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Toner for electrophotography

Imported: 22 Feb '17 | Published: 07 May '02

Katsutoshi Aoki, Yoshihiro Fukushima, Yutaka Kanamaru, Koji Akiyama

USPTO - Utility Patents

Abstract

A toner for electrophotography comprising a resin binder comprising as its main components (a) a crystalline polyester having a softening point of from 85° to 150° C., obtainable by polycondensing an alcohol component which comprises 80% by mol or more of an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component which comprises 80% by mol or more of fumaric acid; and (b) an amorphous polyester and/or an amorphous polyester-polyamide, obtainable by polycondensing monomers comprising 50% by weight or more of an aromatic compound, wherein a weight ratio of the crystalline polyester to the amorphous polyester and/or the amorphous polyester-polyamide, i.e. crystalline polyester/(amorphous polyester and/or amorphous polyester-polyamide), is from 1/99 to 50/50.

Claims

1. A toner for electrophotography comprising a resin binder comprising as its main components:

wherein a weight ratio of the crystalline polyester to the amorphous polyester and/or the amorphous polyester-polyamide, i.e., crystalline polyester/(amorphous polyester and/or amorphous polyester-polyamide), is from 1/99 to 50/50.

2. The toner according to claim 1, wherein the crystalline polyester is obtained by polycondensing monomers comprising 0.1 to 30% by mol of trivalent or higher monomers selected from the group consisting of trihydric or higher polyhydric alcohols and tricarboxylic or higher polycarboxylic acids, acid anhydrides thereof, or esters thereof.

3. The toner according to claim 1, wherein the amorphous polyester has a softening point of from 70° to 180° C., and a glass transition point of from 45° to 80° C.

4. The toner according to claim 1, further comprising at least one wax of which melting point is lower than the softening point of the crystalline polyester by 10° C. or more.