Fujitsu Corporation

Fuji Xerox Co., Ltd.

Fujitsu Isotec Limited

Hiroshi Kera

Akira Nagahara

Yoshio Yamaguchi

Takefumi Takahashi

Nobuo Kuwabara

Toshio Tooda

Yoshiya Ishiyama

Tetsuya Takei

Akira Takahashi

Yoshihiro Tonomoto

Yoshiya Matsumoto

Sachio Sasaki

Kazunori Hirose

Yukio Nishio

Tsuneo Mizuno

Hideki Kamaji

Atsushi Tano

Takeo Kojima

Yoji Houki

Shigeo Nonoyama

Haruyasu Watanabe

Mitsuhito Furukawa

Makoto Matsuoka

Hisashi Hanzawa

Hiroki Ohta

Shizuo Takano

Masanori Nishido

Mituru Sato

The present invention relates to a color image forming device for forming toner images of a plurality of colors on a medium, and is for improving second transfer efficiency from an intermediate transfer body to the medium. The device has image forming units (-to-) for forming the toner images of the plurality of colors on at least one image bearing body (-to-) by a plurality of developing units (-to-) respectively accommodating toner of different colors; an intermediate transfer body (); primary transfer means (-to-) for primary transferring the toner images of the plurality of colors onto the intermediate transfer body sequentially for the respective colors; and secondary transfer means () for secondary transferring the toner images of the plurality of colors on the intermediate transfer body onto the medium. The image forming units form the toner images of the plurality of colors so that the potentials of toner layers transferred onto the intermediate transfer body () are progressively lower in the order in which the plurality of colors are transferred. Since the potential of the toner layer directly adhered to the intermediate transfer body is higher, the directly adhered toner layer becomes easier to be secondary-transferred, and thereby, the secondary transfer efficiency is improved and the reproducibility of the secondary color is improved.

Color image forming method and color image forming device

An image forming device includes an image forming part which forms an image on a recording medium; a recording medium switchback portion which receives the recording medium on a first run, one side of which has been printed when passing the image forming part, and sends the recording medium for a second run; a recording medium path which communicates with the recording medium switchback portion so as to send the recording medium to and from the recording medium switchback portion; an inverted recording medium transfer path through which the recording medium is sent to the image forming part again with an upper surface and a lower surface of the recording medium reversed; and a recording medium transfer part which transfers the recording medium along the inverted recording medium transfer path. The image forming device is further provided with a first recording medium receiving portion which stores the recording medium one on another with a printed surface facing upwards; and a first recording medium ejection path which communicates with the recording medium receiving portion so as to send the recording medium to the first recording medium receiving portion.

Image forming device

An electrophotographic image forming apparatus including a toner circulating mechanism for recovering a residual toner scraped from a photosensitive drum to a developing device. The developing device includes a housing for defining a toner chamber, a developing roller rotatably mounted in the housing, an agitator rotatably mounted in the housing and provided in the toner chamber, and a partition member mounted to the housing to define a carrier chamber between the partition member and the developing roller. The toner circulating mechanism directly returns the residual toner scraped from the photosensitive drum to the toner chamber in the developing device. The toner chamber may contain a foreign matter removing device. The partition member may have various shapes.

Electrophotographic image forming apparatus having a device for

An electrophotographic image forming apparatus includes an electrostatic latent image carrying body, an electrifying unit for electrifying the image carrying body, a light irradiating unit to form an electrostatic latent image in accordance to image information, a developing unit for discharging toner to the image carrying body to develop the latent image, a transfer unit for transferring the toner image to a recording sheet, and a cleaner for removing residual toner on the image carrying body. The toner removed from the image carrying body is recirculated to the developer receiving box. An additional toner image is formed on a position other than a first position where the electrostatic latent image is formed in accordance with the image information. The toner is removed by the cleaner without being transferred to the recording sheet and recirculated from the image carrying body to the developer receiving box.

Electrophotographic image-forming apparatus with uniform toner usage

An image forming apparatus having a developing unit for developing an electrostatic latent image on a photosensitive drum with a one-component toner, consisting of an endless latent image carrier; an image forming unit for forming an electrostatic latent image on the image carrier; a developing unit, for causing the developing roller to contact the image carrier to develop the electrostatic latent image on the image carrier; a mechanism for driving the developing unit; a toner sensor for detecting the presence/absence of the toner in the developing unit; and an abutting/detaching mechanism for abutting or detaching the developing roller of the developing unit on or from the image carrier. According to one aspect of this invention, this apparatus further has a controller for executing an image forming mode to control image formation in response to an image forming instruction, and a developer supply mode for, with the developing roller set apart from the image carrier, driving the driving mechanism to supply the toner to the developing roller in accordance with an output of the toner sensor indicating an insufficient amount of the toner.

Image forming apparatus having contact type, one-component developing

A developing device using a one-component developer composed of toner particles includes a developing roller rotatably provided within the vessel, a portion of the developing roller being exposed therefrom and resiliently pressed against a surface of a photosensitive drum. The toner particles are entrained by the roller surface to form a developer layer therearound and are carried to the drum surface for the development of an electrostatic latent image formed thereon, and a blade member is engaged with the roller for regulating a thickness of the developer layer. A voltage is supplied to the roller to electrostatically move the toner particles from the roller to the latent image, and a voltage is applied to the blade member to inject an electrical charge to the developer layer. When an operation of the device is started, a supply of the voltages to the roller and blade member is carried out after the roller is rotated. When the operation is interrupted or stopped, the supply of the voltage to the blade member is prematurely stopped before the supply of the voltage to the roller and the rotation thereof are stopped.

Developing device used in electrophotographic field

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Kawasaki, Japan

Hiroshi Kera