According to an embodiment, an image forming apparatus includes a sheet conveyance unit that is configured to transport a print medium along a conveyance path. An antenna is configured to emit radio waves towards a predetermined portion of the conveyance path. A controller is configured to control the antenna to emit the radio waves towards the predetermined portion with a polarization direction set according to a type of the print medium being transported by the sheet conveyance unit. The print medium may have, for example, one or more wireless tags thereon or therein.