Image forming apparatus with powder conveying device having reverse rotation mode

An image forming apparatus, comprising:

• a first conveyor to rotate in a first forward direction to convey powder in a supply mode;
• a first conveyance passage in which the first conveyor is disposed;
• a first fall passage to receive the powder from a first outlet port of the first conveyance passage;
• a second conveyor to rotate in a second forward direction to convey the powder in the supply mode;
• a second conveyance passage in which the second conveyor is disposed;
• a second fall passage to receive the powder from a second outlet port of the second conveyance passage;
• and
• a controller configured to execute a reverse rotation mode to first rotate the first conveyor in a first reverse direction and the second conveyor in a second reverse direction, and then to rotate the first conveyor in the first forward direction and the second conveyor in second forward direction immediately thereafter such that the time the first conveyor is rotated in the first forward direction and the second conveyor is rotated in the second forward direction is substantially equal to the time rotated in the first reverse direction and the second reverse direction before execution of the supply mode, wherein
• a first size of the first conveyor and a second size of the second conveyor are substantially the same, and
• a first length of the first conveyor and a second length of the second conveyor are substantially the same.