Canon Kabushiki Kaisha

Takashi Mukai

Nobuo Oshima

Masanori Tanaka

Jun Miura

Takahiro Kawamoto

Kohei Matsuda

Masahiro Yoshida

Kazunari Hagiwara

Koji An

Hideo Kihara

Kuniaki Tamagaki

Koichiro Takashima

Taichi Sato

Shuhei Tokiwa

Yasukazu Ikami

Takaaki Shinkawa

Motoki Adachi

Takayuki Namiki

Takayuki Kanazawa

Shuhei Kawasaki

Kazuhiro Okubo

Shunsuke Mizukoshi

Fuka Enokido

Yuki Yamamoto

Kazuhiro Yamauchi

Minoru Nakamura

Shinji Katagiri

Yuji Kawaguchi

Yuichi Kikuchi

Takumi Furukawa

Masaaki Matsushita

Satoshi Sunahara

Tomonori Matsunaga

Takashi Hiramatsu

Shinichi Agata

Hiroko Katagiri

An image forming apparatus includes a moving unit to move a developing roller, a driving portion to be capable of rotating the developing roller in either case where the developing roller is located in a contact position in contact with a photosensitive drum or a separated position separated from the photosensitive drum, an acquiring portion to acquire information on a rotation amount of the developing roller and a notifying portion. The acquiring portion corrects a first information, on the rotation amount of the developing roller in the contact position, to a third information by using a first correction coefficient, and corrects a second information, on the rotation amount of the developing roller in the separated position, to a fourth information by using a second correction coefficient. The notifying portion performs the notification on a lifetime of the developing roller based on the third and the fourth information.

Image forming apparatus

An image forming apparatus includes an image bearing member, a charging member, an exposure unit, a developing unit including a developer carrying member and a regulating member, a transfer member, a counting portion, a driving portion, and a controller. The controller carries out control so as to perform an image forming operation capable of forming a developer image, on the image bearing member, to be transferred onto a recording material and a non-image forming operation in which the developer image to be transferred onto the recording material is not formed on the image bearing member. Depending on each of count values in a plurality of regions acquired by the counting portion in a predetermined period, the controller controls the driving portion so as to change a rotation amount of the developer carrying member in a developing rotation operation for rotating the developer carrying member during the non-image forming operation.

An image forming apparatus includes a first image forming portion including a first photosensitive member, a first charging member, and a first developing member including a first accommodating portion; a second image forming portion including a second photosensitive member, a second charging member, and a second developing member including a second accommodating portion; an exposure portion; an applying portion; a storing portion; and a controller. When, in the storing portion, information on toner accommodated in the first accommodating portion is changed from first information to second to information and information on toner accommodated in the second accommodating portion is not changed, the controller carries out control so that a transfer voltage is changed from a first transfer voltage to a second transfer voltage and so that a potential of an image portion formed on the second photosensitive member is changed from a first potential to a second potential.

An image forming operation forms an image on a transfer target in a state in which a developing member is located at a first position where a developer is supplied to an image bearing member and a first charging voltage is applied to a charging unit. The image forming operation is followed by: a first rotating operation of rotating the image bearing member in a state in which the developing member is located at the first position and a second charging voltage smaller in absolute value than the first charging voltage is applied; and a second rotating operation of rotating the image bearing member in a state in which the developing member is located at a second position where the developer is not supplied to the image bearing member and a third charging voltage smaller in absolute value than the second charging voltage is applied.

Image forming apparatus and control method, that control charging voltage according to positions of developing roller

An image forming apparatus includes an image bearing member, a developing member that supplies a developer of a regular polarity, a developer supply member that supplies developer to the developing member, and a control unit that applies a first voltage to the developing member and a second voltage to the developer supply member. The control unit executes an image forming operation, and a rotational operation in which the developer supply member rotates in a state in which the first voltage of a regular polarity is applied thereto. The rotational operation includes a first rotational operation in which a potential difference is a first potential difference and a second rotational operation in which the developing member and the developer supply member rotate in a state in which the second voltage having the same polarity as the regular polarity and having a greater absolute value is applied.

Provided is an image forming apparatus, including: an image bearing member; an exposure unit; a developing member which is rotatable at a rotation speed different from the image bearing member; a developer supply member; a developing voltage-applying unit; a supply voltage-applying unit; and a control unit. The control unit controls execution of: an image forming operation in which a developer image is formed by supplying developer on the image bearing member; and a cleaning operation which removes a substance adhered to the image bearing member using the developing member. In the cleaning operation, the control unit controls the developing voltage-applying unit or the supply voltage-applying unit so that the cleaning force using the developing member becomes stronger than that in the image forming operation.

A process cartridge is provided, which is configured to recover, with a developing member, developer remaining on an image bearing member after transfer of a developer image to a transfer receiving member, wherein a charging member has a shaft that is conductive and an elastic layer supported on the shaft and being in contact with the image bearing member; the elastic layer has a matrix containing a first rubber, and a plurality of domains containing a second rubber and an electron-conductive agent and interspersed within the matrix. The electric resistance of the domains is lower than the electric resistance of the matrix. The matrix is exposed on an outer surface of the elastic layer and forms multiple depressed portions, and the domains include a domains exposed at a bottom section of the depressed portion.

Process cartridge and image forming apparatus

A developer bearing member including: a rotational shaft; and an elastic layer on an outer circumference surface of the rotational shaft, developer being borne on a surface of the elastic layer, wherein the elastic layer is configured such that a load per unit area of a contact portion between one surface of a flat glass plate and the surface of the elastic layer is to be 5.8 N/mmor more, in a state that the one surface of the flat glass plate being parallel with an axis direction of the rotational shaft and the one surface of the flat glass plate coming into contact with the surface of the elastic layer with a predetermined penetration level, and wherein a ten-point average roughness Rzjis on the surface of the elastic layer is greater than a volume-average particle diameter of a particle of the developer.

Developer bearing member, developing apparatus, process cartridge, and image forming apparatus

An image forming apparatus includes an image bearing member, a charging member, an exposure unit which performs first exposure to form a non-image portion potential on the electrically charged surface of the image bearing member, and second exposure to form an image portion potential thereon, a developing member, a charging voltage application unit, a current detection unit which detects a current flowing from the image bearing member to the charging member, and a control unit which controls the exposure unit and the charging voltage application unit, wherein, in a case where a current value detected in a predetermined charging voltage application state is a second current value larger than a first current value, the control unit controls the exposure unit to perform image formation with a first exposure amount smaller than that in a case where the detected current value is the first current value.

In an image forming operation of transferring one developer image to a recording material, when a plurality of image forming portions include a non-image forming portion that is an image forming portion which does not form a developer image on an image bearing member, applying means for applying a charging bias to a charging member which comes into contact with and charges the image bearing member applies a second charging bias to the charging member in the non-image forming portion, the second charging bias having a same polarity as a first charging bias for forming a developer image and being a voltage equal to or lower than a discharge start voltage.

A developing apparatus includes a developer carrying member, a developer container, and a regulating member to regulate the thickness of the developer. The regulating member includes a support member having one end fixed to the developer container and the other end free, with the support member extending in a direction opposite to the rotating direction of the developer carrying member, and a contact member to be fixed to the other end of the support member and to contact the developer carrying member. The contact member includes a contact curved surface along a peripheral surface of the developer carrying member, and an opposite surface to face the developer carrying member. The contact pressure of the contact curved surface applied to the developer carrying member decreases as a location on the developer carrying member approaches a downstream side in the rotating direction.

Developing apparatus with regulating member having a curved contact surface and image forming apparatus

A regulating portion includes a first contact portion, a second contact portion, opposed surface portion, and a second opposed surface portion. When, in a plane orthogonal to the rotation axis direction of a developer bearing member, the fixed end and the free end of a supporting member are connected by an imaginary straight line, a contact position where the first contact portion contacts the developer bearing member is located on the downstream side, in the rotation direction of the developer bearing member, of a point of contact of a tangent line parallel to the imaginary straight line with the outer periphery of the developer bearing member.

Developing device, process cartridge and image forming apparatus

A relation between a first thickness of a resin layer in an upstream portion of a contact nip in which the resin layer that covers a supporting member of a regulating blade makes contact with a developing roller and a second thickness of the resin layer in a downstream portion of the contact nip is set such that the second thickness is smaller than the first thickness. A potential difference having the same polarity as a toner charging polarity toward the supporting member is created between the supporting member and the developing roller.

Developing apparatus, process cartridge, and image forming apparatus

An image forming apparatus includes a photosensitive drum life estimation mechanism which estimates wear amounts of a charge transfer layer in both of a toner bearing area and an end portion of a toner non-bearing area of a developing roller and informs a user that the photosensitive drum has reached the end of its life if, out of total wear amounts of the areas corresponding to predetermined life threshold values of the toner bearing and non-bearing areas, either of the total wear amounts reaches the threshold value.

Image forming apparatus having image bearing member life estimation unit

A developing device includes: a flexible container, provide with an opening, for accommodating the developer; a frame for accommodating the container; an urging member, rotatably provided inside the frame, for urging the container by rotation thereof to deform the container; and a developer carrying member for carrying the developer on its surface to feed the developer. A distance X from a rotation center of the urging member to the surface of the developer carrying member and a length T from the rotation center of the urging member to a free end thereof for urging the container satisfy a relationship of X&#x3c;T. A shielding member for preventing contact of the urging member with the developer carrying member is provided between the rotation center of the urging member and the surface of the developer carrying member or in a neighborhood thereof.

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Kawasaki, Japan

Takashi Mukai