| 摘要 |
<p>PROBLEM TO BE SOLVED: To stably apply an electric charge to toner and to obtain a toner coat excellent in uniformity by using magnetic toner having a specific grain diameter, as the toner and providing a surface layer formed in such a manner that carbon conductive grains are dispersed in high polymer synthetic resin, on the surface of the conductive base material of a toner carrier. SOLUTION: The toner 30 is <=7μm in volume average grain size, for instance, 6.5μm and insulating toner including a magnetic material. This kind of toner is used to sufficiently obtain the charge amount (tribo) per unitary mass of the toner. In other words, the magnetic toner 30 housed in a toner housing part 20 is restricted by a magnetic field formed between a magnet 22 and a toner coat forming means 3 made of a ferromagnetic material and the surface of the toner carrier 2 is coated with the toner 30. At this time, the toner 30 is rubbed against the surface of the toner carrier 2 and a specific amount of charge having a prescribed polarity is stably imparted to the toner 30 by triboelectrification.</p> |
