Patent ID: 8909118

Claim:
A fusing device comprising: at least one heat source to generate heat; a fusing belt disposed near the heat source; a rotation unit contacting an outer circumference of the fusing belt; at least one pressurization unit to press toward the rotation unit such that a fusing nip is formed between the fusing belt and the rotation unit; a heat conductor contacting an inner surface of the fusing belt to conduct heat to the fusing nip; and an intermediate unit disposed between the pressurization unit and the heat conductor to prevent transmission of heat from the heat conductor to the pressurization unit, wherein a difference in height CRN_M between a central part of the intermediate unit and each of both ends of the intermediate unit satisfies the following equation: δ1+δ2 ≦CRN — M≦δ 1+δ2 +CRN — R wherein δ 1 represents a flexural level of each of both ends of the pressurization unit, when a pressure is applied to the pressurization unit; δ 2 represents a flexural level of each of both ends of the rotation unit, when a pressure is applied to the pressurization unit; and CRN_R represents R 2 −R 1 indicating a difference between a distance R 1 between the rotation center of the rotation unit and the central part of the rotation unit, and a distance R 2 between the rotation center of the rotation unit and the end of the rotation unit.