PURPOSE: To obtain a magnetic toner used for pressing transfer having a deep black tone and denseness, and capable of forming an image high in Dmax by heat treating a magnetic toner having the difference between the softening point and the softening start point, at a specified value or more.
CONSTITUTION: A magnetic toner powder having ≥5°C difference between the softening point and the softening start point is prepared by heat kneading (A) 10W80wt% magnetic powder having ≥4ml/100g oil absorptivity, (B) 30W65wt% binder black resin, such as polyester resin, (C) 1W30wt% conductive substance, such as carbon having ≥ about 15ml/100g oil absorptivity, and (D) 0.2W20wt% other additives, such as colorant and fluidity improver, in a kneader or the like, cooling, and pulverizing the mixture. Next, this powder is treated in hot air stream at about 400°C and granulated into each spherical form to obtain a magnetic toner used for pressing transfer.
TSUJITA KENJI
OKUYAMA TAKEKI
BAN TSUYAKO
