| 摘要 |
<p>PURPOSE:To obtain stable image quality having a high image density over a long period of time without having fogging of non-image parts by mixedly using at least two kinds of toner particle groups which vary in average grain sizes and vary in the grain size of at least one kind of the external additives to be externally added to the respective toner groups. CONSTITUTION:At least two kinds of the toner particle groups which vary in the average grain sizes and vary in the grain size of at least one kind of the external additives to be externally added to the respective toner groups are mixed. Namely, the classified toner group C having the average grain size exhibiting, for example, an average grain size distribution of about 7mum is again classified to A having the average grain size exhibiting a grain size distribution of about 5mum and B having the average grain size exhibiting a grain size distribution of about 8mum. The external additives, such as a flow property improving agent, lubricating agent, polishing agent, conductivity imparting agent, fixing assistant, are added at need to the respective toner groups A, B and these toner groups are mixed and agitated. At this time, the grain size of at least one kind of the external additives to be externally added to the toner groups A is changed from the grain size of the group B. The mixed and agitated toner groups A, B are charged by the adequate amt. each and thereafter the toners are mixed and agitated again to complete the toners.</p> |
