| 摘要 |
PROBLEM TO BE SOLVED: To suppress a variable magnification error to the minimum, and to shorten an adjusting work time by providing a correction value for correcting the error of the variable magnification of an output picture for plural variable magnification, and correcting the variable magnification based on this correction value. SOLUTION: A variable magnification errorΔE (a difference between set variable magnification and actual variable magnification) is changed according to the value of the variable magnification. The correction of the variable magnification is operated by finely changing an original scanning speed and a writing frequency. The correction of a main scanning direction is operated by changing the writing frequency, and the correction of a sub-scanning direction is operated by changing the original scanning speed. The variable magnification errorΔE is made different according to an input variable magnification (m). However, the change of a relation between the input magnification (m) and the variable magnification errorΔE can be reduced for each device. The relation between them is preliminarily measured with variation, and the central value of the variation width of theΔE is used as a variable magnification correction valueΔm. Thus, it is not necessary to operate measurement for each device for obtaining the variable magnification error, and as a result, it is possible to shorten an adjusting time.
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