Powder transport screw, and development device, process unit and image-forming apparatus comprising this powder transport screw

摘要

A toner transport screw that is capable of maintaining a smooth and stable transport function. The toner transport screw, in which a helical blade is disposed on the circumference of a rotating shaft, has at least one spiral direction reversal part formed by connecting the respective ends of a first blade part and a second blade part, the directions of spiral of the first blade part and the second blade part being in opposite directions. A passage, which allows the toner to pass through the blades in the circumferential direction of the rotating shaft, is formed in the spiral direction reversal part.