IMAGE HEATING DEVICE

PROBLEM TO BE SOLVED: To provide an image heating device capable of reducing the temperature rise at an end and is compatible with sheets having various width sizes in an image heating device 40 that holds and conveys a sheet P carrying a toner image T at a nip part N while heating the toner image.SOLUTION: An image heating device comprises: a first rotor 41 that is cylindrical; a metal member 47 that is fixedly provided therein and is cylindrical; a heating body 43 and a reflection member 43 that reflects radiant heat from the heating body toward an inner surface of the metal member; a backup member 46 that is in contact with an inner surface of the metal member; and a second rotor 44 that contacts with the metal member 47 with the first rotor interposed therebetween at a position opposite to the backup member to form a nip part between the first rotor and the second rotor. The backup member 46 thermally deforms in a direction of reducing the area of a contact region between the metal member 47 and the first rotor at a nip part or a nip adjacent part corresponding to a sheet non-passing part in accordance with the temperature rise at an end caused by continuous introduction of sheets smaller in width than a maximum width sheet that can be used in apparatus.SELECTED DRAWING: Figure 1 【課題】トナー像Ｔを担持したシートＰをニップ部Ｎで挟持搬送してトナー像を加熱する画像加熱装置４０において、端部昇温を低減し、かつ、さまざまな幅サイズのシートに対応が可能な画像加熱装置を提供する。【解決手段】筒状の第１の回転体４１と、その内側に固設された、筒状の金属部材４７発熱体４３および発熱体からの輻射熱を金属部材の内面に向けて反射する反射部材４３と、金属部材の内面に当接するバックアップ部材４６と、これと対向する位置において第１の回転体を介して金属部材４７と当接して第１の回転体との間にニップ部を形成する第２の回転体４４と、を有する。バックアップ部材４６は、装置に使用可能な最大幅シートよりも幅が小さいシートが連続的に導入されることにより生じる端部昇温に応じて、シート非通過部に対応するニップ部及びニップ部近傍部における金属部材４７と第１の回転体との接触領域の面積が減少する方向に熱変形を生じる。【選択図】図１