Image forming apparatus with removable developer container

An image forming apparatus comprising:

• a conveying unit configured to feed a sheet to convey the sheet along a conveying path;
• an image forming unit configured to form an image on the sheet using a developer;
• a mount to which a container is mounted, the container containing the developer;
• a replenishing unit configured to replenish the image forming unit with the developer from the mounted container;
• a controller configured to judge whether or not replacement of the mounted container is necessary, and
• in a case where the mounted container is replaced with another one without replacement of the container necessary during image formation operation by the image forming unit,
• (i) suspend feeding of the sheet by the conveying unit,
• (ii) discharge the sheet remaining in the conveying path, and
• (iii) disable an image forming operation of the image forming unit;
• and
• a display configured to
• display a screen for prompting replacement of the mounted container if replacement of the container is necessary, and
• display a screen for prompting re-mounting of the replaced container in a case where the mounted container is replaced with another one without replacement of the container necessary.