| 摘要 |
PURPOSE:To prevent offset without using an offset preventing liquid in a heat roller fixing system and to enable fixing to be executed at low temp. by using a copolycondensation product of a specified diole component and a specified acid component as a binder resin. CONSTITUTION:The electrophotographic developer compsn. is composed essentially of the binder resin and a colorant, and the binder resin is a polycondensation product of a diole component represented by formula I (R is ethylkene or propylene, x, y are each an integer of >=1, and an average value of x+y is 2-7) and a divalent or a polyvalent carboxylic acid or its anhydride acid components or lower alkyl ester acid components, and the acid components contain polycarboxylic acid or its acid anhydride and their lower alkyl ester obtained by copolymerizing alpha-methylstyrene or/and a compd. of formula IIa (R1 is a 1-3C hydrocarbon group or H), and a compd. of formula IIb (R2, R3 are each H, methyl, or carboxy) in an amt. of 0.05-70mol%, and the binder resin has a ring and ball softening point of 90-180 deg.C. |
