| 摘要 |
An image forming apparatus includes a plurality of loop detecting sensors (S1,S2) which detect various levels of loops formed by a recording material (P); and a controlling device (51) which selects a specific one of the loop sensors in accordance with information on the recording material, and switches then a conveyance speed of a fixing roller pair (5) in response to a detection signal output from the specific sensor to keep the respective loop (L1) of the recording material within a constant range, the controlling device selecting such loop keeping control that prevents an unfixed image on a slack copy sheet between the transfer and fixing nips both from any apparatus contact and from a violent move of its trailing end after passing the transfer rollers. |
