Fixing device and image forming apparatus

A fixing device comprising:

• a cylindrical heat roller;
• a plurality of heaters disposed inside the heat roller, extending along a longitudinal axis of the heat roller;
• and
• a heat adjuster, disposed among the plurality of heaters, to adjust heat from one to another of the plurality of heaters, the heat adjuster comprising glass.

A fixing device comprising:

• a cylindrical heat roller;
• a plurality of heaters including at least three heaters disposed inside the heat roller, extending along a longitudinal axis of the heat roller;
• and
• a heat adjuster, disposed among the plurality of heaters, to absorb heat from one to another of the plurality of heaters, the heat adjuster having a polygonal shape bounded by five or more line segments.