| 摘要 |
<p>PURPOSE: To obtain an electrophotographic toner having satisfactory electrostatic chargeability of each particle, maintaining high image density and a fog-free image and withstanding use over a long period of time by using a specified large particle diameter toner and a specified small particle diameter toner. CONSTITUTION: This electrophotographic toner consists of a large particle diameter toner having tanδof 0.0030-0.0060 and a small particle diameter toner having tanδof 0.0065-0.0090. In this case, tanδexpresses the ratio of lost energy to charged energy as an electrical property of the toner and higher tanδshows larger lost energy. When the tanδof a small particle diameter toner in a toner having a prescribed particle size distribution is increased, the increase of the quantity of electric charges on the toner can be prevented and fogging, toner scattering and the deterioration of toner transfer efficiency are not caused. The tanδis controlled by regulating the carbon black content of the toner and kneading temp. at the time of melting and kneading.</p> |
