Fusing device with a web end detector and image forming apparatus incorporating same

To provide a fusing unit including a fusing roller for fixing an unfixed toner image to a sheet and a fusing roller cleaning unit including a web sheet delivering roller for supplying a web sheet and a winding roller for taking up the web sheet for cleaning the fusing roller, the fusing roller cleaning unit includes a web detecting terminal for detecting the presence of the web sheet and a tension roller for guiding the web sheet, on the upstream side of a pressure roller with respect to the web sheet's direction of conveyance and first and second guide rollers, the second guide roller being disposed upstream of the web detecting terminal.