Kyocera Document Solutions Inc.

Mita Industrial Co., Ltd.

Kyocera Mita Corporation

Norio Kubo

Asami Sasaki

Masashi Fujishima

Tamotsu Shimizu

Yasuhiro Tauchi

Yuji Toyota

Koji Suenami

Akihiro Watanabe

Yukihiro Mori

Akira Matayoshi

Yoshitake Shimizu

Masaru Hatano

Masatomi Funato

Seijiro Ishimaru

Kazuya Nagao

Terumichi Asano

Masaki Kadota

Minoru Wada

Kenichi Tamaki

Ryo Taniguchi

Naruo Yabe

Eiji Gyotoku

Takeo Mizobe

Yoshimi Shimizu

Junichi Nakagawa

Takahiro Okubo

Koju Yamamoto

Eiji Gyoutoku

Shinji Otani

Kouzou Teramoto

Yasushi Imanishi

An image forming apparatus includes: a gear that transmits a drive force, which is supplied from a drive unit, to a photosensitive drum; a formation processing unit that, at arrival of each of specific formation timings, uses the photosensitive drum thereby to form a to-be-detected toner image that is based on a to-be-detected image having a specific density; an acquisition processing unit that acquires a variation width of a density in the to-be-detected toner image formed by the formation processing unit; and a determination processing unit that determines a failure timing of the gear based on the variation width for each of the formation timings.

Image forming apparatus capable of determining failure timing of a gear used therein, and determining method of the failure timing

An image forming apparatus includes an image supporter, a development unit, a cleaning unit, a collection unit, and a controller. The collection unit includes a collection path where a developer discharge path for transport of a waste developer from a discharger of the development unit and a toner discharge path for transport of waste toner from the cleaning unit merge with each other, and collects the waste developer including the waste toner and waste carrier. A place of a high flow resistance is formed at least partially at the collection path. If the weight ratio of the waste carrier to the waste toner included in the waste developer in the collection path is less than a predetermined value, the controller performs carrier discharge process of moving the carrier from the development unit to the image supporter and removing and discharging the carrier using the cleaning unit during non-image formation.

Image forming apparatus

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 determiner executes, in order, a first direct current voltage determination mode (first DC calibration) for determining a provisional reference direct current voltage that is a provisional reference for a direct current voltage of a developing bias applied to a developing roller, an inter-peak voltage determination mode (AC calibration) for determining a reference inter-peak voltage that is a reference for an inter-peak voltage of an alternating current voltage of the developing bias applied to the developing roller in an image forming operation, and a second direct current voltage determination mode (second DC calibration) for determining a reference direct current voltage that is a reference for the direct current voltage of the developing bias applied to the developing roller in the image forming operation.

A bias condition determiner executes a direct current voltage determination mode (DC calibration) for determining a reference direct current voltage that is a reference for a direct current voltage of a developing bias applied to a developing roller in an image forming operation and an inter-peak voltage determination mode (AC calibration) for determining a reference inter-peak voltage that is a reference for an inter-peak voltage of an alternating current voltage of the developing bias applied to the developing roller in the image forming operation. A calibration executor determines whether the inter-peak voltage determination mode needs to be executed in accordance with a value of the reference direct current voltage.

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

A developing device includes a developing container, first and second stirring-conveyance members, a developer carrier, a toner concentration sensor, a scraper, and a scraper attachment unit. The second stirring-conveyance member includes a rotation shaft, a first spiral blade to convey developer in an axial direction, and a second spiral blade to overlap a region where the first spiral blade is formed, which is opposite to the first spiral blade in phase, and lower than the first spiral blade in height in a radial direction. An absent region, where the second spiral blade does not exist, is formed in one pitch of the first spiral blade, the one pitch facing the toner concentration sensor. The scraper attachment unit is formed to extend, along a straight line passing through intersection points of the first and second spiral blades and parallel to the rotation shaft, into the absent region.

Developing device and image forming apparatus including same

A developing device includes a developing roller, a conveyor roller, a developer stirring unit and a development bias applying unit. The developing roller is arranged to face a photoconductive drum at a predetermined developing position and supplies the toner. The conveyor roller is arranged to face the developing roller at a predetermined facing position and supplies the developer to the developing roller. The development bias applying unit applies development biases to the first sleeve of the developing roller and the second sleeve of the conveyor roller during a developing operation of developing the electrostatic latent image on the photoconductive drum with the toner. The development bias applying unit applies the development biases such that a shifting electric field to move the toner on the first sleeve of the developing roller toward the second sleeve of the conveyor roller is formed at the facing position during the developing operation.

Developing device and image forming apparatus provided with same

In the case where development is performed by a two-component developing method, a previous charge removal light-emitting portion applies charge removal light to a first charge removal target region of an effective outer circumferential surface of a photosensitive member on which effective outer circumferential surface an electrostatic latent image can be formed. The first charge removal target region includes a part of a magnetic brush contact region of the effective outer circumferential surface and a region of the effective outer circumferential surface between the magnetic brush contact region and a transfer position of a toner image.

Image forming apparatus having a function to apply charge removal light to photosensitive member

A developing device includes a developing container, a toner carrier, and a plurality of air outlet ports. The plurality of air outlet ports are formed in such part of a wall of the developing container as faces the toner carrier, along a longitudinal direction of the developing container, the air outlet ports communicating with a duct next to the developing container. The toner carrier includes a coat layer on the outer circumferential surface thereof. The coat layer is formed by dripping the toner carrier into a resin coating liquid with one end in the longitudinal direction thereof first, the one end being a lower end of during the dipping, and then lifting the toner carrier out of the resin coating liquid. The toner carrier is arranged such that the lower end of during the dipping is disposed on an upstream side with respect to an airflow direction in the duct.

A developing device includes a housing, a developer carrier, a conveying member and a surface layer. The developer carrier carries a developer on a circumferential surface. The conveying member is rotatably arranged in a first conveying portion and conveys the developer in the first conveying direction and supplies the developer to the developer carrier. The surface layer is formed on a surface of a predetermined cylindrical base member. The surface layer is formed by an immersion method of immersing the base member in a predetermined immersion tank so that an axial direction of the base member extends along a vertical direction. A lower end side of the base member at the time of the immersion is arranged in an upstream side of the housing and an upper end side of the base member at the time of the immersion is arranged in a downstream side of the housing.

Provided is a developing device including: a first helical blade; a second helical blade formed at the same blade pitch as a blade pitch of the first helical blade; a developer discharge port for discharging surplus developer; and a regulating member formed in a reverse phase with respect to the first helical blade. When a proximity portion is at a position facing a communication portion, a blade apex portion of the second helical blade is arranged to fall within a range of from a position facing an end surface portion of the communication portion on a downstream side of the second conveyance path to a position immediately before a position facing the proximity portion, which is reached in accordance with a phase shift of the second helical blade. A first stirring member and a second stirring member are driven at the same rotational speed.

Developing device and image forming apparatus including the same

A stir-transport member is formed on a circumferential surface of a rotation shaft with a first spiral blade, and a second spiral blade formed to overlap the region of the first spiral blade and is opposite the first spiral blade in phase and having a smaller radial-direction height than the first spiral blade. Sections of the spiral blades along the cross longitudinal direction thereof have trapezoidal shapes. The first spiral blade have a plurality of first swell portions, a part of each corresponding to a bottom of the trapezoidal shape and is more swollen than the other portions. The second spiral blade have a plurality of second swell portions, a part of each corresponding to the bottom of the trapezoidal shape and is more swollen than the other portions. The first spiral blade cross the second spiral blade at least at one of the first swell portions per turn.

Stir-transport member, development device provided therewith, and image forming apparatus

Provided is a developing device including: a developing container partitioned into a stirring-transport chamber, a supplying-transport chamber, and a collecting-transport chamber that are arranged substantially in parallel with one another, for storing a two-component developer; a developer carrying member for carrying the developer on a surface thereof; a supplying-transport member located within the supplying-transport chamber; a stirring-transport member located within the stirring-transport chamber; a collecting-transport member located within the collecting-transport chamber, for stirring and transporting the developer in the same direction as the supplying-transport member and at the different speed from the supplying-transport member; a first developer passage for passing the developer from the stirring-transport chamber to the supplying-transport chamber; a second developer passage for passing the developer from the supplying-transport chamber to the stirring-transport chamber; and a communication portion for passing the developer from the collecting-transport chamber to the supplying-transport chamber.

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Osaka, Japan

Norio Kubo