Image heating device and image forming apparatus using the same

An image heating device comprising:

• a heat-generating member comprising a rotatable body having conductivity;
• and
• an exciting coil arranged in opposition to the peripheral surface of the heat-generating member and adapted for allowing the heat-generating member to generate heat with electromagnetic induction;
• further comprising a core made of magnetic material arranged in a state in which the exciting coil is sandwiched between the core and the heat-generating member, the core has opposing portions opposed to the heat-generating member without sandwiching the exciting coil between the opposing portion and the heat-generating member, and magnetic permeable portions opposed to the heat-generating member via the exciting coil,
• wherein at least a part of the opposing portion is arranged in closer contact with the heat-generating member than the magnetic permeable portion, thereby forming an adjacent portion, and at least a part of the core has gaps in the direction of the rotation axis of the heat-generating member.

An image heating device comprising:

• a heat-generating member comprising a rotatable body having conductivity;
• and
• an exciting coil arranged in opposition to the peripheral surface of the heat-generating member and adapted for allowing the heat-generating member to generate heat with electromagnetic induction;
• further comprising a core made of magnetic material arranged in a state in which the exciting coil is sandwiched between the core and the heat-generating member, the core has opposing portions opposed to the heat-generating member without sandwiching the exciting coil between the opposing portion and the heat-generating member, and magnetic permeable portions opposed to the heat-generating member via the exciting coil,
• wherein the area of the portion where the opposing portion is opposed to the heat-generating member is larger than the cross sectional area of the magnetic permeable portion perpendicular to the circumferential direction of the heat-generation member.

An image heating device comprising:

• a heat-generating member comprising a rotatable body having conductivity;
• and
• an exciting coil arranged in opposition to the peripheral surface of the heat-generating member and-adapted for allowing the heat-generating member to generate heat with electromagnetic induction;
• further comprising a core made of magnetic material arranged in a state in which the exciting coil is sandwiched between the core and the heat-generating member,
• wherein a part of the core is divided, thereby forming a movable portion and the movable portion is held movably with respect to the remaining portion of the core.

An image heating device comprising:

• a fixing belt,
• a pressure means that is pressed against the fixing belt to form a nip portion on the right side of the fixing belt,
• a heat-generating roller having at least a part composed of a conductive member and movably suspending the fixing belt, and
• an exciting coil arranged in opposition to the peripheral surface of the heat-generating roller via the fixing belt and adapted for allowing the heat-generating roller to generate heat by exciting the portion where the heat-generating roller is in contact with the fixing belt.

An image heating device comprising:

• a fixing belt;
• a pressure means that is pressed against the fixing belt to form a nip portion on the right side of the fixing belt,
• a heat-generating roller made of magnetic material whose Curie temperature is set to be a predetermined value and movably suspending the fixing belt;
• a conductive member provided inside the heat-generating roller;
• and
• an exciting coil arranged in opposition to the peripheral surface of the heat-generating roller via the fixing belt and adapted for allowing the heat-generating roller to generate heat by exciting the portion where the heat-generating roller is in contact with the fixing belt.