Drum unit and image forming apparatus

A drum unit comprising:

• a photosensitive drum rotating around a rotation axis extending along a rotation axis direction;
• and
• a heater installed inside the photosensitive drum and heating the photosensitive drum, wherein
• the heater includes:
• a heater substrate extending along the rotation axis direction;
• and
• a plurality of resistance elements aligned in the rotation axis direction and mounted on the heater substrate,
• the drum unit further comprising:
• a flange attached to an end portion of the photosensitive drum at an outside in the rotation axis direction;
• and
• a supporter extending along the rotation axis direction and penetrating through the flange, wherein
• the heater is supported by the supporter,
• the drum unit further comprising:
• a connector arranged at an outside of the photosensitive drum;
• and
• a wire connecting the heater to the connector, wherein
• the supporter is formed in a tubular shape,
• the wire passes through an inside of the supporter,
• the heater is supported by the supporter in a cantilever manner,
• the drum unit further comprising a cylindrical heater cover covering an outer circumference of the heater,
• on an end portion at an inside in the rotation axis direction of an outer circumferential face of the supporter, an annular fitting groove is provided, and an end portion at the outside in the rotation axis direction of the heater cover is fitted into the fitting groove, and
• at an end portion at the inside in the rotation axis direction of the supporter, a pair of split grooves are provided at both sides of the fitting groove, and an end portion at the outside in the rotation axis direction of the heater substrate is inserted into the pair of split grooves.