Pressing device, fixing device, and image forming apparatus incorporating fixing device
A fixing device includes a rotator, a secured member, a pressure rotator, and lubricant. The rotator has flexibility and a sleeve form. The rotator includes an inner portion having a sliding surface. The inner portion has an elastic power of 55% or more. The secured member is disposed inside a loop of the rotator and has a slide surface on which the sliding surface of the rotator slides. The slide surface has a larger hardness than a hardness of the sliding surface of the rotator. The pressure rotator presses the rotator against the secured member and forms a nip between the rotator and the pressure rotator. The lubricant is provided between the rotator and the secured member.
1. A pressing device comprising:
a rotator having flexibility and a sleeve form, the rotator including an inner portion having a sliding surface, the inner portion having an elastic power of 55% or more;
a secured structure being disposed inside a loop of the rotator, the secured structure having a slide surface on which the sliding surface of the rotator is to slide, the slide surface having a larger hardness than a hardness of the sliding surface of the rotator;
a pressure rotator to press the rotator against the secured structure and form a nip between the rotator and the pressure rotator; and
lubricant provided between the rotator and the secured structure,
wherein the slide surface of the secured structure has an arithmetic average roughness of 0.05 μm or less.
2. The pressing device according to claim 1 ,
wherein the elastic power of the inner portion of the rotator is 63% or more.
3. The pressing device according to claim 1 ,
wherein the secured structure includes a heater.
4. The pressing device according to claim 3 ,
wherein the heater is a planar heater including heat generators arranged in a longitudinal direction of the heater.
5. The pressing device according to claim 1 ,
wherein the lubricant includes at least one of fluorine grease or silicone oil.
6. The pressing device according to claim 1 ,
wherein the inner portion of the rotator includes polyimide.
7. The pressing device according to claim 1 ,
wherein the sliding surface of the rotator has an arithmetic average roughness of 0.2 μm or more.
8. The pressing device according to claim 1 ,
wherein the sliding surface of the rotator has a valley void volume of 0.01 ml/m 2 or more.
9. The pressing device according to claim 1 ,
wherein the sliding surface of the rotator has a skewness equal to or smaller than zero.
10. The pressing device according to claim 1 ,
wherein the sliding surface of the rotator has a kurtosis equal to or smaller than three.
11. The pressing device according to claim 1 ,
wherein a portion including the slide surface of the secured structure is made of glass.
12. The pressing device according to claim 1 ,
wherein the rotator comprises a base, a surface layer, and an adhesive layer.
13. The pressing device according to claim 1 ,
wherein the pressure rotator includes a solid rubber and has a thermal conductivity from 0.2 to 2.5 W/m·k in a longitudinal direction of the pressure rotator.
14. The pressing device according to claim 1 ,
wherein a difference between a coefficient of static friction and a coefficient of kinetic friction in the sliding surface of the rotator is 0.14 or less.
15. A fixing device comprising
the pressing device according to claim 1 .
16. An image forming apparatus comprising
the fixing device according to claim 15 .