Fixing device having sheet separation members which are displaced by different amounts according to a change in diameter of a heated rotator, and image forming apparatus

An image forming apparatus configured to fix a toner image to a sheet by heat, the image forming apparatus comprising:

• a first rotator;
• a second rotator contacting with a rotating surface of said first rotator;
• a heating unit configured to heat said first rotator during operation of said first rotator such that the heat is transferred to said sheet passing through a first contact portion between said first rotator and said second rotator;
• a plurality of separation members configured to separate said sheet from said first rotator such that said sheet passing through said first contact portion is not caught in said first rotator, said plurality of separation members being provided opposite to the rotating surface of said first rotator;
• a holding member provided opposite to said first rotator, said plurality of separation members being provided in said holding member;
• an abutment member provided in said holding member and in contact with said first rotator;
• and
• an adjustor,
• wherein said abutment member, said holding member, and said plurality of separation members operate in conjunction with a change in diameter of said first rotator at a second contact portion between said first rotator and said abutment member, the change in diameter of said first rotator being caused by thermal expansion of said first rotator which occurs when said heating unit heats said first rotator during the operation of said first rotator,
• wherein said adjustor, during the operation of said first rotator, limits a displacement of a first separation member of said plurality of separation members in a direction separating from said first rotator to be smaller than a displacement of a second separation member of said plurality of separation members in the direction, the displacement of the first separation member and the displacement of the second separation member being displacements which occur in accordance with the change in diameter of said first rotator during the operation of said first rotator,
• wherein said first separation member is provided opposite to a first area, said first area being an area through which a sheet of a first size passes at said first contact portion, and
• wherein said second separation member is provided opposite to a second area, said second area being an area through which a sheet of a second size larger than said first size passes at said first contact portion, and said second area being different from said first area.