| 摘要 |
PURPOSE:To provide a stable image which is substantially free from ground fogging even if humidity is high by removing hygroscopic water soluble matter from the surface exposed to the amt. CONSTITUTION:The water soluble matter is removed from the surface by washing and drying the same after calcination. The typical example of the applicable ferrite carrier is Ba-Ni-Zn ferrite, etc. First the raw material of ferrite is calcined for 0.5-3hr at 900-1,000 deg.C and the calcined powder is pulverized so as to have about <=2.0mum average grain size. The powder is then pelletized to about 10-200mum grain size and the pellets are calcined for 3-5hr at 1,250-1,350 deg.C. The ferrite carrier classified to a suitable grain size range after calcination is put into a large volume of water and is thus washed. The washed carrier is thoroughly dried at about 150-280 deg.C, by which the ferrite carrier is obtd. |
