Fixing device

A fixing device comprising:

• an endless fixing belt configured to heat a recording material;
• a pressure member configured to press the fixing belt;
• and
• a sliding member configured to be in sliding contact with an inner peripheral surface of the fixing belt and being opposed to the pressure member,
• wherein the pressure member and the fixing belt form a fixing nip portion, and heat and pressure are applied to the recording material at the fixing nip portion to fix a toner image onto the recording material,
• wherein the sliding member includes a plurality of protrusions on a surface of the sliding member that is in sliding contact with the inner peripheral surface of the fixing belt, and
• wherein the following expressions are satisfied:
• 1Pd2≤0.8 [N (Newton)] (1)
• 1≤15.6×(Pd4)/(Et3) [mm] (2)
• where P [MPa] represents a pressure on the fixing nip portion, E [MPa] represents a Young's modulus of the fixing belt, t [mm] represents a thickness of the fixing belt, and d [mm] represents a distance between the plurality of protrusions in a sheet width direction of the recording material.