| 摘要 |
PROBLEM TO BE SOLVED: To obtain a length of a sheet to be recorded with high accuracy and high repetition accuracy so as to realize double face-printing or multiple printing of high quality. SOLUTION: In an image-forming apparatus having a transfer function for a sheet 1 to be recorded, a plurality of detection means 11, 12... are arranged along a transfer direction of the sheet 1 to detect the transferred sheet, and an operating means 20 is provided to calculate a length of the sheet 1 on the basis of a distance between the detection means 11, 12... and a detection timing difference at the detection means 11, 12.... The length of the transferred sheet can be detected highly accurately, for instance, with a detection accuracy of approximately several tens μm. |
