Electrophotographic member and electrophotographic image forming apparatus
An electrophotographic member with an endless shape, the electrophotographic member comprising: a cylindrical film; and a surface layer on an outer circumferential surface of the cylindrical film, wherein the cylindrical film comprises: a shrinkage rate αp in a first direction serving as a circumferential direction of the cylindrical film and a shrinkage rate αa in a second direction orthogonal to the circumferential direction, both of which are 2.0% or more; and a crystalline polyester as a binder, and roughness forming particles dispersed in the binder, the surface layer includes protruded portions caused by the roughness forming particles on an outer surface opposite to a surface facing the cylindrical film, and the cylindrical film further comprises an amorphous polyester, and the amorphous polyester extends in the first direction and the second direction around at least the roughness forming particles.
1 . An electrophotographic member with an endless shape, the electrophotographic member comprising:
a cylindrical film; and
a surface layer on an outer circumferential surface of the cylindrical film, wherein
the cylindrical film has a shrinkage rate αp in a first direction serving as a circumferential direction of the cylindrical film and a shrinkage rate αa in a second direction orthogonal to the circumferential direction, both of which are 2.0% or more;
the cylindrical film comprises a crystalline polyester as a binder, and roughness forming particles dispersed in the binder,
the surface layer includes protruded portions caused by the roughness forming particles on an outer surface opposite to a surface facing the cylindrical film, and
the cylindrical film further comprises an amorphous polyester, and the amorphous polyester extends in the first direction and the second direction around at least the roughness forming particles.
2 . The electrophotographic member according to claim 1 , wherein
the cylindrical film further comprises an ionic conducting agent, and the ionic conducting agent is comprised in the amorphous polyester.
3 . The electrophotographic member according to claim 1 , wherein
the crystalline polyester comprises at least one selected from the group consisting of polyalkylene terephthalate, polyalkylene naphthalate, and polyalkylene isophthalate, and a copolymer comprising the polyalkylene terephthalate, the polyalkylene naphthalate, and the polyalkylene isophthalate.
4 . The electrophotographic member according to claim 1 , wherein
the amorphous polyester has
a structure corresponding to at least one phthalic acid selected from the group consisting of terephthalic acid, orthophthalic acid, and isophthalic acid, and
a structure corresponding to at least one diol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, and cyclohexanedimethanol.
5 . The electrophotographic member according to claim 1 , wherein
a content ratio of the amorphous polyester to the crystalline polyester is 30.0 mass % or less.
6 . The electrophotographic member according to claim 1 , wherein the roughness forming particles comprise at least one selected from the group consisting of silicone resin particles and silica particles.
7 . The electrophotographic member according to claim 1 , wherein
the roughness forming particles have a volume average particle diameter of at least 0.4 μm.
8 . The electrophotographic member according to claim 1 , wherein
the electrophotographic member has a ten-point average roughness of at least 0.110.
9 . The electrophotographic member according to claim 1 , wherein
the cylindrical film is a biaxially stretched cylindrical film.
10 . The electrophotographic member according to claim 1 , wherein
the electrophotographic member is an electrophotographic belt with an endless shape.
11 . An electrophotographic image forming apparatus comprising an intermediate transfer belt with an endless shape, wherein
the intermediate transfer belt comprises:
a cylindrical film; and
a surface layer on an outer circumferential surface of the cylindrical film,
the cylindrical film has a shrinkage rate αp in a first direction serving as a circumferential direction of the cylindrical film and a shrinkage rate αa in a second direction orthogonal to the circumferential direction, both of which are 2.0% or more;
the cylindrical film comprises a crystalline polyester as a binder, and roughness forming particles dispersed in the binder,
the surface layer includes protruded portions caused by the roughness forming particles on an outer surface opposite to a surface facing the cylindrical film, and
the cylindrical film further comprises an amorphous polyester, and the amorphous polyester extends in the first direction and the second direction around at least one of the roughness forming particles.