Hitachi, Ltd.

Hitachi Koki Co., Ltd.

Ricoh Printing Systems, Ltd.

Hitachi Printing Solutions, Ltd.

Ryuuichi Shimizu

Tsuneaki Kawanishi

Shigenori Yaguchi

Toshiya Satoh

Teruaki Mitsuya

Takashi Suzuki

Nobuyoshi Hoshi

Junji Kobayashi

Hiroshi Ueno

Tadahiro Kaneko

Kenichi Ito

Hiroyuki Mabuchi

Shinichi Akatsu

Akira Shimada

Hisao Okada

Seiji Maruo

Katsumi Kumada

Kenichi Kugai

Masayoshi Ishii

Takashi Nishimura

Masato Miwa

Hirobumi Ouchi

Masafumi Shimizu

An electrophotographic toner for visualizing an electrostatic latent image formed by an electrophotographic process, an electrostatic printing process, an electrostatic recording process, etc., which is produced in consideration of the environment and safety. The electrophotographic toner includes a fixing resin and a colorant. The electrophotographic toner is a black toner using a titanium compound containing no carbon black as the colorant. The electrophotographic toner may be an electrophotographic two-component black toner using magnetic iron oxide containing no carbon black as the colorant.

Electrophotographic toner

Electrophotographic toner and image-forming system

The invention provides an electrostatic charge image developing toner containing a fixing resin and a wax, characterized in that in a DSC curve measured by a differential scanning calorimeter for the wax, a maximum endothermic peak of endothermic peaks at temperature up is less than 70&#xb0; C., on-set temperature attributable to the maximum endothermic peak is above 50&#xb0; C., and lowest on-set temperature of on-set temperatures attributable to endothermic peaks except the maximum endothermic peak is in a range of from 30&#xb0; C. to 40&#xb0; C.

Electrostatic charge image developing toner, and developer, image forming apparatus and image forming method using the same toner

An electrophotographic toner containing: a fixing resin, a colorant, and wax. The wax at least contains hydrocarbon wax having a number-average molecular weight of not higher than 600, and polyethylene wax having a number-average molecular weight of not higher than 600, a melting viscosity of lower than 15 mPa&#xb7;s at 140&#xb0; C. and a crystallinity of lower than 95%. A ratio of the hydrocarbon wax to the polyethylene wax is in a range of from 1:10 to 2:1. A maximum of absorption peaks in a heat-up time absorption calorie curve in a DSC curve of the toner measured by a differential scanning calorimeter is at a temperature not higher than 75&#xb0; C. An onset temperature in absorption of heat is not higher than 65&#xb0; C.

Electrostatic image developing toner includes fixing resin; and wax. The wax is hydrocarbon-based wax. The wax is containing, as its constitutional components, first wax and second wax. The first wax is higher than 1.5 in ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), lower than 10 mPa&middot;s in melt viscosity at 140&deg; C. and higher than 75% and not higher than 85% in degree of crystallinity. The second wax is not higher than 1.5 in ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), lower than 10 mPa&middot;s in melt viscosity at 140&deg; C. and higher than 85% and not higher than 95% in degree of crystallinity.

Electrostatic image developing toner and image forming method

Electrostatic charge developing toner contains at least fixing resin, a coloring agent and wax. Wax having number average molecular weight of not higher than 600 is contained as a component of the wax. A volume average particle size of the toner is in a range of from 5 &mgr;m to 10 &mgr;m. Toner particles each having a particle size of not larger than 4 &mgr;m are contained by 10% or lower by number of the total number of toner particles.

Electrostatic charge developing toner and image forming method using the same

An electrophotographic printing apparatus using electric potential dividing development processing without the occurrence of primary fringe and fringe caused by auxiliary exposure has reverse electric fields causing primary fringe and fringe caused by auxiliary exposure adjusted to be nearly equal to each other. The auxiliary exposure is applied to an area surrounding one image, and an electric potential of an intermediate electric potential zone is brought close to a bias electric potential of another image which is not subjected to auxiliary exposure. Further, a white portion to produce a reverse electric potential therein at the rear end of an electric potential portion to be developed with toner, relative to a rotating direction of a developing roller, is exposed with a light intensity forming an electric potential between an electric potential developing an image with toner and the intermediate electric potential, and portions at the front end and the sides are exposed with a light intensity forming the intermediate electric potential.

Electrophotographic printing apparatus using electric potential dividing

A transfer belt for use in an electrophotographic apparatus for transporting an image support onto which a toner image formed on a surface of a photoconductor containing a photoconductive layer is transferred, and the transfer belt includes a surface layer formed from a coating liquid containing: a solvent; at least one kind of inorganic or organic fine particles dispersible in the solvent; and at least one kind of organic compound dissolved in the solvent. Also disclosed is an electrophotographic apparatus using the transfer belt.

Transfer belt and electrophotographic apparatus

Image fixing device for use in electrophotographic apparatus, capable of suppressing gloss of fixed toner image, thus stably producing images of high quality and high level of fixing intensity over a long period of time. The fixing device is composed of a belt-type heating member and a pressing roller which are contacted with each other and rotate to form therebetween a nip through which a paper supporting unfixed toner image is passed to have the toner image fixed to the paper. The belt-type heating member comprises a metallic endless belt having fine irregularities formed on its surface and a surface layer made of a resin. The surface roughness of the fine irregularities ranges between 10 and 45 .mu.m, when measured by a ten-point averaging method.

Belt-type fixing device having an irregular surface contour

Image fixing device for use in electrophotographic apparatus, capable of suppressing gloss of fixed toner image, thus stably producing images of high quality and high level of fixing intensity over a long period of time. The fixing device has a fixing roller and a pressing roller which are contacted with each other and rotate to form therebetween a nip through which a paper supporting unfixed toner image is passed to have the toner image fixed to the paper. The fixing roller has a cylindrical core having fine irregularities formed on its surface and a surface layer made of a resin. The surface of the cylindrical core has a greater elastic modulus than that of the surface layer.

Fixing device for electrophotography and electrophotographic apparatus

A electrophotographic image fixing device fixes a toner image on a substrate. The substrate is passed between two pressing rollers disposed in opposition to each other to fix toner images on the substrate. The pressing rollers includes a surface constructed from an elastic material layer such that the elastic material layer can be deformed approximately 0.5-1.5% in terms of thickness. The pressing force against the toner applied side of the substrate is adjusted to 0.3-1 kg/cm.sup.2. As a result, an image with excellent toner fixing strength can be formed on a substrate such as an envelope without wrinkling the substrate during the fixing operation.

Growing community of inventors

Ibaraki, Japan

Ryuuichi Shimizu