| 摘要 |
A polarity control unit comprises: a flag memory unit remembering one of flags assigned to a first polarity pattern applying DC voltage of positive polarity to a discharge needle of a first group, and negative polarity to a discharge needle of a second group, and to a second polarity pattern applying DC voltage of negative polarity to the discharge needle of the first group, and positive polarity to the discharge needle of the second group, respectively; a flag renewing unit one flag remembered in the flag memory unit to the other flag when a power switch is turned on from being off, or turned off from being on; and a command unit outputting a polarity pattern corresponding to the flag remembered in the flag memory unit from a polarity output unit. |
