Ricoh Company, Ltd.

Katsumi Masuda

Hideki Kimura

Takamasa Ozeki

Kiyotaka Sakai

Yoshio Hattori

Yuji Suzuki

Hideo Yoshizawa

Nobuyuki Taguchi

Kyohta Koetsuka

Masayuki Ohsawa

Kazuhisa Sudo

Kazuyuki Sugihara

Hiroyuki Uenishi

Tsuyoshi Imamura

Yuuki Satoh

Akira Azami

Toshiki Hayashi

Hiroyuki Nagashima

Masumi Sato

Toshiyuki Uchida

Takaya Muraishi

Noriyuki Kamiya

Masato Yokoyama

Keiichi Yoshida

Yoshiyuki Takano

Toshio Kojima

Takumi Terasaka

Hiroshi Ishii

Tadashi Kasai

Yasufumi Takahashi

Shunji Katoh

Takeroh Kurenuma

Yoshiyuki Fukuda

Junichi Terai

Takefumi Adachi

Kenji Nakajima

Tsuyoshi Imanura

A development device includes a developer container, a developer carrier, exposed partly from a casing, facing a latent image carrier in a development area, a magnetic field generator inside the developer carrier, having multiple magnetic poles including a conveyance pole to convey the developer downstream from the development area to a developer release portion, a developer agitator, and a developer regulator. A predetermined gap is kept between an outer surface of the developer carrier and an inner wall of the casing downstream from an opening of the casing, upstream from a developer release portion, in a direction in which the developer carrier rotates. Multiple recesses are formed in the outer surface of the developer carrier at a pitch in a circumferential direction shorter than half a width of a magnetic flux density of the developer conveyance pole in a direction perpendicular to an axial direction of the developer carrier.

Development device, and process cartridge and image forming apparatus incorporating same

A development device including a developer container, a developer bearer, a magnetic field generator, a developer agitator to supply the developer to the developer bearer, and a developer regulator to adjust a layer thickness of the developer carried on the developer bearer. Multiple oval recesses oblique to the axial direction of the developer bearer are formed in the outer circumferential surface of the developer bearer and arranged in a circumferential direction and the axial direction thereof. An upstream inner wall of the recess in the rotational direction of the developer bearer applies a force to the developer as the developer bearer rotates, and an angle between a long axis of the recess and the axial direction is set so that the force applied by the upstream inner wall of the recess has a component in a direction substantially identical to the developer conveyance direction of the developer agitator.

Development device, process cartridge, and image forming apparatus including same having multiple recesses formed on a developer bearer

A developing unit includable in a process cartridge and in an image forming apparatus includes a developer bearing member including a magnetic field generator and a nonmagnetic hollow member, a developer container, an agitation/conveyance member, and a developer regulating member. The magnetic field generator has first and second magnetic poles to generate respective magnetic forces for removing the developer from the developer bearing member after the developer passes the development region. A developer-releasing region releases the developer from the developer bearing member using a release force. The developer is disposed higher than a surface of the developer in the developer storing chamber. A component of a magnetic flux density of the magnetic field generated by the magnetic field generator in a direction normal to the developer-releasing region is directed to a same direction as the first and second magnetic poles across the developer-releasing region without forming a local maximum point.

Developing unit, image forming apparatus incorporating same, and process cartridge including same

There is provided a separation member for separating a first conveying path formed by a first conveying member from a second conveying path formed by a second conveying member. There is also provided an opposed member facing a magnetic pole Hat an upstream side of two magnetic poles Hand Hthat forms a developer-releasing magnetic pole H

Developing device, process cartridge, and image forming apparatus

A developing unit includable in a process cartridge and in an image forming apparatus includes a developer bearing member including a magnetic field generator and a nonmagnetic hollow member, a developer container, an agitation/conveyance member, a developer regulating member to regulate the thickness of a layer of the two-component developer. The magnetic field generator has first and second magnetic poles to generate respective magnetic forces for removing the developer from the developer bearing member after the developer passes the development region. The second magnetic pole generates a magnetic force to attract the developer to form a magnetic brush on the developer bearing member. The developer regulating member includes a magnetic member outwardly disposed on an exterior perimeter surface of the developer bearing member upstream from the developer regulating member, and one planar surface of the magnetic member faces the second magnetic pole across an effective development region.

Developer regulating member in a developing unit, process cartridge including same, and image forming apparatus incorporating same

To downsize a developing device in the developing carrier axial direction without generating image concentration irregularities from recirculation of developer in the magnetic roller end regions, an Npole and an Npole, which are mutually adjacent having the same polarity (N polarity), and which are for generating a magnetic force for removing from a developing sleeve a developer that has passed through a developing region, are provided on a magnetic roller. Magnets of this developing device, which are for generating a magnetic field to displace to the inside in the axial direction magnetic force lines that cause peeling force in the direction of separation from the developing sleeve to act on developer on the developing sleeve, based on the magnetic force of the Npole and the Npole, and that pass through the axial direction end regions within a developer separation region on the developing sleeve, are provided on the outside of the magnetic roller.

Developing device, and image forming apparatus and process cartridge comprising the same

A developer bearing member on which grooves slanting in a thrust direction of the developer bearing member cross other grooves reversely slanting relative to the thrust direction, wherein each of the grooves and the reversely slanting grooves is slanting at an angle of greater than 0&#xb0; and not greater than 40&#xb0;. Any two adjacent intersections of the grooves and the reversely slanting grooves in the thrust (or peripheral) direction are preferably on different levels in the peripheral (or thrust) direction. The distance between two adjacent intersections in the thrust direction is preferably from 1.3 mm to 4.8 mm. The distance between two adjacent intersections in the thrust direction is preferably from 0.38 Vd/Vi (mm) to 1.1 Vd/Vi (mm). The deviation in depth of grooves present on a 36&#xb0; arc surface portion of the member is not greater than 15% of the gap between the image bearing member and the developer bearing member.

Developer bearing member, developing device, process cartridge and image forming apparatus

It is an object of the present invention to provide a process unit and an image forming apparatus in which generation of loss of image density due to flying off of developer and the edge effect occurring as a side-effect under developing conditions aimed at improving development performance can be reduced, even when a DC bias development system is adopted, and which can suppress developing density unevenness caused by impact occurring on contact of the teeth of gears in the drive system.

Image forming apparatus including a magnetic brush developing system using a two-component developer comprising toner and carrier

An image forming apparatus includes an image forming mechanism and an image bearing member. The image forming mechanism is configured to form an image. The image bearing mechanism is detachably provided to the image forming apparatus. The image bearing mechanism includes an image bearing member configured to bear the image formed by the image forming mechanism, and a through shaft configured to support the image bearing member.

Image forming apparatus having a detachable cartridge including a photoconductive drum with axis shaft having a minimal rotational eccentricity, and a method of assembling the image forming apparatus

An image forming method and apparatus includes a development device in which two rotary shafts enclosed in respective separate chambers for spirally circulating the developer between the two chambers to supply the developer to a development roller. The development device is provided with an extended circulation enclosure having a fill opening communicating with the two chambers.

Method and apparatus for image forming capable of performing a stable image development

An image forming apparatus whereby it is possible to prevent unevenness in developing density caused by misalignment between the central axes of a driven side rotational coupling section for rotating a developer carrier and a drive side rotational coupling section for transmitting rotational drive force to the driven side rotational coupling section. The driven side rotational coupling section is fixed and the position thereof can be corrected slightly, by engaging the driven side rotational coupling section with a drive side rotational coupling section. A transmission gear is provided which meshes with the driven side rotational coupling section and transmits rotational drive force used to move the surface of the developer carrier. By means of an axle provided on at least one end of the transmission gear engaging with a positioning member on the main body of the image forming apparatus, the developer carrier is positioned in the main body of the image forming apparatus.

Image forming apparatus

A developing device includes a developer carrier and a developer regulating member including a developer regulating part opposing a surface of the developer carrier to regulate the developer carried and conveyed by the developer carrier. The developer regulating member is formed from a single metallic member and includes a space that faces an inner surface of the metallic member. The space extends in a direction perpendicular to a moving direction of the surface of the developer carrier. The developing device can include a cooling device that cools the developer regulating member from an inner surface side of the metallic member facing the space.

Developer regulating member, developing device, electrophotographic image forming process cartridge, and image forming apparatus including the developer regulating member

An image forming apparatus of the present invention includes a charging device made up of a charge roller and a roller cleaning member for cleaning the charge roller. The charge roller is held in contact with a photoconductive element and uniformly charges the element while being driven by the element. The roller cleaning member is held in contact with the charge roller in order to remove impurities from the roller. The charge roller has a resistance ranging from 1.times.10.sup.3 .OMEGA. to 1.times.10.sup.7 .OMEGA.. The cleaning device exhibits a stable charging ability over a long time of use without resorting to a mechanism for moving the charge roller into and out of contact with the photoconductive element or for moving the roller cleaning member into and out of contact with the charge roller.

Image forming apparatus using a roller type charging system

An electrophotographic method and apparatus includes a frame having a used toner inlet, a new toner inlet and a combined toner outlet. Opposing sides of the frame are positioned at predetermined angles with respect to a horizontal line extending from a bottom of the frame. The used toner inlet is positioned in an upper portion of the frame next on one of the sides positioned at a predetermined angle, while the new toner inlet is also positioned in the upper portion of the frame, but next to the other side. The predetermined angle of the frame's side that is next to the used toner inlet is at a greater angle than the other side so as to compensate for any degradation in the flow characteristic of the used toner as a result of the recycling process. The frame is configured to interface with a new toner bottle having an opening that cooperates with the new toner inlet. Accordingly, when the new toner supply is exhausted, the new toner bottle may easily be replaced without having to remove any other components.

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Kanagawa, Japan

Katsumi Masuda