| 摘要 |
PURPOSE:To uniformly and strongly electrostatically charge the toner negative and to obtain a high-quality image by incorporating surface-treated silica obtd. by dispersing fine silica powder by high-velocity gaseous jet flow and bringing the powder into contact with a treating agent simultaneously therewith into the toner. CONSTITUTION:The surface-treated silica obtd. by dispersing the fine silica powder by the high-velocity gaseous jet flow and bringing the powder into contact with the treating agent simultaneously therewith is incorporated into the toner. The degree of water-wetting of the silica incorporated into the toner is >=80% (more preferably >=90%) and the silica having >=50% degree of water wetting after reintegration is more effective. The sharp image having no fogging is obtd. in this way in multicolor and multiplex copying with a high speed machine by the negative chargeable toner which is stable in triboelectrostatic charge quantity, has a sharp and uniform triboelectrostatic charge quantity distribution, and allows the charge quantity control suitable for the developing system to be used. |
