Fujitsu Corporation

Masahiro Wanou

Masatoshi Kimura

Sachio Sasaki

Mitsuru Sato

Hiroshi Nou

Masao Konishi

Akira Nagahara

Takefumi Takahashi

Junzo Nakajima

Shigenobu Utaka

Takeo Kojima

Hideki Kamaji

Masae Ikeda

Yoshihiro Watanabe

Yasushige Nakamura

Kunihiko Sato

Hirofumi Nakayasu

Norio Sawatari

Yuji Uehara

Youji Houki

Tsutomu Nagatomi

Kazunori Hirose

Yukio Nishio

Hirotoshi Shimizu

Satoshi Takezawa

Yoshinori Wada

Tsuneo Watanuki

Masakazu Kinoshita

Morihisa Kawahara

Yoshio Yamaguchi

Hidenori Fujioka

Tsutomu Kawai

Kouichi Kobayashi

Fumihiro Itoh

Teturou Nakashima

Shino Sakai

Akihiko Ishii

Kazuhiko Hamazoe

Kaneastu Uchiyama

Mamoru Horiuchi

Masashi Ogasawara

Nobuo Suematsu

Masakazu Kanaka

Shinichirou Yamamoto

To provide an electrophotography apparatus with which the service life management of a printing unit can be carried out properly, a non-volatile memory for storing a count value for managing the service life of the printing unit is installed in both a main unit and the printing unit of the electrophotography apparatus. Then, the count value is written to the memory on the printing unit (PU) side (PU memory) when print processing is not in progress, and no power is supplied to the PU memory during print processing, so the correct count value is always stored in the PU memory. Therefore, the service life of the printing unit can be correctly evaluated.

Electrophotography apparatus

An electrophotographic recording apparatus includes a photosensitive drum on which an electrostatic latent image can be written, a developing device for developing the latent image of a charged visible image with a one-component developer, and a transferring device for electrostatically transferring the charged visible image from the drum to a sheet or paper. The developing device has a conductive foam rubber roller for entraining the developer to form a developer layer therearound and for bringing the layer to the drum for the development of the latent image, a conductive blade resiliently engaged with the foam rubber roller for uniformly regulating a thickness of the developer, and an electric source for applying electric energy to the blade to electrically charge the developer layer by a charge-injection effect. The transferring device has a conductive foam rubber transfer roller in contact with the drum, and an electric source for applying energy to the transfer roller to give a paper an electric charge having a polarity opposite to that of the charged visible image during a passage of a recording medium through a nip between the drum and the transfer roller.

Electrophotographic recording apparatus using developing device with one-component type developer and having combination of charge injection effect and conductive contact type charger

An image forming apparatus capable of preventing unnecessary adhesion of a developer to an uncharged region of a latent image carrier. The image forming apparatus includes an endless latent image carrier, a charging unit for charging the latent image carrier, a latent image forming unit for forming a latent image on the latent image carrier charged, a developing unit for developing the latent image formed on the latent image carrier with a developer by supplying the developer to the latent image carrier under application of a developing bias voltage, and a transfer unit for transferring the image developed on the latent image carrier to a sheet. The image forming apparatus further includes a driving member for rotating the latent image carrier and for driving the developing unit to supply the developer to the latent image carrier, and a controller for effecting sequence control such that the application of the developing bias voltage to the developing unit is started a predetermined time after the rotation of the latent image carrier and the drive of the developing unit and also the charging operation of the charging unit have been started. Alternatively, a driving member for driving the developing unit is provided separately, and the controller effects sequence control such that the drive of the developing unit and the application of the developing bias voltage to the developing unit are started a predetermined time after the rotation of the latent image carrier and the charging operation of the charging unit have been started.

Image forming apparatus capable of preventing adhesion of a developer to

A toner developing quantity detection unit operates a plurality of electrostatic recording units to transfer Y, M, C and K color component toner marks onto a belt. A toner developing quantity correction unit detects toner developing quantities per unit area of color toners on the basis of detection signals of the color component toner marks on the belt optically detected by a sensor. The toner developing quantity correction unit corrects the toner developing quantities so as to allow the toner consuming quantities of the plurality of electrostatic recording units to be substantially the same level, on the basis of the thus detected toner developing quantities.

Printing apparatus

Disclosed is an image forming apparatus capable of performing an image forming operation in both a horizontal position and an upright position. This image forming apparatus comprises a rotary endless latent image carrier; image forming unit for forming an electrostatic latent image on the latent image carrier; developing unit for developing the electrostatic latent image on the latent image carrier with a powdery developer, the developing unit having a developing room, developing rollers provided in the developing room for supplying the powdery developer to the latent image carrier, a toner supply room for supplying toners, toner supply roller provided in the toner supply room and rotatable to supply the toners to the developing room, and a partition member for partitioning the developing room and the toner supply room and forming a toner supply passage for supplying the toners to the developing room; and transfer unit for transferring the developed image on the latent image carrier to a sheet.

Image forming apparatus having a developing apparatus which includes a

An electrostatic latent image is developed on a latent image carrier and residual toners are collected at the same time. An electrostatic latent image is formed on a rotary endless latent image carrier; developer, including magnetic toners and magnetic carriers, is supplied to a developing area for developing the latent image carrier, and a magnetic brush is formed with the developer in the developing area to thereby collect residual toners on the latent image carrier and develop the electrostatic latent image on the latent image carrier; and the developed image on the latent image carrier is transferred to a sheet. An electrostatic latent image may be developed with a rotary endless latent image carrier; an image forming unit for forming an electrostatic latent image on the latent image carrier; a developing unit having a developer, including magnetic toners and magnetic carriers, and a developer supplying unit for supplying the developer to a developing area for developing the latent image carrier and forming a magnetic brush with the developer in the developing area in order to develop the electrostatic latent image on the latent image carrier with a powdery developer and collect residual toners on the latent image carrier; and a transfer unit for transferring the developed image on the latent image carrier to a sheet.

Image forming method and apparatus with magnetic brush

Disclosed is an image forming apparatus capable of performing an image forming operation in both a horizontal position and an upright position. This image forming apparatus comprises a rotary endless latent image carrier; image forming unit for forming an electrostatic latent image on the latent image carrier; developing unit for developing the electrostatic latent image on the latent image carrier with a powdery developer, the developing unit having a developing room, a developing roller provided in the developing room for supplying the powdery developer to the latent image carrier, a toner supply room for supplying toners, toner supply roller provided in the toner supply room and rotatable to supply the toners to the developing room, and a partition member for partitioning the developing room and the toner supply room and forming a toner supply passage for supplying the toners to the developing room; and transfer unit for transferring the developed image on the latent image carrier to a sheet.

Image forming apparatus

A toner image transferring device has a roller formed of a conductive rubber foam material having a resistivity of more than 10.sup.7 .OMEGA.cm. In a toner image transferring process, a constant current is applied to the roller, whereby a charged toner image can be transferred to a sheet or paper at a desired toner transfer efficiency regardless of a size of the paper or sheet. To remove a toner pollution of the roller, a constant voltage having a polarity opposite to that of the charged toner is applied to the roller. The roller is constituted such that pore openings appear over a surface of the roller, whereby a residual part of a toner polluting the roller will not leave a stain on a rear surface of the sheet or paper.

Conductive roller transfer device with improved transfer efficiency and

A process unit to be loaded into an image forming apparatus, includes at least a photosensitive drum to be rotated and a conductive brush type charger for uniformly charging a surface of the photosensitive drum. The conductive brush fibers having tips which touch the surface of the photosensitive drum and apply a charge voltage of 500 V to 1,500 V to the surface of the photosensitive drum through the conductive brush fibers for uniformly charging the surface of the photosensitive drum.

Process unit for image forming apparatus, including a charging brush

A brush type charging unit having a constant-current regulated power supply for supplying a constant current to a moving photosensitive medium through a conductive brush fiber contacting the moving photosensitive medium for charging the photosensitive medium uniformly such that the charged potential varies within a range smaller than 10 V when an atmospheric condition changes from 5.degree. C.-20% RH to 35.degree. C.-80% RH. The constant-current regulated power supply has a pulse removing circuit for charging the moving photosensitive medium uniformly even when a few pin-holes exist in the photosensitive medium. A fiber element has a resistance between 4.5.times.10.sup.7 ohm and 1.times.10.sup.13 ohm when the fiber element has 1 denier in size and 1 mm in length, for charging the photosensitive medium and avoiding burning of the fiber element.

Brush contact type charging unit in an image forming apparatus

A checking method for a device having a plurality of light emitting elements, especially an LED array installed in electronic printing equipment. The check is done while the LED array is mounted in the equipment and does not require removal thereof. The check is done in a short time period, so it can be done during a period of page change of the printer, without disturbing the operation of the printer. Each of the LEDs are lighted one by one with a pulse. The output emission of the array is detected by a photoelectric detector which is positioned to detect the emission from any of the LEDs. The output of the detector becomes a burst of pulses, each of the pulses representing the emission property of a corresponding LED. Each pulse is converted into a digital signal and stored in a RAM as emission data. The emission data is fed back to the driver of each LED to compensate for differences in the emission characteristics of the LEDs. This improves the uniformity of the output image the electronic printer. Each time of the check is performed, the RAM is rewritten. Thereby, a change in the emission data indicates a change or degradation of one or more of the LEDs. This enables one to forecast the life expectancy of the LED array, and maintenance of the printer becomes easier.

Method and apparatus for detecting and compensating light emission from

A compact and simple structured electrophotographic printing apparatus having a single magnetic developer, in which an accumulation of toner particles is formed on a photosensitive member at a downstream position from the magnetic developer. The accumulation of the toner particles is formed by moving a photosensitive film and a magnetic brush in rubbing contact with the film in mutually opposite directions, or by deforming a magnetic field generated by the magnetic developer, using a magnetic piece. A recording electrode is disposed on a sleeve of the magnetic developer and facing the photosensitive film. Bias voltages, having polarities opposite to each other with respect to the photosensitive film, are respectively applied to the recording electrode and the sleeve. An optical beam is projected onto the photosensitive film in a region facing the recording electrode. Thus, with the aid of toner particles located between the recording electrode and the photosensitive film and the accumulation of the toner particles, sensitizing, developing and scavenging are carried out simultaneously, and thus a toner image is produced on the photosensitive film. For a magnetic developer having a rotatable sleeve, a specially designed recording electrode is disclosed. The photosensitve member may be in the form of a solid flat plane, a drum, or a flexible belt-like film.

Compact electrophotographic printing apparatus having an improved

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Kawasaki, Japan

Masahiro Wanou