| 摘要 |
<p>PURPOSE: To determine the absolute correction value per LED based on the data and data meeting a first table by a method wherein a light sensor is placed near an LED array to measure the relative light-output of each LED and further, the first table to store the relative light output of each LED and an aging table to periodically store the light output are provided. CONSTITUTION: A photodiode 41 is placed near an LED array to measure the relative light output of each LED. The measured relative light output signal is fed to a controller 42 via an A/D converter 46 and stored in a first table of a memory 10. This first table is placed in the memory when the LED array is manufactured. A volatile memory 44 is also connected to the controller 42 via a bus 45. When a printer is started, the relative light output of each LED is measured by the photodiode 41 and stored in the again table of the volatile memory 44 by the A/D converter 46 and controller 42. The newly measured correction values are fed to a combination circuit 11 via a bus 13. As described above, new absolute correction values are computed with respect to all LEDs 24-27 and used for forming an image.</p> |
