| 摘要 |
<p>PURPOSE:To obtain an image showing excellent reproducibility of line and solid images and excellent gradation by forming a coating layer containing both of carbon black (A) having an adsorption amt. equal to or greater than a specified value of dibutyl phthalate and carbon black B having an adsorption amt. equal to or less than a specified value on the surface of a nuclear particle so that the coating layer has desired conductivity and charge amt. without decreasing the wear resistance. CONSTITUTION:A coating layer containing both of carbon black (A) having >=450ml/100g adsorption amt. of dibutyl phthalate and carbon black (B) having <=400ml/100g adsorption amt. is formed on the surface of a nuclear particle. The weight ratio of the carbon black (A) to the carbon black (B) ranges from 20:80 to 80:20. The amts. of (A) and (B) added are controlled to obtain desired values of the conductivity of the coating layer and the charge amt. of the carrier. By adding a silane coupling agent to the coating layer, dispersibility of the carbon black is improved, and further dropout of the carbon black is prevented even for repetition of use. Thus, stable picture images can be obtd. for a long time.</p> |
