| 摘要 |
PROBLEM TO BE SOLVED: To provide a development apparatus having high transfer efficiency and suppressing contamination on a fixation film even after long-term service.SOLUTION: A development apparatus 4 includes a magnetic toner carrier 3 and a regulation member 12. In the magnetic toner carrier 3, a work function value is 4.6-4.9 eV on a surface thereof. In the regulation member 12, a portion making contact with a magnetic toner is made of any of polyphenylene sulfide and polyolefin. The development apparatus employs the magnetic toner including a charge control agent having a center element selected from aluminum, boron, chromium, iron and zinc. If an existing amount of the center element of the charge control agent in the magnetic toner to a binder resin 100 parts by mass is A parts by mass, and an existing amount of the center element of the charge control agent existing on a surface of the magnetic toner to the binder resin 100 parts by mass is B parts by mass, B/A is 0.20-0.60. |
