US Patent 7239336 Image exposing apparatus having a beam scanner

An image exposing apparatus forms an image on photosensitive material by the technique of exposing and forming an image through direct modulation of a semiconductor laser device. The exposing apparatus includes a beam scanning unit for scanning a beam emitted from a semiconductor laser device to photosensitive material, a laser driving unit for driving the semiconductor laser device, the laser driving unit being operable to vary its driving current to the semiconductor laser device in accordance with a received image signal, and a laser output controller operable to measure current-beam output characteristics of the semiconductor laser device over a predetermined current range and then set a correlation between the image signal for the laser driving unit and the driving current for the semiconductor laser device, based on the measurement information.