Electrophotographic photosensitive member, and electrophotographic apparatus and process cartridge each including the electrophotographic photosensitive member

An electrophotographic apparatus, comprising:

• an electrophotographic photosensitive member;
• a charging unit;
• an exposing unit;
• a developing unit;
• and
• a transferring unit;
• the electrophotographic photosensitive member comprising a support, a charge-generating layer formed on the support, a first hole-transporting layer formed on the charge-generating layer, and a second hole-transporting layer formed on the first hole-transporting layer, the second hole-transporting layer being a surface layer of the electrophotographic photosensitive member and comprising a copolymer of a composition containing hole-transportable compounds represented by formulae (1) and (3), and optionally comprising at a hole-transportable compound represented by formula (2)
• where R11 and R12 independently represent an alkylene group having 2 to 6 carbon atoms, R13 and R14 independently represent a hydrogen atom or a methyl group, n1 represents 1, R15 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x11 represents an integer of from 0 to 5 and when x11 represents an integer of from 2 to 5, R15s may be identical to or different from each other, R16 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x12 represents an integer of from 0 to 4 and when x12 represents an integer of from 2 to 4, R16s may be identical to or different from each other, R21 and R22 independently represent an alkylene group having 2 to 6 carbon atoms, R23 and R24 independently represent a hydrogen atom or a methyl group, n2 represents 1, R25 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x21 represents an integer of from 0 to 5, and when x21 represents an integer of from 2 to 5, R25s may be identical to or different from each other, R26 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x22 represents an integer of from 0 to 4 and when x22 represents an integer of from 2 to 4, R26s may be identical to or different from each other, R31 and R32 independently represent an alkylene group having 2 to 6 carbon atoms, R33 and R34 independently represent a hydrogen atom or a methyl group, n3 represents 1, R35 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted phenyl group, x31 represents an integer of from 0 to 5 and when x31 represents an integer of from 2 to 5, R35s may be identical to or different from each other, R36 represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and x32 represents an integer of from 0 to 4 and when x32 represents an integer of from 2 to 4, R36s may be identical to or different from each other, wherein
• (W2+W3)/(W1+W2+W3)×100 (% by mass) is 0.05 to 5.0% by mass
• when W1 is a mass of the hole-transportable compound represented by formula (1) in the composition, W2 is a mass of the hole-transportable compound represented by formula (2) in the composition, and W3 is a mass of the hole-transportable compound represented by formula (3) in the composition, and
• 0.05 (eV)≤|CTM2HOMO|−|CTM1HOMO|≤0.30 (eV)
• when CTM1HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (1) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by a density functional theory B3LYP/6-31G*, and
• CTM2HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (3) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by the density functional theory B3LYP/6-31G*.

A process cartridge, comprising:

• an electrophotographic photosensitive member;
• and
• at least one unit selected from the group consisting of a charging unit, a developing unit, a transferring unit and a cleaning unit,
• the process cartridge integrally supporting the electrophotographic photosensitive member and the at least one unit, and being removably mounted onto a main body of an electrophotographic apparatus;
• the electrophotographic photosensitive member comprising a support, a charge-generating layer formed on the support, a first hole-transporting layer formed on the charge-generating layer, and a second hole-transporting layer formed on the first hole-transporting layer,
• the second hole-transporting layer being a surface layer of the electrophotographic photosensitive member and comprising a copolymer of a composition containing hole-transportable compounds represented by formulae (1) and (3), and optionally comprising a hole-transportable compound represented by formula (2)
• where R11 and R12 independently represent an alkylene group having 2 to 6 carbon atoms, R13 and R14 independently represent a hydrogen atom or a methyl group, n1 represents 1, R15 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x11 represents an integer of from 0 to 5 and when x11 represents an integer of from 2 to 5, R15s may be identical to or different from each other, R16 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x12 represents an integer of from 0 to 4 and when x12 represents an integer of from 2 to 4, R16s may be identical to or different from each other, R21 and R22 independently represent an alkylene group having 2 to 6 carbon atoms, R23 and R24 independently represent a hydrogen atom or a methyl group, n2 represents 1, R25 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x21 represents an integer of from 0 to 5, and when x21 represents an integer of from 2 to 5, R25s may be identical to or different from each other, R26 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x22 represents an integer of from 0 to 4 and when x22 represents an integer of from 2 to 4, R26s may be identical to or different from each other, R31 and R32 independently represent an alkylene group having 2 to 6 carbon atoms, R33 and R34 independently represent a hydrogen atom or a methyl group, n3 represents 1, R35 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted phenyl group, x31 represents an integer of from 0 to 5 and when x31 represents an integer of from 2 to 5, R35s may be identical to or different from each other, R36 represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and x32 represents an integer of from 0 to 4 and when x32 represents an integer of from 2 to 4, R36s may be identical to or different from each other, wherein
• (W2+W3)/(W1+W2+W3)×100 (% by mass) is 0.05 to 5.0% by mass
• when W1 is a mass of the hole-transportable compound represented by formula (1) in the composition, W2 is a mass of the hole-transportable compound represented by formula (2) in the composition, and W3 is a mass of the hole-transportable compound represented by formula (3) in the composition, and
• 0.05 (eV)≤|CTM2HOMO|−|CTM1HOMO|≤0.30 (eV)
• when CTM1HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (1) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by a density functional theory B3LYP/6-31G*, and
• CTM2HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (3) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by the density functional theory B3LYP/6-31G*.

A method of producing an electrophotographic photosensitive member including a support, a charge-generating layer formed on the support, a first hole-transporting layer formed on the charge-generating layer, and a second hole-transporting layer formed on the first hole-transporting layer, the second hole-transporting layer being a surface layer, the method comprising:

• forming a coat of an application liquid for the second hole-transporting layer containing hole-transportable compounds represented by formulae (1) and (3), and optionally comprising a hole-transportable compound represented by formula (2);
• and
• copolymerizing a composition incorporated into the coat to form the second hole-transporting layer of the electrophotographic photosensitive member
• where R11 and R12 independently represent an alkylene group having 2 to 6 carbon atoms, R13 and R14 independently represent a hydrogen atom or a methyl group, n1 represents 1, R15 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x11 represents an integer of from 0 to 5 and when x11 represents an integer of from 2 to 5, R15s may be identical to or different from each other, R16 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x12 represents an integer of from 0 to 4 and when x12 represents an integer of from 2 to 4, R16s may be identical to or different from each other, R21 and R22 independently represent an alkylene group having 2 to 6 carbon atoms, R23 and R24 independently represent a hydrogen atom or a methyl group, n2 represents 1, R25 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a substituted or unsubstituted phenyl group, x21 represents an integer of from 0 to 5, and when x21 represents an integer of from 2 to 5, R25s may be identical to or different from each other, R26 represents an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, x22 represents an integer of from 0 to 4 and when x22 represents an integer of from 2 to 4, R26s may be identical to or different from each other, R31 and R32 independently represent an alkylene group having 2 to 6 carbon atoms, R33 and R34 independently represent a hydrogen atom or a methyl group, n3 represents 1, R35 represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a substituted or unsubstituted phenyl group, x31 represents an integer of from 0 to 5 and when x31 represents an integer of from 2 to 5, R35s may be identical to or different from each other, R36 represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and x32 represents an integer of from 0 to 4 and when x32 represents an integer of from 2 to 4, R36s may be identical to or different from each other, wherein
• (W2+W3)/(W1+W2+W3)×100 (% by mass) is 0.05 to 5.0% by mass
• when W1 is a mass of the hole-transportable compound represented by formula (1) that is incorporated into the application liquid for the second hole-transporting layer, W2 is a mass of the hole-transportable compound represented by formula (2) that is incorporated into the application liquid for the second hole-transporting layer, and W3 is a mass of the hole-transportable compound represented by formula (3) that is incorporated into the application liquid for the second hole-transporting layer, and
• 0.05 (eV)≤|CTM2HOMO|−|CTM1HOMO|≤0.30 (eV)
• when CTM1HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (1) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by a density functional theory B3LYP/6-31G*, and
• CTM2HOMO is an energy value of a highest occupied molecular orbital of the hole-transportable compound represented by formula (3) obtained as a result of energy calculation of the hole-transportable compound after structure optimization thereof by the density functional theory B3LYP/6-31G*.