| 摘要 |
<p>PURPOSE: To provide a developer which contains specific carrier and specific toner, which has a sufficient chargeability with no charge control agent, which scatters little toner and which is excellent in image quality. CONSTITUTION: A binary system developer is composed of carrier and toner containing toner particles whi.ch in turn contain fixing resin, magnetic powder dispersed in the resin. The fixing resin contains styreneacrylic group polymer having an anionic polar group, a component having an alkyl group with an oxide number of more than 12 in the side chain, and a grafted wax component. This styrene-acrylic group polymer has a peak molecular weight of 4,000 to 30,000, and a weight-average molecular weight of 70,000 to 200,000, and has an acid value of 4 to 20. The magnetic powder is contained by 0.1 to 5 weight parts with respect to 100 weight parts of the fixing resin. Each of the carrier particles is composed of a core particle and a cover layer. The core particle is made of a magnetic material which is exhibited by MOFe3 (where M is metal such as Cu, Zn). The cover layer is composed of a resin composition containing methyl silicone resin and methylated melamine resin, the weight- average molecular weight of the methylated melamine resin being more than 700.</p> |
