| 摘要 |
<p>PURPOSE: To provide a developer which contains specific toner and carrier, which has a satisfactory chargeability without containing any charge control agent, which little scatters, little toner and which exhibits an excellent image quality. CONSTITUTION: A binary system developer is composed of carrier and toner containing toner particles which in turn contain fixing resin, magnetic powder dispersed in the resin, and polyester group resin. The fixing resin contains resin having an anionic polar group, having an acid value of 4 to 20. The magnetic powder is contained 01. to 5 weight parts with respect 100 weight pats of the fixing resin. The polyester group resin has a molecular weight of 500 to 10,000, and is contained by 0.5 to 20 weight parts with respect to 100 weight parts of the fixing resin. The carrier particles contains thermoplastic resin and high resistance magnetic powder dispersed in the resin, having a volumetric reference mean particle size of 50 to 150μm, and the thermoplastic resin contains resin having a cationic polar group. Further, the high resistance magnetic powder has a specific resistance of higher than 1×10<5>Ωcm, and is contained by 60 to 90 weight parts in the carrier particles.</p> |
