| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent secondary faults and to obtain high picture quality and a long life. SOLUTION: This electrostatic charge image developing toner consists of toner main particles of 4-12μm average particle size containing a binder resin and a coloring agent, and an external additive. This external additive consists of a fine powder (A) of 5-50nm average particle size and a fine powder (B) of 0.1-3μm average particle size, and 65-95wt.% of the fine powder (A) and >55wt.% of the fine powder (B) are firmly deposited on the toner main particles. The toner is produced by adding and mixing the external additive comprising the fine powder (A) and the fine powder (B) with the toner main particles according to the following procedure. After the fine powder (B) is added to the toner main particles and mixed under the condition of formula (1), the fine powder (A) is added and mixed under the condition of formula (2). In the formulae (1) and (2), CA (wt.%) and CB (wt.%) are proportions of the fine powder (A) and the finer powder (B) to the toner main particles, respectively, n is the number of revolution and d (m) is the diameter of stirring vanes of a mixing machine, and t (min) is the stirring time.</p> |
