A collector plate 74a, which serves as a contact surface of a rotational electrode member 71, is disposed to intersect an imaginary rotational axis RA of a thermal roller 10. The stationary electrode member 72 can be brought into contact with the collector plate 74a at a position near the rotational center of the collector plate 74a. As a result, friction between the two electrode members can be suppressed so that the electrode members do not wear out as quickly. Defective contact or damage of electrode members can be reduced.