Pfu Limited

Yutaka Nakashima

Akihiko Inamoto

Masanari Takabatake

Shigeharu Okano

Motoharu Ichida

Satoru Moto

Seiichi Takeda

Tadashi Nishikawa

Satoshi Sakai

Satoshi Miyamoto

Hironaga Hongawa

Hitoshi Terashima

Shigeki Uesugi

Masanobu Hongo

Hideaki Shibata

Yasuhiko Kishimoto

Tatsuo Nozaki

Jiyun Du

Norihiro Yamasaku

Isao Nagata

Eri Yamanishi

Shigrki Uesugi

Tadasuke Yoshida

Yoshiaki Fujimoto

Satoshii Moriguchi

Yoshiaki Kawamoto

A liquid-development electrophotographic apparatus forms on a toner-image-bearing body a plurality of color images developed by a plurality of developing units, one for each color, that use liquid toner. One or more carrier-removing units for removing excessive carrier from a toner layer that forms a toner image are disposed downstream of each developing unit and upstream of the next developing unit disposed upstream of the former developing unit with respect to a process progress direction. Each carrier-removing unit includes two or more conductive collection rollers to which a bias voltage is applied in such a direction as to press toner against the toner-image-bearing body and which is brought into contact with the toner-image-bearing body. The upstream roller is rotated in the same direction as the direction of surface movement of the toner-image-bearing body, whereas the downstream roller is rotated in the opposite direction. The result is that influence of carrier on the already transferred image is suppressed, and hence occurrences of irregular transfer of the images and occurrences of disturbance of the already transferred image are minimized.

Liquid development electrophotographic device

An electrode module in the form of a flexible sheet which contacts with a toner layer and to which a bias voltage is applied is provided on a developing roller before development. The electrode module is adapted to separate the toner layer largely into a toner-rich layer and a carrier-rich layer by utilizing electrical migration occurring in the toner layer when an electric field is applied to the toner layer on the basis of the bias voltage. The electrode module is constructed in such a manner that the sheet is pulled toward a surface of the developer bearer body by a force attributable to surface tension or wetting characteristic of the liquid developer existing between the sheet and the developer carrying body, whereby the sheet comes into contact with the surface of the developer bearer body. This electrode construction increases the contact area or nip width of a bias blade provided for the developing roller and enhances its contact stability.

Liquid developing system developing device

In the present invention, a toner image produced through a development process of supplying a liquid toner onto an image bearing body bearing an electrostatic latent image is transferred from the image bearing body onto an intermediate transfer body and then transferred from the intermediate transfer body onto a printing medium by use of a backup roller in a transfer-and-fixation zone. The printing medium is preheated to a temperature required for transfer and fixation before the printing medium reaches the transfer-and-fixation zone. No heating means is provided in the transfer-and-fixation zone, and the intermediate transfer body and the backup roller are pressed against each other at a high pressure ranging from 10 kg/cm to 60 kg/cm . Alternatively, the intermediate transfer body is provided with heating means; resin for use in the liquid toner has a softening temperature not higher than withstand temperatures of members other than the intermediate transfer body such as a photosensitive drum; and the intermediate transfer body is heated to a temperature not lower than the softening temperature of the resin and not higher than the withstand temperatures of the other members.

Transfer-and-fixation system with preheated printing medium for creating images using liquid-development electrophotographic apparatus

A liquid-development electrophotographic apparatus utilizes a nonvolatile, high-viscosity, high-concentration liquid toner as a liquid developer. A developing section is in contact with photosensitive drums , on which an electrostatic latent image is formed, so that the liquid developer is supplied onto photosensitive drums - . Toner particles contained in the liquid developer adhere to the photosensitive drums - according to an electric field established between the developing section and the photosensitive drums - to form toner images. The toner images are transferred from the photosensitive drums - to an intermediate transfer section. A transfer-and-fixation section includes a heater to melt-transfer the toner images onto the printing medium. A development section is disposed at a lower portion of the apparatus to prevent smudging of the printing medium and the intermediate transfer section even when the liquid toner spills.

Liquid-development electrophotographic apparatus

The present invention provides a toner recycling control system which stably feeds a liquid developer of an appropriate concentration to a liquid developing apparatus employing a high-viscosity liquid developer; appropriately adjusts the concentration of residual developer collected after development and after transfer; and feeds the adjusted developer to the developing apparatus. The toner recycling control system collects a post-development residual developer from a developer-bearing body and a post-transfer residual developer from an image-bearing body; performs developer concentration adjustment to yield an adjusted developer; and feeds the adjusted developer back to the developer-bearing body. Thus, the toner recycling control system includes a concentration adjustment tank which stores the collected developer and is replenished with a concentrated developer and carrier liquid for developer concentration adjustment; and a buffer tank which receives and stores a liquid developer which has undergone concentration adjustment in the concentration adjustment tank. Once adjusted to an appropriate concentration, the liquid developer is fed to the developer-bearing body from the buffer tank.

Toner recycle control system of electrophotographing device using viscous liquid developing solution

A liquid-development full-color electrophotographic apparatus utilizes a development section having a liquid toner as a liquid developer to form a toner image according to an electric field established between the development section and a photosensitive drum. The toner image is transferred from the photosensitive drum onto an intermediate transfer roller according to an electric field established between the intermediate transfer roller and the photosensitive drum, from the intermediate transfer roller to an intermediate transfer belt, and then to a transfer-and-fixation section, which melt-transfers the toner image onto a printing medium. A voltage controlled according to electric characteristics of each color toner is applied to the corresponding photosensitive drums while the roller is grounded. A toner cohesion enhancement unit is provided for enhancing the degree of toner cohesion of a toner image transferred and reverse transfer is suppressed.

Liquid-development full-color electrophotographic device

Provided are an applicator roller for conveying and applying liquid toner onto a developing roller in the form of a level, thin layer, and a conductive blade which comes into contact with a liquid toner layer on the developing roller. A predetermined amount of liquid toner passes through a gap between the conductive blade and the developer roller; and voltage is applied to the conductive blade so as to establish a state such that toner particles contained in the liquid toner are sparsely scattered in a surface region of a level, thin toner layer on the developing roller. Subsequently, the liquid toner, whose surface region is in a state such that toner particles are sparsely scattered, is brought into contact with an image bearer body for performing development.

Liquid developing electrophotographic device

A toner image is transferred from a photosensitive member onto an intermediate transfer belt . Toner particles transferred onto the intermediate transfer belt are melted through application of heat, and the molten toner is transferred onto a printing medium. A carrier-removing roller is disposed downstream of a position where a toner layer on the intermediate transfer belt is melted through application of heat. Through utilization of a phenomenon that toner particles (resin component) are melted and integrated in a heating process and a phenomenon that the carrier solvent (liquid component) is isolated in the heating process, the carrier solvent is removed efficiently. Also, there is disposed at the position of the heating process a carrier-removing roller for removing the carrier solvent from the intermediate transfer belt while the toner layer on the intermediate transfer belt is being melted through application of heat.

Electrophotographic device of liquid toner developing type

A wet type electrophotography apparatus including a non-volatile, high-viscosity, high-concentration liquid toner as a developing solution. The wet type electrophotography apparatus includes a photoconductive medium on which an electrostatic latent image is formed, a prewetting device for applying a film of a prewetting solution to the surface of the photoconductive medium, a developing device including a developing roller, and a developing solution applying device for applying a film of the developing solution on the developing roller. The developing roller feeds the developing solution to the photoconductive medium by making contact with the photoconductive medium, and causes toner particles in the developing solution to deposit on an image carrier in accordance with an electrical field formed between the developing roller and the photoconductive medium. The developing solution applying device includes a plurality of interconnecting rotating rollers for transporting the developing solution while spreading and applying it on the surface with the rotating rollers, and applies a film of the developing solution on the surface of the final-stage rotating roller in accordance with an electrical field formed between the final-stage rotating roller and the developing roller by a bias voltage fed to the final-stage rotating roller.

Wet type electrophotography apparatus to evenly apply developing solution on a developing roller

A wet-type electrophotography apparatus using a non-volatile, high-viscosity, high-concentration liquid toner as a liquid developer and having a photoconductive medium, a prewetting device applying a film of prewetting solution to the surface of the photoconductive medium, a developing roller feeding the liquid developer to the photoconductive medium while making contact with the photoconductive medium, and causing toner particles in the liquid developer to adhere to the photoconductive medium in accordance with a electric field formed between the developing roller and the photoconductive medium, so that a toner image formed on the photoconductive medium is transferred directly to a printing medium, or to a printing media via an intermediate transfer medium to obtain a printed image. The apparatus also has oil removal means making contact with the formed toner image surface to remove the excess prewetting solution and the excess carrier solution in the liquid toner from the toner image surface on either the photoconductive medium or the intermediate transfer medium.

Wet-type electrophotography apparatus, using non-volatile, high viscosity, high concentration liquid toner

A wet type electrophotography apparatus according using a non-volatile, high-viscosity, high-concentration liquid toner as a developing solution, and including a photoconductive medium on which an electrostatic latent image is formed, a prewetting device for coating the surface of the photoconductive medium with a film of prewetting solution, a developing device, an intermediate transfer medium for transferring the toner particles deposited on the photoconductive medium, a pressure roller rotating in contact with the intermediate transfer medium for transferring a printing medium while forcing the printing medium onto the intermediate transfer medium, and a heating device for heating locally the surface of the intermediate transfer medium at a location immediately before the intermediate transfer medium comes in contact with the pressure roller. The wet-type electrophotography apparatus can efficiently heat and fuse the toner transferred on the intermediate transfer medium without causing thermal effects on the photoconductive medium.

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Kanazawa, Japan

Yutaka Nakashima