| 摘要 |
<p>PURPOSE:To improve an image density in the case of multiple piece copying and to prevent a drum from adhesion, damage, and scattering of a toner excellently by externally adding a magnetic powder with the specific weight average particle diameter to a toner particle. CONSTITUTION:A magnetic powder with a weight average particle diameter of lmum or more is externally added to a toner particle containing a resin and a coloring agent. It is necessary that the weight average particle diameter of the magnetic powder to be externally added is lmum or more, and the weight average particle diameter in the 1-3mum range is desirable. When the particle diameter is excessively small, adhesion of the toner onto a drum, penetration of the magnetic powder into between a cleaning blade and the drum, or the like occurs, while linear damage is generated in the drum when the particle diameter is excessively large. A ferrite powder is especially desirable for the material of the magnetic powder, and ferrite having structure such as (MO)m, (Fe2O8)n, (M represents metal such as Fe, Co, Ni, Zn) are available, and especially Mn-Zn ferrite or Ni-Zn ferrite is desirable.</p> |
