An image forming device includes an image forming arrangement including a medium passage and motor, and a temperature detecting unit. A supplying control unit allows supply of a recording medium in the medium passage responsive to an image-forming signal, and prevents supply of a recording medium in the passage responsive to a warm-up signal. A warm-up control unit controls the motor to drive, responsive to the warm-up signal, at a first speed if a detected temperature is least a first temperature, and a second speed lower than the first speed if the detected temperature detected is lower than the first temperature. An image forming control unit controls the motor to drive, responsive to the image-forming signal, at a third speed if the detected temperature is at least a second temperature, and a fourth speed lower than the third speed if the detected temperature is lower than the second temperature.