| 摘要 |
PROBLEM TO BE SOLVED: To acquire the image of high quality by compensating easily the linearity deviation of the main scanning direction due to a temperature change or the like with a simple configuration without causing the cost increase. SOLUTION: The linearity characteristic of the main scanning direction and the data of a temperature gradient measured for every laser scanning optical unit are held in a ROM 6, and the irradiation operation of a laser beam of a laser diode(LD) 1 is controlled by the dot clock by a control circuit 4. When variation in the performance or differences in the mounting position of a fθlens 3 exists, the quantity of compensation to a printing displacement based on the data of the linearity characteristic of main scanning direction is calculated, and the modulation of the dot clock is performed. When the temperature monitored by a thermistor 7 changes, the quantity of compensation of the dot clock to the temperature change monitored from the data of the temperature gradient held in the ROM 6 is calculated, and the modulation of the dot clock is performed according to the quantity of compensation. |
