Developing device and image forming apparatus

A developing device comprising:

• a developer container section including a toner supply port, a carrier supply port, and a developer outlet, the developer container section being configured to contain therein a two-component developer composed of toner and magnetic carrier;
• a developer bearing member configured to supply the developer contained in the developer container section to an image bearing member on which an electrostatic latent image is formed;
• a toner supplying section configured to supply the toner to the developer container section via the toner supply port;
• a carrier supplying section provided separately from the toner supplying section, the carrier supplying section being configured to supply the carrier to the developer container section via the carrier supply port;
• and
• a carrier detection section disposed at a position near the carrier supply port and at a same level as a powder surface of the developer contained in the developer container section, the carrier detection section being configured to detect carrier supplied from the carrier supplying section.