Semiconductor laser driver and image forming apparatus incorporating same

An image forming apparatus, comprising

• at least one semiconductor laser to emit light;
• an image control unit to generate image data and an automatic power control signal to obtain a predetermined light emission intensity of light for the semiconductor laser;
• a semiconductor laser driver to drive the semiconductor laser and receive the image data and the automatic power control signal output from the image control unit;
• the semiconductor laser comprising:
• a control circuit to control a light emission intensity of the semiconductor laser based on light emission intensity and on a predetermined light emission intensity setting value;
• and
• a light detection circuit to detect a quantity of light emitted from the semiconductor laser as the detected light emission intensity and output the detected light emission intensity to the control circuit,
• the light detection circuit comprising:
• a photoelectric conversion element to convert the quantity of light emitted from the semiconductor laser into an electrical current and output the electrical current as a monitor current;
• a current magnification setting circuit to amplify the monitor current output from the photoelectric conversion element into a predetermined amplified current at one of multiple different predetermined magnifications;
• and
• a detection resistor to convert the amplified current output from the current magnification circuit into a voltage and output the voltage as the detected light emission intensity.