Optical scanning device with automatic compensation

摘要

The scanning device includes at least one laser source with a polygon mirror with several reflecting surface areas for diverting a laser beam from the laser source. The beam produces a scanning point on a projection surface. A detector unit recognises the reflecting surface area, on which the laser beam is momentarily directed. A memory is provided for the storage of data which correspond to irregularities of the reflecting surface areas. A correction unit is provided for correcting the position of the laser beam. A control mechanism controls the correction unit with output signals from the detector unit and with data read from the memory.