| 摘要 |
PURPOSE:To obtain an electrophotographic developer having stable triboelectrified amt. and a sharp and uniform distribution thereof, and capable of controlling it to a charge suitable for a developing system to be used, and visualizing a negative electrostatic latent image to give a high-quality image, by incorporating specified fine silica powder in the developer. CONSTITUTION:The present developer unaffected by change of temp. and humidity, and capable of retaining the initial characteristics even during long- term storage is obtained by treating the fine silica powder produced by vapor phase oxidation of silicon halide compds. with a silane coupling agent represented by formula I (R is alkoxy or C; m is 1-3; Y is a hydrocarbon group contg. at least one of amino, vinyl, glycidoxy, mercapto, methacrylic, or ureido; and n is 3-1), and further subjecting said silica to a treatment for enhancing hydrophobicness, so that it exhibits 30-80 hydrophobic value measured by the methanol titration test, and adding it to a toner. |
