Heat fixing belt, method for producing heat fixing belt, and image fixing device

1. A heat fixing belt comprising a tubular belt base formed of an insulative heat-resistant resin, an elastic resistive heat generation layer containing a conductive material and formed of an elastic base material including an elastic material, a toner release layer, and a pair of electrode layers to feed power to the elastic resistive heat generation layer,

wherein:

the elastic resistive heat generation layer is provided on an outer circumferential surface of the belt base;

the toner release layer is provided as an outermost layer; and

the pair of electrode layers are provided at both side end portions of an outer circumferential surface of the elastic resistive heat generation layer and have a volume resistance value that is lower than a volume resistance value of the elastic resistive heat generation layer.

2. The heat fixing belt of claim 1 , wherein the elastic resistive heat generation layer has a volume resistivity of 1.0×10−3 Ω·cm or higher and 1.0×103 Ω·cm or lower.

3. The heat fixing belt of claim 1 , further comprising an elastic layer between the elastic resistive heat generation layer and the toner release layer, the elastic layer being in contact with the elastic resistive heat generation layer and the toner release layer.

4. The heat fixing belt of claim 1 , wherein the elastic material is fluorocarbon rubber, silicone rubber, fluorosilicone rubber, hydrogenated nitrile rubber, or a combination thereof.

5. The heat fixing belt of claim 4 , wherein the elastic material is fluorocarbon rubber alone, a mixture of fluorocarbon rubber and one of silicone rubber, fluorosilicone rubber and hydrogenated nitrile rubber, fluorosilicone rubber alone, or a mixture of fluorosilicone rubber and one of silicone rubber and hydrogenated nitrile rubber.

6. The heat fixing belt of claim 1 , wherein the pair of electrode layers each have a volume resistance value of 1.0×10−3 Ω·cm or lower.

7. The heat fixing belt of claim 1 , wherein:

the pair of electrode layers are formed of binder containing metallic particles, respectively;

the binder includes an elastic base material of a same type as that of an elastic base material of the elastic resistive heat generation layer; and

the pair of electrode layers and the elastic resistive heat generation layer are coupled directly without using an adhesive.

8. The heat fixing belt of claim 1 , wherein the elastic base material further includes a heat-resistant material other than the elastic material.

9. The heat fixing belt of claim 8 , wherein the heat-resistant material is polyphenylene sulfide, polyimide, polyamide-imide, polyether ether ketone or fluorine resin.

10. A method for manufacturing a heat fixing belt, comprising the steps of:

preparing coating material for an elastic base material containing curing agent and a heat-resistant elastic material;

preparing dispersion of a conductive material;

mixing the coating and the dispersion to obtain an elastic resistive heat generation layer material;

applying the elastic resistive heat generation layer material to an outer circumferential surface of a tubular belt base formed of an insulative heat-resistant resin and drying to form an elastic resistive heat generation layer that has not been cured;

applying an electrode material to both side end portions of an outer circumferential surface of the elastic resistive heat generation layer that has not been cured, drying, and thermally curing to form, on the belt base, an elastic resistive heat generation layer containing the conductive material and the elastic material and a pair of electrode layers to feed power to the elastic resistive heat generation layer, which having a volume resistance value that is lower than a volume resistance value of the elastic resistive heat generation layer; and

forming a toner release layer on an outermost layer.

11. An image fixing device to heat unfixed toner on a support to form a toner image, the device comprising:

the heat fixing belt of claim 1 ;

pressure rolls whose central axis is parallel to each other and which are disposed opposite to the heat fixing belt to sandwich the support between circumferential surfaces thereof; and

a pair of power feed sections configured to feed power to each of the pair of electrode layers.