| 摘要 |
<p>This invention provides an electrostatographic developer composition comprising carrier particles and toner particles with a toner particle size distribution having a volume average particle size (T) such that 4 mν ≤ T ≤ 12 νm and an average charge (absolute value) pro diameter in femtocoulomb/10 νm (CT) after triboelectric contact with said carrier particles such that 1 fC/10νm ≤ CT ≤ 10 fC/10 νm characterised in that (i) said carrier particles have a saturation magnetization value, Msat, expressed in Tesla (T) such that Msat ≥ 0.30 T; (ii) said carrier particles have a volume average particle size (Cavg) such that 30 νm ≤ Cavg ≤ 60 νm; (iii) said volume based particle size distribution of said carrier particles has at least 90 % of the particles having a particle diameter C such that 0.5Cavg ≤ C ≤ 2Cavg; (iv) said volume based particles size distribution of said carrier particles comprises less than b % particles smaller than 25 νm wherein b = 0.35 x (Msat)2 x P with M¿sat?: saturation magnetization value, Msat, expressed in T; P: the maximal field strength of the magnetic developing pole expressed in kA/m; (v) said carrier particles comprise a core particle coated with a resin coating in an amount (RC) such that 0.2 % w/w ≤ RC ≤ 2 % w/w.</p> |
