Exposure device having means for correcting intensity of laser beam dependent on variation in rotational speed of photosensitive member

摘要

In an image recording apparatus including a rotary drum on which a photosensitive sheet is wound, the drum is rotated by a motor through a speed reduction gear assembly to rotate at a constant speed V. To maintain an average exposure amount applied to the photosensitive sheet at constant as it is not the case when the rotational or peripheral speed of the drum vary due to a backlash of the speed reduction gears or a load imposed on the drum, a speed detector is attached to the shaft of the drum to detect the rotational speed of the drum. Based on the detected rotational speed, the exposure amount is increased or decreased by DELTA V/V times as much as the average exposure amount where V is a regular rotational speed of the drum and DELTA V is a variation in the drum speed from the speed V.