Patent ID: 8073351

Claim:
An image forming device including a fixing portion including a nip that is formed between a heat roller and a back-up roller pressurized by a pressurizing mechanism and holds and conveys a toner-bearing sheet, the image forming device comprising: a pressure switching mechanism for changing a pressurizing force of the pressurizing mechanism to change the pressurizing force applied to the toner-bearing sheet by the heat roller and the back-up roller from a first force level applying pressure to the toner-bearing sheet and a second force level applying pressure to said toner-bearing sheet, said pressurizing force being applied to said toner-bearing sheet while conveying the toner-bearing sheet through the fixing portion; a sheet detecting portion for detecting a sheet conveyed to the fixing portion and for changing a sheet detection logic of an output signal indicating sheet presence based on a switching state of pressure by the pressure switching mechanism being such as to apply said first force level or said second force level; a pressurization state determining portion for determining a state of pressurization of the pressurizing mechanism on the basis of an output logic of the sheet detecting portion; and a pressurization state display portion for displaying the pressurization state determined by the pressurization state determining portion.