| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently form an image and, if necessary, to form an image of good finish quality. SOLUTION: When a high image quality mode is selected, the LED chips for high image quality of the end part on an upstream side in a sub-scanning direction are selected to form four main scanning lines and sub-scanning is performed in sub-scanning quantity of a four-line pitch. By this constitution, an image is formed in narrow exposure width and, even if actual moving quantity is different from sub-scanning quantity, a cycle of density irregularity becomes fine and, rather, density irregularity is inconspicuous as a whole. When a usual mode is selected, all of LED chips are selected and 10 scanning lines are formed and sub-scanning is performed in sub-scanning quantity of 10-line pitch. By this constitution, an image can be efficiently formed.</p> |
