Fixing device having reduced increase in rotational torque of second rotatable member providing an image with reduced unevenness in gloss to be formed and image forming apparatus using the same

A fixing device comprising:

• a first rotatable member;
• a second rotatable member disposed in contact with the first rotatable member;
• a pressing member that is disposed on an inner circumferential surface of the second rotatable member and presses the inner circumferential surface of the second rotatable member such that the second rotatable member is pressed against the first rotatable member;
• a sliding member interposed between the inner circumferential surface of the second rotatable member and the pressing member;
• and
• a lubricant interposed between the inner circumferential surface of the second rotatable member and the sliding member,
• wherein the inner circumferential surface of the second rotatable member contains a resin having at least one group selected from the group consisting of an amido group, an imido group, a ketone group, and a sulfide group,
• wherein a sliding surface of the sliding member contains (A) a heat resistant thermoplastic resin and (B) a resin having a siloxane group,
• wherein the lubricant contains an oil having a siloxane group in a main chain,
• wherein the heat resistant thermoplastic resin is at least one resin selected from the group consisting of polyether ether ketone resins, polyphenylene sulfide resins, polyetherimide resins, polyphenylsulfone resins, polyethersulfone resins, and polysulfone resins,
• wherein the heat resistant thermoplastic resin is not a fluorocarbon resin,
• wherein the resin having a siloxane group is at least one selected from the group consisting of thermosetting silicone resin particles and silicone oil gums, silicone elastomers, and siloxane-modified polyetherimides.