PURPOSE: To prevent overlapped transfer of a plural pieces of copying paper to an image transfer part from a both-side inversion tray and to reutilize it when unused transfer paper is left on the inversion tray.

CONSTITUTION: At the time when both sides are printed, after the one face of the transfer paper which is fed from a paper feeding tray 1 is printed, it is sent to an inversion tray 2 through an inversion route 3, a driving roller 21 is rotated reversely and the transfer paper is fed to the transfer part again. When the other face is printed, since a follower roller is not rotated if fixed torque larger than friction between the pieces of transfer paper is not applied when plural transfer papers are sent, carrying of the second and subsequent paper are prevented and both sides of a piece of transfer paper are surely printed. The pieces of residual paper are fed and used at the time of next printing or discharged to a discharging tray 13 as blank sheets of paper.