A transparent toner image printing apparatus includes a photosensitive member, an exposing device to expose the photosensitive member based on image information to form an electrostatic image, a developing device to develop the electrostatic image on the photosensitive member to form a transparent toner image using a two component developer, and a voltage applying device to apply a DC voltage biased with an AC voltage to the developing device. In addition, a transferring device transfers the transparent toner image on the photosensitive member onto a non-preprinted sheet or a preprinted sheet, a fixing device heat-fixes the transparent toner image on the non-preprinted sheet or the preprinted sheet in a fixing nip thereof, and a selecting device selects a first mode in which the transparent toner image is formed on the preprinted sheet or a second mode in which the transparent toner image is formed on the non-preprinted sheet. A controlling device controls an operation of the voltage applying device so that an amplitude of the AC voltage in the first mode is larger than an amplitude of the AC voltage in the second mode.