| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain a toner which can be fixed at a low temp. and which can prevent blocking during storage or offset development during fixing by specifying the glass transition temp. of an outer shell layer which covers the surface of a core and specifying the glass transition temp. of the core material. SOLUTION: In this electrophotographic toner, the glass transition temp. of the outer shell layer which covers the surface of the core is 50 to 70 deg.C and the glass transition temp. of the core material is >=75 deg.C. Since the outer shell layer melts and fixes at a low temp. during fixing, the toner can be fixed with small energy and can be used for fast fixing. Further, such problems that the toner melts by heat and sticks during stored and that the surface of a copy sticks to the back surface of a copy sheet just after copying on a tray are prevented. It is preferable to use a resin for the outer shell layer, which is stable at the glass transition temp., preferably of 50 to 100 deg.C, and then rapidly melts over that temp. As for the resin for the core material, a resin which hardly deforms by heat compared to the material of the outer shell layer is preferably used.</p> |
