Canon Kabushiki Kaisha

Motonari Ito

Atsushi Toda

Akira Suzuki

Motoki Adachi

Hideo Kihara

Taku Watanabe

Takanori Watanabe

Hiroki Tanaka

Naoki Matsumaru

Junichi Matsumura

Masahito Kato

Go Shindo

Takashi Hiramatsu

Akihisa Matsukawa

Kuniaki Tamagaki

Yusuke Usui

Katsuichi Abe

Kazuhiro Yamauchi

Satoshi Sunahara

Masahiro Kurachi

Yu Fukasawa

Kosuke Fukudome

Tsuneyoshi Tominaga

Kazuhisa Shida

Kozue Uratani

Shohei Tsuda

Seiichi Shinohara

Makoto Fukatsu

Noriyoshi Umeda

Shohei Kototani

Makoto Tokudome

Ryosuke Kanai

Takashi Koyanagi

Hiroyoshi Iwayama

Tomohiro Unno

Dai Nozaki

Yuta Komiya

Koichiro Masui

Toshiki Okamura

Yuta Isobe

An image forming apparatus includes a rotatable image bearing member, a charging member, a developing unit, a cleaning member, and a supply container. In an accommodating portion of a new developing unit, an initial developer which is a developer in a predetermined amount is filled in advance. The initial developer contains toner particles of which charge polarity is a predetermined polarity, and to the toner particles of the initial developer, lubricant particles of a polarity opposite in charge polarity to the predetermined polarity are externally added. A supply developer which is the developer accommodated in the supply container contains the toner particles. An external addition amount of the lubricant particles to the toner particles in the supply developer is smaller than an external addition amount of the lubricant particles to the toner particles in the initial developer.

Image forming apparatus in which initial developer is filled in advance

An image forming apparatus includes a developer carrying member that bears and conveys developer. The developer carrying member has at least a base and a surface layer, with the surface layer having an electron donating portion that mainly donates charge to the developer when the developer and the surface layer make frictional contact to exchange charge and an electron accepting portion that mainly accepts charge from the developer when the developer and the surface layer makes frictional contact to exchange charge. A controller applies an AC voltage to the developer carrying member during a period in which an image forming operation is not performed and the developer carrying member is driven, with the AC voltage being different from that applied during an image forming period, and a rotating speed of the developer carrying member during a non-image forming period is slower than that during an image forming period.

Image forming apparatus having toner charging

An electrophotographic apparatus having an electrophotographic photosensitive member, a charging unit, and a developing unit for forming a toner image on a surface of the electrophotographic photosensitive member, wherein the charging unit has a conductive member disposed to be contactable with the electrophotographic photosensitive member; a conductive layer at the surface of the conductive member has a matrix and a plurality of domains dispersed in the matrix; at least a portion of the domains is exposed at the outer surface of the conductive member; the outer surface of the conductive member is constituted of at least the matrix and the domains; a volume resistivity R1 of the matrix is greater than 1.00&#xd7;10&#x3a9;&#xb7;cm; a volume resistivity R2 of the domains is smaller than R1; the developing unit contains the toner; and a dielectric loss tangent of the toner is at least 0.0027.

Electrophotographic apparatus, process cartridge, and cartridge set

An electrophotographic apparatus including an electrophotographic photosensitive member, a charging unit, and a developing unit, wherein the charging unit includes a conductive member disposed to be contactable with the electrophotographic photosensitive member, a conductive layer of the conductive member has a matrix-domain structure, at least some of the domains are exposed at the outer surface of the conductive member, the volume resistivity RI of the matrix is greater than 1.00&#xd7;10&#x3a9;&#xb7;cm and not greater than 1.00&#xd7;10&#x3a9;&#xb7;cm, the matrix volume resistivity R1 is at least 1.0&#xd7;10-times the domain volume resistivity R2, and the developing unit includes a toner, the toner includes a binder resin-containing toner particle and an external additive, and the external additive contains fine particles of a hydrotalcite compound.

A method of manufacturing a developer container including a frame configured to define a developer containing portion, a first electrode, and a second electrode arranged on a surface of the frame and having a surface opposed to the first electrode, a developer amount in the developer containing portion being detected based on a capacitance between the first electrode and the second electrode, the method including: holding a conductive resin member constituting the second electrode on a mold configured to mold the frame, a surface of the conductive resin member being in contact with a surface of the mold configured to mold a surface of the frame on a side of the developer containing portion; injecting a resin to be formed into the frame, into the mold on which the conductive resin member is held; and curing the resin to form the frame to which the second electrode is fixed.

Method of manufacturing developer container, developer container, developing apparatus, process cartridge, and image forming apparatus

A developing device includes a rotatable sleeve for carrying a developer including a magnetic material to develop a latent image on an image bearing member, a developer chamber, a rotatable stirring member provided inside the chamber to stir the developer while being in contact with at least a part of an inner surface of the chamber and a magnet generating a magnetic field in at least a part of a contact region between the stirring member and the inner surface. A magnetic flux density of the magnetic field at a first position in the contact region generated by the magnet is different from that in a second position which is adjacent to the first position in a rotational axis direction of the sleeve.

Developing device having magnetic field generating members, image forming apparatus and cartridge

A developing apparatus includes a developer bearing member bearing a developer on a surface in a developing operation, a regulating member configured to regulate layer thickness of the developer borne on the developer bearing member, a development chamber provided with the developer bearing member and the regulating member and having an opening, a storage chamber to store the developer, and a conveying member to convey the developer stored in the storage chamber to the development chamber through the opening. When the developing operation is performed, a bottom section of the development chamber is located above a bottom section of the storage chamber in a vertical direction, and a contact region of the developer bearing member in contact with the regulating member is located directly above the opening in the vertical direction.

Developing apparatus having a layer thickness regulating member, cartridge, and image forming apparatus

An image forming apparatus includes a control portion configured to perform a cleaning operation including: a first step of causing a developer, which has a reversed polarity and is attracted to a surface of a charging roller, to have a normal polarity under a state in which the developer bearing member is separated from the image bearing member with the contact/separation unit; and a second step of collecting the developer, which has the normal polarity and is attracted to the surface of the image bearing member, to the developer bearing member, by rotating the image bearing member and the developer bearing member under a state in which the developer bearing member is brought into contact with the image bearing member with the contact/separation unit after performing the first step.

Image forming apparatus

An image forming apparatus includes an image bearing member, a developer bearing member, a fixing unit including a heating member, a rotary member which is heated by the heating member, and a nip area where the rotary member comes into contact with a sheet, and configured to perform fixing by heating a developer image transferred to the sheet and fixing the developer image to the sheet in the nip area, and a control unit configured to execute, while the fixing is not performed, a mode in which the image bearing member is rotated with the developer bearing member being in a separated position and the heating member is controlled such that a temperature of a portion of a surface of the rotary member, after the rotary member passes through the nip area, is maintained higher than the temperature of the portion during the fixing.

Method of manufacturing developer container

In an axial direction of a developing sleeve that bears magnetic developer on an outer circumferential surface thereof, ends of a sheet-shaped stirring member that stirs the magnetic developer in a container frame to move the magnetic developer toward the developing sleeve are disposed on an outer side of a region in a magnetic field region generated by a magnet roller disposed on an inner side of the developing sleeve. The region has a magnetic field strength equal to or larger than a predetermined magnetic flux density at which the magnetic developer can be borne on the surface of the developing sleeve.

Developing apparatus, process cartridge, and image forming apparatus

A developing apparatus includes a developer bearing member configured to bear a developer on a surface, a regulating member that regulates layer thickness of the developer on the developer bearing member, and a developer conveying member. In addition, a frame has a development chamber in which the developer bearing member and the regulating member are provided, a storage chamber in which the conveying member is provided and the developer is stored, and an opening through which the developer passes into the development chamber. The developing apparatus collects the developer remaining on the developer bearing member into the storage chamber after the developer on the developer bearing member is transferred onto a transfer material. The regulating material includes a step portion that forms a gap between the regulating member and the developer bearing member.

Developing apparatus having a layer thickness regulation member, cartridge, and image forming apparatus

A charging member includes a force receiving portion that receives a force in a direction in which the charging member is moved in a longitudinal direction of the charging member while rotating. The charging member is in contact with a brush member at a place different from the place of the force receiving portion. A component of the force received by the charging member at the force receiving portion in the longitudinal direction and a component of a force received by the charging member resulting from tilting of bristles in the brush member are in the same direction.

Charging device, process cartridge, and image forming apparatus

When an outer diameter of a charging member is defined as Hc, a ratio of the circumferential velocity of the charging member to the circumferential velocity of an image bearing member is defined as Rc, an outer diameter of a developer bearing member is defined as Hd, and a ratio of the circumferential velocity of the developer bearing member to the circumferential velocity of the image bearing member is defined as Rd, the relationship Hc/Rc&#x2267;Hd/Rd is satisfied.

Image forming apparatus having simultaneous development and cleaning

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Suntou-gun, Japan

Motonari Ito