Patent ID: 7769316

Claim:
A developing unit for developing a latent image formed on an image carrier, the developing unit comprising: a developer carrier configured to bear a developer and facing the image carrier at a first position; a developer regulator configured to regulate an amount of the developer, the developer regulator disposed facing the developer carrier at a second position upstream of the developer carrier in a moving direction thereof relative to the first position; and a sealing member configured to come into contact with the image carrier at a third position upstream of the image carrier in a moving direction thereof relative to the first position, wherein gas is prevented from flowing from an outside area of the developing unit into an area defined by the second position to the third position, and wherein the developer regulator includes a substantially vertical wall, the wall having a vent hole disposed substantially horizontally through the wall such that the developer on the developer carrier does not cover the vent hole and air travels from an inside of the developing unit through the developer regulator and exits proximate to an upper surface of the developer carrier.