TONER FOR ELECTROSTATIC CHARGE DEVELOPMENT AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge development capable of preventing the falling of a releasing agent and spending on a carrier by specifying the shape of a releasing agent existing in a toner. SOLUTION: The toner consists essentially of a bonding resin, a colorant and a flat releasing agent having a shape factor of >=1.6. The shape factor of >=75% of the releasing agent is >=2 and >=75% of the releasing agent dispersed in the toner has <=1μm diameter equivalent to the diameter of a sphere. The toner contains 1-10 wt.% releasing agent having an SP value of >=1 to the bonding resin and 65-100 deg.C m.p. or contains two or more releasing agents different from each other in SP value and m.p. The toner is obtd. by kneading the constituent materials at a temp. below (the m.p. of the bonding resin) +20 deg.C and above the m.p. of the releasing agent. Because of continuous kneading, the materials are kneaded and conveyed under repetitive tension in a certain direction.