Device including rotator and belt, such as a fixing unit for an image forming apparatus

A device comprising:

• a rotator having a rotation axis;
• a belt configured to move in a moving direction orthogonal to the rotation axis;
• an upstream nip forming member configured to, with the rotator, pinch the belt to form an upstream nip;
• a first restricting member configured to restrict upward movement of the upstream nip forming member in the moving direction by contacting the upstream nip forming member;
• a downstream nip forming member configured to, with the rotator, pinch the belt to form a downstream nip, the downstream nip forming member being located downstream of the upstream nip forming member in the moving direction;
• a second restricting member configured to restrict downward movement of the downstream nip forming member in the moving direction by contacting the downstream nip forming member;
• a holder configured to hold each of the upstream nip forming member and the downstream nip forming member;
• and
• a spring attached to the holder and configured to urge the upstream nip forming member toward the first restricting member and the downstream nip forming member toward the second restricting member.