Fixing device and image forming apparatus

An image forming apparatus including a fixing device for thermally fixing an unfixed image formed on a recording sheet by transporting the recording sheet through a fixing nip, the fixing device comprising:

• a heat-generating endless belt that rotatably runs about a rotation axis;
• a first pressure member disposed inside a running path of the heat-generating endless belt;
• and
• a second pressure member disposed to press the endless belt against the first pressure member from outside the running path to form the fixing nip, wherein
• the heat-generating endless belt includes:
• a resistive heat layer that generates heat upon having electric current applied thereto;
• and
• a pair of electrode layers that receive electric current, each electrode disposed along a different one of widthwise edges of the heat-generating endless belt,
• the resistive heat layer has (i) reduced thickness portions each along a widthwise edge thereof and (ii) a middle portion between the reduced thickness portions, each reduced thickness portion being thinner than the middle portion and connected to the middle portion with a wall surface upright in a direction perpendicular to the rotation axis of the heat-generating endless belt to define a stair shape, and
• each electrode layer is disposed on the resistive heat layer to be in contact with a corresponding one of the wall surfaces.