Developing device and image forming apparatus

A developing device, comprising:

• a developer comprising a toner and a carrier;
• and
• a developer bearer configured to have a surface thereof bear the developer thereon and endlessly move, and to develop a latent image over a surface of a latent image bearer by supplying the toner in the developer to the latent image in a developing region where the developer bearer faces the latent image bearer,
• wherein:
• the carrier comprises fine particles, and a value X in a volume resistivity R (=10X) (Ω·cm) of the carrier is from 11.5 to 16.0;
• the developer bearer comprises:
• a magnetic field generating unit that comprises a plurality of magnetic poles;
• and
• a developing sleeve having a cylindrical shape enclosing the magnetic field generating unit, and configured to bear the developer over an outer circumferential surface of the cylindrical shape by means of a magnetic force of the magnetic field generating unit and to perform surface moving by rotating relative to a body of the developing device;
• and
• the developing device comprises a developing sleeve voltage applying unit configured to apply a voltage that comprises an alternating-current component to the developing sleeve.