Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Masahisa Maeda

Yasuhito Yuasa

Noriaki Hirota

Hidekazu Arase

Hideki Tatematsu

Mamoru Soga

A toner or two-component developer is obtained by mixing, aggregating, and heating resin particles, colorant particles, and wax particles in an aqueous medium. A gel permeation chromatography (GPC) measurement of the resin particles shows that a weight-average molecular weight is 10000 to 60000, and the ratio of the weight-average molecular weight to a number-average molecular weight is 1.5 to 6. The wax particles include at least a first wax and a second wax. An endothermic peak temperature (melting point Tmw(&#xb0; C.)) of the first wax based on a DSC method is 50&#xb0; C. to 90&#xb0; C. An endothermic peak temperature (melting point Tmw(&#xb0; C.)) of the second wax based on the DSC method is at least 5&#xb0; C. to 50&#xb0; C. higher than Tmw. Thus, the toner can have a smaller particle size and a sharp particle size distribution without requiring a classification process, can achieve a longer life, and can suppress transfer voids or scattering during transfer.

Toner, process for producing toner, and two-component developing agent

Toner of the present invention is produced by mixing in an aqueous medium at least a resin particle dispersion in which resin particles are dispersed, a colorant particle dispersion in which colorant particles are dispersed, and a wax particle dispersion in which wax particles are dispersed and heating and aggregating the mixed dispersion. The main component of a surface-active agent used for the resin particle dispersion is a nonionic surface-active agent. The main component of at least one surface-active agent selected from a surface-active agent used for the wax particle dispersion and a surface-active agent used for the colorant particle dispersion is a nonionic surface-active agent. With this configuration, the toner can have a smaller particle size and a sharp particle size distribution without requiring a classification process. The toner and a two-component developer can achieve oilless fixing, eliminate spent of the toner components on a carrier to make the life longer, and ensure high transfer efficiency by suppressing transfer voids or scattering during transfer.

Toner, process for producing toner, two-component developer and image forming apparatus

In an electrophotographic apparatus, which forms a color image by transferring a plurality of toner images having different colors onto an image-receiving sheet so as to be stacked and fixed thereon, even in the case of carrying out an oil-less fixing process and allowing the process speed to vary within wide range, the present invention provides a binder resin, toner and an electrophotographic apparatus which make it possible to achieve both superior fixing property and anti-offset property, and consequently to form a color image with high color reproducibility and high quality. In the present invention, a toner comprising a molecular weight maximum peak in a range of molecular weights from 2&#xd7;10to 3&#xd7;10in molecular weight distribution of GPC chromatogram, and a molecular weight maximum peak or shoulder in a range from 3&#xd7;10to 1&#xd7;10, wherein said molecular weight maximum peak or shoulder located on a range of molecular weights from 3&#xd7;10to 1&#xd7;10is obtained by kneading a toner composition containing a specific binder resin containing a high molecular weight component at not less than a specific amount so that the high molecular weight component of the binder is converted into a low molecular weight component by thermal or mechanical energy exerted at the time of kneading, is provided.

Binding resin for toner, toner and electrophotographic apparatus

Toner of the present invention at least includes binder resin, a colorant, and an external additive, wherein a loss modulus G&Prime;t (frequency: 10 rad/s) of the toner at 170&deg; C. satisfies 100&lE;G&Prime;t&lE;5000 (Pa), a storage modulus G&prime;t (frequency: 10 rad/s) of the toner at 190&deg; C. satisfies 10&lE;G&prime;t&lE;3000 (Pa), and the toner contains 5 to 50% by number of toner particles with a size of 2&times;10 to 5&times;10 m in size distribution of the toner.

Toner and electrophotographic method

In an electrophotographic apparatus, which forms a color image by transferring a plurality of toner images having different colors onto an image-receiving sheet so as to be stacked and fixed thereon, even in the case of carrying out an oil-less fixing process and allowing the process speed to vary within wide range, the present invention provides a binder resin, toner and an electrophotographic apparatus which make it possible to achieve both superior fixing property and anti-offset property, and consequently to form a color image with high color reproducibility and high quality. In the present invention, a toner comprising a molecular weight maximum peak in a range of molecular weights from 2&times;10 to 3&times;10 in molecular weight distribution of GPC chromatogram, and a molecular weight maximum peak or shoulder in a range from 3&times;10 to 1&times;10 , wherein said molecular weight maximum peak or shoulder located on a range of molecular weights from 3&times;10 to 1&times;10 is obtained by kneading a toner composition containing a specific binder resin containing a high molecular weight component at not less than a specific amount so that the high molecular weight component of the binder is converted into a low molecular weight component by thermal or mechanical energy exerted at the time of kneading, is provided.

Binding resin for toner, toner, and electrophotograph

The present invention provides a toner comprising a binding resin, a colorant, and an ester based wax having an iodine value of not more than 25 and a saponification value of 30 to 300 (for example, at least one selected from the group consisting of meadowfoam oil and derivatives thereof and jojoba oil and derivatives thereof) and a method for producing the same. The present invention also provides a toner comprising silica fine powder containing a component having a polydimethyl siloxane skeleton extracted by an organic solvent at a content of not more than 2.5 wt %, and a method for producing the same. This stabilizes the chargeability and flowability of the toner during long period use, and reduces the filming on a photoconductive member or a transfer medium, Moreover, toner that provides good fixability, anti-offset properties, waste toner recycle properties, and transfer efficiency can be obtained with good reproducibility.

Toner and method for producing the same

The present invention provides a toner comprising a binding resin, a colorant, and an ester based wax having an iodine value of not more than 25 and a saponification value of 30 to 300 (for example, at least one selected from the group consisting of meadowfoam oil and derivatives thereof and jojoba oil and derivatives thereof) and a method for producing the same. The present invention also provides a toner comprising silica fine powder containing a component having a polydimethyl siloxane skeleton extracted by an organic solvent at a content of not more than 2.5 wt %, and a method for producing the same. This stabilizes the chargeability and flowability of the toner during long period use, and eliminates the filming on a photoconductive member or a transfer medium. Moreover, toner that provides good fixability, anti-offset properties, waste toner recycle properties, and transfer efficiency can be obtained with good reproducibility.

The present invention provides a toner comprising a binding resin, a colorant, and an ester based wax having an iodine value of not more than 25 and a saponification value of 30 to 300 (for example, at least one selected from the group consisting of meadowfoam oil and derivatives thereof and jojoba oil and derivatives thereof) and a method for producing the same. The present invention also provides a toner comprising silica fine powder containing a component having a polydimethyl siloxane skeleton extracted by an organic solvent at a content of not more than 2.5 wt %, and a method for producing the same. This stabilizes the chargeability and flowability of the toner during long period use, and eliminates the filming on a photoconductive member or a transfer medium, Moreover, toner that provides good fixability, anti-offset properties, waste toner recycle properties, and transfer efficiency can be obtained with good reproducibility.

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Osaka, Japan

Masahisa Maeda