Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus
An electrophotographic photosensitive member includes a support member, a charge generating layer containing a phthalocyanine pigment as a charge generating material, a charge transport layer containing a charge transporting material in this order. The charge generating layer has a thickness of less than 200 nm, and the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of Φi and Ψi is 0.31 or more.
1. An electrophotographic photosensitive member comprising in this order:
a support member;
a charge generating layer having a thickness of less than 200 nm and containing a phthalocyanine pigment as a charge generating material; and
a charge transport layer containing a charge transporting material,
wherein the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of Φi represented by equation (E1) and Ψi represented by equation (E2) is 0.31 or more:
Φ
i
=
1
-
0.425
kR
i
∑
n
=
1
∞
[
1
-
Γ
(
n
,
kR
i
/
0.425
)
Γ
(
n
)
]
[
1
-
Γ
(
n
,
15.7
/
(
kR
i
)
)
Γ
(
n
)
]
(
E1
)
Ψ
i
=
{
1
-
10
-
α
d
(
Pd
/
R
i
>
1
)
(
Pd
/
R
i
)
(
1
-
10
-
α
R
i
/
P
)
(
Pd
/
R
i
≤
1
)
(
E2
)
wherein k is a parameter representing the ratio r/R of the crystallite correlation length r of the phthalocyanine pigment to the volume average diameter R of the crystalline particles in the particle size distribution of the phthalocyanine pigment, and Ri represents the respective diameters of the crystalline particles in the particle size distribution, and wherein α represents the absorption coefficient of the charge generating layer, d represents the thickness of the charge generating layer, and P represents the ratio of the volume of the charge generating material to the total volume of the charge generating layer.
2. The electrophotographic photosensitive member according to claim 1 , wherein the phthalocyanine pigment is a hydroxygallium phthalocyanine pigment having crystallites exhibiting peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in the CuKα X-ray diffraction spectrum thereof.
3. The electrophotographic photosensitive member according to claim 1 , wherein the parameter k is in the range of 0.17 to 0.42.
4. The electrophotographic photosensitive member according to claim 1 , wherein the volume ratio P is in the range of 0.42 to 0.72.
5. The electrophotographic photosensitive member according to claim 1 ,
wherein the volume ratio P is in the range of 0.42 to 0.72, and
wherein the thickness of the charge generating layer is 100 nm or more and less than 200 nm.
6. A process cartridge capable of being removably attached to an electrophotographic apparatus, the process cartridge comprising:
an electrophotographic photosensitive member; and
at least one device selected from the group consisting of a charging device, a developing device, and a cleaning device, the at least one device being held together with the electrophotographic photosensitive member in one body,
wherein the electrophotographic photosensitive member includes a support member, a charge generating layer having a thickness of less than 200 nm and containing a phthalocyanine pigment as a charge generating material, and a charge transport layer containing a charge transporting material in this order,
wherein the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of Φi represented by equation (E1) and Ψi represented by equation (E2) is 0.31 or more:
Φ
i
=
1
-
0.425
kR
i
∑
n
=
1
∞
[
1
-
Γ
(
n
,
kR
i
/
0.425
)
Γ
(
n
)
]
[
1
-
Γ
(
n
,
15.7
/
(
kR
i
)
)
Γ
(
n
)
]
(
E1
)
Ψ
i
=
{
1
-
10
-
α
d
(
Pd
/
R
i
>
1
)
(
Pd
/
R
i
)
(
1
-
10
-
α
R
i
/
P
)
(
Pd
/
R
i
≤
1
)
(
E2
)
wherein k is a parameter representing the ratio r/R of the crystallite correlation length r of the phthalocyanine pigment to the volume average diameter R of the crystalline particles in the particle size distribution of the phthalocyanine pigment, and Ri represents the respective diameters of the crystalline particles in the particle size distribution, and wherein α represents the absorption coefficient of the charge generating layer, d represents the thickness of the charge generating layer, and P represents the ratio of the volume of the charge generating material to the total volume of the charge generating layer.
7. An electrophotographic apparatus comprising:
an electrophotographic photosensitive member;
a charging device;
an exposure device;
a developing device; and
a transfer device,
wherein the electrophotographic photosensitive member includes a support member, a charge generating layer having a thickness of less than 200 nm and containing a phthalocyanine pigment as a charge generating material, and a charge transport layer containing a charge transporting material in this order,
wherein the phthalocyanine pigment includes phthalocyanine crystalline particles having a particle size distribution and satisfies a requirement that the volume average of the products of Φi represented by equation (E1) andΨi represented by equation (E2) is 0.31 or more:
Φ
i
=
1
-
0.425
kR
i
∑
n
=
1
∞
[
1
-
Γ
(
n
,
kR
i
/
0.425
)
Γ
(
n
)
]
[
1
-
Γ
(
n
,
15.7
/
(
kR
i
)
)
Γ
(
n
)
]
(
E1
)
Ψ
i
=
{
1
-
10
-
α
d
(
Pd
/
R
i
>
1
)
(
Pd
/
R
i
)
(
1
-
10
-
α
R
i
/
P
)
(
Pd
/
R
i
≤
1
)
(
E2
)
wherein k is a parameter representing the ratio r/R of the crystallite correlation length r of the phthalocyanine pigment to the volume average diameter R of the crystalline particles in the particle size distribution of the phthalocyanine pigment, and Ri represents the respective diameters of the crystalline particles in the particle size distribution, and wherein α represents the absorption coefficient of the charge generating layer, d represents the thickness of the charge generating layer, and P represents the ratio of the volume of the charge generating material to the total volume of the charge generating layer.