US Patent 8000639 Developing device and image forming apparatus

A developing device is disclosed that is capable of preventing the hysteresis phenomenon, and which contains a toner and a carrier. The toner and the carrier are charged to different polarities by frictional contact thereof. The developing device has a first conveyance member and a second conveyance member which faces an electrostatic latent image bearing body via the second region. An electric field forming device forms a first electric field between the first conveyance member and the second conveyance member to move the toner in the developer retained by the first conveyance member to the second conveyance member, and forms a second electric field between the second conveyance member and the electrostatic latent image bearing body to move the toner retained by the second conveyance member to an electrostatic latent image of the electrostatic latent image bearing body.