JP2007114524A5 - - Google Patents

Claims (9)

A fixing device for fixing an unfixed image formed on a recording material,
An endless belt member having a conductive layer and rotatably disposed;
A pressure member disposed in pressure contact with the outer peripheral surface of the belt member;
Induction heating means for induction heating the belt member via the conductive layer;
Look including a detection means for detecting the performance degradation of the conductive layer to the induction heating by the induction heating means,
The detection means includes
A sensor coil disposed opposite to the belt member;
A power supply for supplying a high-frequency current to the sensor coil;
A power factor measurement unit for measuring a power factor of electric power when the high frequency current is passed through the sensor coil by the power source;
A fixing device. The fixing device according to claim 1 , wherein the sensor coil is disposed to face the belt member outside a sheet passing area of a recording material having a maximum size.   The fixing device according to claim 1, further comprising a control unit that stops a fixing operation using the belt member and the pressure member when a decrease in performance of the conductive layer is detected by the detecting unit. apparatus. A fixing belt having a metal layer and rotatably disposed;
A nip forming member that forms a fixing nip portion for inserting a recording material carrying an unfixed image between the fixing belt and the outer peripheral surface of the fixing belt;
A pressing pad that presses the fixing belt from the inside of the fixing belt toward the nip forming member and deforms the shape of the fixing belt in the fixing nip portion; and
A fixing device including a crack detection unit that detects occurrence of a crack in the metal layer of the fixing belt; The crack detection unit generates cracks in the metal layer on the axial end portion side of the fixing belt and affects the temperature distribution in the sheet passing area of the maximum size recording material that can be fixed by the fixing device. The fixing device according to claim 4 , wherein the fixing device is detected. The fixing device according to claim 4 , further comprising an end cap member that is fitted to both axial end portions of the fixing belt and drives the fixing belt. 5. The fixing according to claim 4 , wherein the pressing pad is different in shape of a portion in contact with the fixing belt at an axial center portion through which the recording material passes and at both axial end portions through which the recording material does not pass. apparatus. A method for determining deterioration of a fixing belt having a conductive layer and rotatably disposed,
Supplying a high-frequency current to a coil member disposed in close proximity to the fixing belt;
Measuring a power factor of power when the high-frequency current is passed through the coil member;
Determining whether or not a crack has occurred in the conductive layer of the fixing belt facing the coil member based on the measured power factor. 9. The fixing belt deterioration determining method according to claim 8, wherein, in the determining step, it is determined that a crack has occurred in the conductive layer when the power factor falls below a predetermined reference value.