FOCUS ADJUSTMENT AUXILIARY DEVICE AND FOCUS ADJUSTMENT METHOD

摘要

PROBLEM TO BE SOLVED: To provide a focus adjustment auxiliary device and a focus adjustment method by which the focus adjustment in the subscanning direction can easily be made. SOLUTION: Moving a belt-shaped chart 6 in parallel in the subscanning direction allows a solid-state image pickup device 22 to sequentially read a read face consisting of a plurality of lines at an equal interval in the subscanning direction. For example, since connecting a detector 24 a solid-state image pickup device 22 of an image read device 23 can obtain an output equal to the case with reading the chart 6 through the scanning of a light source 15 in the subscanning direction, the focus adjustment in the subscanning direction can easily be made by moving only required components without the need for scanning the light source 15 in the subscanning direction.