| 摘要 |
A method and apparatus that prevent degradation of an image quality due to a change of a beam pitch in a subscanning direction of each optical beam on a record medium. At a given time, for example, when power is first turned on, a CPU detects a beam pitch on a record medium, e.g., a photosensitive drum, by using a CCD line image sensor. If the detected value differs from a value set according to a currently-selected scanning density, an LD arrangement change motor is rotated via a motor driver so that the beam pitch matches the set value so as to change an arrangement of laser diodes in a laser diode array. Control over the beam pitch occurs for a variety of conditions including control at regular intervals, power-on events, or when a scanning density specification signal indicates a different beam pitch than the detected beam pitch. Similarly, adjustment over the beam pitch is not typically made during a copying operation.
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