Electrophotographic photosensitive member, process cartridge, electrophotographic apparatus, and method of producing electrophotographic photosensitive member
An electrophotographic photosensitive member includes a surface layer which exhibits excellent dispersibility of fluorine atom-containing resin particles, and suppresses the occurrence of ghost images. The surface layer contains a fluorine atom-containing resin particle, a binder material, and a polymer A having specific structural units.
1 . An electrophotographic photosensitive member, comprising:
a surface layer, the surface layer comprising a fluorine atom-containing resin particle, a binder material and a polymer A, wherein
polymer A is obtained by polymerizing a composition comprising compounds according to formulae (1), (2) and (3)
where R 11 represents a hydrogen atom or a methyl group,
R 12 represents a single bond, a methylene group or an ethylene group,
Rf 1 s independently represent a perfluoroalkylene group having 1 to 5 carbon atoms, or a perfluoroalkylidene group having 1 to 5 carbon atoms,
Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms,
“n” represents an integer of 1 to 3, and when “n” represents 2 or 3, “n” Rf 1 s may be identical to or different from each other,
R 21 represents a hydrogen atom or a methyl group,
Y represents a divalent organic group,
Z represents a polymer moiety,
R 31 represents a hydrogen atom or a methyl group, and
R 32 represents a cyano group.
2 . The electrophotographic photosensitive member according to claim 1 , wherein the compound according to formula (2) is represented by formula (5)
where Y A1 represents an unsubstituted alkylene group,
Y B represents an unsubstituted alkylene group, an alkylene group substituted with a halogen atom, an alkylene group substituted with a hydroxy group, an ester bond (—COO—), an amide bond (—NHCO—), or a urethane bond (—NHCOO—), or a divalent linking group that may be derived by combining one or more kinds selected from these groups and bonds, and —O— or —S—, or a single bond,
R 51 and R 52 independently represent a hydrogen atom or a methyl group,
“m” represents an integer of 25 to 150, and
Z A represents a cyano group, a phenyl group or a structure represented by formula (2A)
where Z A1 represents an alkyl group having 1 to 4 carbon atoms.
3 . The electrophotographic photosensitive member according to claim 2 , wherein —Y A1 —Y B — is —Y A1 —(Y A2 ) b —(Y A3 ) c —(Y A4 ) d —(Y A5 ) e —(Y A6 ) f —
where Y A1 represents an unsubstituted alkylene group,
YA 2 represents a methylene group substituted with at least one member selected from the group consisting of a hydroxy group and a halogen atom,
YA 3 represents an unsubstituted alkylene group,
YA 4 represents an ester bond, an amide bond or a urethane bond,
YA 5 represents an unsubstituted alkylene group,
YA 6 represents an oxygen atom or a sulfur atom, and
“b”, “c”, “d”, “e”, and “f” independently represent 0 or 1.
4 . The electrophotographic photosensitive member according to claim 1 , wherein a total number of carbon atoms of “n” Rf 1 s and Rf 2 is 5 to 8.
5 . The electrophotographic photosensitive member according to claim 1 , wherein “n” is 1 or 2.
6 . The electrophotographic photosensitive member according to claim 1 , wherein each Rf 1 independently represents a perfluoroalkylene group having 2 or 3 carbon atoms, or a perfluoroalkylidene group having 2 or 3 carbon atoms, and
Rf 2 represents a perfluoroalkyl group having 2 or 3 carbon atoms.
7 . The electrophotographic photosensitive member according to claim 1 , wherein a content of the compound represented by formula (1) is 5 to 95 mol % with respect to a total content of the compounds represented by formulae (1), (2) and (3) in the composition, and
a content of the compound represented by formula (3) is 0.10 to 1.0 mol % with respect to the content of the compound represented by formula (1) in the composition.
8 . The electrophotographic photosensitive member according to claim 7 , wherein the content of the compound represented by formula (3) is 0.10 to 0.50 mol % with respect to the content of the compound represented by formula (1) in the composition.
9 . The electrophotographic photosensitive member according to claim 1 , wherein the polymer A is obtained by polymerizing only the compounds represented by formulae (1), (2) and (3).
10 . The electrophotographic photosensitive member according to claim 1 , wherein a content of polymer A in the surface layer is 2 to 10 mass % with respect to a mass of the fluorine atom-containing resin particle in the surface layer.
11 . The electrophotographic photosensitive member according to claim 1 , wherein polymer A has a weight-average molecular weight of 16,000 to 100,000.
12 . The electrophotographic photosensitive member according to claim 1 , wherein a content of the fluorine atom-containing resin particle in the surface layer is 5 to to 40 mass % with respect to a total mass of the surface layer.
13 . The electrophotographic photosensitive member according to claim 1 , wherein the fluorine atom-containing resin particle is a polytetrafluoroethylene resin particle, and
an arithmetic average of long diameters of primary particles is 150 to 300 nm measured observing a section of the surface layer from a secondary electron image of the polytetrafluoroethylene resin particle obtained with a scanning electron microscope.
14 . A process cartridge, comprising:
at least one unit selected from the group consisting of a charging unit, a developing unit, a transfer unit and a cleaning unit;
the process cartridge integrally supporting an electrophotographic photosensitive member and the at least one unit, and being detachably attachable to a main body of an electrophotographic apparatus;
the electrophotographic photosensitive member comprising a surface layer, the surface layer comprising a fluorine atom-containing resin particle, a binder material and a polymer A, wherein
polymer A is obtained by polymerizing a composition comprising compounds according to formulae (1), (2) and (3)
where R 11 represents a hydrogen atom or a methyl group,
R 12 represents a single bond, a methylene group or an ethylene group,
Rf 1 s independently represent a perfluoroalkylene group having 1 to 5 carbon atoms, or a perfluoroalkylidene group having 1 to 5 carbon atoms,
Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms,
“n” represents an integer of 1 to 3, and when “n” represents 2 or 3, “n” Rf 1 s may be identical to or different from each other,
R 21 represents a hydrogen atom or a methyl group,
Y represents a divalent organic group,
Z represents a polymer moiety,
R 31 represents a hydrogen atom or a methyl group, and
R 32 represents a cyano group.
15 . An electrophotographic apparatus, comprising:
a charging unit;
an exposing unit;
a developing unit;
a transfer unit; and
an electrophotographic photosensitive member including a surface layer, the surface layer comprising a fluorine atom-containing resin particle, a binder material and a polymer A, wherein
polymer A is obtained by polymerizing a composition comprising compounds according to formulae (1), (2) and (3)
where R 11 represents a hydrogen atom or a methyl group,
R 12 represents a single bond, a methylene group or an ethylene group,
Rf 1 s independently represent a perfluoroalkylene group having 1 to 5 carbon atoms, or a perfluoroalkylidene group having 1 to 5 carbon atoms,
Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms,
“n” represents an integer of 1 to 3, and when “n” represents 2 or 3, “n” Rf 1 s may be identical to or different from each other,
R 21 represents a hydrogen atom or a methyl group,
Y represents a divalent organic group,
Z represents a polymer moiety,
R 31 represents a hydrogen atom or a methyl group, and
R 32 represents a phenyl group, a cyano group.
16 . A method of producing an electrophotographic photosensitive member including a surface layer, the method comprising the steps of:
preparing a coating liquid comprising (i) a fluorine atom-containing resin particle, (ii) at least one member selected from the group consisting of a binder material and a raw material for the binder material, and (iii) a polymer A obtained by copolymerizing compounds according to formulae (1), (2) and (3); and
forming the surface layer by forming a coating film of the coating liquid, and drying and/or curing the coating film
where R 11 represents a hydrogen atom or a methyl group,
R 12 represents a single bond, a methylene group or an ethylene group,
Rf 1 s independently represent a perfluoroalkylene group having 1 to 5 carbon atoms, or a perfluoroalkylidene group having 1 to 5 carbon atoms,
Rf 2 represents a perfluoroalkyl group having 1 to 5 carbon atoms,
“n” represents an integer of 1 to 3, and when “n” represents 2 or 3, “n” Rf 1 s may be identical to or different from each other,
R 21 represents a hydrogen atom or a methyl group,
Y represents a divalent organic group,
Z represents a polymer moiety,
R 31 represents a hydrogen atom or a methyl group, and
R 32 represents a cyano group.