Patent ID: 7512364

Claim:
An image forming apparatus comprising: a carrier storing portion storing a carrier; a conveying path configured to convey the carrier to a developing unit from the carrier storing portion; air sending means for sending air under pressure to said conveying path as a conveying force for conveying the carrier; and replenishing means for replenishing the carrier stored in said carrier storing portion to said conveying path; said replenishing means being provided on a carrier replenishing passage extending from said carrier storing portion to a portion where said carrier replenishing passage joins said conveying path, said replenishing means being configured to obstruct entry of air to said carrier storing portion and replenish the carrier by a preselected amount, wherein said carrier comprises a powdered carrier and said replenishing member comprises a rotatable roller housed within said carrier replenishing passage and provided outside said carrier storing portion, said rotatable roller having a diameter large enough to block said carrier conveying path and being formed with a metering cavity in a circumferential surface thereof.