Fixing rotating member, fixing apparatus, electrophotographic image forming apparatus, and method for producing fixing rotating member
A fixing rotating member comprising a base layer, an elastic layer and a surface layer, in this order, the surface layer containing PFA and PFPE, and having pores with openings at a first surface; at least part of the pores containing the PFPE, wherein when after removing the PFPE in the pores, placing a first observation region on the first surface, defining a ratio of a sum of areas of the openings in the first observation region relative to an area of the first observation region as P 1 ; and placing a second observation region in a cross section of the surface layer, and defining a ratio of a sum of areas of the pores in the second observation region relative to an area of the second observation region as P 2 , P 2 /P 1 is 1.3 or higher.
1. A fixing rotating member comprising a base layer, an elastic layer and a surface layer, in this order,
the surface layer containing a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and a perfluoropolyether;
the surface layer having pores with openings at a first surface thereof constituting an outer surface of the fixing rotating member; and
at least part of the pores containing the perfluoropolyether,
wherein:
when a first observation region 8 μm long×11 μm wide is placed on the first surface of the surface layer after removing the perfluoropolyether in the pores, and a ratio of a total sum of areas of the openings observed in the first observation region relative to an area of the first observation region is defined as P 1 ; and
when a second observation region 8 μm long×11 μm wide is placed in a cross section of the surface layer after removing the perfluoropolyether in the pores, the cross section including an entire thickness portion of the surface layer along a circumferential direction of the fixing rotating member, and a ratio of a total sum of areas of the pores observed in the second observation region relative to an area of the second observation region is defined as P 2 ,
P 2 /P 1 is 1.3 or higher.
2. The fixing rotating member according to claim 1 , wherein:
P 1 is 1.0 to 15.0%; and
P 2 is 20.0 to 60.0%.
3. The fixing rotating member according to claim 1 , wherein a content of the perfluoropolyether in the surface layer is 20 to 60 mass %.
4. The fixing rotating member according to claim 1 , wherein an average opening diameter of the openings in the outer surface of the surface layer is 1 to 5 μm.
5. The fixing rotating member according to claim 1 , wherein a thickness of the surface layer is 12 to 100 μm.
6. The fixing rotating member according to claim 1 , wherein the perfluoropolyether has a structure represented by formula (1):
wherein, in the formula (1), a, b, c, d, e and f are each independently 0 or a positive integer, satisfy 1≤a+b+c+d+e+f≤600, and at least one from among a, b, c and d represents a positive integer.
7. The fixing rotating member according to claim 1 , wherein the perfluoropolyether has at least one structure selected from the group consisting of formulae (2) to (5):
wherein, in the formula (2), n is a positive number such that PFPE viscosity at a temperature of 40° C. is 30 to 500 mPa·s;
wherein, in the formula (3), n′ is a positive number such that PFPE viscosity at a temperature of 40° C. is 10 to 2500 mPa·s;
wherein, in the formula (4), n″ and m are each independently a positive number, m/n″ is a number from 0.5 to 2, and n″+m is a number such that PFPE viscosity at a temperature of 40° C. is 20 to 1400 mPa·s; and
wherein, in the formula (5), n′″ and m′ are each independently a positive number, m′/n′″ is a number from 20 to 1000, and n′″+m′ is a number such that PFPE viscosity at a temperature of 40° C. is 20 to 1200 mPa·s.
8. The fixing rotating member according to claim 1 , wherein P 2 /P 1 is 5.0 or higher.
9. The fixing rotating member according to claim 1 , wherein the fixing rotating member is a fixing belt having an endless belt shape.
10. The fixing rotating member according to claim 1 , wherein P 2 /P 1 is 20.0 or lower.
11. A fixing apparatus, comprising a fixing rotating member, and heating means for heating the fixing rotating member,
wherein:
the fixing rotating member comprises a base layer, an elastic layer and a surface layer, in this order;
the surface layer contains a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and a perfluoropolyether;
the surface layer has pores with openings at a first surface thereof constituting an outer surface of the fixing rotating member;
at least part of the pores contains the perfluoropolyether;
when a first observation region 8 μm long×11 μm wide is placed on the first surface of the surface layer after removing the perfluoropolyether in the pores, and a ratio of a sum total of areas of the openings observed within the first observation region relative to an area of the first observation region is defined as P 1 ; and
when a second observation region 8 μm long×11 μm wide is placed on a cross section of the surface layer after removing the perfluoropolyether in the pores, the cross section including an entire thickness portion of the surface layer along a circumferential direction of the fixing rotating member, and a ratio of a total sum of areas of the pores observed in the second observation region relative to an area of the second observation region is defined as P 2 ,
P 2 /P 1 is 1.3 or higher.
12. The fixing apparatus according to claim 11 , wherein:
the fixing rotating member is a fixing belt having an endless belt shape; and
the heating means is a heater disposed in contact with an inner peripheral surface of the fixing belt.
13. An electrophotographic image forming apparatus, comprising the fixing apparatus of claim 11 .
14. The fixing rotating member according to claim 1 , wherein a content of the perfluoropolyether in the surface layer is 26 to 60 mass %.