Ricoh Company, Ltd.

Tokuya Ohjimi

Toshio Koike

Atsushi Sampe

Masami Tomita

Hiroyuki Nagashima

Masanori Kawasumi

Takeshi Uchitani

Naohiro Kumagai

Takeshi Shintani

Eisaku Murakami

Masato Yanagida

Kentaroh Matsumoto

Masayuki Yamane

Shin Hasegawa

Yutaka Takahashi

Hiroto Higuchi

Kunihiro Ohyama

Fumihiro Sasaki

Maiko Kondo

Mugijiroh Uno

Takeyoshi Sekine

Masaki Sukesako

Kazunori Karasawa

Hiroya Hirose

Junichi Sano

Yuji Arai

Hiroshi Ono

Hiroyuki Sugiyama

Hideo Yoshizawa

Kiyonori Tsuda

Hitoshi Ishibashi

Shinji Tamaki

Ken Amemiya

Yukiko Iwasaki

Kazuhisa Sudo

Shunji Katoh

Takatsugu Fujishiro

Shinichi Kawahara

Jun Yura

Haruji Mizuishi

Kazuaki Kamihara

Masahiko Yamada

Tsuyoshi Imamura

Jun Shiori

Junichi Terai

Mikio Ishibashi

Takuzi Yoneda

Hironobu Takeshita

Ryota Kidera

Disclosed is an image forming device including a fixing unit that fixes a first image to be fixed onto a sheet, the first image to be fixed being supported on the sheet, a target fixing temperature varying unit that varies a target fixing temperature during a time period in which a fixing process is performed, and a gradation processing unit that applies a gradation process to first image information. The target fixing temperature varying unit varies the target fixing temperature for the sheet of the recording medium to which the fixing process is applied, depending on presence or absence of a halftone process, and depending on a type of the gradation process to be utilized.

Image forming device

A toner replenishing device includes a toner container that stores toner, a toner replenishing device that supplies toner from the toner container to a developing device, and a toner condition detector that detects an aggregated condition of the toner stored in the toner container. A toner softening device is provided to soften toner stored in the toner container. A controller is also provided to drive the toner softening device for a prescribed time period in accordance with a detection result obtained by the toner condition detector.

Toner replenishing device capable of effectively softening toner and image forming apparatus with toner replenishing device

An image forming apparatus including an image bearing member, a charging member, and a measuring member. The image forming member is configured to bear an image. The charging member is configured to charge a surface of the image bearing member when a direct current bias voltage is added to at least an alternating bias voltage which is applied to the charging member, and has a frequency fc of the alternating bias voltage. The measuring member is configured to measure a potential of the surface of the image bearing member, and has a drive frequency fvsen. The relationship of the frequency fc and the drive frequency fvsen is expressed as fc&#x2260;fvsen&#xd7;n and fc&#xd7;n&#x2260;fvsen.

Method and apparatus for image forming capable of effectively preventing resonance of frequencies

A cleaning unit includes a first blade and a second blade. The first blade is in contact with an image carrier or a paper carrier and removes adhered substances remained on surface of these. The second blade has an abrasive layer that is formed by including abrasive particles in an elastic material and is disposed in the downstream side of the first blade. The second blade is allowed to be in contact with the image carrieror the paper carrier. Volume occupancy of abrasive particles in an area of contact of the second blade with either the image carrier or the paper carrier is not less than 50 percent and not more than 90 percent.

Cleaning unit and image forming apparatus having multiple cleaning blades

A charging device including: a charging roller having a metal cylinder and an elastic layer located on the metal cylinder; a cleaner configured to clean the charging roller, which includes an electroconductive brush roller including a roller having a shaft; and hair located overlying the roller, wherein the hair includes a fiber which has a width of from 0.1 to 20 denier, and a length of from 0.3 to 2.5 mm and which is planted at a density of from 7,000 to 46,000 lines/cm, and a member configured to impart substantially the same potential as that of the charging roller to the electroconductive brush roller when a bias voltage is applied to the charging roller. A process cartridge and an image forming apparatus including the charging device are also provided.

Charging device, and process cartridge and image forming apparatus using the charging device

Cleaning unit, process cartridge, and image forming apparatus

A developing device including a developer containing magnetic toner grains and includes a main pole for development disposed in a sleeve. Flux density generated by the magnetic pole in a direction normal to the surface of the sleeve outside of the surface has an attenuation ratio of 50% or above. The toner grains have a weight mean grain size of 6.0 &#x3bc;m to 8.0 &#x3bc;m while the toner grains having grain sizes of 5 &#x3bc;m and below occupy 40% to 80% of the entire developer. The toner grains have magnetization strength of 10 emu/g to 25 emu/g in a magnetic field of 5 kOe or magnetization strength of 7 emu/g to 20 emu/g in a magnetic field of 1 kOe. The toner grains reduce toner scattering and image defects despite that they are magnetic, thereby implementing ultrahigh resolution.

Developing device using a two-ingredient type developer and image forming apparatus including the same

A developing device developing a latent image on a latent image carrier with a developer, and including a casing having an opening facing the latent image carrier and a developer carrier. Also included is a magnetic field generating device including a first magnetic pole generating a magnetic field causing the developer to rise on the developer carrier in a form of a magnet brush in a developing region, and a second magnetic pole generating a magnetic field at a downstream side of the first magnetic pole in a rotating direction of the developer carrier. Further, a toner-scattering restraining device is provided on an end portion of the casing at the downstream side of the developing region, and a magnetic member provided on a side of the toner-scattering restraining device facing the latent image carrier. A peak of a magnetic flux density set by the second magnetic pole in its normal direction is located outside of the opening.

Developing device including magnetic member provided on toner-scattering restraining device and image forming apparatus including the developing device

A developing apparatus, an image formation apparatus and a process cartridge is provided. Even though the sealing materials of the initial developer container are stripped off in such a way that the process cartridge having the developing apparatus is tilted, the initial developer can be uniformly supplied along the central axis line of the developer carrier. The developing apparatus performs a self toner control and has an initial developer case for containing the non-used initial developer that is input into the developer containing space S. The initial developer case is divided internally into a plurality of partition spaces along the direction of the central axial line D of the developing sleeve so that a plurality of partitions is formed inside the initial developer case Based on the opening for inputting the initial developer, the partition surface F facing to the partition space of each partition is tilted from an imaginary plane G perpendicular to the central axial line D of the developing sleeve toward one end H along the direction of the central axial line D of the developing sleeve

Developing apparatus, image formation apparatus, and process cartridge

In an image forming apparatus having a reverse development system and using a two-component developer, respective potentials applied when charging an image bearing member and when applying a development bias to a developer bearing member are attenuated when the image bearing member is driven for an operation other than an image forming operation, compared to respective level of potentials applied when the image bearing member is driven for the image forming operation. Thus, an occurrence of an adhesion of a carrier to an image bearing member is reduced to produce a high quality image, when a power switch of the apparatus is turned off or when a door of the apparatus is opened while the image bearing member is driven for an operation other than the image forming operation, or when the apparatus is activated again after the power switch is turned off.

Method and apparatus for reducing adhesion of carrier to image bearing member

A developing device includes a developer bearing member including an internal magnetic field generating device and configured such that a surface thereof moves to carry and convey a developer including toner and carrier. A developer regulating member regulates a quantity of the developer carried and conveyed by the developer bearing member toward a developing area, and a developer accommodating unit accommodates the developer regulated to be conveyed toward the developing area by the developer regulating member. A toner accommodating unit includes a toner supplying opening opposing a surface of the developer bearing surface of the developer bearing member at a position adjacent to and upstream of the developer accommodating unit in a developer conveying direction. The toner in the toner accommodating unit is taken into the developer on the developer bearing member based on a toner density of the developer on the developer bearing member by a movement of the developer with a conveyance of the developer on the developer bearing member. The developing device further includes a peeling off member that opposes, without contacting, a surface of the developer bearing member in the developer accommodating unit so as to peel off an upper layer part of the developer carried and conveyed by the developer bearing member.

Image forming apparatus and developing device with improved self toner density control

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Kanagawa, Japan

Tokuya Ohjimi