Fixing apparatus having uniform surface potential difference between fixing film and pressure roller and image forming apparatus thereof

A fixing apparatus comprising:

• a cylindrical flexible member;
• a heater disposed in an interior space of the cylindrical flexible member, the heater including a substrate and a heating element provided on the substrate;
• a pressure roller configured to contact an outer circumferential surface of the cylindrical flexible member and, in cooperation with the heater, to form a nip portion between the cylindrical flexible member and the pressure roller, wherein a recording material bearing an image is nipped and conveyed at the nip portion and the image is fixed to the recording material at the nip portion;
• a first contact member configured to contact an inner circumferential surface of the cylindrical flexible member and to electrically ground the cylindrical flexible member;
• and
• a second contact member configured to contact an outer circumferential surface of the pressure roller and to electrically ground the pressure roller,
• wherein, when a recording material having a maximum width in a longitudinal direction of the heater passes through the nip portion, a region of the nip portion through which the recording material passes is defined as a first region and another region of the nip portion through which the recording material does not pass is defined as a second region,
• wherein the first contact member contacts the inner circumferential surface of the cylindrical flexible member at a position corresponding to the first region in the longitudinal direction, and
• wherein the second contact member contacts the outer circumferential surface of the pressure roller at a position corresponding to the second region in the longitudinal direction.