Patent ID: 8301056

Claim:
A developing device comprising: a developing unit housing; a developer carrier that configured to carry developer; the developer carrier being rotatably supported by the developing unit housing; a side seal member that comes into slidable contact with both ends of the developer carrier; a sheet-like elongated seal member that extends in an axial direction of the developer carrier so as to come into slidable contact with the developer carrier; a side seal attachment surface that is formed in the developing unit housing and to which the side seal member is attached; and a support portion that is formed in the developing unit housing and protrudes toward the developer carrier from the side seal attachment surface to support the elongated seal member, wherein the elongated seal member is attached onto the support portion in a state where both ends thereof overlap the side seal member and are opposite the side seal attachment surface, a filler is filled in a gap surrounded by the elongated seal member, the side seal member, the support portion, and the side seal attachment surface, and a protrusion for suppressing a spread of the filler is formed at the side seal attachment surface at a predetermined interval from the support portion.