Semiconductor laser driving device and image forming apparatus having the semiconductor laser driving device

A semiconductor laser driving device driving a semiconductor laser, the semiconductor laser driving device comprising:

• a driving current output terminal configured to output a driving current;
• a driving current monitoring terminal configured to output a driving current monitoring current having a value of 1/α, α≧1, of the driving current, the driving current monitoring terminal be in connected in parallel with a line of the driving current output terminal and a voltage;
• a detector configured to detect whether the driving current monitoring terminal has reached a reference voltage, wherein
• the driving current monitoring terminal is connectable to a current-voltage conversion resistor outside the semiconductor laser driving device and the current-voltage conversion resistor is configured to convert the driving current monitoring current having the value of 1/α of the driving current into a corresponding driving current monitoring voltage;
• a resistor disconnection detector configured to detect a disconnection of the current-voltage conversion resistor from the driving current monitoring terminal;
• and
• an alarm unit configured to externally report a detected result of the detector when the corresponding driving current monitoring voltage has reached the reference voltage,
• wherein provided that the resistor disconnection detector has detected the disconnection of the current-voltage conversion resistor from the driving current monitoring terminal, the alarm unit does not externally report the detected result of the detector even if the corresponding driving current monitoring voltage has reached the reference voltage.