Image heating apparatus and image forming apparatus

An image heating apparatus comprising:

• a rotatable heating member configured to heat a toner image on a sheet;
• a belt unit including an endless belt configured to heat said rotatable heating member in contact with an outer surface of said rotatable heating member, and a supporting roller configured to rotatably support an inner surface of said endless belt;
• a contact portion configured to contact a widthwise edge of said endless belt;
• an urging portion configured to urge said contact portion toward the widthwise edge of said endless belt;
• a detecting portion configured to detect a widthwise position of said endless belt depending on a position of said contact portion;
• a tilting portion configured to tilt, on the basis of an output of said detecting portion, said belt unit so that an axis of said supporting roller placed in a state in which said supporting roller presses said endless belt against said rotatable heating member crosses with a generatrix of said rotatable heating member;
• and
• a retracting portion configured to retract said contact portion from said endless belt against an urging force of said urging portion.

An image heating apparatus comprising:

• a rotatable heating member configured to heat a toner image on a sheet;
• an endless belt configured to heat said rotatable heating member in contact with an outer surface of said rotatable heating member;
• two supporting rollers configured to rotatably support an inner surface of said endless belt;
• a holding portion configured to hold said endless belt and said two supporting rollers;
• a contact portion configured to contact a widthwise edge of said endless belt;
• an urging portion configured to urge said contact portion toward the widthwise edge of said endless belt;
• a detecting portion configured to detect a widthwise position of said endless belt depending on a position of said contact portion;
• and
• a swinging portion configured to swing, on the basis of an output of said detecting portion, said holding portion so that said two supporting rollers placed in a state in which said two supporting rollers press said endless belt against said rotatable heating member cross as a unit with said rotatable heating member.

An image forming apparatus comprising:

• a belt unit including an endless belt and a supporting portion configured to rotatably support an inner surface of said endless belt;
• a rotatable driving member configured to rotate said endless belt by rotation thereof in contact with an outer surface of said endless belt;
• a contact portion configured to contact a widthwise edge of said endless belt;
• an urging portion configured to urge said contact portion toward the widthwise edge of said endless belt;
• a detecting portion configured to detect, that said endless belt is out of a predetermined zone, depending on a position of said contact portion;
• a tilting portion configured to tilt said belt unit in a direction of causing said endless belt to return into the predetermined zone on the basis of an output of said detecting portion;
• and
• a retracting portion configured to retract said contact portion from said endless belt against an urging force of said urging portion.

An image forming apparatus comprising:

• a belt unit including an endless belt and a supporting roller configured to rotatably support an inner surface of said endless belt;
• a rotatable driving member configured to rotate said endless belt by rotation thereof in contact with an outer surface of said endless belt;
• a contact portion configured to contact a widthwise edge of said endless belt;
• an urging portion configured to urge said contact portion toward the widthwise edge of said endless belt;
• a detecting portion configured to detect a widthwise position of said endless belt depending on a position of said contact portion;
• a tilting portion configured to tilt, on the basis of an output of said detecting portion, said belt unit so that an axis of said supporting roller placed in a state in which said supporting roller presses said endless belt against said rotatable heating member crosses with a generatrix of said rotatable heating member;
• and
• a retracting portion configured to retract said contact portion from said endless belt against an urging force of said urging portion.

An image forming apparatus comprising:

• an endless belt:
• two supporting rollers configured to rotatably support an inner surface of said endless belt;
• a rotatable heating member configured to rotate said endless belt by rotation thereof in contact with an outer surface of said endless belt;
• a holding portion configured to hold said endless belt and said two supporting rollers;
• a contact portion configured to contact a widthwise edge of said endless belt;
• an urging portion configured to urge said contact portion toward the widthwise edge of said endless belt;
• a detecting portion configured to detect a widthwise position of said endless belt depending on a position of said contact portion;
• and
• a swinging portion configured to swing, on the basis of an output of said detecting portion, said holding portion so that said two supporting rollers placed in a state in which said two supporting rollers press said endless belt against said rotatable heating member cross as a unit with said rotatable heating member.