| 摘要 |
PROBLEM TO BE SOLVED: To enable a patch image region to be detected with high accuracy by reducing the error of a detection position of a patch image due to the edge density variation phenomenon.SOLUTION: There is provided an image forming apparatus which comprises: an image forming station for forming a patch image corresponding to respective colors of a position detection object on an intermediate transfer belt 12 in order to detect displacement of a toner image in respective colors of the position detection object; an optical sensor 21 for outputting a signal corresponding to the reflected light amount by irradiating light to the intermediate transfer belt 12; and a control part 100 for correcting the displacement by detecting the position of each patch image formed by determining a threshold of the output signal of the optical sensor 21. The control part 100 holds a reference value corresponding to each patch image, calculates a peak value of a first signal corresponding to the reflected light amount from the patch image and a correction value from the reference value corresponding to the patch image and determines the position of the patch image by correcting the first signal based on the calculated correction value and determining a threshold of the first signal after correction. |
