Electrophotographic member, heat fixing apparatus, and electrophotographic image forming apparatus
An electrophotographic member including a substrate, and an elastic layer on an outer peripheral surface of the substrate; wherein the elastic layer has silicone rubber, a tensile modulus of the elastic layer in a direction perpendicular to a thickness direction thereof is 0.20 MPa or less, a compressive modulus of the elastic layer in the thickness direction is 0.19 to 0.57 MPa, a value (tensile modulus/compressive modulus) of a ratio of the tensile modulus of the elastic layer in a direction perpendicular to the thickness direction, relative to the compressive modulus of the elastic layer in the thickness direction, is 0.80 or lower, and a rate of decrease of each of the compressive moduli of the samples from the elastic layer in a direction corresponding to the thickness direction of the elastic layer is 5% or lower.
1. An electrophotographic member comprising:
a substrate, and
an elastic layer on an outer peripheral surface of the substrate; wherein
the elastic layer comprises silicone rubber,
a tensile modulus of the elastic layer in a direction perpendicular to a thickness direction thereof is 0.20 MPa or less,
a compressive modulus of the elastic layer in the thickness direction is 0.19 to 0.57 MPa,
a value (tensile modulus/compressive modulus) of a ratio of the tensile modulus of the elastic layer in the direction perpendicular to the thickness direction, relative to the compressive modulus of the elastic layer in the thickness direction, is 0.80 or lower, and
with compressive moduli H0 to H100 as respective values of compressive modulus of a cuboid sample 50 mm long, 50 mm wide and 150 μm thick that is sampled from the elastic layer, in a direction corresponding to the thickness direction of the elastic layer, every 10 hours, up to 100 hours, in an atmosphere at a temperature of 240° C. and at an oxygen concentration of 1% or lower, a rate of decrease of each of the compressive moduli H10 to H100, relative to a compressive modulus H0 as a reference, is 5% or lower.
2. The electrophotographic member according to claim 1 , wherein the silicone rubber comprises a cured product of an addition-curable silicone rubber composition.
3. The electrophotographic member according to claim 1 , wherein a value (T unit/D unit) of a ratio of an integration value of a peak corresponding to a T unit, relative to an integration value of a peak corresponding to a D unit, in a chart obtained in an 29 Si-NMR measurement using the elastic layer as a sample, is 0.030 or higher.
4. The electrophotographic member according to claim 1 , wherein a total generation amount of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane, upon heating of the silicone rubber at 150° C. for 1 hour, is 1.5 ppm or larger.
5. The electrophotographic member according to claim 1 , wherein the elastic layer comprises a filler, and the filler content in the elastic layer is from 30 to less than 50 vol %, relative to the silicone rubber.
6. The electrophotographic member according to claim 5 , wherein
with binarized images having a size of 150 μm×100 μm as obtained at 5 sites in a first cross section of the elastic layer in thickness-circumferential directions, and with binarized images having a size of 150 μm×100 μm as obtained at 5 sites in a second cross section of the elastic layer in thickness-axial directions, an average value of area ratios of large particle filler having a circle-equivalent diameter of 5 μm or larger, in the total 10 binarized images, is 20 to 40%,
an average arrangement degree fL of the large particle filler is 0.00 to 0.15,
an average value of an area ratio of a small particle filler having a circle-equivalent diameter smaller than 5 μm, in the binarized images, is 10 to 20%,
an average arrangement degree fS of the small particle filler is 0.20 to 0.50, and
an average arrangement angle ΦS of the small particle filler is 60 to 120°.
7. The electrophotographic member according to claim 1 , wherein the electrophotographic member is a fixing member having an endless shape.
8. The electrophotographic member according to claim 1 , wherein the electrophotographic member is a pressing member having an endless shape.
9. A heat fixing apparatus in an electrophotographic image forming apparatus, the heat fixing apparatus comprising:
a fixing member and a pressing member disposed opposite the fixing member,
wherein at least one selected from the group consisting of the fixing member and the pressing member is the electrophotographic member according to claim 1 .
10. An electrophotographic image forming apparatus comprising a heat fixing apparatus, wherein
the heat fixing apparatus comprises a fixing member and a pressing member disposed opposite the fixing member, and at least one selected from the group consisting of the fixing member and the pressing member is the electrophotographic member according to claim 1 .