| 摘要 |
PROBLEM TO BE SOLVED: To correct a printing position deviation due to skew of an optical system, etc., by effectively measuring plotting data by a position-detecting means in an electrophotographic apparatus having a plurality of light sources. SOLUTION: In order to measure a plotted evaluation image, there are a method of measuring the formed evaluation image by the position-detecting means while the image is kept still, and a method of measuring the formed evaluation image by the position-detecting means while the image is moved. Here is provided the former method of measuring the evaluation image while the image is kept still. C, M, Y and B evaluation images of each optical system are plotted to an intermediate transfer body 6, and then the intermediate transfer body 6 is kept still. Thereafter, when a position detection unit 11 is scanned only by a segment of an image correction region, a CCD sensor 13 obtains data on the evaluation image of each color. Corrected desired printing is enabled by correcting a printing position based on the measured plotting data. When the evaluation image is measured while moved, the intermediate transfer body 6 and the position detection unit 11 are moved synchronously. |
