A laser scanning unit for an image forming device includes a light source for emitting a laser beam, a scanning member having at least one reflective surface for scanning the laser beam onto an imaging surface across a plurality of scan lines, and driver circuitry for driving the light source to emit the laser beam. The driver circuitry has a first input for receiving a first signal indicating image information and a second input for receiving a second signal indicating shading information. The driver circuitry modulates the laser beam based on the first signal to form an image on the imaging surface corresponding to the image information and adjusts an output power of the modulated laser beam based on the second signal to substantially reduce energy variation across each scan line.