| 摘要 |
PURPOSE:To obtain a toner suited for a dry type copying machine using a toner concn. sensor which detects the reflectivity of the developer by so controlling the grain size distributions of toner particles as to satisfy the specific relations between the number average grain sizes and volume average grain sizes of particles. CONSTITUTION:The toner of the sharp grain size distributions wherein number average grain sizes Xn are 7.0-11.0mu and the ratio between volume average grain sizes Xw and said Xn is <=1.25 is made by such a method of kneading, for example, 90pts.wt. a methyl methacrylate resin and 10pts.wt. carbon black with heat rolls then cooling the mixture, grinding the same with a jet grinder, thence removing coarse powder with a zigzag classifier then increasing the number of revolutions and removing the fine powder. This toner sticks uniformly on carriers without deviation owing to grain sizes, and does not fluctuate in toner grain size distributions. Since the concn. of the toner is detected with good accuracy and the concn. is controlled well, always stable images are obtained even in the copying cycle of a long time. |
