| 摘要 |
PROBLEM TO BE SOLVED: To reduce bending stress of a wire without requiring an intricate voltage application control. SOLUTION: A plurality of wires 9 having rear ends contiguous to each other within a predetermined range are divided into a plurality of groups G1-G6 and the forward ends of the wires 9 are arranged on a line in the sub-scanning direction in units of groups G1-G6 such that the forward ends of the wires 9 in the central groups G3, G4 are arranged on the outside of the forward ends of the wires 9 in the terminal groups G1, G2, G5 and G6. According to the arrangement, bending stress of the wires 9 in the groups G3, G4 under disadvantageous conditions can be reduced. Since all wires 9 are not driven simultaneously, capacity of power supply and noise can be reduced. Furthermore, an intricate voltage application control can be eliminated because arrangement of the forward ends of the wires 9 in the main scanning direction differs in units of groups G1-G6.
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