Developing device and blade assembly

A developing device comprising:

• a casing;
• a developing roller;
• a blade which contacts the developing roller and includes an opening;
• a blade holder which has a first mounting section mounted on the casing, a first nipping section and a projection formed on the first nipping section, the projection projecting toward the blade and fitted into the opening;
• and
• a blade supporting plate which has a second mounting section mounted on the casing and a second nipping section for nipping the blade together with the first nipping section.

A blade assembly comprising:

• a thickness regulation blade which slidably contacts a developing roller to regulate a thickness of developing agent on the developing roller;
• and
• first and second holding members which fix the thickness regulation blade on a casing of a developing device,
• wherein the first holding member includes:
• a first nipping surface which contacts the thickness regulation blade;
• a projection formed on the first nipping surface and projecting toward the thickness regulation blade;
• and
• a first mounting section including a first fixing surface which extends in a direction different from a direction in which the first nipping surface extends,
• wherein the second holding member includes:
• a second nipping surface which opposes the first nipping surface;
• and
• a second mounting section including a second fixing surface which extends in a direction different from a direction in which the second nipping surface extends, the second fixing surface contacting the first fixing surface;
• wherein the thickness regulation blade includes a positioning opening and is sandwiched between the first nipping surface and the second nipping surface,
• wherein the first holding member and the second holding member are fixed to each other with the first mounting section and the second mounting section;
• wherein at least one of the first holding member and the second holding member is attached to the casing by the first mounting section or the second mounting section, and
• wherein the projection fits into the positioning opening of the thickness regulation blade.