Fujitsu Corporation

Yoshihiro Tonomoto

Keiko Tonai

Katsumi Sugimoto

Kenji Fuke

Eiji Suzuki

Katsuya Shimatsu

Toshimasa Toyama

Masaaki Ohyama

Toshio Hino

Katsumi Adachi

Hiroaki Yoshida

Kunihiko Sato

Tomoaki Tanaka

Kiyoshi Chinzei

Yoshinori Wada

Masaru Iida

Naoto Hirao

Akihiro Komuro

Yoji Houki

Yasuhiro Wakabayashi

Tsutomu Kawai

Hitoshi Yoshii

Tomokazu Akuta

Hiroki Ohba

Kiyohisa Yanagita

Shozo Tonai

Mituaki Ono

Takashi Suzuki

Kazunori Hirose

Tsutomu Nagatomi

Yukio Nishio

Masao Konishi

Hiroshi Kera

Makoto Koshi

Hiroaki Naito

Osamu Watanabe

Jun Shimizu

Akiyoshi Iwamasa

Shizuo Takano

Yuzuru Sugiura

Masayuki Hida

Katsumi Tateno

A printer including a photosensitive drum on which a toner image is formed, a plurality of transfer wires held in facing relation to the drum, and a static-eliminating wire located downstream from the transfer wires. Transfer currents are conducted through a selected one or more of the transfer wires in accordance with the thickness of recording paper used in the printer.

Printer and transfer charger

A developing apparatus develops a latent image formed on a latent image carrying body with a developer. The developing apparatus includes a developing unit having a means for supplying the developer to the latent image carrying body to develop the latent image on the latent image carrying body and a developer housing for accommodating the developer. A developer storage box stores the developer which is to be supplied to the developing unit. The developer storage box is detachably mounted on the developing unit and has a volume substantially the same as a volume of the developer which can be accommodated in the developer case of the developing unit. The developer in developer storage box is supplied to the developing unit.

Image forming apparatus utilizing a two-component developing apparatus with automatic toner replenishment and developer replacement

A developing apparatus of an electrophotographic apparatus includes a housing for accommodating a developer, first, second and third developing rollers are rotatably disposed in the housing and arranged opposite to a photoconductor drum for conveying a developer carried on respective surfaces of the developing rollers, and a conveyor roller rotatably disposed in the housing for conveying the developer carried on a surface thereof to one of the developing rollers. First and second screw conveyors are disposed in the housing for conveying the developer in an axial direction opposite to each other. Each of these conveyors has an axial length larger than an axial length of the developing rollers. A partition wall is disposed between the first and second screw conveyors. A toner container for accommodating a toner is mounted on the housing. The toner in the toner container is supplied into the housing and agitators agitate the toner in the housing. A first doctor blade regulates the developer carried on the conveyor roller, a second doctor blade regulates the developer on the first developing roller, and scrapers scrape the developer from the second and third developing rollers.

Electrophotographic image-forming apparatus having developing device

A developing device for developing an electrostatic latent image with a two-component developer comprises a developer container (46) including a developer-accumulating chamber (50), and a developer-agitating chamber (56) provided above the developer-accumulating chamber. A communication passage (64) is provided between the developer-agitating chamber and the developer-accumulating chamber, and is opened to the developer-agitating chamber to define an overflow opening for the developer. The device also comprises a developer-carrying body (48) provided in the developer-accumulating chamber of the developer container, and the developer-carrying body is exposed to face an electrostatic latent image carrying body, and brings the developer from the developer-accumulating chamber to a facing zone therebetween for development of an electrostatic latent image formed on the electrostatic latent image carrying body. The device further comprises a developer-lifting means (68, 68', 70) for lifting the developer, brought to the facing zone by the developer-carrying body, to the developer-agitating chamber of the developer container, and a developer-agitating means (58) for agitating the developer in the developer-agitating chamber of the developer container, a part of the developer agitated by the developer-agitating means being fed to the developer-accumulating chamber through the overflow opening and the communication passage.

Developing device for electrostatic latent image

An image forming apparatus including a plurality of developing units each having a developer storage portion for accommodating a developer; a plurality of feeding devices for discharging used developers from the respective developing units; and a single collecting device for collecting the used developers discharged by the respective feeding device.

Toner recovery device

An image forming apparatus includes a plurality of process units contacting a continuous recording medium and transferring images on the recording medium, a separating and contacting mechanism for controlling at least one of the recording medium and each of the process units to a separated state where the recording medium and the process unit are separated from each other and a contacting state where the recording medium and the process unit contact each other, and a controller for controlling the separating and contacting mechanism at a position where the process unit confronts a non-printing region on the recording medium so as to put the recording medium and the process unit to the contacting state.

Image forming apparatus

An image forming apparatus includes a fixing unit including at least a pair of rollers which thermally fix a toner image formed on a surface of a recording medium by pressing against the recording medium, and a separating and contacting mechanism supporting the pair of rollers so that the rollers can separate from and make contact with the recording medium, where the separating and contacting mechanism controls the rollers when contacting the rollers to the recording medium, by contacting each of the rollers approximately perpendicularly to the surface of the recording medium and so that the recording medium thereafter makes contact with a surface of each of the rollers for a wrap-around angle greater than 0.degree..

A toner near empty discriminating unit discriminates a near empty indicating that the toner approaches an empty state on the basis of a detection value of a toner sensor. When the toner near empty is determined, a toner supply amount calculating unit calculates a toner supply amount (w) per time as w=W/X from the number (X) of toner supplying times of a toner supply counter and a specified toner filling amount (W) when a toner cartridge is set. On the basis of the calculated toner supply amount (w) of one time, a correction processing unit corrects a rotational speed of a supply roller of a toner supply control unit and an operation time of the supply roller, or the number of discriminating times of the toner empty and the number of discriminating times of a replacement of an expendable item.

Electrophotographing apparatus having a toner empty discriminating unit

A multicolor electrostatic recording apparatus in which two or more different color toner image are superimposed by respective electrostatic recording units. Each of the electrostatic recording units includes an electrostatic latent image carrier, a developer for developing an electrostatic latent image formed on the carrier with a color toner, and a detector for detecting the density of the developed image on the basis of a detecting mark which is formed on the carrier as a part of the latent image and developed by the developer. A discriminating means compares the density data with an optional desired density value to discriminate whether the density data falls in an allowable range. A controller feed-back controls at least one of parameters for determining the density of the developed image so that the density becomes to be in the allowable range, when the density falls out of the allowable range. The parameter is memorized as a compensating data for the density of the developed image, when the density falls in the allowable range. Thus, with the compensating data, a process using the parameter for determining the density of the developed image is carried out.

Electrostatic recording apparatus utilizing superimposition of colors in

To provide a photo-sensitive drum having excellent properties which are not at all inferior to those of the prior art photo-sensitive drums assembled with a larger number of parts, capable of being easily manufactured at a reduced production cost. A blank tube 23d consisting of a cylinder section 23a, a center axis section 23b arranged within the cylinder section 23a concentrically therewith and a plurality of rib sections 23c for rigidly connecting the cylinder section 23a with the center axis section 23b is integrally formed through extrusion or draw-forming.

Photo-sensitive drum formed from extruded or drawn blank and image

To provide a hot roller type thermal fixation device, incorporated in an electrostatic recording apparatus, particularly suitable for the thermal fixation of a multicolor toner image, said apparatus comprising a plurality of electrostatic recording units arranged in series with each other, wherein the surface smoothness of a fixed toner image is maintained at a favorable level for a long period by providing an anti-abrasive treatment onto an elastomeric covering of the heating roller. An elastomeric covering (32b) is applied on the surface of a heating roller (32) of a hot roller type thermal fixation device (22), and an anti-abrasive covering (32c) is further applied on the elastomeric covering.

Hot roller for thermal fixation device having elastomeric and

Multicolor electrostatic recording apparatus and electrostatic latent

A computer controlled printer is capable of printing at different print densities. This makes it possible to automatically determine an optimum print density according to a normal operational mode with serious consideration given to print quality and an economy operational mode with serious consideration given to operating costs, thereby decreasing the print consumables. The printer has a print mechanism section for printing papers according to print data and a print controlling section for controlling the print mechanism section. The print controlling section selects either a print density in a normal mode or a print density in an economy mode according to the normal/economy instructions and controls the print density of the print mechanism section correspondingly.

Printer with print density switching means

A color image forming apparatus which forms a monochromatic toner image or a toner image in a plurality of colors and which can considerably reduce power consumption, while preventing an offset at the time of fixing a toner image. The color image forming apparatus includes a toner image forming device for forming a monochromatic toner image or a toner image in a plurality of colors on a recording medium; first heating device, located on a toner image side of the recording medium for fixing the toner image on the recording medium by heat; second heating device located on an opposite side to the toner image side of the recording medium; and a controller for making an amount of power supply to the second heating device constant and changing an amount of power supply to the first heating device depending on whether the toner image is monochromatic or is in a plurality of colors, while making a set temperature of the first heating device constant. The controller sets the power supply of the fixing or fusing device as a function of whether the toner image is a monochromatic, plural colors or full colored toner image.

Color image forming apparatus having toner image forming device

A printer capable of operation in an economy mode as well as in a normal mode. The printer includes a print mechanism for printing in accordance with print data. The printer also includes a print controller which controls the print mechanism. The printer is provided with a mode of operation selector for selecting between a normal mode of operation in which the print quality is relatively emphasized and an economy mode of operation in which operating costs are relatively emphasized. The print controller controls the print density at a first level when the normal mode of operation has been selected and at a second reduced level when the economy mode of operation has been selected.

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Kawasaki, Japan

Yoshihiro Tonomoto