PURPOSE: To produce images in high accuracy and in high printing quality by a method wherein a third electrode of an ion cartridge sheet is kept flat constantly, and fluctuation of a gap between the third electrode and a drum positioned on the printer main body side is certainly prevented.

CONSTITUTION: The title apparatus constitutes characteristic feature of being provided to its ion cartridge sheet 11 with a tension-adjusting device 21 that makes, in accordance with temperature variation occurring to a printer main body when the same is in operation, a third electrode 9 of an ion cartridge sheet 11 stretch in the direction wherein the distance between the opposite ends of the electrode is extended as the temperature in the printer main body rises, and also makes the third electrode 9 of the ion cartridge sheet 11 given tensile force acting in the axial direction of a dielectric drum.