An image forming apparatus has a recording element array including plural recording elements, an image forming section for causing a relative movement between the recording element array and a recording medium, thereby to form an image, and a drive section for driving the recording element array based on image data. A duty control unit varies the recording duty of the recording elements according to the relative movement speed between the recording element array and the recording medium. In another version, an image forming apparatus has a recording element array including plural recording elements, an image forming unit that effects a relative movement between the recording element array and a recording medium, memory for storing image data, a drive unit for driving the recording element array based on the image data read from the memory and an inhibitor for selectively inhibiting the recording operation by the image read from the memory, according to the relative movement speed between the recording element array and the recording medium. In yet another version, an image forming apparatus has a recording element array including plural recording elements, an image forming unit for causing a relative movement between the recording element array and a recording medium, a smoothing unit for applying a smoothing process to the image data, according to the relative movement speed between the recording element array and the recording medium and drive means for driving the recording element array, based on the image data subjected to the smoothing process by the smoothing unit.