| 摘要 |
<p>PROBLEM TO BE SOLVED: To decrease fogging toners and reverse transfer toners as far as possible, to additionally improve transfer efficiency and to make electrostatic charge characteristics stabler. SOLUTION: Hydrophobic negative charge type silica 13 and 14 of a small average primary particle diameter and large particle diameter, hydrophobic rutile anatase type titanium oxide 15 of a relatively low electric resistance and hydrophobic positive charge type silica 16 of the same diameter or nearly the same diameter as the particle diameter of the negative charge type silica 14 are used for external additives 12 of the negative charge toners 8. The positive charge type silica 16 directly adheres to the surfaces of the mother toner particles 8a and exhibits a function of a microcarrier, making the rise of the electrostatic charge of the mother toner particles 8a faster. The rutile anatase type titanium oxide 15 adheres to the surface of the mother toner particles 8a through the negative charge type silica 13 of the small particle diameter and suppresses the negative overelectrostatic chargeability by its low electric resistance and simultaneously suppresses the generation of the toners of a positive polarity and therefore the reverse transfer toners and the fogging are eventually effectively suppressed.</p> |
