Takeo Shoji

Takahiro Ikeda

Takashi Hibi

Yasunao Ohtomo

When, in a state where a developer borne by a developer bearing member is sandwiched by an opposing portion of an image bearing member and the developer bearing member, C denotes capacitance between the image bearing member and the developer bearing member, &#x394;V denotes a development contrast, Q/S denotes a charge amount per unit area of the developer borne by the developer bearing member, and &#x394;v denotes a peripheral velocity ratio which is a ratio of a peripheral velocity of the developer bearing member to a peripheral velocity of the image bearing member, a first peripheral velocity ratio is set so that |Q/S&#xd7;&#x394;v|&#x2264;|C&#xd7;&#x394;V| is satisfied, and a second peripheral velocity ratio which is larger than the first peripheral velocity ratio is set so that |Q/S&#xd7;&#x394;v|&#x3e;|C&#xd7;&#x394;V| is satisfied.

Image forming apparatus controlling development contrast according to temperature, humidity and peripheral velocity ratio

An image forming apparatus includes a motor configured to rotationally drive an image bearing roller and a developer bearing roller at a first peripheral velocity ratio and a second peripheral velocity ratio which is larger than the first peripheral velocity ratio. A development contrast formed between a developing bias to the developer bearing roller and a light-part potential formed on the image bearing roller in a case where a development operation is performed at the second peripheral velocity ratio is larger than a development contrast formed between the developing bias to the developer bearing roller and the light-part potential formed on the image bearing roller in a case where the development operation is performed at the first peripheral velocity ratio.

Image forming apparatus having first and second peripheral velocity ratios

In a state where a developer borne by a developer bearing member is sandwiched by an opposing portion of an image bearing member and the developer bearing member, C denotes capacitance between the image bearing member and the developer bearing member, &#x394;V denotes a development contrast, Q/S denotes a charge amount per unit area of the developer borne by the developer bearing member, and Av denotes a peripheral velocity ratio, which is a ratio of a peripheral velocity of the developer bearing member to a peripheral velocity of the image bearing member. A first peripheral velocity ratio is set so that |Q/S&#xd7;&#x394;v|&#x2264;|C&#xd7;&#x394;V| is satisfied, and a second peripheral velocity ratio which is larger than the first peripheral velocity ratio is set so that |Q/S&#xd7;&#x394;v|&#x3e;|C&#xd7;&#x394;V| is satisfied.

An image forming apparatus includes an image bearing member on which an electrostatic latent image is formable, and a developing device including a developer carrying member, a container, and a supply roller. When the developing device including the developer carrying member, to which a lubricant different from the developer is applied, is used for the first time, a first initial operation of transferring the lubricant from the developer carrying member to the image bearing member together with the developer is performed. The image forming apparatus further includes a storage unit configured to store a suspension state when suspension is detected before the initial operation completes, and a controller configured to execute a second initial operation as an operation of resuming the suspended first initial operation on the basis of the stored suspension state.

Image forming apparatus

An image forming apparatus includes: an image bearing member; a developer carrying member configured to contact with the image bearing member and to be separated from the image bearing member; a control unit for controlling the image bearing member and the developer carrying member; and a contact member disposed in contact with the image bearing member. The control unit is configured to sequentially execute: (1) rotating the image bearing member at a first speed in a separated state; (2) switching the image bearing member and the developer carrying member from the separated state to a contact state in a state in which the image bearing member rotates at the first speed; and (3) rotating the image bearing member by decreasing a rotation speed of the image bearing member from the first speed to a second speed smaller than the first speed in the contact state.

Image forming apparatus including developer carrying member

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

Changing of a peripheral speed ratio, resulting in change of the developer amount per unit area, enables the detection unit to detect the developer amount with sufficient accuracy.

Electrophotographic or electrostatic recording type 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.

A developing device configured to develop a latent image formed on an image bearing member includes a rotatable developing-agent bearing member configured to bear developing agent, a developing container configured to form a developing-agent storage chamber that stores the developing agent, a developing-agent regulating portion provided in the developing container to regulate an amount of the developing agent born on the developing-agent bearing member, a support portion configured to support the developing-agent bearing member movably relative to the developing-agent regulating portion, and a pressurizing member configured to pressurize the developing-agent bearing member toward the developing-agent regulating portion. A contact portion of the developing-agent regulating portion with the developing-agent bearing member is fixed to the developing container without forming a gap from the developing container on a downstream side in a pressurizing direction of the pressurizing member.

Process cartridge with developing container for an image forming apparatus

When an edge effect or sweeping occurs in a developing material, pixels, among a plurality of pixels that configure image data, will arise in which a developing material consumption amount rises beyond an original consumption amount. A CPU corrects the developing material consumption amount for the pixels, among the plurality of pixels that configure the image data, in which the developing material consumption amount will rise beyond the original consumption amount.

Image forming apparatus employing technique that reduces amount of coloring material consumed

A developing apparatus includes a developing container for accommodating a developer; a developer carrying member for carrying the developer to a developing zone for developing a latent image; a developer regulator in contact with the developer carrying member to regulate a developer layer thickness on the developer carrying member; a developer feeding member in contact with the developer carrying member to supply the developer to the developer carrying member; an urging member for urging the developer carrying member toward the developer regulator; and a moving mechanism for moving the developer carrying member in a first direction which is a direction in which the urging member urges the developer carrying member and in a second direction crossing with the first direction. The moving mechanism moves the developer carrying member in the second direction to reduce or remove press-contact forces applied by the developer regulator and the developer feeding member.

Moving mechanism for a developing device, process cartridge and image forming apparatus that reduces or removes press-contact forces on a developer carrying member

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Numazu, Japan

Norihito Naito