Patent ID: 7342949

Claim:
A laser scanning device, comprising: a semiconductor laser that emits a laser beam; a laser power detector that detects a laser beam power of said semiconductor laser; a reference voltage generator that generates a reference voltage for controlling the laser beam power of said semiconductor laser in accordance with a laser power control signal provided from an external device; a laser driver that compares the reference voltage generated by said reference voltage generator and the laser beam power detected by said laser power detector to control a driving current supplied to said semiconductor laser for emitting the laser beam; and an abnormal condition detector that detects, prior to emission of the laser beam, the laser power control signal received by said reference voltage generator and inhibits said laser driver from emitting the laser beam when the laser power control signal differs from a predetermined value, and that permits said laser driver to emit the laser beam when the laser power control signal is the same as the predetermined value, wherein said reference voltage generator has a plurality of input terminals, and said abnormal condition detector includes an NAND gate having a number of inputs that is not less than a number of said input terminals of said reference voltage generator.