Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Koji Suenami

Tamotsu Shimizu

Yoshihiro Yamagishi

Masashi Fujishima

Norio Kubo

Hiroyuki Hamakawa

Eiji Nimura

Yasuhiro Tauchi

Hirohisa Endou

Takaaki Kamei

Akifumi Yamaguchi

Kenichi Tamaki

Akira Matayoshi

Yuji Toyota

Yu Sasaki

Asami Sasaki

Asami Kotera

Takahiko Murata

Masaki Kadota

Yukihiro Mori

Ryoji Nishimura

Yoshimi Shimizu

Tetsuya Toichi

Shinji Otani

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 a development device, a toner storage part, a drive unit, a control unit, and an image carrying member. The development device includes a development casing, a developer carrying member, a first stirring transport member, a second stirring transport member, a discharge impeller, and a reverse transport impeller. The development casing includes a first partition wall, a communication part, a developer replenishment port, and a developer discharge part. The first stirring transport member includes a first rotation shaft and a first transport impeller. The second stirring transport member includes a second rotation shaft and a second transport impeller. The control unit can perform a developer discharge mode, in which the first rotation shaft and the second rotation shaft are rotated reversely during a non image formation period, so that the developer around the reverse transport impeller is discharged through the developer discharge part.

Image forming apparatus that can decrease variations in volume and weight of developer in a development casing

A developing device includes a developer container, a developer carrier, and first and second members for stirring/conveying. The developing container has a first partition wall between first and second chambers, communication portions 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 second partition wall is lower than the first partition wall, and an upper end part of the second partition wall is between upper and lower end parts of the rotary shaft of the second stirring/conveying member.

Developing device which supplies two-component developer containing toner and carrier and which discharges excessive developer and image forming apparatus therewith

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.

An image forming apparatus includes a storage unit and a charging amount acquisition unit. The charging amount acquisition unit performs a charging amount acquisition operation for forming a measurement toner image on the image carrier while changing the frequency of the alternating current voltage of the development bias with a potential difference in a direct current voltage between the developing roller and the image carrier being kept constant, acquiring a tilt of a measurement straight line representing a relationship between the change amount of the frequency and a density change amount of the measurement toner image, and acquiring the charging amount of the toner based on the acquired tilt of the measurement straight line and the reference information in the storage unit.

Image forming apparatus with a charging amount acquisition unit that performs a charging amount acquisition operation for forming a measurement toner image on an image carrier

In the first charge amount acquisition operation, based on density of a plurality of toner images for measurement or based on a direct component of a developing current at the time of forming the plurality of toner images in addition to the density of the plurality of toner images for measurement, the charge amount acquisition section acquires a first toner charge amount that is a charge amount of toner included in the toner image for measurement. In the second charge amount acquisition operation, based on the toner density detected at the time of image formation and a relationship between the first toner charge amount and the toner density detected in the first charge amount acquisition operation, the charge amount acquisition section acquires a second toner charge amount that is a charge amount of the toner in the development device.

Image forming apparatus

A developing device includes a developer container, a developer carrier, first and second stirring/transporting members, a driving motor, first and second magnetic permeability sensors, and a control portion. The first magnetic permeability sensor is arranged in a first conveying chamber in the developer container, in a region other than a part facing a communication portion and senses the toner concentration in developer in the developer container. The second magnetic permeability sensor is arranged in a second conveying chamber in the developer container, in a region between a regulating portion and a downstream end of the developer carrier in the second direction. The control portion controls the supply amount of developer based on the output value of the first magnetic permeability sensor, and calculates the stable volume of developer in the developer container based on the difference between the output values of the first and second magnetic permeability sensors.

Developing device and image forming apparatus therewith to prevent degradation in charging performance

A stirring conveyance member includes a rotary shaft, a first spiral blade, and a second spiral blade. The first spiral blade has first cutouts each provided in a specific region adjacent to and upstream of a point of intersection with the second spiral blade in the conveyance direction of the powder by the first spiral blade. The second spiral blade has second cutouts each provided in a specific region adjacent to and upstream of a point of intersection with the first spiral blade in a conveyance direction of the powder by the second spiral blade. A radial height of the first spiral blade in portions where the first cutouts are provided is lower than a radial height of the second spiral blade in portions where the second cutouts are not provided.

Stirring conveyance member, developing device including the same, and image forming apparatus

A developing device includes a storage portion, a developer carrying member, a stirring portion, a layer thickness restricting portion, and a guide portion. The guide portion is disposed between the stirring portion and the layer thickness restricting portion. The stirring portion faces the developer carrying member with a first gap between them. The layer thickness restricting portion faces the developer carrying member with a second gap between them. The guide portion includes a first guide surface and a second guide surface. On the first guide surface, convex portions or concave portions are formed. The first guide surface faces the stirring portion with, between them, a third gap that is a passage through which the developer passes toward the first gap. The second guide surface faces the developer carrying member with, between them, a fourth gap that is a passage through which the developer passes toward the second gap.

Developing device including a guide portion and an image forming apparatus provided with the same

A developing device includes a developing container, a first stirring member, a second stirring member, and a developer discharge port. The developing container has a first and a second transport chamber. The first stirring member has a rotary shaft and a first helical blade. The second stirring member has a rotary shaft and a second helical blade. Through the developer discharge port, surplus developer inside the developing container is discharged. On the second stirring member, a restricting portion for restricting movement of developer toward the developer discharge port is formed downstream of the second helical blade. The restricting portion has two or more turns of a restricting blade wound in the direction opposite to the second helical blade, and the restricting blade has an increasingly large outside diameter from upstream to downstream with respect to the developer transport direction inside the second transport chamber.

A developing device includes a developer container, a first stirring member, a second stirring member, and a developer carrying member. The second stirring member includes a second transport blade for transporting developer inside a second transport chamber, a regulating portion formed next to, on the downstream side of, the second transport blade in the transport direction of the developer inside the second transport chamber and formed by a transport blade that transports developer in the opposite direction to the second transport blade, a discharge blade formed next to, on the downstream side of, the regulating portion in the transport direction of the developer and transporting developer in the same direction as the second transport blade to discharge the developer through the developer discharge port, a first disk formed between the second transport blade and the regulating portion, and a second disk formed between the regulating portion and the discharge blade.

A developing device includes a developer container, a first stirring member, a second stirring member, and a developer carrying member. The second stirring member includes a second transport blade for transporting developer inside a second transport chamber; a regulating portion having a first regulating blade formed next to, downstream of, the second transport blade in the transport direction of the developer inside the second transport chamber, for transporting developer in the same direction as the second transport blade with a smaller transporting force than the second transport blade, and a second regulating blade formed next to, downstream of, the first regulating blade for transporting developer in the opposite direction to the first regulating blade, and a discharge blade formed next to, downstream of, the second regulating blade for transporting developer in the same direction as the second transport blade to discharge the developer through the developer discharge port.

A developing device includes a developer container, a first stirring member, a second stirring member, and a developer carrying member. The second stirring member includes a second transport blade for transporting developer inside a second transport chamber, a regulating portion formed next to, on the downstream side of, the second transport blade in the transport direction of the developer inside the second transport chamber and formed by a transport blade that transports developer in the opposite direction to the second transport blade, a discharge blade formed next to, on the downstream side of, the regulating portion in the transport direction of the developer and transporting developer in the same direction as the second transport blade to discharge the developer through the developer discharge port, and an annular portion arranged at least either between the second transport blade and the regulating portion or between the regulating portion and the discharge blade.

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.

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Osaka, Japan

Koji Suenami