FIXATION DEVICE AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide a fixation device in which a sheet member is hardly torn in a case where both end sides in the longitudinal direction of the sheet member that is held between a heating belt and a pressing member pressing the heating belt to a pressure body and has heat shrinkability shrink in the longitudinal direction following the fixation operation.SOLUTION: A fixation device includes: a heating belt; a heat source which applies heat to the heating belt; a pressure body which forms a nip with the heating belt, rotates the heating belt, and presses a medium formed with an image with the heating belt; a pressing member 75 which is arranged in the heating belt with the longitudinal direction made to be along the axis of the pressure body, and presses a formation part for forming the nip of the heating belt to the pressure body; and a sheet member 76 which is held between the formation part and the pressing member 75 in the state where the longitudinal direction is along the axis, is fixed at at least portions on the center side and both end sides in the longitudinal direction of the portions other than a portion between the formation part and the pressing member, and in which the portions on both end sides can be displaced largely in the longitudinal direction with respect to the portion on the center side.SELECTED DRAWING: Figure 4 【課題】本発明は、加熱ベルトと加熱ベルトを加圧体に押付ける押付部材との間に挟まれ、熱収縮性を有するシート部材の長手方向の両端側が定着動作に伴い長手方向に縮んだ場合、シート部材が裂け難い定着装置の提供を目的とする。【解決手段】定着装置は、加熱ベルトと、加熱ベルトに熱を付与する熱源と、加熱ベルトとでニップを形成し、加熱ベルトを周回させ、加熱ベルトとで像が形成された媒体を加圧する加圧体と、長手方向を加圧体の軸に沿わせて加熱ベルト内に配置され、加熱ベルトのニップを形成する形成部分を加圧体に押付ける押付部材７５と、長手方向を前記軸に沿わせた状態で形成部分と押付部材７５と間に挟まれ、前記間の部分以外の部分における少なくとも長手方向の中央側及び両端側の部分で固定され、両端側の部分は中央側の部分よりも長手方向に大きくずれることが可能なシート部材７６と、を備えている。【選択図】図４