Sanyo Chemical Industries, Ltd.

Tomoyuki Ariyoshi

Masaru Honda

Masakazu Iwata

Takashi Akutagawa

Provided is a toner binder which combines excellent low-temperature fixing properties and excellent hot-offset resistance (namely which permits a wide fixing-temperature range) and which exhibits excellent storage stability. The toner binder comprises (A) a polyester resin, (B) a specific crystalline resin and, if necessary, (C) a non-crystalline linear polyester resin. The polyester resin (A) comprises a carboxylic acid component (x) and a polyol component (y) as the essential constituent units, said component (x) comprising two or more kinds of dicarboxylic acids (x1) selected from among aromatic dicarboxylic acids and ester-forming derivatives thereof in a total amount of 80 mol % or more and further containing an at least trivalent polycarboxylic acid (x2) as another essential component, and said component (y) comprising a C2-10 aliphatic diol (y1) in an amount of 50 mol % or more. Further, the polyester resin (A) exhibits a storage modulus at 150&#xb0; C. [G'(150)] of 2000 Pa or more, and the [G&#x2032;(150)] and [G&#x2032;(180)] (storage modulus at 180&#xb0; C.) of the resin (A) satisfy a specific relationship.

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Kyoto, Japan

Tomoyuki Ariyoshi