Patent ID: 8867967

Claim:
A development apparatus, comprising: a developer bearing member which develops a latent image; a first room which supplies a developer to the developer bearing member, disposed at a position facing the developer bearing member; a second room which recovers the developer from the developer bearing member, disposed at a position facing the developer bearing member, wherein the second room is connected to the first room via open portions formed at both ends of the first room, with the first room and the second room forming a circulation passage for circulating the developer; a partition wall partitioning the first room and the second room; a first conveying member disposed in the first room and being rotatable to convey the developer in the first room; a second conveying member disposed in the second room are being rotatable to convey the developer in the second room; a replenishment conveying portion containing a replenishing screw disposed coaxially to the second conveying member and conveying the developer from outside of the circulation passage to the second room; a replenishment passage which houses the replenishment conveying portion therein and replenishes the developer; a discharge port disposed in the circulation passage and through which surplus developer is discharged; a replenishing port through which the developer is replenished to the replenishment passage; and a ventilation port formed outside of the developer circulation passage.