Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Ricoh Printing Systems, Ltd.

Other

Ricoh Company, Ltd.

Hitachi Printing Solutions, Ltd.

Teruaki Mitsuya

Keisuke Kubota

Masayoshi Ishii

Hisao Okada

Takashi Suzuki

Hiroyuki Mabuchi

Tsuneaki Kawanishi

Shinya Kobayashi

Nobuyoshi Hoshi

Shinichi Akatsu

Takao Kumasaka

Ryuuichi Shimizu

Toshiya Satoh

Masataka Kawauchi

Yasuo Takuma

Yutaka Kako

Asahiko Isobe

Tomomi Mizuno

Takao Umeda

Seiji Maruo

Shigetaka Fujiwara

Akira Arimoto

Masayasu Anzai

Yasuro Hori

Yoshihiro Sonohara

Shinichi Nishino

Masato Miwa

Akira Terakado

Daisuke Hara

Yoshihiro Gunji

Hiroyoshi Matsumoto

Hisayoshi Kato

Natsuki Kuribayashi

Shintaro Yamada

Yutaka Ito

Koji Kato

Hiroshi Sasaki

Yoshito Tsunoda

Tatsuya Sugita

Kenichi Ito

Toru Miyasaka

Isao Nakajima

Yoshitaka Fujinuma

Minoru Kadowaki

Masayoshi Nakayama

Mamoru Okano

Riichi Kato

Tsutomu Maekawa

Yasuyuki Tsuji

Kenichi Kawashima

Yasuo Kikuchi

Akio Tsujita

Mieko Ishii

Isamu Komatsu

Mitsuyoshi Shouji

Atsushi Onose

Yuzuru Shimazaki

Atsuko Uozumi

Tsutomu Nakagawa

Katsuhiko Suzuki

Yoshihiko Sano

Kazuo Uno

Kousuke Noda

Masato Yamada

Katsuya Kawai

Takashi Rokutanda

Tadahiro Kaneko

Susumu Monma

Masaru Higaki

Hideharu Miki

Ryozo Nakamura

Masami Ishikawa

Makoto Yagawara

Michio Yokosuka

Yosuke Saito

Hiroshi Hakuta

Hiroyuki Kashiwada

Ikuo Shimokobe

Kazuo Sakaki

Kozi Kato

Hideki Ando

Michio Endou

Shigetaka Fumiwara

Shin-ichi Nishino

Shigetaka Fujiware

Heigo Ueki

An image forming apparatus for performing an image forming operation is disclosed that includes an image carrier on which a toner image is formed, an intermediate transfer member configured to transfer the toner image to a recording medium, the intermediate transfer member having a toner image forming area including an output image forming area and a non-output image forming area located outside of the output image forming area, the toner image forming area being wider than the output image forming area, and a detecting part configured to measure a physical quantity regarding an image quality of a first reference image formed in the output image forming area and a second reference image formed in the non-output image forming area.

Image forming apparatus and image forming method on measured physical quantity

In a fixing device in which fixing defects can be suppressed and which can be reduced in size, and an image forming apparatus comprising the fixing device, setting is performed such that the surface temperature of an outer peripheral belt surface serving as a non-heated belt surface of a fixing belt is substantially equal at a heating region inlet at the upstream end of a heating region and a heating region outlet at the downstream end of the heating region such that the temperature difference between the surface temperature of the outer peripheral belt surface at the heating region inlet and the surface temperature of the outer peripheral belt surface at the heating region outlet is no more than 5 [&#xb0; C.].

Fixing device and image forming apparatus comprising same

An electrophotographic apparatus includes: a photoconductor; and two developing rollers facing the photoconductor. A developer fed out from between the two developing rollers is supplied to the photoconductor by the two developing rollers to form a toner image on the photoconductor. The developer includes a carrier having a volume-average particle size smaller than 70 &#x3bc;m and a volume resistivity not lower than 10&#x3a9;&#xb7;cm. A volume ratio of the carrier in a facing portion between the photoconductor and the developing rollers is not lower than 30% and not higher than 46%.

Developing device and electrophotographic apparatus using the same

A fixing device, which fixes an unfixed toner image on a recording medium, includes a heating roller, a fixing roller, a pressurizing roller, and an endless belt that stretches over the heating roller and the fixing roller. A heat source and a heat pipe are arranged in a heating roller. The heat pipe substantially uniformly heats the surface of the heating roller.

Fixing device for fixing an unfixed toner image on a recording medium and image forming apparatus including the fixing device

An axis-to-axis distance between a heating roller and a back-up roller is expanded beforehand in inserting a thick paper to prevent a rush/exhaust impact when fixing the thick paper without changing a condition of pressing mechanism.

Fixing device and electro-photographic recording apparatus using the same

A fixing device wherein supposing that the total load given to a heating roller and a pressure roller is W (kgf) and the area of the pressure contact portion of the heating roller with respect to the pressure roller (nip area) is S (cm), the nip pressure (=W/S) is 2.7 kgf/cmor more and the length of the pressure contact portion in the direction parallel to the direction of conveyance of a recording material is defined to be 14 mm or more.

Fixing device including heating roller and pressure roller

A color image forming apparatus includes a developing unit to which a developing bias with an AC component superposed is applied, wherein the DC voltage of the developing bias is adjusted to set the detected density of a solid image at a specified value, the light amount of radiation for exposing an image area having a width of a few dots adjacent to the white paper is adjusted to set the detected density of an image developed under a peripheral electric field at a specified value, and the gradation density curve is regulated by alternately adjusting the DC voltage, the light amount of radiation for exposing the image area having a width of a few dots adjacent to the white paper, and the amplitude of the AC component until the detected density of a mesh point image having an area ratio from 60 to 80% falls within a specified range.

Color image forming apparatus

In an image forming method, when viewed from the moving direction of a photosensitive bodythere is disposed, on the upstream side, a first developing rolleropposed to and adjacent to the photosensitive bodyand rotatable in the opposite direction to the photosensitive bodywhile the peripheral speed ratio of the rollerto the photosensitive bodyranges from 0.8 to 2.0; on the downstream side of the rollerthere is disposed a second developing rollerrotatable in the same direction to the photosensitive bodywhile the peripheral speed ratio of the rollerto the photosensitive bodyranges from 1.05 to 2.0; and the shape coefficient SFof the toners of two-component developing agent ranges from 120 to 170, while the shape coefficient SFranges from 110 to 130.

Image forming method and image forming apparatus

In an electrophotographic recording device, a multicolor toner image is formed by images in each color superimposed on one another. In order to detect image misalignment, image-forming units form a color registration detection pattern, and sensors detect the pattern and output detection signals. A control unit detects the position of the patterns based on only portions of the detection signals corresponding to leading edges of the patterns.

Image position detecting method

A cooling device used in an electrophotographic image forming device includes a cooling roller, which is a heat roller, and a backup roller pressed against the cooling roller to form a nip portion therebetween. After being discharged from a fixing device that thermally fixes a toner image onto a recording sheet, the recording sheet passes through the nip portion, whereby the cooling roller cools the recording sheet. The cooling roller is maintained at 100&#xb0; C. or higher.

Cooling device for cooling recording sheet

A transfer member transporting section is disposed so as to bring a tip end of a transfer member into contact with a peripheral face of a transfer rotary member before the tip end of the transfer member enters a nip area. A bias power supply has a polarity inverting function of, during a period from a timing when the tip end of the transfer member is brought into contact with the transfer rotary member by the transfer member transporting section, to that when the tip end of the transfer member enters the nip area, applying a voltage of a polarity which is identical with that of a toner, to the transfer rotary member, and after the tip end of the transfer member enters the nip area, applying a voltage of a polarity which is opposite to that of the toner, to the transfer rotary member.

Image forming apparatus with transfer bias inverting function

A developing unit in an electro-photographic apparatus such as a printer, a facsimile and a copier for actualizing an image employing colored particles such as toner, and more particularly to a developing unit for forming a toner image on the surface of a photosensitive body. The developing unit includes a plurality of developing rollers each having a core and a sleeve. The sleeve accommodates the core. The plurality of developing rollers include a first developing roller and a second developing roller. The sleeve for the first developing roller is rotated to move in the same direction as a moving direction of the surface of the photosensitive body. The sleeve for the second developing roller is rotated to move in an opposite direction to the moving direction of the surface of the photosensitive body. The core of only one of the plurality of developing rollers is driven in rotation while the other core is fixed. Alternatively, a magnetic pole of one of the developing rollers is placed at an opposing position where the developing rollers mutually oppose while an intermediate portion between two poles of the second developer roller is placed at the opposing position.

Electro-photographic developing unit

A transfer flow-in current which flows from a transferring device into an image carrier, a separation flow-in current which flows from a separating device into the image carrier, an aperture width in the recording member transporting direction of an aperture of the transferring device, and an aperture width in the recording member transporting direction of an aperture of the separating device are set so as to have the relationship: separation flow-in current&equals;transfer flow-in current&times;(transfer aperture width/separation aperture width).

Electrophotographic apparatus including transferring device

An electrophotographic cluster printing system for performing printing by using a plurality of electrophotographic recording apparatuses such as printers, facsimile machines or copying machines each capable of manifesting an image by using colored particles such as toner. The electrophotographic cluster printing system includes a plurality of electrophotograhic recording apparatuses each including a photoconductor, a charger, an exposure device, a developing device, and an image quality controller for detecting a factor concerning image quality and controlling image quality of an output image on the basis of information of the detected factor. In the system, at least two of the electrophotograhic recording apparatuses is used for printing one job and image quality of any one of the electrophotograhic recording apparatuses is controlled on the basis of detected information of the other electrophotograhic recording apparatuses.

Electrophotographic cluster printing system with controlled image quality

In order to provide a miniature full-color recorder having an excellent color reproducibility and to provide a full-color recorder having a wider color reproduction range beyond the range of subtraction color mixing of three primary colors, first and second potential split developing processes are continuously arranged for one recording medium.

Full-color recorder using potential split developing process

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Ibaraki, Japan

Teruaki Mitsuya