Dainippon Ink and Chemicals, Incorporated

Shinji Amaya

Toshiro Kogawara

Yoshiyuki Iwanari

Seiichi Shimizu

Katsunori Ohba

Takeshi Isonaka

Masahiro Yoshida

Masanobu Nakamura

Kinji Shinzo

Isao Tabayashi

Sadahiro Inoue

Yutaka Yamada

Hideki Gambayashi

Kazuya Kuriyama

Syuuichi Yamazaki

Noboru Nakaibayashi

Modified nigrosine which has satisfactory dispersibility in resin and which reduces the residual aniline amount is offered, and its production method is also offered. Moreover, toner for developing electrostatic charge images is offered, which uses modified nigrosine colorant that resolves the aforementioned problems, which has excellent charge-imparting properties, which exhibits no fogging, which experiences no scattering of toner inside the developing apparatus, and which has little fluctuation of image density. Modified nigrosine, which is nigrosine (b) that has been modified by rosin-modified resin (a) with an acid value of 110 or less.

Modified nigrosine, its production method, and toner for developing electrostatic charge images using this modified nigrosine

The present invention provides a carrier for electrophotography, which is capable of charging the toner in the developer very rapidly to a target electrostatic charge and at the same time, is capable of maintaining the target electrostatic charge during printing, so that the chemical fogging related to the slow charging rate can be eliminated and the image density related to the maintenance of the electrostatic charge can be preserved during printing. The charging rate and the charge maintenance of the electrophotographic carrier can be preserved if the carrier composed of magnetic core particles and the resin coat satisfies the following equation (B)>&lsqb;(&minus;19.4)&times;(A)&plus;31&rsqb;, wherein (A) represents a carbon content (weight %) of the carrier and (B) represents a ratio of the square root of the number of emitted photoelectrons ((CPS) ) and the photon energy (eV).

Electrophotographic carrier, developer using the same, and developing method

The present invention relates to a developer for electrostatic image development comprising: a toner for electrostatic image development which comprises a resin and a colorant; and a carrier formed by a carrier core material and a resin layer including a resistance control agent which is formed on the surface of the carrier core material, wherein the resin layer of the carrier has a concentration gradient of the resistance control agent toward the thickness direction of the resin layer, a concentration of the resistance control agent is the highest in the vicinity of the carrier core material, and is gradually lowered toward the surface of the resin layer, and the resistance control agent is present on the surface of the resin layer, as well as relates to an image forming method, wherein it comprises a step of developing an electrostatic image at a developing speed of 20 m/min or higher, by means of employing the developer for electrostatic image development. The developer for electrostatic image development of the invention exhibits a stable development and transfer behavior without any variation of triboelectric charging performance, electric resistance, or the like, even when used as a two-component developer, and in addition, affords a printed image with high image quality and high grade without any fogging.

Developer for electrostatic image development and image forming method using the same

The present invention provides a toner for electrostatic image development which reconciles anti-offset properties and fixation properties and is superior in resistance to abrasion and peel of the fixed image in uses where the development and fixation are conducted at a wide range of a fixing speed, particularly high speed which exceeds 20 or 30 m/min. The toner comprises a polyester resin, a colorant, and a releasing agent, wherein the flow beginning temperature Tfb of the toner as measured by a constant load extrusion type capillary rheometer is within a range of 70-105&deg; C. and the flow ending temperature Tend is within a range of 120-144&deg; C.

Toner for electrostatic image development and image forming method employing the same

An ink for jet printer is disclosed, which contains an oil soluble dye, a synthetic resin, and an organic solvent, wherein the synthetic resin contains a terpene-phenol copolymer resin and a styrene-acrylic copolymer resin.

Ink for jet printer

A magenta toner, a yellow toner, a cyan toner, and a black toner each for development of an electrostatic latent image ad a combination of the four color toners for obtaining a full color image are disclosed, the magenta toner containing a naphthol type organic pigment represented by formula (I): ##STR1## the yellow toner containing a disazo type organic pigment represented by formula (II): ##STR2## the cyan toner containing a .beta. type copper phthalocyanine pigment and a polychlorocopper phthalocyanine pigment, and the black toner containing at least one of an isoindolinone type yellow pigment and a tetrachloroisoindolinone type yellow pigment, at least one of a quinacridone type red pigment and a perylene type red pigment, and a phthalocyanine type blue pigment. The color toners are unaffected by environmental changes and capable of providing color images having stable characteristics.

Combination of color toners for developing electrostatic latent image

A color toner composition for an electrostatic developer is disclosed, comprising a cyan pigment, a magenta pigment or a yellow pigment, a binder resin and a negative charging-controlling agent, wherein the binder resin is a vinyl-modified polyester resin as obtained by graft polymerizing.

Color toner composition for electrostatic developer

A color toner composition for developing electrostatic images comprises a coloring agent and a binder resin, wherein the binder resin is a vinyl-modified polyester resin obtained by graft polymerizing

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Saitama, Japan

Shinji Amaya