The present invention prevents a recording sheet from generating wrinkles, by expanding means having an inverted crown shape pressing roll or a special sheet shape discharge restraining baffle, at the nip portion, expanding the recording sheet toward the right and left sides from the central portion in the sheet moving direction, temporal adsorbing means having discharge-output control means for an adsorbing charger or a contact pressure adjustment mechanism of the pressing roll temporarily adsorbing, in the nip portion, the leading end of the recording sheet to the dielectric film with small adsorbing force, correction means having an outer roll and an inner roll or the like disposed between the recording-sheet adsorbing apparatus and a portion for electrostatically transferring a toner image disposed downstream from the recording-sheet adsorbing apparatus applying pressure to the dielectric film to which the recording sheet has been adsorbed so that a state of adsorption of the recording sheet before a first transfer operation is performed is corrected.