Dainippon Ink and Chemicals, Incorporated

Dainippon Ink Chemicals, Inc.

Hideki Gambayashi

Masanobu Nakamura

Toshiro Kogawara

Kinji Shinzo

Shinji Amaya

Ryozo Sugawara

Yoshinori Shimane

Katsunori Ohba

Katsuyuki Ogura

Norio Aoki

The present invention provides a toner for electrostatic image development which employs a black colorant free from a toxic substance and exhibits stable charge behavior even after extended use or printing of a large number of sheets, thus making it possible to provide printed images having sufficient image density without causing toner dispersion, fogging, and variation in image density. This is a toner for electrostatic image development comprising a binder resin and a colorant, wherein the colorant is made of black fine particles obtained by coating the surface of titanium dioxide particles with a complex oxide of titanium and iron.

Toner for electrostatic image development

Developer for electrostatic image development

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 electrostatic image developer is provided which has superior fixation properties and anti-offset properties, exhibits stable charge behavior even during continuous printing, and has superior durability and permits a high-quality image to be obtained. This electrostatic image developer is a toner composition containing colored resin particles comprising at least a binder resin, a colorant, and a charge control agent, wherein (1) an epoxy compound with a valence of 5 or more, (2) a polybasic acid compound having a valence of 2 or more selected from the group consisting of polybasic acids and/or acid anhydrides and/or lower alkyl esters thereof, and (3) a polyvalent alcohol having a valence of 2 or more, are employed as chief structural components of the binder resin, and a polyester resin is produced by reacting components (1)-(3) simultaneously, or by first reacting components (1) and (3), and subsequently reacting component (2), or by first reacting components (1) and (2), and subsequently reacting component (3).

Toner composition and developer for electrostatic image development

Growing community of inventors

Ageo, Japan

Hideki Gambayashi