Scanning exposure unit, semiconductor laser driving circuit and image forming apparatus

A semiconductor laser driving circuit that controls driving of a semiconductor laser used as a light source when an outer surface of a photosensitive body is subjected to scanning exposure with a laser beam, comprising:

• an optical output control circuit that generates overshoot by increasing a level of an output from the semiconductor laser to a level higher than that of a steady-state optical output, and controls the output at a semiconductor laser lighting starting time, wherein the overshoot is optimized by setting values of at least one component of the optical output control circuit on the basis of at least one of a wiring density, a wiring speed, and diameters of the laser beam in fast and slow scanning directions.

An image forming apparatus comprising:

• a scanning exposure unit that turns on a semiconductor laser by a semiconductor laser driving circuit on the basis of image information, and subjects a photosensitive body to scanning exposure with a laser beam outputted from the semiconductor laser having an optical intensity at a rising edge thereof at each laser lighting time higher than a steady-state optical intensity thereof, wherein the optical intensity at the rising edge is optimized based upon at least one of a wiring density, a wiring speed, and diameters of the laser beam in fast and slow scanning directions.