Temperature detection apparatus having a base member that moves in a thickness direction of a heater, fixing apparatus, and image forming apparatus

A fixing apparatus configured to fix a toner image to a recording material in a nip portion, the fixing apparatus comprising:

• a first rotary member;
• a nip forming member provided in an inner space of the first rotary member;
• a second rotary member configured to be in contact with an outer circumferential surface of the first rotary member such that the first rotary member is interposed between the second rotary member and the nip forming member, and thus form the nip portion between the first rotary member and the second rotary member;
• a temperature detection element configured to detect a temperature of the nip forming member;
• a holder configured to hold the temperature detection element;
• and
• an urging member configured to urge the holder toward the nip forming member to bring the holder into contact with the nip forming member,
• wherein the holder includes
• a base member configured to receive an urging force from the urging member, and
• a head member to which the temperature detection element is attached, the head member being configured to be in contact with the base member and tiltable with respect to the base member with a contact portion between the head member and the base member as a fulcrum, and
• wherein the head member is configured to be urged toward the nip forming member by the urging force and to tilt following a portion of the nip forming member opposing the head member,
• wherein the nip forming member includes
• a heater that is provided with a heating element configured to heat the nip portion and has a plate shape elongated in a longitudinal direction, and
• a heater holder configured to hold the heater and form the nip portion, and
• wherein the base member is engaged with the heater holder to be positioned in the longitudinal direction and a short direction of the heater with respect to the heater holder, while the base member is allowed to move in a thickness direction of the heater with respect to the heater holder.