Patent ID: 7526225

Claim:
A developing apparatus comprising: a case having a slit-shaped opening and a holder, the holder being configured to communicate with the opening and to hold developer, the opening being formed in a longitudinal direction; a first wall portion provided at an upper side of the opening, the first wall portion extending along a longitudinal direction of the opening and along a communication direction extending between the opening and the holder; a second wall portion extending from the first wall portion in both the longitudinal direction and a height direction perpendicular to both the communication direction and longitudinal direction; a developer retainer configured to retain the developer on a surface thereof, the developer retainer being arranged at the opening along the longitudinal direction of the opening and rotatably supported at the case; a layer thickness regulating member comprising: a blade, one end of which is arranged opposite to the first wall portion and the other end of which extends from the one end toward the surface of the developer retainer such that the other end is pressed against the surface of the developer retainer; and a first supporting member comprising: a first supporting portion arranged opposite to the first wall portion, the first supporting portion extending in the communication direction; and a second supporting portion arranged opposite to the second wall portion, the blade being supported at the second supporting portion and extending in the height direction, the second supporting portion being integrally formed with the first supporting portion; and a first sealing portion interposed between the first wall portion and the first supporting portion, the first sealing portion being configured to seal a space between the first wall portion and the first supporting portion; and a second sealing portion interposed between the second wall portion and the second supporting portion, the second sealing portion being configured to seal a space between the second wall portion and the second supporting portion; wherein the first sealing portion and the second sealing portion are formed integrally.