| 摘要 |
<p>PROBLEM TO BE SOLVED: To maintain enough image density and to prevent fog or scattering of a toner by incorporating a binder resin, a coloring agent and magnetic particles having a specified range of average primary particle size, and controlling the amt. of the magnetic particles in the toner and the volume average particle size of the magnetic particles to specified ranges. SOLUTION: This toner contains a binder resin, a coloring agent and magnetic particles having 10-60nm average primary particle size and >=30emu/g max. magnetization in 1KOe magnetic field for measurement. The amt. of the magnetic particles to the toner is 0.5-5wt.% and the volume average particle size of the magnetic particles is 5-10μm. Any magnetic particles can be used as far as the average primary particle size ranges 10 to 60nm and the max. magnetization in 1KOe magnetic field for measurement is >=30emu/g. Namely, a metal, metal alloy or mixture of these can be used, and especially, a magnetite is preferable because >=30emu/g max. magnetization can be easily obtd. Magnetic particles having <10nm average particle size have lower magnetic force per one particle, which causes scattering of a toner.</p> |
