| 摘要 |
<p>PURPOSE: To obtain a toner having stable environmental characteristics, satisfactory flowability and transferability and giving a stable high-quality image by adding inorg. fine powder of a specified average particle diameter subjected to treatment for imparting hydrophobic property so that the concn. of ethanol at the time when the fine powder begins to settle and that at the time when the settlement of the fine powder finishes are regulated to a specified value each. CONSTITUTION: This electrophotographic toner contains inorg. fine powder of 0.01-0.1μm average particle diameter subjected to treatment for imparting hydrophobic property so that the concn. A (%) of ethanol at the time when the fine powder begins to settle and the concn. B (%) of ethanol at the time when the settlement of the fine powder finishes are regulated to >=10% and 30-90%, respectively, while satisfying the relation of 0<=(B-A)<=15 when the hydrophobic degree of the fine powder is measured using ethanol. Various coupling agents such as silane and titanate coupling agents may be used as a treating agent for imparting hydrophobic property. In the case of <0.01μm average particle diameter, the fine powder is liable to embedding in the surface of a toner and the toner is early deteriorated. In the case of >0.1μm, the fine powder remarkably reduces, the flowability of a toner and electrostatic charge is made ununiform to cause the deterioration of image quality, the scattering of the toner and fogging.</p> |
