Member for electrophotography and heat fixing device

1. A member for electrophotography, comprising:

a substrate;

an elastic layer containing a cured silicone rubber having a methyl group bonded to a silicon atom; and

a fluorine resin release layer bonded to a surface of the elastic layer by an addition-curing-type silicone rubber adhesive,

wherein the elastic layer contains a titanium oxide particle having an anatase-type crystal structure,

wherein a volume-average particle diameter of primary particles of the titanium oxide particle is from 20 nm to 40 nm, and

wherein the volume-average particle diameter is obtained from a sample cut out from the elastic layer.

2. The member for electrophotography according to claim 1 , wherein a content of the titanium oxide particle with respect to 100 parts by mass of the cured silicone rubber in the elastic layer is from 0.5 part by mass to 12.0 parts by mass.

3. The member for electrophotography according to claim 2 , wherein the content of the titanium oxide particle is from 6.0 parts by mass to 10.0 parts by mass.

4. The member for electrophotography according to claim 1 , wherein the elastic layer has a hardness increase ratio defined by Hμ1/Hμ0 of 1.0 to less than 1.5, where Hp denotes a microhardness of a sample cut out of the elastic layer, and HO denotes a microhardness of a rubber obtained by soaking the sample in a methyl hydrogen silicone oil for 24 hours, and then further curing the sample.

5. The member for electrophotography according to claim 1 , wherein:

the member for electrophotography has a belt shape in which the elastic layer is formed on an outer peripheral surface of an endless belt-shaped substrate; and

the elastic layer has a thickness of 100 μm to 500 μm.

6. The member for electrophotography according to claim 5 , wherein the elastic layer has a thickness of 200 μm to 500 μm.

7. The member for electrophotography according to claim 1 , wherein:

the member for electrophotography has a roller shape in which the elastic layer is formed on a peripheral surface of a mandrel as the substrate; and

the elastic layer has a thickness of 300 μm to 10 mm.

8. The member for electrophotography according to claim 7 , wherein the thickness of the elastic layer is from 1 mm to 5 mm.

9. The member for electrophotography according to claim 1 , wherein the fluorine resin release layer contains a compound selected from the group consisting of a tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer, polytetrafluoroethylene, and a tetrafluoroethylene-hexafluoropropylene copolymer.

10. A heat fixing device, which is configured to fix an unfixed toner image formed on a recording medium onto the recording medium through heating and pressurization,

wherein, the heat fixing device comprises a member for electrophotography comprising:

a substrate;

an elastic layer containing a cured silicone rubber having a methyl group bonded to a silicon atom; and

a fluorine resin release layer bonded to a surface of the elastic layer by an addition-curing-type silicone rubber adhesive,

wherein the elastic layer contains a titanium oxide particle having an anatase-type crystal structure,

wherein a volume-average particle diameter of primary particles of the titanium oxide particle is from 20 nm to 40 nm, and

wherein the volume-average particle diameter is obtained from a sample cut out from the elastic layer.