PURPOSE: To reduce load imposed on a driving means by preventing remaining cleaners from cleaning a wire when one cleaner out of plural cleaners cleans the wire.

CONSTITUTION: The driving wire 24 makes a turn under a shield case 2. When the driving means 19 moves the driving wire 24, a part of the wire 24 moving the cleaner 25 below a separation chamber and another part of the wire 24 moving the cleaner 26 below a transfer chamber are reversed in their moving directions. As a result, when the driving means 19 moves the driving wire 24 in one direction, either of the cleaners 25 and 26 abuts on charge wires 8 and 9 to clean them, whereas the other cleaner is away from the charge wires 8 and 9 and does not clean them. Thus, load applied to the driving means at the time of cleaning can be reduced.