Ricoh Company, Ltd.

Asahi Kasei Kogyo Kabushiki Kaisha

Tsutomu Teraoka

Tsuneo Kurotori

Tsutomu Sasaki

Masahiko Itaya

Kunio Satake

Eishu Ohdake

Tomiho Sone

Naonori Kurokawa

Shunji Kamiya

A liquid developer that comprises a colorant and a liquid for dispersing the colorant and serves to develop the latent image by causing the colorant to adhere to the latent image on the latent image carrier. The liquid comprises a first liquid comprising a photocurable liquid and a second liquid that is not mutually soluble with the photocurable liquid and comprises a liquid with a specific resistance higher than that of the photocurable liquid.

Liquid developer and image forming apparatus using same

A liquid developer capable of preventing each of the disadvantages of uneven development density caused by uneven distribution of colored particles, poor transfer due to an insufficient amount of the liquid, and poor fixing due to an excess amount of the liquid, without complicating handling with the generation of volatile gas. Present on the surface of toner particles to be dispersed in a carrier liquid made of dimethyl silicone are a silicone group of one-end methacryloxy-modified silicone and a basic group. The silicone group prevents agglutination of the toner particles with each other. The silicone group functions as an affinity group and provides the toner particles with an affinity to the carrier liquid. Thus, it becomes possible to disperse the toner particles uniformly in the carrier liquid. Besides, the basic group on the surface of toner particles allows the toner particles to ensure the desired charge amount. Therefore, colored particles such as the toner particles hardly agglutinate with each other in a nonpolar insulating liquid to be provided as a nonaqueous solvent, while the colored particles can be electrophoresed at high speed by an electric field.

Liquid developer for image forming apparatus

A liquid developer which includes an insulating liquid, and toner fine particles containing a coloring agent and a toner resin. In the liquid developer, its electric capacitance does not significantly vary in an electric circuit where an electrical double-layer capacitor and an electronic resistance corresponding to a velocity of an electron exchange during an electrode reaction are connected in parallel, and a resistance corresponding to an electric conductivity of the insulating liquid is connected in series. The coloring agent has a coating layer so as to maintain distances between the toner fine particles. The insulating liquid has a viscosity of 0.5 mPa&#xb7;s to 1000 mPa&#xb7;s, a specific resistance of 1&#xd7;10&#x3a9;cm or more, and a surface tension of 30 dyn/cm or less, and may be a nonvolatile liquid having a boiling point of 100&#xb0; C. or higher.

Liquid developer, image-fixing apparatus using the same, and image-forming apparatus using the same

An attriter which applies a strong stress to a liquid developer, sufficient for generating the chemically non-equilibrium state therein, is parallel-connected with a developing unit, so that the stress is applied to a part of the liquid developer carried from a storage tank to a developing tank. However, in order to suppress crushing of the toner due to the application of excessive stress, the operation of the attriter is controlled in the following manner. That is, a charge quantity detection unit which detects the toner charge quantity of the liquid developer in the developing tank is provided, and based on the detection result thereof, the attriter is controlled.

Liquid development apparatus and image formation apparatus

A block copolymer latex composition comprising (A) an aqueous latex containing at least one of block copolymers consisting of conjugated diolefin blocks and monovinyl-substituted aromatic compound blocks prepared by solution-polymerization, and having a molecular weight of 5,000 to 500,000 and a content of monovinyl-substituted aromatic compound of 10 to 70% by weight, and (B) a latex of rubber system, latex of synthetic resin system or a mixture thereof, the composition containing 5 to 87% by weight of (A) and 95 to 13% by weight of (B) in terms of solid matters, has very superior film-forming properties and provides films having improved strength.

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Kanagawa, Japan

Tsutomu Teraoka