FIXATION DEVICE AND IMAGE FORMATION APPARATUS

PROBLEM TO BE SOLVED: To provide a fixation device which can suppress the temperature unevenness when induction-heating a heating rotor even if the heating rotor is in the non-rotation state or low-speed rotation state.SOLUTION: A fixation device includes: a heating rotor 11 which generates heat with the induction current; an exciting coil 122 which is arranged on the outer side of the heating rotor 11; a pressure roller 10 which rotates while holding the sheet developed with a toner image between the heating rotor 11 and itself; and a relative position change unit which changes the relative position between the exciting coil 122 and the heating rotor 11 to the first relative position when fixing the toner image on the sheet and changes the relative position to the second relative position when not fixing the toner image on the sheet. The distance from the point closest to the pressure roller 10 on the outer peripheral surface of the heating rotor 11 to the exciting coil 122 is shorter in the second relative position with respect to the first relative position on the cross section vertical to the rotational shaft of the heating rotor 11.SELECTED DRAWING: Figure 7 【課題】加熱回転体が非回転状態または低速回転状態であっても、加熱回転体を誘導加熱する際の温度ムラを抑制できる定着装置を提供する。【解決手段】定着装置は、誘導電流により発熱する加熱回転体１１と、加熱回転体１１の外部に配置された励磁コイル１２２と、トナー像が現像された用紙を加熱回転体１１との間で挟持しながら回転する加圧ローラー１０と、励磁コイル１２２と加熱回転体１１との相対位置を、トナー像を用紙に定着させるときには第１相対位置に変化させ、トナー像を用紙に定着させないときには第２相対位置に変化させる相対位置変更部とを備える。加熱回転体１１の回転軸に垂直な断面において、加熱回転体１１の外周面における加圧ローラー１０に最も近い点から励磁コイル１２２までの距離は、第１相対位置よりも第２相対位置の方が短い。【選択図】図７