Electrophotographic member, process cartridge, and electrophotographic image forming apparatus
An electrophotographic member including a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member; wherein the conductive layer includes a matrix including a first rubber, and at least one domain dispersed in the matrix, volume resistivity of the matrix is 1.00×10 8 to 1.00×10 12 Ω·cm, the at least one domain includes a domain A including a second rubber and an electronic conductive agent; the conductive layer further includes an insulating region including a third rubber; in a case where impedance of the electrophotographic member is measured under specific conditions, impedance X at a specific frequency is 1.00×10 6 to 1.00×10 8 Ω; and a relationship between impedance Y under specific frequency and the impedance X satisfies X/Y≥7.5.
1 . An electrophotographic member comprising:
a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member, wherein
the conductive layer comprises
a matrix comprising a first rubber, and
at least one domain dispersed in the matrix;
volume resistivity of the matrix is 1.00×10 8 to 1.00×10 12 Ω·cm;
the at least one domain comprises a domain A comprising a second rubber and an electronic conductive agent;
the conductive layer further comprises an insulating region comprising a third rubber;
a volume resistivity of the insulating region is greater than 1.00×10 12 Ω·cm;
in a case where a platinum electrode is directly disposed on an outer surface of the electrophotographic member and impedance is measured under an environment at a temperature of 23° C. and a relative humidity of 50% while a DC voltage of 1 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode,
impedance X at a frequency of 1.0×10 −1 Hz is 1.00×10 6 to 1.00×10 8 Ω; and
in a case where impedance is measured while a DC voltage of 10 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode,
a relationship between impedance Y at a frequency of 1.0×10 −1 Hz and the impedance X satisfies an expression (1) below:
X
/
Y
≥
7.5
.
(
1
)
2 . The electrophotographic member according to claim 1 , wherein the at least one domain comprises a domain B constituting the insulating region.
3 . The electrophotographic member according to claim 2 , wherein at least 8 samples out of samples with a cube shape with a side length of 9 μm sampled from 9 points of the conductive layer satisfy condition (A) below:
(A) in a case where one of the samples is divided into 27 unit cubes with a side length of 3 μm and a volume Vd of the domain included in the unit cube is determined, the number of the unit cubes with a Vd of 2.7 to 10.8 μm 3 is at least 23.
4 . The electrophotographic member according to claim 3 , wherein the at least 8 samples satisfying the condition (A) satisfy condition (B) below:
(B) a proportion of the number of the domain A in a total number of the domain accounts for 10 to 50 number %.
5 . The electrophotographic member according to claim 4 , wherein the at least 8 samples satisfying the condition (A) satisfy condition (B2) below:
(B2) a proportion of the number of the domain A in a total number of the domain accounts for 30 to 40 number %.
6 . The electrophotographic member according to claim 1 , wherein the impedance Y and the impedance X satisfy expression (2) below:
20.
≥
X
/
Y
≥
7.5
.
(
2
)
7 . The electrophotographic member according to claim 1 , wherein the electronic conductive agent is carbon black.
8 . The electrophotographic member according to claim 1 , wherein
in a case where a perimeter length of the domain A is taken as A and an envelope perimeter length of the domain A is taken as B, expression (5) below is satisfied:
1.
≤
A
/
B
≤
1
.10
.
(
5
)
9 . The electrophotographic member according to claim 1 , wherein:
the first rubber is NBR;
the second rubber is at least one rubber selected from the group consisting of SBR, EPDM, and IR; and
the third rubber is at least one rubber selected from the group consisting of SBR, EPDM, and IR.
10 . The electrophotographic member according to claim 1 , wherein a volume resistivity of the domain A is 1.00×10 1 to 1.00×10 4 Ω·cm.
11 . The electrophotographic member according to claim 1 , wherein the electrophotographic member is a charging member.
12 . A process cartridge detachably attached to a main body of an electrophotographic image forming apparatus, wherein
the process cartridge comprises an electrophotographic member,
the electrophotographic member comprises:
a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member;
the conductive layer comprises
a matrix comprising a first rubber, and
at least one domain dispersed in the matrix;
volume resistivity of the matrix is 1.00×10 8 to 1.00×10 12 Ω·cm;
the at least one domain comprises a domain A comprising a second rubber and an electronic conductive agent;
the conductive layer further comprises an insulating region comprising a third rubber;
a volume resistivity of the insulating region is greater than 1.00×10 12 Ω·cm;
in a case where a platinum electrode is directly disposed on an outer surface of the electrophotographic member and impedance is measured under an environment at a temperature of 23° C. and a relative humidity of 50% while a DC voltage of 1 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode, impedance X at a frequency of 1.0×10 −1 Hz is 1.00×10 6 to 1.00×10 8 Ω; and
in a case where impedance is measured while a DC voltage of 10 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode,
a relationship between impedance Y at a frequency of 1.0×10 −1 Hz and the impedance X satisfies an expression (1) below:
X
/
Y
≥
7.5
.
(
1
)
13 . An electrophotographic image forming apparatus comprising an electrophotographic member, wherein
the electrophotographic member comprises:
a support member having a conductive outer surface; and a conductive layer disposed on an outer surface of the support member;
the conductive layer comprises
a matrix comprising a first rubber, and
at least one domain dispersed in the matrix;
volume resistivity of the matrix is 1.00×10 8 to 1.00×10 12 Ω·cm;
the at least one domain comprises a domain A comprising a second rubber and an electronic conductive agent;
the conductive layer further comprises an insulating region comprising a third rubber;
a volume resistivity of the insulating region is greater than 1.00×10 12 Ω·cm;
in a case where a platinum electrode is directly disposed on an outer surface of the electrophotographic member and impedance is measured under an environment at a temperature of 23° C. and a relative humidity of 50% while a DC voltage of 1 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode,
impedance X at a frequency of 1.0×10 −1 Hz is 1.00×10 6 to 1.00×10 8 Ω; and
in a case where impedance is measured while a DC voltage of 10 V and an AC voltage of 1 V in amplitude are applied in a superimposed manner between the outer surface of the support member and the platinum electrode,
a relationship between impedance Y at a frequency of 1.0×10 −1 Hz and the impedance X satisfies an expression (1) below:
X
/
Y
≥
7.5
.
(
1
)