Patent ID: 8665303

Claim:
A laser drive apparatus for controlling a light amount of a laser beam scanned by a scanning unit, the laser drive apparatus comprising: a first light amount detection unit configured to receive the laser beam that is output from a laser light-emitting element and to output a first detection signal that indicates a light amount of the laser beam; a second light amount detection unit arranged side by side with the first light amount detection unit in a scanning direction of the laser beam, and configured to receive the laser beam output from the laser light-emitting element and to output a second detection signal that indicates the light amount of the laser beam; an amplification unit configured to amplify the second detection signal that is output by the second light amount detection unit; a binarization unit configured to binarize the second detection signal amplified by the amplification unit and to output the binarized second detection signal as a synchronization signal; a modification unit configured to subject the second detection signal amplified by the amplification unit to analog/digital conversion, and to modify the converted second detection signal with a modification coefficient that corresponds to an amplification factor of the amplification unit; a light amount adjustment unit configured to obtain a first driving current that flows through the laser light-emitting element when the light amount indicated by the first detection signal that is output by the first light amount detection unit reaches a first target light amount, and a second driving current that flows through the laser light-emitting element when the light amount indicated by the second detection signal that is output by the modification unit reaches a second target light amount that is lower than the first target light amount; a determination unit configured to determine a driving current that serves as a threshold at which the laser light-emitting element starts to emit light, on the basis of the first target light amount, the first driving current, the second target light amount, and the second driving current.