Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Akira Matayoshi

Tamotsu Shimizu

Masashi Fujishima

Yasuhiro Tauchi

Mitsuhiro Hashimoto

Takeshi Watanabe

Hiroshi Inui

Norio Kubo

Yuji Toyota

Masaru Watanabe

Koji Suenami

Asami Sasaki

Einosuke Kikuchi

Akihiro Watanabe

Masaki Kadota

Minoru Wada

Masahito Ishino

Masaru Hatano

Hironori Daigo

Shinji Yamane

Katsuya Ota

Motoki Moriguchi

Yoshinori Horiuchi

Ayaka Kondo

A developing device includes a developer container, a developer carrier, and first and second stirring/conveying members. The developer container includes a first partition wall partitioning between the two conveying chambers longitudinally, a first communication portion for passing developer from the first to the second conveying chamber, a second communication portion for passing developer from the second to the first conveying chamber, a developer supply port for supplying developer in, a developer discharge portion for discharging excessive developer, a second partition wall arranged, adjacent to the regulating portion, downstream of the second communication portion to partition between the first conveying chamber and the regulating portion, and a shield portion connected to the two partition walls to bridge between them to shield a top part of the second communication portion. A gap is formed between an upper end part of the shield portion and the inner surface of the developer container.

Developing device and image forming apparatus therewith

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developer container includes a first partition wall between first and second chambers, a communication portion through which those chambers communicate at opposite ends of the first partition wall, a developer supply port, and a developer discharge portion. The first member stirs and conveys developer in the first chamber in a first direction. The second member stirs and conveys developer in the second chamber in a second direction and includes a regulating portion and a discharging blade. The developer container includes a second partition wall between the first chamber and the regulating portion. The gap from the upper end of the second partition wall to the inner surface of the developer container is larger than the gap thereto from the upper ends of a first helical blade and the regulating portion.

A bias condition determination portion of an image forming device executes each of: a first approximation expression determination operation that respectively acquires the DC component of the development current with at least three peak-to-peak voltages included in a first measurement range and determines a first expression showing a relation between the peak-to-peak voltage and the DC component of the acquired development current, a second approximation expression determination operation that respectively acquires the DC component of the development current with at least three peak-to-peak voltages included in a second measurement range larger than the first measurement range and determines a second approximation expression showing a relation between the peak-to-peak voltage and the DC component of the acquired development current, and a reference voltage determination operation that determines, as a reference peak-to-peak voltage, the peak-to-peak voltage at an intersection where the first approximation expression and the second approximation expression intersect each other.

Image forming device

Provided is an image forming apparatus capable of suppressing the occurrence of image defects in response to a difference in carrier resistance and obtaining high image quality. A developing unit has a developing roller that carries toner in a two-component developer that includes a toner and a magnetic carrier on the surface thereof, and forms a toner image on the surface of a photosensitive drum. A current detecting unit detects developing current flowing between the developing roller and the photosensitive drum when a developing voltage is applied to the developing roller by a developing power supply. When the developing voltage is applied to the photosensitive drum, a control unit derives a carrier resistance based on the developing current detected by a current detecting unit, and controls an AC amplitude of an AC voltage of the developing voltage based on the carrier resistance.

Image forming apparatus capable of suppressing occurrence of image defects in response to difference in carrier resistance and obtaining high image quality

An image forming apparatus includes a developing section, storage, a first calculation section, a comparing section, and an executing section. The developing section develops an electrostatic latent image with toner. The storage stores coverage rates. The first calculation section calculates a first coverage rate and a second coverage rate. The comparing section compares the first coverage rate with the second coverage rate. The first coverage rate includes one or more coverage rates stored earlier in the storage than the second coverage rate. The second coverage rate includes coverage rates of a specified number of latest images individually formed on a specified number of sheets. A running-in operation is driving the developing section. The executing section executes the running-in operation.

Image forming apparatus capable of executing a running-in operation for a developing section

An image forming apparatus includes a developing section, storage, a first calculation section, a comparing section, and an executing section. The developing section contains toner and develops an electrostatic latent image with the toner. The storage stores coverage rates. The first calculation section calculates a first coverage rate and a second coverage rate. The comparing section compares the first coverage rate with the second coverage rate. The executing section executes a running-in operation based on a result of comparison by the comparing section. The first coverage rate includes one or more coverage rates stored earlier in the storage than the second coverage rate. The second coverage rate includes coverage rates of a specified number of latest images individually formed on the specified number of sheets. The running-in operation is driving the developing section.

Image forming apparatus

An image forming apparatus includes a toner containing portion, a first conveying member, an image conveying portion, and an image forming portion. The first conveying member is configured to convey the toner in a conveyance direction within the toner containing portion. The image conveying portion includes a surface layer portion having a first end portion located at an upstream side in the conveyance direction and a second end portion located at a downstream side in the conveyance direction. The first end portion has a larger layer thickness than second end portion. The image conveying portion is configured to convey a toner image formed on a surface of the surface layer portion at a predetermined image forming position, to a transfer position for transfer to a transfer target medium. The image forming portion is configured to form the toner image on the surface layer portion by using the toner being conveyed.

Image forming apparatus forming toner image on surface layer portion of image conveying portion

An image forming apparatus includes: a photosensitive body including a photosensitive layer having a first end and a second end, the first end having a larger thickness than the second end; a charging portion charges the photosensitive layer; a light irradiation portion applies light to the photosensitive layer; a developing device develops by toner charged with the same polarity as charge polarity of the photosensitive layer; an intermediate transfer medium including a surface layer having a third end and a fourth end, the third end having a larger thickness than the fourth end, the third end being opposed to the second end, the fourth end being opposed to the first end; and a transfer portion transfers a toner image developed on the photosensitive layer, onto the surface layer when a voltage having polarity opposite to the charge polarity is applied to the transfer portion.

Image forming apparatus transferring toner image onto surface layer portion of intermediate transfer medium

A developing device includes a housing, a stirring member, a developing unit body, a driving device, a detecting device, and a control device. The housing accommodates developer supplied from a supply means and including toner and carrier. The stirring member rotates in the housing to stir the developer. The developing unit body rotates in the housing to convey the developer toward an image carrying member from the stirring member and attaches the toner to the image carrying member. The driving device rotationally drive at least one of the stirring member and the developing unit body. The detecting device detects the torque of the driving device. The control device performs a recovery process of controlling the supply means to supply at least one of the carrier and the developer to an interior of the housing when a detection result of the detecting device has a value lower than a threshold value.

Developing device having a control device that performs a recovery process and image forming apparatus including the same

A developing device includes a storing portion, a stirring member, a developing roller, a shield plate, and a guide portion. The storing portion stores developer. The stirring member is rotatably provided in the storing portion and stirs the developer in the storing portion by being rotationally driven in a predetermined first rotation direction. The developing roller is rotatably provided above the stirring member, has a magnet that attracts the developer in the storing portion by a magnetic force, and is rotationally driven in a predetermined second rotation direction. The shield plate is made of a nonmagnetic material and provided at a facing position where the developing roller and the stirring member face each other. The guide portion is provided more on an upstream side in the first rotation direction than the facing position, and guides the developer from the storing portion to the developing roller side.

Developing device and image forming apparatus including the same

A photosensitive drum is axially rotatable and has a surface on which an electrostatic latent image is formed. A developing device includes a development roller spaced from the photosensitive drum. The development roller includes a cylindrical sleeve and a coating layer, and the photosensitive drum includes a cylindrical tube and a functional layer. Each of the coating layer and functional layer is formed by dipping the sleeve or tube into a dipping bath with the sleeve or tube directed axially vertically. An axial end portion of the development roller that is lower during the dipping process is disposed opposite to an axial end portion of the photosensitive drum that is higher during the dipping process, and an axial end portion of the development roller that is higher during the dipping process is disposed opposite to an axial end portion of the photosensitive drum that is lower during the dipping process.

A transfer device includes image bearing members, an intermediate transfer belt, transfer members, a transfer bias applying unit and a bias control unit. The transfer bias applying unit applies a transfer bias to the transfer. The bias control unit causes a transfer bias having a polarity opposite to that of the toner to be applied to a first transfer member during the transfer process in the first transfer nip and during an adjacent transfer process which is the non-transfer process in the first transfer nip and the transfer process in a second transfer nip adjacent to the first transfer nip. Further, the bias control unit causes a transfer bias having the same polarity as that of the toner to be applied to the first transfer member during an adjacent non-transfer process which is the non-transfer process in the first transfer nip and the non-transfer process in the second transfer nip.

Transfer device and image forming apparatus provided with same

An intermediate transfer belt that temporarily holds a toner image which is formed on an image carrier and transferred to the intermediate transfer belt includes a base member, an elastic layer laminated on the base member and a surface layer covering the elastic layer. With respect to the intermediate transfer belt, a volume resistivity of the surface layer is lower than a volume resistivity of an entirety of the intermediate transfer belt.

Intermediate transfer belt and tandem color image forming apparatus

An endless belt is provided with an endless belt body and a meandering prevention member in the form of a flat bar. The belt body includes a folded trace extending in the width direction thereof. The meandering prevention member is attached on one widthwise end of a circumferential surface of the belt body such that one widthwise end of the folded trace is covered thereby and the opposite longitudinal ends of the meandering prevention member abut each other in a rotating direction of the belt body. An abutting portion at the opposite ends of the meandering prevention member is arranged at a position displaced from the folded trace by a specified distance in the rotating direction of the belt body.

Endless belt, belt conveyor and image forming apparatus

An image forming apparatus includes an image bearing member with an image bearing surface adapted to move in a given direction and carry a toner image thereon. A main cleaning device is opposed to the image bearing surface and electrically removes residual toner remaining on the image bearing surface. A power supply is adapted to apply to the main cleaning device a bias having a polarity reverse to a charge polarity of the residual toner. An auxiliary cleaning device is provided near and upstream of the main cleaning device with respect to the moving direction of the image bearing surface and can be brought into contact with the image bearing surface. A support structure supports the auxiliary cleaning device and permits the auxiliary cleaning device to be moved swingingly while following a displacement of the image bearing surface during the moving.

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Osaka, Japan

Akira Matayoshi