Kao Corporation

Tetsuhiro Semura

Yoshihiro Ueno

Katsutoshi Aoki

Kuniyasu Kawabe

Hiroyuki Kawaji

Eizi Morimoto

Ken-ichi Suenaga

Shinji Moriyama

Tetsuya Asano

Shinichiro Omatsu

Eiji Morimoto

Shingo Nonohara

A toner for electrostatic image development comprising a resin binder comprising (a) a high-softening point polyester having a softening point of greater than 120&#xb0; C. and 160&#xb0; C. or less; and (b) a low-softening point polyester having a softening point of 75&#xb0; C. or more and 120&#xb0; C. or less, each of the high-softening point polyester (a) and the low-softening point polyester (b) being obtained by polycondensing an alcohol component consisting essentially of an aliphatic alcohol with a carboxylic acid component, wherein a difference in the softening points between the high-softening point polyester (a) and the low-softening point polyester (b) is 10&#xb0; C. or more. This toner has excellent pulverizability and fixing ability, and hardly causes filming, so that it can be applied to a laser beam printer having a linear speed of 280 mm/sec or more.

Toner for electrostatic image development

A resin binder composition for a non-contact fixing process comprising two or more polyesters having different softening points, wherein the polyesters comprise at least one polyester having a softening point of 80&deg; C. or more and less than 120&deg; C. (low-softening point polyester), and at least one polyester having a softening point of 120&deg; C. or more and 160&deg; C. or less (high-softening point polyester), wherein each of said polyesters is obtained from a carboxylic acid component consisting essentially of an aromatic carboxylic acid compound, and wherein the high-softening point polyester is a cross-linked polyester; a toner for a non-contacting fixing process comprising the resin binder composition, and a developer comprising the toner for a non-contacting fixing process; and a method for fixing the toner in a non-contact fixing process.

Resin binder composition for non-contact fixing process

A toner for electrophotography including a binder resin and a colorant, in which the binder resin includes as a main component a thermoplastic resin, which is a linear polyester prepared by using upon polymerization in an amount of 20 mol % or more in an entire alcohol component at least one of the following alcohol components (A) a bisphenol A having polyoxypropylene group containing 90% or more of the compound represented by the general formula (I): ##STR1## wherein each of m and n is 0 to 2, m+n being 2.0; and (B) a bisphenol A having polyoxyethylene group containing 88% or more of the compound represented by the general formula (II): ##STR2## wherein each of p and q is 0 to 2, p+q being 2.0.

Toner for electrophotography

A toner for electrophotography comprising a resin binder comprising a polyester resin, as a main component, obtained by polycondensing an alcohol component with a carboxylic acid component, wherein the alcohol component comprises an alkylene oxide adduct of bisphenol A represented by the formula (I): ##STR1## wherein R is an alkylene group having 2 or 3 carbon atoms; x and y are positive numbers showing an average molar number of an added oxyalkylene group, wherein a sum of x and y is from 1.5 to 10, in an amount of 60% by mol or more of the alcohol component, and wherein the carboxylic acid component comprises a tricarboxylic acid compound, wherein a number-average molecular weight of the polyester resin is 1,000 to 8,000; and a coloring agent, wherein an alkylene oxide adduct of bisphenol A of which addition molar number is 3 or more is not present in the polyester resin, or remains in an amount of less than 1.0% by weight.

The toner for electrophotography contains a binder resin, wherein the binder resin has a condensation polymerization-type resin for forming a matrix and an addition polymerization-type resin for forming a dispersed domain. The dispersed domain with a cross-sectional diameter of not more than 2 .mu.m has an areal proportion of not less than 90%, based on the total cross-sectional area of the dispersed domain. This toner is stable, which is capable of maintaining a suitable tribo electric charge, thereby providing a high image quality in which the formed images do not undergo deterioration even under severe environmental conditions. Moreover, in a fixing method using a heat roller; fixing at a low temperature can be performed without using an offset inhibiting liquid.

Process for producing a toner for electrophotography

The toner for full-color electrophotography usable for a fixing process by a heat roller, wherein a releasing oil is not applied on a surface of the heat roller, includes at least (a) a binder resin having as a main component a linear polyester obtainable using one or more monomers selected from the group consisting of saturated or unsaturated, aliphatic dicarboxylic acids, acid anhydrides thereof, and lower alkyl esters thereof as an acid component, provided that the saturated aliphatic dicarboxylic acids have carbon atoms of not less than 3, and that the unsaturated aliphatic dicarboxylic acids have carbon atoms of not less than 5, the linear polyester having a softening point of from 90.degree. to 120.degree. C. determined by 'koka' type flow tester; (b) a releasing agent comprising carnauba wax; and (c) a coloring agent. The method for forming fixed images for full-color electrophotography includes the steps of forming an unfixed image by using three or four kinds of toners on a recording medium in single or more toner layers wherein said toners include at least one toner for full-color electrophotography of the present invention; and fixing by heat and pressure the unfixed image using a heat roller without a device for applying a releasing oil.

Toner for full-color electrophotography and method for forming fixed

The binder resin for producing a toner includes the following three resins (A) to (C): resin (A) having a softening point of 120.degree. C. or more and 170.degree. C. or less, a glass transition temperature of 58.degree. C. or more and less than 75.degree. C., and a weight percentage of components insoluble to chloroform at 25.degree. C. of 5% by weight or more and 50% by weight or less; resin (B) having a softening point of 90.degree. C. or more and 120.degree. C. or less, a glass transition temperature of 58.degree. C. or more and less than 75.degree. C., and a weight percentage of components insoluble to chloroform at 25.degree. C. of less than 5% by weight; and resin (C) having a softening point of 80.degree. C. or more and less than 110.degree. C., a glass transition temperature of 45.degree. C. or more and less than 58.degree. C., and a weight percentage of components insoluble to chloroform at 25.degree. C. of less than 5% by weight.

Binder resin and toner for electrostatic development containing the same

The encapsulated toner for heat-and-pressure fixing includes a heat-fusible core material containing at least a thermoplastic resin and a coloring agent and a shell formed thereon so as to cover the surface of the heat-fusible core material, a main component of the shell being a hybrid resin having a molecular structure including a molecular chain obtainable by condensation polymerization and a molecular chain obtainable by addition polymerization, the two types of the molecular chains being chemically bonded.

Encapsulated toner for heat-and-pressure fixing

A toner for electrophotography includes at least a binder resin and a colorant, the binder resin containing a linear polyester as a main component and having a pulverization index of from 14 to 40 obtained by a given method. A developer composition includes the above toner for electrophotography.

Toner for electrophotography and developer composition containing the

The method of producing a binder resin has the steps of blending in advance (a) a starting material monomer mixture for two polymerization reaction types, (b) a compound which can react with both of starting material monomers for the two polymerization reaction types, and (c) a tricarboxylic or higher polycarboxylic acid or a derivative thereof, the two polymerization reaction types having independent reaction paths to each other in one reaction vessel; and concurrently carrying out the two polymerization reactions in one reaction vessel to give the binder resin. According to the present invention, the binder resin which has an excellent environmental stability in the tribo electric charge and the image quality, and also has good pulverizability and transparency can be produced. Moreover, in a fixing method using a heat roller, fixing at a low temperature can be performed without using an offset inhibiting liquid. By using such a binder resin, a toner for electrophotography and a developer having excellent performance can be obtained.

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Wakayama, Japan

Tetsuhiro Semura