| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic toner which can maintain favorable developing property and durability even when the toner is made into finer particles, and which has excellent environmental stability of high developing property with resistance against fogging and scattering even in a high temperature high humidity or low temperature and low humidity environment. SOLUTION: In the magnetic black toner containing a binder resin, a charge controlling agent and a magnetic material, the weight average particle diameter of the toner is 5μm to 12μm, the charge controlling agent has a first acid value (A) and a second acid value (B) measured by potentiometric titration (1), the first acid value (A) is 2 mg/mgKOH to 10 mg/mgKOH (2), and the first acid value (A) and the second acid value (B) satisfy the inequlity of 1.20≤B/A≤2.00 (3), and also an inorganic fine powder material exists on the surfaces of the toner particles. COPYRIGHT: (C)2005,JPO&NCIPI
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