Electrophotographic photosensitive member, process cartridge and electrophotographic apparatus
Provided is an electrophotographic photosensitive member which enables a reduction in unevenness in distribution of the post-exposure potential of the photosensitive member and a reduction in unevenness in life of the photosensitive member in the axial direction. An electrophotographic photosensitive member, including a cylindrical support, a charge generating layer, and a charge transport layer in this order, wherein when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in the axial direction of the cylindrical support is equally divided into five regions, average film thicknesses of the charge generating layer in the five regions satisfy specific relations in a film thickness of the charge generating layer and average film thicknesses of the charge transport layer in the five regions satisfy specific relations in a film thickness of the charge transport layer.
1. An electrophotographic photosensitive member, comprising:
a cylindrical support, a charge generating layer and a charge transport layer in this order;
the charge generating layer comprising titanyl phthalocyanine crystals as a charge generating substance, said titanyl phthalocyanine crystals having a strong peak at a Bragg angle 2θ of 27.2°±0.3° in CuKα characteristic X-ray diffraction, wherein
d 1 <d 2 <d 3 <d 4 <d 5 and D 1 <D 2 <D 3 <D 4 <D 5 when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in an axial direction of the cylindrical support is equally divided into five regions, d 1 , d 2 , d 3 , d 4 and d 5 are average film thicknesses (nm) of the charge generating layer in the five regions and D 1 , D 2 , D 3 , D 4 and D 5 are average film thicknesses (μm) of the charge transport layer in the five regions.
2. The electrophotographic photosensitive member according to claim 1 , wherein
1.00< D 2 /D 1 <1.10
1.01< D 3 /D 1 <1.25
1.05< D 4 /D 1 <1.45 and
1.10< D 5 /D 1 <1.70.
3. The electrophotographic photosensitive member according to claim 2 , wherein
1.00< D 2 /D 1 <1.08
1.02< D 3 /D 1 <1.13
1.07< D 4 /D 1 <1.20 and
1.15< D 5 /D 1 <1.35.
4. The electrophotographic photosensitive member according to claim 1 , wherein
0.8 A<D 1 /d 1 <1.2 A
0.8 A<D 2 /d 2 <1.2 A
0.8 A<D 3 /d 3 <1.2 A
0.8 A<D 4 /d 4 <1.2 A
0.8 A<D 5 /d 5 <1.2 A
where d ave is an average of d 1 , d 2 , d 3 , d 4 and d 5 , D ave is an average of D 1 , D 2 , D 3 , D 4 and D 5 and A=D ave /d ave .
5. The electrophotographic photosensitive member according to claim 1 , wherein the film thickness of the charge generating layer is between (d−0.2Δ) and (d+0.2Δ) in all the values of Y where 0≤Y≤Y max for a value of d=d(Y) calculated from
d
(
Y
)
=
d
0
+
Δ
(
1
-
βΔ
)
Y
2
Y
ma
x
2
+
βΔ
2
Y
4
Y
ma
x
4
where Y (mm) is a distance from the central position of the image formation region in the axial direction of the cylindrical support, Y max is a value Y at the end position of the image formation region, β [nm −1 ] is an absorption coefficient of the charge generating layer, and Δ is a difference (d 6 −d 0 ) between a film thickness of the charge generating layer do at the central position of the image formation region and a film thickness of the charge generating layer d 6 at the end position of the image formation region.
6. The electrophotographic photosensitive member according to claim 1 , wherein
1
-
e
-
2
β
d
6
1
-
e
-
2
β
d
6
≥
1.2
□
where d 0 is a film thickness of the charge generating layer at the central position of the image formation region and d 6 is a film thickness of the charge generating layer at the end position of the image formation region.
7. The electrophotographic photosensitive member according to claim 1 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 5 μm or more,
the conductive layer contains a binder resin, and a fine particle of a metal oxide having an average diameter of 100 to 400 nm, and
the fine particle of a metal oxide comprises a core material containing titanium oxide, and a containing titanium oxide doped with niobium or tantalum.
8. The electrophotographic photosensitive member according to claim 1 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 10 μm or more, and
the conductive layer contains a binder resin and a fine particle of a metal oxide.
9. A process cartridge that integrally supports an electrophotographic photosensitive member including a cylindrical support, a charge generating layer and a charge transport layer in this order, and at least one unit selected from the group consisting of a charging unit, a developing unit and a cleaning unit, and is detachably attachable to a body of an electrophotographic apparatus,
the charge generating layer co comprising titanyl phthalocyanine crystals as a charge generating substance, said titanyl phthalocyanine crystals having a strong peak at a Bragg angle 2θ of 27.2°±0.3° in CuKα characteristic X-ray diffraction, wherein
d 1 <d 2 <d 3 <d 4 <d 5 and D 1 <D 2 <D 3 <D 4 <D 5 when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in an axial direction of the cylindrical support is equally divided into live regions, d 1 , d 2 , d 3 , d 4 and d 5 are average film thicknesses (nm) of the charge generating layer in the five regions and D 1 , D 2 , D 3 , D 4 and D 5 are average film thicknesses (μm) of the charge transport layer in the five regions.
10. An electrophotographic apparatus, comprising:
an electrophotographic photosensitive member including a cylindrical support, a charge generating layer, and a charge transport layer in this order, a charging unit, an exposing unit, a developing unit, and a transferring unit,
the charge generating layer comprising titanyl phthalocyanin ne crystals as a charge generating substance, said titanyl phthalocyanine crystals having a strong peak at a Bragg angle 2θ of 27.2°±0.3° in CuKα characteristic X-ray diffraction, wherein
d 1 <d 2 <d 3 <d 4 <d 5 and D 1 <D 2 <D 3 <D 4 <D 5 when a region from a central position of art image formation region of the electrophotographic photosensitive member to an end position of the image formation region in an axial direction of the cylindrical support is equally divided into five regions, d 1 , d 2 , d 3 , d 4 and d 5 are average film thicknesses (nm) of the charge generating layer in the five regions and D 1 , D 2 , D 3 , D 4 and D 5 are average film thicknesses (μm) of the charge transport layer in the five regions.
11. An electrophotographic photosensitive member, comprising:
a cylindrical support, a charge generating layer and a charge transport layer in this order;
the charge generating layer containing hydroxygallium phthalocyanine crystals as a charge generating substance, said hydroxygallium phthalocyanine crystals having strong peaks at Bragg angles 2θ of 7.4°±0.3 and 28.2±0.3° in CuKα characteristic X-ray diffraction, wherein
d 1 <d 2 <d 3 <d 4 <d 5 and D 1 <D 2 <D 3 <D 4 <D 5 when a region from a central position of an image formation region of the electrophotographic photosensitive member to an end position of the image formation region in an axial direction of the cylindrical support is equally divided into five regions, d 1 , d 2 , d 3 , d 4 and d 5 are average film thicknesses (nm) of the charge generating layer in the five regions, and D 1 , D 2 , D 3 , D 4 and D 5 are average film thicknesses (μm) of the charge transport layer in the five regions.
12. The electrophotographic photosensitive member according to claim 11 , wherein
0.8 A<D 1 /d 1 <1.2 A
0.8 A<D 2 /d 2 <1.2 A
0.8 A<D 3 /d 3 <1.2 A
0.8 A<D 4 /d 4 <1.2 A and
0.8 A<D 5 /d 5 <1.2 A
where d ave is an average of d 1 , d 2 , d 3 , d 4 and d 5 , D ave is an average of D 1 , D 2 , D 3 , D 4 and D 5 , and A=D ave /d ave .
13. The electrophotographic photosensitive member according to claim 11 , wherein
1
-
e
-
2
β
d
0
1
-
e
-
2
β
d
0
≥
1.2
where d 0 is a film thickness of the charge generating layer at the central position of the image formation region and d 6 is a film thickness of the charge generating layer at the end position of the image formation region.
14. The electrophotographic photosensitive member according to claim 11 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 5 μm or more,
the conductive layer contains a binder resin, and a fine particle of a metal oxide having an average diameter of 100 to 400 nm, and
the fine particle of a metal oxide comprises a core material containing titanium oxide, and a coating layer containing titanium oxide doped with niobium or tantalum.
15. The electrophotographic photosensitive member according to claim 11 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 10 μm or more, and
the conductive layer contains a binder resin and a fine particle of a metal oxide.
16. All electrophotographic photosensitive member, comprising:
a. cylindrical support, a charge generating layer and a charge transport layer in this order, wherein
d 1 <d 2 <d 3 <d 4 <d 5 and D 1 <<D 2 <D 3 <D 4 <D 5 when a region from a central position of art image formation region of the electrophotographic photosensitive, member to an end position of the image formation region in an axial direction of the cylindrical support is equally divided into five regions, d 1 , d 2 , d 3 , d 4 and d 5 are average film thicknesses (nm) of the charge generating, layer in the five regions, and D 1 , D 2 , D 3 , D 4 and D 5 are average film thicknesses (μm) of the charge transport layer in the five regions, and
the film thickness of the charge generating layer is between (d−0.2Δ) and (d−0.2Δ) in all the values of Y where 0≤Y≤Y max for a value of d=d(Y) calculated from
d
(
Y
)
=
d
0
+
Δ
(
1
-
βΔ
)
Y
2
Y
max
2
+
βΔ
2
Y
4
Y
max
4
where Y (mm) is a distance from the central position of the image formation region in the axial direction of the cylindrical support, Y max is a value Y at the end position of the image formation region, β [nm −1 ] is an absorption coefficient of the charge generating layer, and Δ is a difference (d 6 −d 0 ) between a film thickness of the charge generating layer d 0 at the central position of the image formation region and a film thickness of the charge generating layer d 6 at the end position of the image formation region.
17. The electrophotographic photosensitive member according to claim 16 , wherein
0.8 A<D 1 /d 1 <1.2 A
0.8 A<D 2 /d 2 <1.2 A
0.8 A<D 3 /d 3 <1.2 A
0.8 A<D 4 /d 4 <1.2 A and
0.8 A<D 5 /d 5 <1.2 A
where d ave is an average of d 1 , d 2 , d 3 , d 4 and d 5 , D ave is an average of D 1 , D 2 , D 3 , D 4 and D 5 , and A=D ave /d ave .
18. The electrophotographic photosensitive member according to claim 16 , wherein
1
-
e
-
2
β
d
0
1
-
e
-
2
β
d
0
≥
1.2
where d 0 is a film thickness of the charge generating layer at the central position of the image formation region and d 6 is a film thickness of the charge generating layer at the end position of the image formation region.
19. The electrophotographic photosensitive member according to claim 16 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 5 μm or more, and contains a binder resin and a fine particle of a metal oxide having an average diameter of 100 to 400 nm, and
the fine particle of metal oxide comprises a core material containing titanium oxide, and a coating layer containing titanium oxide doped with niobium or tantalum.
20. The electrophotographic photosensitive member according to claim 16 , comprising a conductive layer between the cylindrical support and the charge generating layer, wherein
the conductive layer has a film thickness of 10 μm or more, and
the conductive layer contains a binder resin and a fine particle of a metal oxide.