| 摘要 |
<p>PURPOSE:To prevent transfer of particles in a visualized picture to a nonpicture part, chipping in the lead, and edging in the trail of picture by incorporating specified conductive particles and fine powder into the developer. CONSTITUTION:This developer contains at least picture-developing magnetic particles having magnetism, conductive particles having smaller average particle size than that of the picture-developing particles but larger than 0.1mum and an insulating inorg. oxide fine powder. This insulating inorg. oxide fine powder is treated with silicone to become hydrophobic and has the opposite triboelectricity to the picture-developing particles. As for the conductive particles, metals such as Fe, oxide particles such as magnetite, CrO2, and TiO2 are used and the particles have <10<11>OMEGA.cm electric resistivity, more preferably <10<9>OMEGA.cm. he insulating inorg. oxide fine powder is selected from SiO2, Al2O3, W2O3, ZrO2, SeO, etc., having >=10m<2>/g, more preferably >=50m<2>/g BET (adsorption isohumidity) specific surface area and showing the opposite polarity to the picture-developing particles. The selected powder is subjected to surface treatment with silicone to become hydrophobic.</p> |
