Image heating apparatus

摘要

An image heating apparatus includes: a rotating mechanism for rotating a belt unit in a direction for returning a belt into a predetermined zone; a displacing mechanism for permitting a first supporting member to be displaced in a direction for substantially equalizing forces, from the first supporting member, urging the belt toward a rotatable heating member at opposite end portions of the first supporting member with respect to a belt widthwise direction and to permit a second supporting member to be displaced in a direction for substantially equalizing forces, from the second supporting member, urging the belt toward the rotatable heating member at opposite end portions of the second supporting member; and a limiting mechanism for limiting the amount of the displacement permitted by the displacing mechanism within a predetermined amount.

主权项

1. An image heating apparatus comprising:
a rotatable heating member configured to heat a toner image on a recording material; a belt unit including an endless belt configured and positioned to contact said rotatable heating member to heat said rotatable heating member, and first and second supporting members rotatably supporting an inner surface of said belt and configured to urge said belt to said rotatable heating member; a detector configured and positioned to detect that said belt is deviated from a predetermined zone with respect to a widthwise direction said belt; a rotating mechanism configured to rotate said belt unit in a direction for returning said belt into the predetermined zone on a basis of an output of said detector; a displacing mechanism configured to permit said first supporting member to be displaced, with rotation of said belt unit by said rotating mechanism, in a direction for substantially equalizing forces, from said first supporting member, urging said belt toward said rotatable heating member at opposite end portions of said first supporting member with respect to the widthwise direction and to permit said second supporting member to be displaced, with the rotation of said belt unit by said rotating mechanism, in a direction for substantially equalizing forces, from said second supporting member, urging said belt toward said rotatable heating member at opposite end portions of said second supporting member with respect to the widthwise direction; and a restricting mechanism configured to restrict displacement of said first supporting member beyond a first predetermined position and to restrict displacement of said second supporting member beyond a second predetermined position, wherein the first predetermined position is outside an area in which said first supporting member is displaceable with the rotation of said belt unit by said rotating mechanism, and the second predetermined position is outside an area in which said second supporting member is displaceable with the rotation of said belt unit by said rotating mechanism.