Image forming apparatus

An image forming apparatus comprising:

• a fixing device including a laser irradiator emitting laser light onto a recording medium being conveyed to thermally fix an unfixed toner image onto the recording medium;
• a controller controlling image formation;
• a developing device performing development using a dual-component developer including a toner and a carrier;
• a toner concentration detector detecting the toner concentration in the developing device;
• and,
• a storage storing the toner concentration and a reference toner concentration, characterized in that
• the controller compares the toner concentration detected by the toner concentration detector with the reference toner concentration, calculates the output level of the laser irradiator, controls the laser irradiator based on the calculation, controls to increase the output level of the laser irradiator in accordance with the detected toner concentration when the toner concentration is lower than the reference toner concentration, and controls to lower the output level of the laser irradiator in accordance with the detected toner concentration when the toner concentration is higher than the reference toner concentration.