Process cartridge and electrophotographic apparatus capable of suppressing lateral running while maintaining satisfactory potential function
Provided is a process cartridge in which lateral running is suppressed while satisfactory potential fluctuation is maintained. The process cartridge includes: an electrophotographic photosensitive member including a support, a lowermost layer, and a photosensitive layer; and a charging member including a support and a conductive layer. In a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the lowermost layer while changing the AC voltage, is represented by f OPC (Hz), and in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the charging member while changing the AC voltage, is represented by f C (Hz), the f OPC and the f C each have a value within a certain range.
1. A process cartridge comprising:
an electrophotographic photosensitive member; and
a charging member,
the process cartridge being removably mounted onto a main body of an electrophotographic apparatus,
wherein the electrophotographic photosensitive member includes a first support having a cylindrical shape, a lowermost layer formed immediately on the first support, and a photosensitive layer formed on the lowermost layer,
wherein the charging member is an electrophotographic charging member including a second support having a columnar shape and a second conductive layer formed on the second support,
wherein the second conductive layer includes a matrix containing a first rubber and a plurality of domains dispersed in the matrix,
wherein the plurality of domains each contain a second rubber and an electron conductive agent,
wherein the matrix has a volume resistivity ρ M that is 1.0×10 5 times or more as large as a volume resistivity ρ D of each of the plurality of domains, and
wherein, in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the lowermost layer while changing the AC voltage at a frequency within a range of from 1.0×10 −2 (Hz) to 1.0×10 6 (Hz), is represented by f OPC (Hz), and in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the charging member while changing the AC voltage at a frequency within a range of from 1.0×10 −2 (Hz) to 1.0×10 6 (Hz), is represented by f C (Hz), the f OPC and the f C satisfy a relationship of one of the following expression (D1) and the following expression (D2):
10≤ f OPC /f C ≤10,000 Expression (D1)
0.0001≤ f OPC /f C ≤0.1 Expression (D2).
2. The process cartridge according to claim 1 , wherein, in the electrophotographic photosensitive member and the charging member, the f OPC and the f C satisfy a relationship of one of the following expression (D3) and the following expression (D4):
30≤ f OPC /f C ≤3,000 Expression (D3)
0.0003≤ f OPC /f C ≤0.03 Expression (D4).
3. The process cartridge according to claim 1 , wherein, in the electrophotographic photosensitive member, the f OPC is 5 (Hz) or more.
4. The process cartridge according to claim 1 , wherein, in the electrophotographic photosensitive member, the f OPC is 100 (Hz) or more.
5. The process cartridge according to claim 1 , wherein when, in the electrophotographic photosensitive member, an impedance per unit area of the lowermost layer at a frequency of f OPC /10 (Hz) is represented by z OPC (Ω·cm 2 ), and when, in the charging member, an impedance per unit area of the charging member at a frequency of f C /10 (Hz) is represented by z C (Ω·cm 2 ), the z OPC and the z C satisfy a relationship of the following expression (D5):
( z OPC ×z C )≥1.0×10 6 Expression (D5).
6. The process cartridge according to claim 1 , wherein, in the electrophotographic photosensitive member, an impedance z OPC per unit area of the lowermost layer at a frequency of f OPC /10 (Hz) is 3.0×10 5 (Ω·cm 2 ) or more.
7. The process cartridge according to claim 1 , wherein, in the electrophotographic photosensitive member, an impedance z OPC per unit area of the lowermost layer at a frequency of f OPC /10 (Hz) is 1.0×10 9 (Ω·cm 2 ) or less.
8. The process cartridge according to claim 1 , wherein, in the charging member, an impedance z C per unit area of the charging member at a frequency of f C /10 (Hz) is 1.0×10 6 (Ω·cm 2 ) (Hz) or more.
9. The process cartridge according to claim 1 , wherein, in the charging member, the matrix has a volume resistivity ρ M of 1.0×10 12 (Ω·cm) or more.
10. An electrophotographic apparatus comprising:
an electrophotographic photosensitive member; and
a charging member,
wherein the electrophotographic photosensitive member includes a first support having a cylindrical shape, a lowermost layer formed immediately on the first support, and a photosensitive layer formed on the lowermost layer,
wherein the charging member is an electrophotographic charging member including a second support having a columnar shape and a second conductive layer formed on the second support,
wherein the second conductive layer includes a matrix containing a first rubber and a plurality of domains dispersed in the matrix,
wherein the plurality of domains each contain a second rubber and an electron conductive agent,
wherein the matrix has a volume resistivity ρ M that is 1.0×10 5 times or more as large as a volume resistivity ρ D of each of the plurality of domains, and
wherein, in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the lowermost layer while changing the AC voltage at a frequency within a range of from 1.0×10 −2 (Hz) to 1.0×10 6 (Hz), is represented by f OPC (Hz), and in a case where a maximum frequency at which a phase of an impedance reaches 45°, when the impedance is measured by applying an AC voltage to the charging member while changing the AC voltage at a frequency within a range of from 1.0×10 −2 (Hz) to 1.0×10 6 (Hz), is represented by f C (Hz), the f OPC and the f C satisfy a relationship of one of the following expression (D1) and the following expression (D2):
10≤ f OPC /f C ≤10,000 Expression (D1)
0.0001≤ f OPC /f C ≤0.1 Expression (D2).