Image fixing device and image forming apparatus having the same

An image forming apparatus comprising an image fixing device which is configured to apply heat and pressure to a printing medium passing through a fixing nip and thus to fix a non-fixed image on the printing medium, the image fixing device comprising:

• a heat source configured to generate heat;
• a fixing belt heated by the heat source and disposed to be in contact with a surface of the printing medium having a non-fixed image and to transfer heat thereto;
• a rotational member disposed to be in pressure contact with an outer circumferential surface of the fixing belt;
• a pressure member disposed in the fixing belt to press the fixing belt to the rotational member;
• and
• a supporting member pressed by the pressure member so as to form the fixing nip between the fixing belt and the rotational member and to support an inner circumferential surface of the fixing belt, the supporting member comprising:
• a supporting surface to support the pressure member and the inner circumferential surface of the fixing belt;
• and
• a plurality of heat insulation grooves which are formed to be relatively more concave than the supporting surface.

An image fixing device comprising:

• a fixing belt disposed to be rotatable;
• a rotational member disposed to pressure an outer circumferential surface of the fixing belt;
• a supporting member to support an inner circumferential surface of the fixing belt so as to form a fixing nip between the fixing belt and the rotational member;
• and
• a pressure member to press the supporting member to the fixing belt,
• wherein the supporting member comprises:
• a base part disposed in the fixing belt in a length direction of the fixing belt;
• and
• a plate insulation part to reduce thermal conductivity of the supporting member and comprising a nip forming part extending and protruding from the base part so as to form the fixing nip, and a plurality of heat insulation grooves formed in the nip forming part to receive air.