Door opening and closing apparatus

A door opening and closing apparatus comprising:

• a plate-like frame that structures part of a wall surface of a transfer room and is provided with an opening for opening the transfer room;
• a door part capable of opening and closing the opening;
• and
• a placing pedestal on which a storage container having a storage container body and a lid part capable of opening and closing an inner space of the storage container body can be placed such that the lid part faces the door part,
• wherein the door part opens and closes when a transfer target object is transferred by a transfer robot disposed in the transfer room between the storage container and the transfer room, the door part opening and closing while shifting between a totally closed position where the inner space of the storage container body is sealed at least by the lid part held by the door part and a totally open position where the inner space of the storage container body is totally opened frontward,
• in a direction along which the storage container placed on the placing pedestal and the frame are aligned with each other, a side where the frame is positioned is referred to as a front side and a side where the storage container is positioned is referred to as a rear side,
• the lid part has an inner surface facing the inner space of the storage container body, the inner surface having a rearmost inner surface being nearest to a back surface of the storage container body,
• the frame has a frame foremost surface which is situated at a circumference of the opening and farthest from the storage container body, and
• every time a single access operation or a series of access operations of the transfer robot to the storage container subjected to a purge process with an environmental gas ends and until immediately before next access operation of the transfer robot to the storage container is performed, the door part becomes on standby at a predetermined halfway stop position on the front side than the totally closed position and where the rearmost inner surface of the lid part is on the rear side than the frame foremost surface of the frame.