| 摘要 |
A magnetic toner is constituted by at least a binder resin and a magnetic iron oxide. The magnetic iron oxide is characterized by having an Fe(II) content of 18.5 - 24.1 wt. %, and shows a BET specific surface area of S (m<2>/g) and an X-ray diffraction pattern giving a half-value width W (deg.) of a diffraction peak corresponding to 311 plane of the magnetic iron oxide in spinel structure, the values S and W satisfying: 4.5x10<-><3>S + 0.130 </= W </= 4.5x10<-><3>S + 0.160, and 4.5 </= S </= 11.0. Alternatively, the magnetic iron oxide is characterized by having a number-average particle size D satisfying a relationship with W of: -0.08D + 0.180 </= W </= -0.08D + 0.212, and 0.10 </= D </= 0.45. The relationship between W and S or D indicates a good crystallinity of the magnetic iron oxide which provides the magnetic toner with a stable performance for a long period of time. The magnetic iron oxide can be obtained through a heating treatment at a temperature of 130 - 360 DEG C within a gaseous mixture of hydrogen and nitrogen containing 50 vol. % or less of hydrogen or at a temperature of 150 - 450 DEG C in an inert gas. |
