| 摘要 |
<p>PURPOSE: To provide a developer that is provided with a good chargeability with no electrostatic charge control agent, less in toner scattering and excellent in image quality by comprising a toner and a carrier specified each. CONSTITUTION: The developer comprises a toner and a carrier. Toner grains contain a kind of fixing resin and magnetic powder dispersed in this resin. The fixing resin consists of a composition containing a kind of resin with an anionic polar group, and the magnetic powder is contained in the rate of 0.1 to 5 pt.wt to 100 parts by weight of the fixing resin. The toner grain is 5 to 15um of its volume reference mean grain size, and a spacer grain of 0.05 to 1.0um in mean grain size and 10<1> to 10<5>Ω.cm in resistivity and another space grain of 0.05 to 1.0um in mean grain size and 10<8> to 10<13>Ω.cm in resistivity both are stuck to the toner grain surface. Carrier grains have a core grain and a covered layer. This core grain is composed of a magnetic material expressed by a formula of MOFe2 O3 (M is metal of Cu, Zn or the like), and this covered layer consists of a resin composition containing a resin with a cationic polar group.</p> |
