| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an image free from diffused transfer by using a toner obtained by adding hydrophobic fine rutile type titanium dioxide powder and hydrophobic fine silica powder each having a specified average particle diameter to toner matrix particles. SOLUTION: Hydrophobic fine rutile type titanium dioxide powder having 0.005-0.2μm average particle diameter and hydrophobic fine silica powder having 0.005-0.2μm average particle diameter are added as additives to toner matrix particles consisting essentially of a bonding resin, a colorant and an electrostatic charge controlling agent to obtain the objective toner. The ratio of the weight(Wt) of the hydrophobic fine rutile type titanium dioxide powder to the weight(Ws) of the hydrophobic fine silica powder in the toner is preferably 0.5<=Wt/Ws<=1.3 in the case of a black toner, 0.7<=Wt/Ws<=1.5 in the case of a magenta toner, 0.8<=Wt/Ws<=1.6 in the case of a cyan toner and 0.9<=Wt/Ws<=1.8 in the case of a yellow toner. The electrostatic charge controlling agent is preferably a quaternary ammonium salt, an amino-containing polymer or a complex compound of salicylic acid.</p> |
