An image processing device includes a printing unit printing an image on a sheet including first and second tags. The first and second tags have first and second antennas extending along first and second directions. The device further includes a tag reading unit including a third antenna and configured to transmit, towards the sheet from the third antenna, first radio waves polarized in the first direction and second radio waves polarized in the second direction in each of a first period during which the sheet is conveyed towards the third antenna and a second period during which the sheet is conveyed away from the third antenna, and determine an orientation of the sheet based on intensities of third radio waves polarized in the first direction and fourth radio waves polarized in the second direction, which have been received by the third antenna in each of the first and second periods.