A first determining section determines whether a recording medium is conveyed in a first direction. A setting section sets a first current value as a current initially outputted to a DC motor each time the first determining section determines that the recording medium is conveyed in the first direction. A first current outputting section outputs a current at the first current value, and subsequently outputs by steps a current gradually higher than the first current value motor until the first determining section again determines that the recording medium is conveyed in the first direction. A second determining section determines whether the recording medium is conveyed in a second direction opposite the first direction after the first current outputting section outputs a current at the first current value. A first updating section updates the first current value to a second current value higher than the first current value, when the second determining section determines that the recording medium is conveyed in the second direction.