Fixing device and image forming apparatus including the same

A fixing device comprising:

• a heat generating member formed of a magnetic shunt alloy and having a thickness less than a magnetic-field permeation depth at a temperature higher than or equal to a Curie temperature of the heat generating member;
• a flexible fixing belt member configured to rotate on an axis extending in a width direction of a recording medium to be conveyed while being in contact with the heat generating member, the fixing belt member being operable in fixing a toner image on the recording medium by heating;
• a coil provided along the fixing belt member, the coil configured for generating magnetic flux that penetrates the fixing belt member so as to subject the heat generating member to induction heating;
• and
• an electrically conductive arch-shaped saddle ring member, the ring member being disposed at a position opposing the coil with the heat generating member being disposed therebetween and in an orientation such that magnetic flux leakage associated with loss of ferromagnetism of the heat generating member penetrates the ring member.

An image forming apparatus comprising:

• an image forming section configured to form a toner image;
• a transfer section that is operable to transfer the toner image onto a recording medium to be conveyed;
• and
• a fixing device that is operable to fix the transferred toner image on the recording medium,
• wherein the fixing device includes:
• a rotating fixing body configured to rotate on an axis extending in a width direction of the recording medium and configured to fix the toner image on the recording medium by heating, the rotating fixing body having a cylindrical metal core formed of a magnetic shunt alloy and having a thickness less than a magnetic-field permeation depth at a temperature higher than or equal to a Curie temperature of the metal core,
• a coil provided along an outer surface of the rotating fixing body, the coil operable for generating magnetic flux that subjects the rotating fixing body to induction heating, and
• an electrically conductive arch-shaped saddle ring member, the ring member being fixed at a position opposing the coil with the metal core being disposed therebetween and in an orientation such that magnetic flux leakage associated with loss of ferromagnetism of the metal core penetrates the ring member.

An image forming apparatus comprising:

• an image forming section configured to form a toner image;
• a transfer section operable to transfer the toner image onto a recording medium to be conveyed;
• and
• a fixing device operable to fix the transferred toner image on the recording medium,
• wherein the fixing device includes:
• a heat generating member formed of a magnetic shunt alloy and having a thickness less than a magnetic-field permeation depth at a temperature higher than or equal to a Curie temperature of the heat generating member,
• a flexible fixing belt member configured to rotate on an axis extending in a width direction of the recording medium while being in contact with the heat generating member, the fixing belt member being operable in fixing the toner image on the recording medium by heating,
• a coil provided along the fixing belt member, the coil operable for generating magnetic flux that penetrates the fixing belt member so as to subject the heat generating member to induction heating, and
• an electrically conductive arch-shaped saddle ring member, the ring member being disposed at a position opposing the coil with the heat generating member being disposed therebetween and in an orientation such that magnetic flux leakage associated with loss of ferromagnetism of the heat generating member penetrates the ring member.