| 摘要 |
<p>PURPOSE: To secure a developer that is provided with a good chargeability without containing any electrostatic charge control agent, less in toner scattering and excellent in image quality by comprising a toner and a carrier specified each. CONSTITUTION: This developer comprises a toner and a carrier. Toner grains contain fixing resin and magnetic powder dispersed in this resin. The fixing resin is made up of a composition containing a kind of resin with an anionic polar group, while the magnetic powder is contained in the toner grains at a rate from 0.1 to 5 pt.wt. to 100 pt.wt. in the fixing resin. Carrier grains have a cire grain and a covered layer covering this grain. This core grain is composed of a magnetic material to be shown in an equation of MOFe2 O3 , and here M is a kind of metal to be selected out of a group consisting of Cu, Zn, Fe, Ba, Ni, Mg, Mn, Al and Co. The covered layer consists of a resin composition containing thermosetting resin and thermoplastic resin. In this connection, this thermoplastic resin contains a quaternary ammonium group of 0.1 to 20 millimol to 100g of the resin composition.</p> |
