| 摘要 |
PURPOSE:To prevent the generation of a reverse polarity toner in repetitive use and to obtain an image having excellent quality by sticking fine silica particles and fine alumina particles of specific sizes to the surfaces of toner particles. CONSTITUTION:The fine silica particles having <=0.1mum average grain size and the fine alumina particles having >=0.1mum average grain size are stuck to the surfaces of the toner particles. The fine silica particles are not particularly limited if the average grain size thereof is <=0.1mum. On the other hand, the fine alumina particles having the average grain size ranging 0.1 to 1.0mum are preferably used. The reverse polarity toner is liable to be generated if the average grain size of the fine alumina particles is smaller than 0.1mum even if, for example, the average grain size of the fine silica particles is <=0.1mum. Defects of image density such as unequal densities are generated if the fine silica particles are larger than 0.1mum. The generation of the reverse polarity toner is suppressed in this way and the copied image having the excellent image quality is obtd. |
