| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an electrophotographic toner which is stable in the dispersion state of a charge control agent in toner particles and electrostatic charge characteristics, does not give a surface fogging, toner splashing and intra-machine contaminating and is stable in mass production quality by adjusting the compressibility of a material mixture in a mixing process to be in a specific range. SOLUTION: The compressibility of the material mixture in a stage for mixing materials including a fixing resin, coloring agents and the charge control agent is adjusted to a range of 25.0 to 35.0% at the time of the production of the toners having the stage described above. In such a case, the compressibility of the mixture or the powder characteristics, such as loosening and apparent specific gravity, of the mixture have a high level of a correlative relation with the dispersion state of the charge control agent and, therefore, the dispersion state of the charge control agent can be adequately maintained by adjusting the compressibility of the mixture or the loosening and apparent specific gravity of the mixture. Even if there is a difference in the grain sizes among the lots of the resins to be used in material mixture, the always uniform toners can be obtained by transferring to the ensuing stage after the uniform dispersion state is controlled.</p> |
