| 摘要 |
<p>PURPOSE:To judge the occurrence of jamming and to eliminate defective fixing without providing a special work on a heating roll and to reduce a cost by judging that a transfer sheet winds round the heating roll when the changed value of the detected temperature by a temperature detecting element is drastically larger than a prescribed value. CONSTITUTION:When a transfer sheet 6 on which a toner image is formed in an image forming part winds round a heating roll 2 and the jamming occurs, the transfer sheet 6 enters between the temperature detecting element 5 for detecting the temperature of the heating roll 2 which is brought into contact with the outer peripheral surface of the transfer sheet 6 passing area on the heating roll 2 and the heating roll 2, then the temperature detected by the temperature detecting element 5 is drastically lowered. The lowering of the detected temperature is calculated and when it is drastically larger than a prescribed value, it can be judged that the transfer sheet 6 winds round the heating roll 2. Thus, it can be judged with a low cost whether the jamming occurs or not without providing the special work on the heating roll 2.</p> |
