When the same image is continuously printed and the image data includes a line of a predetermined length along a sheet conveying direction, the control circuit 22 generates the control signal CTL so as to shift the effective light emitting elements by a predetermined number of light emitting elements corresponding to the width of the line. 制御回路22は、同一画像の連続印刷であり、且つ、用紙の搬送方向に所定の長さの線がある場合、線幅に応じた数の発光素子だけ、有効発光素子をずらすように制御信号CTLを生成する。 - 特許庁