Developing device and image forming apparatus having a reverse helical blade on a downstream end of a developer transport path

A developing device comprising:

• a development-region passing body that passes a development region while holding a developer;
• a first transport path in which the developer to be supplied to the development-region passing body is transported at least in a first transport direction;
• a second transport path in which the developer to be sent to the first transport path is transported at least in a second transport direction;
• a first connection portion through which a portion of the first transport path positioned short of a first-transport-direction-downstream end of the first transport path and a portion of the second transport path positioned short of a second transport-direction-upstream end of the second transport path are connected to one another;
• and
• a first transport member having a rotating shaft on which a helical first forward-transport blade is provided, the helical first forward-transport blade rotating to forward-transport the developer in the first transport direction in the first transport path,
• wherein the first transport member has a helical reverse-transport blade that reverse-transports the developer in a reverse direction reverse to the first transport direction, the reverse-transport blade is provided on at least a portion of part of the rotating shaft adjacent to the first connection portion, and a reverse-direction-downstream end of the reverse-transport blade reaches at least a first-transport-direction-upstream end of the first connection portion,
• wherein the helical reverse-transport blade is wound with a predetermined pitch, and the reverse-direction-downstream end of the reverse-transport blade is positioned, in the first transport path, further upstream in the first transport direction than the first-transport-direction-upstream end of the first connection portion by a distance less than or equal to one pitch.