Patent ID: 7911491

Claim:
An apparatus for controlling power of a laser diode, which generates a control voltage by compensating for an optical power deviation of the optical power accumulated on a surface of a photosensitive drum of an image forming apparatus during a power control period and applies the control voltage to the laser diode during a printing period, the apparatus comprising: an output voltage sensing unit, which senses an output voltage of the laser diode and which has been sampled during the power control period; an output voltage control unit, which receives the sensed output voltage of the laser diode and obtains an error voltage between a reference voltage and the sensed output voltage of the laser diode and proportionally integrates the error voltage to generate the control voltage; and an optical power compensation unit, which receives the generated control voltage and generates a compensated control voltage based on a predetermined compensation value corresponding to the optical power deviation, determined according to a position of the photosensitive drum, the predetermined compensation value to be one of directly added to and subtracted from the generated control voltage to compensate for the optical power deviation on the photosensitive drum during the printing period, wherein the optical power compensation unit comprises an optical power deviation storage which stores optical power deviations on the photosensitive drum and compensation values by which the optical power deviations should be respectively compensated.