Cover member, developing cartridge and developing unit for image forming apparatus

A developing unit, comprising:

• a developing cartridge including a developer supply unit, which contains developer, and a mounting portion having an opening facing a wall surface on one side of the developing cartridge;
• a developer cartridge, which is configured to be inserted into the mounting portion to supply developer to the developer supply unit;
• and
• a cover member which closes the opening of the mounting portion when the developer cartridge is not inserted into the developing cartridge,
• wherein the cover member is removed when the developer cartridge is inserted into the developing cartridge, and
• the cover member comprises a waste developer collecting portion.

A developing cartridge usable in an image forming apparatus, comprising:

• a developing cartridge body including a mounting portion into which a developer cartridge containing a supplemental quantity of developer is to be received, the developing cartridge body including therein a supply of developer for use by the developing cartridge to allow the developing cartridge to operate without the developer cartridge being installed in the mounting portion;
• and
• a cover member receivable into, and to thereby close, an opening of the mounting portion when the developer cartridge is not installed in the mounting portion,
• wherein the cover member comprises a waste developer collecting portion in which to store waste developer.