| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method of correcting the light quantity of an optical writing head by anticipating the temperature distribution of the optical writing head, and canceling the effects to printing quantity caused by the self temperature rise of the optical writing head. SOLUTION: When a first light emitting diode 201 is lit, its forward voltage can be measured by measuring the voltage V0 at a voltage output terminal 130. The forward voltage, which is hardly dependent upon current value, varies linearly against temperatures TH. The temperature TH of the first light emitting diode is anticipated by use of the temperature characteristics. By measuring the voltage V0 of two chips located apart on one head, environment temperature is estimated, and the temperature distribution of the head is anticipated from the difference in temperature of the two light emitting element arrays. Thus, light quantity of the light emitting elements is corrected in accordance with the anticipated temperature distribution.</p> |
