Image fixing apparatus with heater and heater holder contacting the heater
The image fixing apparatus includes a heater having a heat generating resistor on a substrate, a heater holder for holding said heater, and a backup roller for forming a nip portion in cooperation with said heater, wherein said heater holder has, in a direction along a short side of said heater, a contact area facing said resistor forming area and coming into contact with said heater, and non-contact areas provided on both sides of the contact area and not coming into contact with said heater, and the contact area has a width equal to or larger than the resistor forming area. With this configuration, it is possible to provide the image fixing apparatus capable of restraining a stress applied to the heater and an image heating apparatus capable of restraining a rise in temperature of a sheet non-feeding portion.
1. An image fixing apparatus comprising:
a heater having a heat generating resistor on a substrate;
a heater holder for holding said heater; and
a backup roller for forming a nip portion in cooperation with said heater,
wherein said heater holder includes, in a direction along a short side of said heater, a contact area facing a resistor forming area of said heater and coming into contact with said heater, and non-contact areas provided on both sides of the contact area, the non-contact areas facing said heater without contacting said heater,
wherein the contact area has a width equal to or larger than the resistor forming area in a direction along the short side of said heater, and
wherein the contact area and the non-contact areas in said heater holder overlap a whole of the resister forming area of said heater in a longitudinal direction of said heater.
2. An image fixing apparatus according to claim 1 , wherein said heater holder further includes second contact areas not facing the resistor forming area and coming into contact with said heater on both sides of the non-contact area.
3. An image fixing apparatus according to claim 1 , wherein said resistors for heat generation are disposed in symmetry with respect to a center in a direction along the short side of said substrate.
4. An image fixing apparatus according to claim 1 , wherein said heater holder further includes wider contact areas at both end portions of said heater holder in the longitudinal direction of said heater, the wider contact areas each having a wider contact width in the direction along the short side of said heater than the contact areas facing the resistor forming area.
5. An image fixing apparatus according to claim 4 , wherein a part of the wider contact areas exist within an area of the nip portion.
6. An image fixing apparatus according to claim 1 , further comprising a flexible sleeve rotating while its internal peripheral surface is brought into contact with said heater,
wherein a recording material bearing an unfixed image passes through between said flexible sleeve and said backup roller.