| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative charge type monocomponent toner which is free of fogging, toner scattering, and toner leakage even after long-time continuous printing, is also free of lowering of transfer efficiency, brings about no increase in the amount of toner to be cleaned, allows miniaturization of a waste toner container, and thereby allows miniaturization of an image forming apparatus, and to provide a color image forming apparatus. SOLUTION: The negative charge type monocomponent toner is obtained by externally adding (1) negative charge type silica fine particles having a smaller particle diameter, (2) negative charge type spherical silica fine particles having a larger particle diameter, (3) titanium oxide fine particles, (4)α-alumina fine particles and (5) metallic soap particles to spherical toner base particles consisting essentially of a binder resin and a colorant, wherein the work function (Φa) of theα-alumina fine particles, the work function (Φt) of the toner base particles and the work function (Φs) of the titanium oxide fine particles satisfy a relationship ofΦa<Φt<Φs. COPYRIGHT: (C)2007,JPO&INPIT
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