Hitachi Koki Co., Ltd.

Hitachi, Ltd.

Ricoh Printing Systems, Ltd.

Katsuya Kawai

Masayasu Anzai

Tsuneaki Kawanishi

Koji Kato

Takashi Suzuki

Yasuo Takuma

Tomonari Hokkyo

Shinya Kobayashi

Takahiro Yamada

Hitoshi Kida

Teruaki Mitsuya

Takao Umeda

Satoru Tobita

Yoshitaka Fujinuma

Hiroyuki Mabuchi

Hisao Okada

Masayuki Ainoya

Shinichi Nishino

Masato Miwa

Tsutomu Nakagawa

Yuichiro Suzuki

Hiroyoshi Matsumoto

Toshimitsu Harada

Yosuke Saito

An ink jet recording head unit includes a plurality of nozzle elements, a plurality of piezoelectric elements and a driving unit. The plurality of piezoelectric elements is provided in one-to-one correspondence with the plurality of nozzle elements. Each piezoelectric element has a positive pole and a negative pole. Each piezoelectric element expands and contracts when a voltage potential difference between the positive pole and the negative pole is varied. The plurality of nozzle elements includes a first nozzle element and a second nozzle element adjacent to the first nozzle element. A first piezoelectric element and a second piezoelectric element correspond to the first nozzle element and the second nozzle element respectively. The driving unit controls the first piezoelectric element and the second piezoelectric element to expand and contract in a complementary manner.

Recording head for inkjet recording device

An electrostatic recording apparatus including: an image carrier including an organic photoconductive photoreceptor having an abrasion-resisting outermost periphery; an exposing unit which exposes the image carrier to form an electrostatic latent image thereon; a developing unit which contains a toner and develops the electrostatic latent image with the toner to form a toner image; a transferring unit which transfers the toner image thus formed onto a recording medium; and a fixing unit which fixes the transferred toner image on said recording medium, wherein the toner contained in said developing unit includes an electrically conductive fine powder attached to the surface thereof.

Electrostatic recording apparatus

A uniform image is obtained by matching the sliding friction force, the moving speed and the developing agent in a developing region of two developing rollers and an electric characteristic of a photosensitive body used for image development. Two developing rollers rotating in directions opposite to each other are used, the moving direction of the first developing roller being opposite to the moving direction of the photosensitive body, and a circumferential speed ratio of a circumferential speed of the first developing roller to a circumferential speed of the photosensitive body is within a rage of 0.5 to 2.5; and the moving direction of the second developing roller is equal to the moving direction of the photosensitive body, and a circumferential speed ratio of a circumferential speed of the second developing roller to a circumferential speed of the photosensitive body is within a range of 1.5 to 3.5. A ratio of the sliding friction force between a magnetic brush for developing agent and the photosensitive body formed in the first developing roller and the sliding friction force between a magnetic brush for developing agent and the photosensitive body formed in the second developing roller is within a range of 0.9 to 2.1.

Electrophotographic apparatus

A toner for recording electrostatic image having a volume-average particle diameter of from 6 to 10 .mu.m, which exhibits a compression stress of from 50 to 500 kgf/cm.sup.2 at the middle temperature between room temperature and the glass transition temperature of the toner, and a compression stress of from 0.2 to 10 kgf/cm.sup.2 at the middle temperature intermediate between the glass transition temperature and the softening temperature of the toner.

Toner for recording electrostatic image and electrostatic recording

A bias cleaning system has an electrically conductive brush roller for collecting toner which has to adhered a transfer belt by scrubbing the toner off the transfer belt under a condition in which a direct current voltage of the opposite polarity to the charge of the toner is applied to the brush roller. A corona charger is also provided for decreasing the amount of charge on the toner on the transfer belt in a region of the belt up-stream of the electrically conductive brush roller in the moving direction of the transfer belt.

Bias cleaning system and electrostatic printing apparatus therewith and

In an electrophotograpic recording apparatus, a charge supply unit and a light erasing unit are disposed in the stated order when viewed in the direction in which a photoreceptor rotates, at a location between a transfer unit and a bias cleaning unit, and light from the light erasing unit is projected onto a photoreceptor surface area except the charge supplied area. A developing apparatus of the type in which a cleaner section for removing and collecting residual toner on a photoreceptor is coupled through a toner transport pipe with a toner hopper of a developing unit, wherein a meshed foreign material collector, which may be vibrated, is disposed at a location in a residual toner collecting path ranging from the cleaner section, the toner transport pipe, and the toner hopper.

Electrophotographic recording apparatus having improved residual toner

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Hitachinaka, Japan

Katsuya Kawai