Developing device, process cartridge, and image forming apparatus

A developing device comprising:

• a developer bearing member that bears developer;
• a supply member that comes into contact with the developer bearing member and thereby supplies the developer to the developer bearing member;
• a developing chamber in which the developer bearing member and the supply member are disposed;
• a developer containing chamber that contains the developer and at least part of which is positioned at a level below the developing chamber;
• a partition wall that partitions the developing chamber and the developer containing chamber from each other and is provided with an opening, the opening communicates the developing chamber and the developer containing chamber with each other, a lower edge of the opening is positioned at a level below an upper end of a contact portion formed by the supply member and the developer bearing member;
• and
• a conveyance member that is rotatably disposed within the developer containing chamber and that conveys the developer from the developer containing chamber to the developing chamber via the opening and is provided with a hole through which the developer can pass,
• wherein the developer bearing member and the supply member rotate in such a manner that movement directions of respective surfaces of the developer bearing member and the supply member at the contact portion include a downward component in a gravity direction, and
• wherein in a state where a leading edge of the conveyance member is positioned at a level above the upper end of the contact portion, a lower edge of the hole is positioned at a level below the upper end of the contact portion and an upper edge of the hole is positioned at a level above the lower edge of the opening.