Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Masashi Fujishima

Akihiro Watanabe

Tamotsu Shimizu

Yasuhiro Tauchi

Yukihiro Mori

Norio Kubo

Chikara Ishihara

Yasuhiro Oishi

Shoichi Sakata

Sakae Saito

Sayo Uemura

Hiroshi Yamazaki

Takahisa Nakaue

Koji Suenami

Akira Matayoshi

Yukimasa Watanabe

Toyotsune Inoue

Hiroyuki Hamakawa

Asami Sasaki

Asami Kotera

Yuji Toyota

Yuji Kamiyama

Shizuka Okada

Hiroaki Sakai

Kiyotaka Kobayashi

Yu Sasaki

Yoshinobu Yoneima

Yoshimi Shimizu

Takahiko Murata

Masanobu Maeshima

Jun Azuma

Masaki Kadota

Kenichi Tamaki

Takashi Nagashima

Keisuke Oba

Hisashi Mukataka

Ayako Yashima

Junichi Nakagawa

Shinji Otani

Sayo Mabuchi

Yuki Matsui

Eriko Takeuchi

An image forming apparatus includes a developer, a development device, and an image bearing member. The developer includes an initial developer containing an initial carrier and a replenishment developer containing a replenishment carrier. The initial carrier has a surface roughness Sa1 of at least 0.3 μm and no greater than 1.0 μm. A ratio Sa1/Sa2 of the surface roughness Sa1 of the initial carrier to a surface roughness Sa2 of the replenishment carrier is at least 1.2 and no greater than 3.4. The packing volume Vp calculated from equation (1)'Vp=100×Y/(Z×DS)' was at least 40% and no greater than 70%. In equation (1), Y represents an amount of the developer conveyed by a developer bearing member. Z represents an apparent density of the initial developer. DS represents a width of a space between the developer bearing member and the image bearing member.

Image forming apparatus and image formation method

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 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

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

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 roller includes a roller main body disposed to face, without contact, an outer circumferential surface of an image carrier. The roller main body includes an aluminum oxide thin film and a resin coat layer, the aluminum oxide thin film being formed on an outer circumferential surface of a base body that is made of a metal including aluminum, the resin coat layer being formed on a surface of the aluminum oxide thin film that has been subjected to a predetermined heating process, the resin coat layer being made of a resin material and having electric conductivity.

Developing roller, developing device, image forming apparatus, and manufacturing method of developing roller

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 device supplies a developer to a photosensitive drum, which has a cylindrical shape, and is rotatable around an axis thereof for forming an electrostatic latent image on the circumferential surface thereof. The developing device is provided with a developing roller. The developing roller is disposed to face the photosensitive drum, and has a cylindrical shape. The developing roller is rotatable around an axis thereof for carrying a developer on the circumferential surface thereof. The developing roller is provided with a small diameter portion. The small diameter portion is a part of the circumferential surface of the developing roller. The small diameter portion extends from an axial end of the developing roller axially inward by a predetermined length, and has an outer diameter smaller than an axially middle portion of the developing roller.

Developing device, and image forming apparatus provided with the same

An image forming apparatus includes an image carrier, a developing device, a bias applying unit, a leakage detecting unit, a bias control unit and a leakage detection control unit. The developing device includes a magnetic roller and a developing roller. The magnetic roller carries a developer layer by being rotated. The developing roller receives the toner from the developer layer and supplies the toner to the image carrier. The leakage detection control unit performs a leakage detecting operation of detecting a value of an inter-peak voltage, at which the leakage occurred. The leakage detection control unit simultaneously starts the leakage detecting operation for a plurality of developing devices and performs the leakage detecting operations of the developing devices in which leakage simultaneously occurred while switching the leakage detecting operations one by one if the leakage simultaneously occurs in a plurality of developing devices at an inter-peak voltage.

Image forming apparatus with leakage detecting unit for detecting leakage

Developing device includes developing roller and magnetic roller. Developing roller includes aluminum oxide thin film and resin coat layer. Magnetic roller is disposed to face, without contact, outer circumferential surface of developing roller, and includes aluminum oxide thin film formed on outer circumferential surface of base body that is made of metal including aluminum. Magnetic roller forms toner layer on surface of developing roller via magnetic brush composed of toner and magnetic carrier. AC impedance Z1 is in range from 1.0&#xd7;10&#x3a9; to 1.0&#xd7;10&#x3a9; and surface roughness Ra of resin coat layer is in range from 0.057 &#x3bc;m to 0.280 &#x3bc;m, AC impedance Z1 being obtained when AC voltage at predetermined frequency is applied to between base body of magnetic roller and base body of developing roller in a state where the magnetic brush is formed on magnetic roller.

Developing device, image forming apparatus

The present disclosure relates to a developing roller having a conductive support base, a surface of which is covered with a resin layer, wherein the resin layer contains conductive fine particles and soluble nylon serving as a binder resin, and the resin layer surface has a surface roughness Ra of at least 0.4 &#x3bc;m, a waviness curve cycle of 50 to 400 &#x3bc;m, and a waviness curve height of 2 to 10 &#x3bc;m.

Growing community of inventors

Osaka, Japan

Masashi Fujishima