| 摘要 |
PURPOSE:To obtain stable triboelectrostatic charge characteristics and sharp image characteristics which are free from fogging by regulating the grain size and specific electric resistance of an external additive and forming this additive of org. resin particles which are electrostatically charged to the polarity reverse from the polarity of the coloring agent-contg. resin particles when triboelectrostatically charged with a carrier. CONSTITUTION:The external additive of the color developer is formed to have 20 to 200mum grain size and 10<5> to 10<14>OMEGA.cm specific electric resistance and are formed of the org. resin particles which are electrostatically charged to the polarity reverse from the polarity of the coloring agent-contg. resin particles when triboelectrostatically charged with the carrier. The developer to be added with these org. resin particles as the external additive has the excellent stability of the electrostatic chargeability in various environments, such as a change in temp. and humidity, and the good images free from fogging are obtd. The reason thereof lies in that the charge up by the excess rubbing of the nonmagnetic coloring agent-contg. resin particles and the carrier is neutralized by the org. resin particles. Further, the rising of the electrostatic charge of the toner is accelerated and the extremely stable electrostatic chargeability is attained from the beginning. The always good images are obtd. even in various environments in this way. |
