Kyocera Document Solutions Inc.

Mita Industrial Co., Ltd.

Kyocera Mita Corporation

Akihiro Watanabe

Masashi Fujishima

Tamotsu Shimizu

Yukihiro Mori

Masahiko Kubo

Yoshihisa Kuramae

Noriaki Tsubota

Hiroshi Yamazaki

Hiroyuki Hamakawa

Eiji Gyotoku

Kazuo Fuji

Sayo Uemura

Takahisa Nakaue

Toyotsune Inoue

Yasuhiro Oishi

Asami Kotera

Shoichi Sakata

Yasuhiro Tauchi

Norio Kubo

Sakae Saito

Yuji Kamiyama

Shizuka Okada

Yoshinobu Yoneima

Mitsushi Kuroki

Yu Sasaki

Naruo Yabe

Chikara Ishihara

Tsutomu Uezono

Hironori Maruyama

Takafumi Nagai

Kiyotaka Kobayashi

Yasuyuki Ishiguro

Minoru Wada

Akira Matayoshi

Yukimasa Watanabe

Toshinori Nishimura

Yuji Toyota

Ryo Taniguchi

Masahiro Higashitani

Kensuke Fujihara

Akira Nakakuma

Yoshimi Shimizu

Kazuhisa Edahiro

Takahiro Okubo

Shoji Tomita

Hiroaki Sakai

Yasushi Imanishi

Nobuyuki Fuchimoto

Ryo Yamada

Sayo Mabuchi

Toshio Nishino

Shizuka Ikazaki

Takeshi Amano

Yuki Matsui

Katsumi Oyama

Toshio Nishio

Uto Syu

A development device includes a development container, a first conveying member, a second conveying member, a toner concentration sensor, and a developer carrier. The toner concentration sensor is arranged at a wall portion of the first conveying chamber in which the first conveying member is arranged. The first and second conveying members are equal to each other in outer diameter and shaft diameter, the outer diameter being 2.3 times the shaft diameter or more but 3.0 times the shaft diameter or less. Where D represents the shaft diameter of the first conveying member, L represents an axial length of the first conveying member, and K represents a distance of a center position of a sensing surface of the toner concentration sensor from a downstream end of the first conveying chamber in the first direction, formula (1) is satisfied: 500<(L×K)/D<2500 (1).

Developing device and image forming apparatus including developer conveying member and toner concentration sensor

A development device includes a development container, a first conveying member, a second conveying member, a toner concentration sensor, and a developer carrier. The first and second conveying members are equal to each other in outer diameter and shaft diameter, the outer diameter being 1.3 times the shaft diameter or more but 1.6 times the shaft diameter or less. Where L represents an axial length of the first conveying member, K represents a distance of a center position of the sensing surface of the toner concentration sensor from a downstream end of a first conveying chamber of the development container in the first direction, P represents a pitch of the conveying blade of the first conveying member, and R represents a rotational speed of the first conveying member, formula (1) is satisfied: 30000<(P×R×L)/K<45000 (1).

Image forming apparatus including developer conveying member and toner concentration sensor

A toner conveyance device includes a vertical conveyance portion, a horizontal conveyance portion, a conveyance member, and a loosening member. The vertical conveyance portion conveys a toner or developer conveyed therein through an entry port connected to a main-body-side conveyance path by causing the toner or developer to fall vertically. The horizontal conveyance portion is connected to a lower end of the vertical conveyance portion and conveys the toner or developer in a horizontal direction by using the conveyance member. the loosening member is arranged at a first position below a connection portion between the main-body-side conveyance path and the entry port and at a second position protruding upward beyond the connection portion. A toner loosening mode is executable in which the toner or developer is fed into the vertical conveyance portion so as to cause the loosening member to reciprocate at the second position.

Toner conveyance device that can execute toner loosening mode, and developing device and image forming apparatus including the same

A developing device includes a developing container, a first stirring conveyance member, a second stirring conveyance member, a developer carrying member including a developing sleeve and a magnet, and a regulation member. The regulation pole in the magnet has a region extending over 10° or more in which a maximum value of a vertical magnetic force is not more than 65 [mT] and a vertical magnetic force gradient is not more than 0.3 [mT/°]. A peak position of the vertical magnetic force gradient of the regulation pole is arranged at a position opposed to the second stirring conveyance member, and when a value of the vertical magnetic force gradient and a value of the vertical magnetic force at the peak position of the vertical magnetic force gradient are indicated as A [mT/°] and K [mT], respectively, A≥2.8 and A×K≥62.5 are satisfied.

Developing device including developer carrying member and containing two-component developer and image forming apparatus including the developing device

A toner conveyance device includes a vertical conveyance portion, a horizontal conveyance portion, a conveyance member, and a loosening member. The vertical conveyance portion conveys a toner or a developer containing the toner conveyed therein through an entry port connected to a main-body-side conveyance path by causing the toner or the developer to fall vertically. The horizontal conveyance portion is connected to a lower end of the vertical conveyance portion and conveys the toner or the developer in a horizontal direction by using the conveyance member arranged in the horizontal conveyance portion. The loosening member is arranged so as to be movable between a first position below a connection portion between the main-body-side conveyance path and the entry port and a second position protruding upward beyond the connection portion and reciprocates in a vertical direction at each of the first position and the second position.

Toner conveyance device, and developing device and image forming apparatus including the same

A toner conveying device includes a toner conveying portion having vertical and horizontal conveying portions, a conveying member arranged in the horizontal conveying portion, a toner loosening member, and first and second magnetic members. The toner loosening member is arranged in the vertical conveying portion to be movable vertically. The first magnetic member is attached to the bottom end of the toner loosening member. The second magnetic member is attached to a part of the conveying member facing the toner loosening member. The magnetic pole of the first magnetic member on its side facing the conveying member is the same as the magnetic pole of the second magnetic member on its side facing the toner loosening member. The toner loosening member vertically reciprocates as the repulsive magnetic field between the first and the second magnetic members changes periodically with the rotation of the conveying member.

Toner conveying device, and developing device and image forming apparatus therewith

A developing device includes a developing container including a first conveyance chamber and a second conveyance chamber disposed above the first conveyance chamber, a first stirring-conveyance member which conveys developer in the first conveyance chamber in a first direction, a second stirring-conveyance member which conveys the developer in the second conveyance chamber in a second direction opposite to the first direction, and a developer carrier. A second communication portion is formed which allows the first and second conveyance chambers to communicate with each other at their end portions on a downstream side in the second direction. In the first conveyance chamber, a guide member is disposed which guides, to the downstream side in the first direction, the developer passing through the second communication portion to fall into the first conveyance chamber.

Developing device having first conveyance chamber and second conveyance chamber disposed above first conveyance chamber, 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

An image forming apparatus includes an image carrier, a developer carrier, a bias applying section, a leakage detecting section, and a bias controlling section. The developer carrier carries developer in the form of a layer of magnetized filaments to supply toner to the image carrier. The bias applying section applies to the developer carrier a development bias including a direct current voltage VmagDC and an alternating current voltage VmagAC superposed on each other. The leakage detecting section causes a discharge between the image carrier and the developer carrier and detects a leakage voltage when the discharge occurs. The leakage detecting section performs the leakage voltage detection in a blank region of the image carrier bearing no electrostatic latent image. The bias controlling section determines an alternating current voltage VmagAC according to a detected leakage voltage, and a frequency of the alternating current voltage VmagAC according to the voltage VmagAC.

Image forming apparatus with function of setting appropriate development bias

A developing device includes a developer carrying body, a layer thickness limiting portion, and a rotation control portion. The layer thickness limiting portion includes a base body and a flexible member. The base body protrudes toward a part at a third position between a first position and a second position on the outer circumferential surface of the developer carrying body. The flexible member is a sheet-like member having flexibility, and is attached to the base body such that the flexible member covers, via a gap, a range of the base body from a front end surface facing the developer carrying body to an upper surface, and a bent portion covering a boundary portion between the front end surface and the upper surface of the base body is closer to the outer circumferential surface of the developer carrying body than the other part is.

Developing device and image forming apparatus

A developing deviceincludes a first rotation control portion and a second rotation control portion. When a developing process is performed, the first rotation control portion causes a developer carrying member to rotate in a first rotation direction at a first rotation speed previously determined. When the developing process is not performed, the second rotation control portion causes the developer carrying member to rotate at a second rotation speed Vfaster than a rotation speed Vduring the developing process in a direction Xreverse to a development rotation direction X, and then, causes the developer carrying member to rotate at a third rotation speed Vslower than the second rotation speed Vin the direction X

Developing device with reverse rotation control, image forming apparatus, and method for controlling developing device

A development execution control portion executes a development process by causing an intermediate lateral conveyance portion and a developing portion to operate. A developer replenishment control portion causes a developer replenishment portion to operate when a detection result of a developer amount sensor satisfies a predetermined shortage condition. A post-development processing control portion causes the intermediate lateral conveyance portion and the developing portion to operate continuously from and after a development process and then stop.

Developing device, image forming apparatus

A developing device includes a housing, a development roller, and a roller gear. The roller gear is disposed at one axial end of the development roller and transmits a rotational drive force to the development roller. The development roller includes a sleeve and a coating layer. The coating layer is formed by dipping the sleeve in a dipping bath with the sleeve directed axially vertically. The development roller is mounted to the housing such that a lower axial end of the development roller at the time of the dipping is an opposite axial end to the one axial end at which the roller gear is disposed.

Developing device and image forming apparatus including the same

A developing roller includes a roller main body disposed to face, without contact, an outer circumferential surface of an image carrier. In the roller main body, a boehmite layer has been formed on an outer circumferential surface of a base body that is made of a metal including aluminum, by a surface treatment by a boehmite method, and a resin coat layer has been formed on a surface of the boehmite layer, the resin coat layer being made of a resin material having electric conductivity.

Developing roller, developing device, and image forming apparatus including developing device

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.

Image forming apparatus

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Osaka, Japan

Akihiro Watanabe