Apparatus and method for replenishing a developing device with toner while suppressing toner remaining

A method for replenishing toner, comprising:

• sucking toner from a container body through a mouth of the container body so as to discharge the toner to a developing device;
• pumping air into the container body through the mouth during a period of time toner is not being sucked from the container body;
• and
• allowing excess air pumped into the container body to escape through an opening located at a position opposite to the mouth to an outside of the container body such that a maximum amount of air may be pumped into the container body.

A toner replenishing device comprising:

• a toner conveyance path extending from a toner container to a developing device;
• a toner conveying device configured to convey the toner from the toner container to the developing device along the toner conveyance path;
• and
• an air supplying device configured to supply the toner container with air,
• wherein the toner container includes,
• a container body having a mouth configured to allow toner contained in the container body to be discharged to a developing device, and having an opening located at a position opposite to the mouth;
• a filter corresponding to a position of the opening of the container body and configured to allow air within the container body to escape;
• and
• a mouthpiece member mounted on the mouth of the container body and including an open/closeable valve configured to allow a stationary nozzle in a set portion of an image forming apparatus to protrude through the valve into the container body when the toner container is mounted to the set portion, and configured to close and seal the mouth when the toner container is not mounted to the set portion.