| 摘要 |
An image forming apparatus is configured so that a first detection position (3) and a second detection position (4) are set along the direction of conveying a transfer material (5) between adjacent conveyance rollers. The image forming apparatus has four sensors (SN1,...SN4), two of which are disposed in the first detection position at a predetermined interval and perpendicular to the conveyance direction, and the remaining two of which are disposed in the second detection position similarly. An actual length of the transfer material can be detected with high accuracy by computing the cancellation of errors in detection signals caused by i.) speed variations at which the transfer material is conveyed, ii.) a skewed position of the transfer material, and iii.) oblique passing thereof. |
