PURPOSE: To easily produce the toner which has excellent fixability in a heat roll fixing system and is excellent in an offset preventive property as well by forming the toner consisting of a vinyl polymer which contains an acetone insoluble component and is specified in the weight average mol. wt. and number average mol. wt. of an acetone soluble component.
CONSTITUTION: The toner is formed of the toner binder resin consisting of the vinyl polymer which contains 1 to 50wt.% acetone insoluble component and in which the weight average mol. wt. of the acetone soluble component is 2,000 to 200,000 and the number average mol. wt. thereof is 1,000 to 100,000. The offset resistance of the toner is insufficient if the content of the acetone insoluble component is <1wt.%. The fixability is insufficient if the content exceeds 50wt.%. The good hot meltability and high elasticity are obtd. in this way and the toner and developer which have the excellent fixability in the heat roll fixing system and are excellent in the offset preventive property as well are obtd. by using such toner binder resin.
HOSHINO YUKIHISA
SAKAGAMI MASAYOSHI
