| 摘要 |
PROBLEM TO BE SOLVED: To make precise corrections by removing the influence of other subscan driving irregularity from correction data for correcting polygon irregularity by selecting the number of surfaces and read sampling pitch of a rotary polygon mirror and the driving pitch of a subscan driving means so that the spatial frequencies of the polygon irregularity and subscan driving irregularity of not match each other. SOLUTION: A correcting means 150 calculates correction data for correcting polygon irregularity due to the rotary polygon mirror by the reflecting surfaces of the rotary polygon mirror by a correction data calculating means 159 and stores the correction data in a correction data memory 160. A correcting circuit 151 corrects read image data with the correction data. The number of surfaces and read sampling pitch of the rotary polygon mirror and the driving pitch of the subscan driving means are selected so that the spatial frequency of the irregularity due to the rotation of the rotary polygon mirror and the spatial frequency of periodic irregularity due to mechanical vibration of a subscan do not match each other. |
