Patent ID: 8094178

Claim:
An image forming apparatus comprising: a plurality of light sources that respectively emit a laser beam, all the light sources being driven by a common drive current; a separating unit that separates each of the laser beams into a first laser beam used for measuring light intensity and a second laser beam used for scanning a photosensitive element; a photoelectric converting unit that measures a light intensity of each of the first laser beams and outputs a voltage indicative of the light intensity; and a control unit that controls a light intensity of each of the laser beams based on the common drive current and a corresponding one of a current correction value, which is set by each of the laser beams to correct a light intensity of a corresponding one of the laser beams based on a corresponding one of the voltages output by the photoelectric converting unit, wherein the control unit controls a light intensity of each of the laser beams by performing any of a first light-intensity correction including correcting the light intensity of each of the laser beams in response to a synchronization signal indicating a timing of updating the current correction value when the photosensitive element is scanned by the second laser beam, and a second light-intensity correction including correcting the light intensity of each of the laser beams in response to a sheet-interval signal indicating a timing of correcting the common drive current in an interval between end of scanning of the photosensitive element by the second laser beam for an image to be output on a first recording medium and start of scanning of the photosensitive element by the second laser beam for an image to be output on a subsequent second recording medium, and the control unit performs the first light-intensity correction when the current correction value is within a predetermined current correctable range for which it is possible to correct the light intensity to a target light intensity, and the control unit performs the second light-intensity correction when the current correction value is out of the current correctable range.