Structure for electrically protecting fixing apparatus provided in image forming apparatus

An image forming apparatus comprising:

• a metal frame configured to provide a ground potential;
• an image forming unit configured to form a toner image on a sheet;
• a fixing apparatus configured to fix the toner image on the sheet, the fixing apparatus comprising:
• a heater, the heater including
• a substrate,
• a heating element configured to generate heat by being supplied with power from an alternating current power source and provided on a first surface side of the substrate,
• a first insulating layer provided on the first surface side of the substrate and covering the heating element,
• a conductive layer provided on a second surface side of the substrate opposite from the first surface side of the substrate, and
• a second insulating layer provided on the second surface side of the substrate and covering the conductive layer;
• a tube-shaped member configured to be heated by the heating element;
• a pressing member arranged opposing the tube-shaped member and configured to form a nip portion in cooperation with the tube-shaped member;
• and
• a capacitive element whose one end is connected to the metal frame and whose other end is connected to the conductive layer of the fixing apparatus,
• wherein the second surface side of the substrate opposes an inner circumferential surface of the tube-shaped member, and
• wherein the inner circumferential surface of the tube-shaped member slides with the second insulating layer.