Sharp Kabushiki Kaisha Corporation

Other

Tadayuki Sawai

Toshihisa Ishida

Kouji Kida

Satoshi Ogawa

Keiichi Kikawa

Yoritaka Tsubaki

Masahiko Kubo

Keigo Mitamura

Shintaro Fukuoka

Yui Kawano

Tadashi Nakamura

Yoshiaki Akazawa

Toshihiko Murakami

Toru Nishikawa

Masanori Matsumoto

Kiyoshi Toizumi

Junichi Saito

Hiroshi Onda

Takafumi Nagai

Syouichi Fujita

Tohru Nishikawa

Takahiro Bito

Yoshimi Kojima

Yasuharu Morinishi

Akihiko Kawahara

Kouichi Takenouchi

Katsuaki Sumida

Teruhiko Noguchi

Tomoko Toizumi

Kinji Shinzo

Yuichiro Takesue

Ken Yamagishi

Yukihisa Imaue

Yoshinori Shimane

Keizo Kitamura

Masao Suzuki

Kazuya Korematu

Hiroyuki Terada

Yuko Takeda

Kazuya Korematsu

Akio Matsumoto

Tatsuya Itou

Toner of one aspect of the present invention has a weight average molecular weight Mw of 30,000&#x2266;Mw&#x2266;95,263 as determined from a molecular weight distribution based on GPC, includes a THF-insoluble gel component at a weight proportion of less than 5%, and includes components each having a molecular weight of 500 to 1500 which components have an area occupancy of 4% to 10% on a chart of the molecular weight distribution based on GPC.

Method for producing ground toner

A two-component color developer containing a toner and a resin-coated carrier, the toner containing at least a polyester resin as a binding resin, an organic pigment as a colorant and inorganic fine particles as an external additive, wherein the inorganic fine particles have a negative polarity, the toner has a volume resistivity of 40&#xd7;10to 220&#xd7;10&#x3a9;cm and a negative polarity, and the carrier has a coat durability of 90% or greater.

Two-component color developer and image formation device using same

Toners of respective colors of a full-color toner set each contain a binder resin which is polyester resin; and a release agent dispersing aid which is styrene acrylic copolymer resin having at least one of an &#x3b1;-methylstyrene structure and a styrene structure. The styrene acrylic copolymer resin is contained in an amount of 7 parts by weight to 14 parts by weight with respect to 100 parts by weight of the polyester resin. The full-color toner set has a sum of resistivities of the toners of the respective colors of 410&#xd7;10to 510&#xd7;10(&#x3a9;&#xb7;cm).

Full-color toner set, full-color developer set, image-formation method using same, and image-formation device

Provided is a toner not undergoing the effect of change of temperature and humidity, with high charging stability and having good fixing property and releasability. This is an electrophotographic toner containing at least a binder resin, a colorant, a charge controller and a wax in which the binder resin comprises a polyester resin having an aromatic alcohol ingredient, the charge controller comprises an organic bentonite and the wax comprises a non-polar paraffin wax.

Electrophotographic toner

An object of the invention is to provide a black toner that can satisfy further the requirement for low energy, high-speed and high performance, a color toner that can be used in an image forming apparatus provided with an oil-less fixation device, and a color toner including the black toner and the color toner. For the black toner, a polyester resin having an acid value of 7 to 20 mgKOH/g is used as the binding resin, and a carboxylic acid-modified paraffin wax having an acid value of 4 to 30 mgKOH/g is used as the wax. For the color toner, polyester resin having an acid value of 7 to 20 mgKOH/g is used as the binding resin, and a carboxylic acid-modified paraffin wax having an acid value of 6 to 25 mgKOH/g is used as the wax.

A non-magnetic single component developing device that is included in combination with a photoreceptor in an image forming apparatusof the electro-photographic system. The non-magnetic single component developing device includes a developing roller, a supplying roller, a doctor, a toner bath and a stirring blade. The supplying roller contains a rubber foam at least in its surface layer portion, the rubber foam including closed cells and open cells and having a foam ratio (porosity) of 0.75 to 0.85 and an average foam cell diameter of 350 to 500 &#x3bc;m.

Non-magnetic single component developing device

A non-magnetic mono-component toner of the present invention is composed of a coloring powder at least containing a binder resin, coloring agent and wax and at least one kind of external additive having a mean particle diameter of 0.04 &#x3bc;m or greater, wherein the relationship between the Vickers hardness of the above coloring powder and the mean particle diameter of the external additives satisfies the predetermined expression. Thereby, the present invention is effective in preventing the external additive particles from sinking into the toner surface as well as from falling off from the surface when the toner particles are stressed in the developing unit. As a result, it is possible to provide stable image quality free from degradation of toner charge performance and toner supply performance even for long-term use.

Non-magnetic mono-component toner and developing method with the same

An image forming apparatus having a tandem system configuration, includes: a multiple number of photoreceptors which each form an electrostatic latent image; and a multiple number of developing devices each holding a different color toner from the others for development of the corresponding static latent image, and is constructed so that the plural toners at least include a black toner, and the abrading force of the black toner or its carrier therein acting on the photoreceptor surface is adjusted so as to be smaller than that of the other developing toners or their carrier therein. Since, in a tandem type color image forming apparatus, the developing devices, photoreceptors and toners for all colors will reach the end of their life at the same time, the image forming apparatus can be operated at low cost.

Image forming apparatus

A toner for electrophotography comprises: a coloring agent and a binding resin comprising a polyester resin constituted of cyclohexanedimethanol as an essential polyol component, wherein the toner has, at 110&deg; C., a storage elastic modulus of 3&times;10 Pa or less and a loss elastic modulus of 6&times;10 Pa or less, and, at 150&deg; C., a storage elastic modulus of 1&times;10 Pa or more and a loss elastic modulus of 1&times;10 Pa or more.

Toner for electrophotography

A photosensitive element is produced with a minimum amount of a conductive synthetic resin material. A draft for injection molding is formed in the inner circumferential surface as a supporting body, and a driven member provided with a gear is fixed to the end of the supporting body with a smaller inner diameter, that is, the thicker end. A driven portion in which a plurality of projections and depressions are formed alternately to be adjacent to each other in the circumferential direction is arranged on an axial end of a cylindrical supporting body made of a conductive synthetic resin, including a photosensitive layer on the outer circumferential surface. By a joint member removably engaged with the driven portion, the supporting body is rotated around the axis. In one arrangement, only the end of the supporting body is solid. In another arrangement, the supporting body is solid in the almost entire length in the axial direction.

Photosensitive element for electrophotography

An image forming device includes an optical system for forming an electrostatic latent image on a photosensitive body by exposure of an original in light, a development system for developing the electrostatic latent image, and a control system for controlling the optical system and the development system. The control system detects the concentration of a toner in a developing agent tank, calculating a difference between the detected toner concentration and a predetermined toner concentration, replenishing the toner to the developing agent tank until the detected toner concentration makes a recovery to the predetermined toner concentration, clocking a time period for the recovery and controlling at least one of the amount of the exposure light and the amount of the toner adhering to a photosensitive body based on the clocked time period for the recovery.

Image forming apparatus having a toner concentration controlling

The electrostatic charge image-developing toner contains a colorant, a binder resin, and polyethylene having a melt viscosity of 22000 to 26800 mPa.multidot.s at 140.degree. C. This electrostatic charge image-developing toner prevents an offset phenomenon on the surface of a fixing roller, and does not adhere to and fuse on a photoreceptor drum to cause no stripy and dotwise stain on a reproduced image, that is, preventing a so-called filming phenomenon. The toner also prevents an offset phenomenon on the photoreceptor drum.

Electrostatic charge image-developing toner with polyethylene additive

Growing community of inventors

Nara, Japan

Tadayuki Sawai