Patent ID: 8849166

Claim:
A developing device comprising: a developer supporting rotator including a first rotating sleeve and a developer supporting side magnetic member, the first rotating sleeve supporting a two-component developer including at least a carrier and toner, and composing a longitudinally extending surface, on which a magnetic brush is formed by the carrier contained in the two-component developer, and the developer supporting side magnetic member being disposed inside the first rotating sleeve and longitudinally extending; a toner supporting rotator including a second rotating sleeve and a toner supporting side magnetic member, the second rotating sleeve being arranged opposite to the developer supporting rotator, composing a longitudinally extending surface, on which the toner supplied from the developer supporting rotator is supported and a toner layer is formed by the magnetic brush, and the toner supporting side magnetic member being disposed inside the second rotating sleeve and longitudinally extending; and a voltage application unit configured to apply a developing bias voltage between the toner supporting rotator and the image carrier, such that the toner supported by the toner supporting rotator flies to an electrostatic latent image on a surface of an image carrier in order to develop the electrostatic latent image into a toner image, wherein a longitudinal end portion of the toner supporting side magnetic member is positioned more longitudinally outside than a longitudinal end portion of the developer supporting side magnetic member, and wherein a surface of the second rotating sleeve positioned more outside than the end of the developer supporting side magnetic member is composed of a surface of low adherence having lower toner adherence and a higher dielectric constant than those of a surface positioned more inside.