| 摘要 |
<p>In a replenishment toner for use in an image forming apparatus that detects the toner concentration in a two-component developer by the use of a magnetic permeability detecting means, the percentage by volume of toner particles with particle diameters of 5.04 mu m or smaller contained in the replenishment toner is in the range from 1.5 to 3.5 times the percentage by volume of such toner particles contained in the initial toner loaded initially in the image forming apparatus. This makes it possible to minimize the variation in magnetic permeability even when the toner is charged with an increasingly large amount of electric charge as image formation proceeds, and thereby maintain the toner concentration in the developer properly. By limiting the median particle diameter on a volume basis of the replenishment toner in the range from 8.0 to 12.0 mu m, it is possible to further reduce the variation in magnetic permeability resulting from the variation in the amount of electric charge with which the toner is charged. <IMAGE></p> |
