DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a developing device which stably charges toner over a long period of time and an image forming apparatus.

SOLUTION: A developer in the developing device includes toner and carrier. The toner and carrier are charged to different polarities by mutual frictional contact. The developing device has a first conveyance member and a second conveyance member facing to an electrostatic latent image carrier via a second area. 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 held 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 carrier to move the toner held by the second conveyance member to an electrostatic latent image on the electrostatic latent image carrier. The developer further includes charged particles. The charged particles are supplied in a state where they are detachably held on the surface of the toner, and the charged particles are separated from the surface of the toner by biasing force based on the first electric field and are then held on the surface of the carrier. The charged particles held on the carrier come in frictional contact with the toner to charge the toner to the first polarity.

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