| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a process for producing an electrophotographic toner which is capable of averting the degradation in productivity by fusion of a binder resin and maintaining high productivity even with small grain size toners without adversely affecting the basic performance of toners, such as electrostatic charge performance, fixing performance and colors. SOLUTION: The toner is produced by melting and kneading the binder resin, coloring agents and a petroleum resin of a weight average mol.wt. of <=5000. At this time, the toner is melted and kneaded by using a screw extruder which has a feed screw section and at least two kneading sections and has (1) the melting and kneading section set at the kneading temp. of the first kneading section so as to attain a temp. range of -20 to +80 deg.C with respect to the melting temp. of the binder resin and (2) the melting and kneading section set at the kneading temp. of the second and subsequent kneading sections so as to attain a range of -100 to +10 deg.C with respect to the melting temp. of the binder resin and (3) in which the kneaded matter temp. right after discharge is so set as to attain a range of -30 to +40 deg.C with respect to the melting temp. of the petroleum resin described above.</p> |
