IP Library Granted Patent US 12699334
Granted Patent B2
US 12699334 · App. 18/135,815 · Granted Aug 4, 2026

Electrophotographic photoreceptor, electrophotographic photoreceptor cartridge, and image forming device

Inventors: Akira Ando (Tokyo, JP); Takahiro Choda (Tokyo, JP)
Assignee: Mitsubishi Chemical Corporation
G03G5/14769G03G5/047G03G5/14704
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Quick Facts
Patent No.
US 12699334
App. No.
18/135,815
Granted
Aug 4, 2026
Kind
B2
Abstract

As an electrophotographic photoreceptor including a protective layer (an outermost layer), a photosensitive layer and a conductive support, wherein the protective layer (the outermost layer) comprises a polymer obtained by polymerizing a compound having a chain polymerizable functional group, and the photosensitive layer comprises a hole transport material satisfying the following formula (1) and an electron transport material satisfying the following formula (2): 600≤ a   (1) 400≤ b   (2) in the formula (1), a represents a molecular weight of the hole transport material, and in the formula (2), b represents a molecular weight of the electron transport material.

Claims (90)

1 . An electrophotographic photoreceptor comprising:

a conductive support; and

a photosensitive layer and a protective layer disposed on the conductive support, wherein

the protective layer comprises a polymer obtained by polymerizing a compound having a chain polymerizable functional group, and

the photosensitive layer in contact with the protective layer comprises a hole transport material satisfying the following formula (1) and an electron transport material satisfying the following formula (2),

the electron transport material comprises a compound represented by the following formula (6),

the compound represented by the following formula (6) comprises a compound represented by the following formula (7) or (8):

600 ≤a   (1)

400 ≤b   (2)

in the formula (1), a represents a molecular weight of the hole transport material, and

in the formula (2), b represents a molecular weight of the electron transport material,

in the formula (6), R 61 to R 64 each independently represents a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms which may be substituted, or an alkenyl group having 2 or more and 20 or less carbon atoms which may be substituted, R 61 and R 62 or R 63 and R 64 may be bonded to each other to form a cyclic structure, and X represents an organic residue having a molecular weight of 120 or more and 250 or less;

in the formula (7), R 71 to R 73 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms;

in the formula (8), R 81 to R 84 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms.

2 . The electrophotographic photoreceptor according to claim 1 , wherein

the photosensitive layer is a single layer comprising a binder resin, a charge generation material, the hole transport material, and the electron transport material.

3 . The electrophotographic photoreceptor according to claim 2 , wherein

the photosensitive layer satisfies the following formula (3),

0.15≤( A/a )+( B/b )  (3)

in the formula (3), A represents a content (part by mass) of the hole transport material with respect to 100 of a binder resin content, a represents the molecular weight of the hole transport material, B represents a content (part by mass) of the electron transport material with respect to 100 of the binder resin content, and b represents the molecular weight of the electron transport material.

4 . The electrophotographic photoreceptor according to claim 2 , wherein

the photosensitive layer satisfies the following formula (4),

0.80≤ A/B≤ 3.00  (4)

in the formula (4), A represents a content (part by mass) of the hole transport material with respect to 100 of a binder resin content, and B represents a content (part by mass) of the electron transport material with respect to 100 of the binder resin content.

5 . The electrophotographic photoreceptor according to claim 2 , wherein

the photosensitive layer satisfies the following formula (5),

1.20≤( B/b )/( A/a )≤1.60  (5)

in the formula (5), A represents a content (part by mass) of the hole transport material with respect to 100 of a binder resin content, a represents the molecular weight of the hole transport material, B represents a content (part by mass) of the electron transport material with respect to 100 of the binder resin content, and b represents the molecular weight of the electron transport material.

6 . The electrophotographic photoreceptor according to claim 1 , wherein

the hole transport material satisfies the following formula (1′),

600 ≤a ≤1200  (1′)

in the formula (1′), a represents the molecular weight of the hole transport material.

7 . The electrophotographic photoreceptor according to claim 1 , wherein

the electron transport material satisfies the following formula (2′),

400 ≤b ≤1000  (2′)

in the formula (2′), b represents the molecular weight of the electron transport material.

8 . The electrophotographic photoreceptor according to claim 1 , wherein

a ratio (a/b) of the molecular weight of the hole transport material a to the molecular weight of the electron transport material b is 1.40 or more and 1.90 or less.

9 . The electrophotographic photoreceptor according to claim 1 , wherein

the electrophotographic photoreceptor is positively charged.

10 . The electrophotographic photoreceptor according to claim 1 , wherein

the protective layer comprises a polymer obtained by radically polymerizing the compound having a chain polymerizable functional group.

11 . The electrophotographic photoreceptor according to claim 1 , wherein

the protective layer comprises metal oxide fine particles.

12 . The electrophotographic photoreceptor according to claim 11 , wherein

the metal oxide fine particles are surface-treated with a surface treatment agent having a polymerizable functional group.

13 . The electrophotographic photoreceptor according to claim 1 , wherein

the compound having a chain polymerizable functional group comprises a urethane acrylate.

14 . An electrophotographic photoreceptor cartridge comprising:

the electrophotographic photoreceptor according to claim 1 .

15 . An image forming device comprising:

the electrophotographic photoreceptor according to claim 1 .

16 . An electrophotographic photoreceptor comprising:

a conductive support;

a photosensitive layer disposed on the conductive support; and

an outermost layer disposed on the photosensitive layer, wherein

the outermost layer comprises a polymer obtained by polymerizing a compound having a chain polymerizable functional group, and

the photosensitive layer in contact with the outermost layer comprises a hole transport material satisfying the following formula (1) and an electron transport material satisfying the following formula (2),

the electron transport material comprises a compound represented by the following formula (6),

the compound represented by the following formula (6) comprises a compound represented by the following formula (7) or (8):

600 ≤a   (1)

400 ≤b   (2)

in the formula (1), a represents a molecular weight of the hole transport material, and

in the formula (2), b represents a molecular weight of the electron transport material,

in the formula (6), R 61 to R 64 each independently represents a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms which may be substituted, or an alkenyl group having 2 or more and 20 or less carbon atoms which may be substituted, R 61 and R 62 or R 63 and R 64 may be bonded to each other to form a cyclic structure, and X represents an organic residue having a molecular weight of 120 or more and 250 or less;

in the formula (7), R 71 to R 73 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms;

in the formula ( 8 ), R 81 to R 84 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms.

17 . An electrophotographic photoreceptor comprising:

a conductive support; and

a photosensitive layer and a protective layer disposed on the conductive support, wherein

the protective layer comprises a polymer obtained by polymerizing a compound having a chain polymerizable functional group,

the photosensitive layer in contact with the protective layer comprises a binder resin, a hole transport material, and an electron transport material, and

the photosensitive layer in contact with the protective layer satisfies the following formula (5),

1.20≤( B/b )/( A/a )≤1.60  (5)

in the formula (5), A represents a content (part by mass) of the hole transport material with respect to 100 of the binder resin content, a represents a molecular weight of the hole transport material, B represents a content (part by mass) of the electron transport material with respect to 100 of the binder resin content, and b represents a molecular weight of the electron transport material,

the electron transport material comprises a compound represented by the following formula (6),

the compound represented by the following formula (6) comprises a compound represented by the following formula (7) or (8):

in the formula (6), R 61 to R 64 each independently represents a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms which may be substituted, or an alkenyl group having 2 or more and 20 or less carbon atoms which may be substituted, R 61 and R 62 or R 63 and R 64 may be bonded to each other to form a cyclic structure, and X represents an organic residue having a molecular weight of 120 or more and 250 or less;

in the formula (7), R 71 to R 73 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms;

in the formula (8), R 81 to R 84 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms.

18 . An electrophotographic photoreceptor comprising:

a conductive support; and

a photosensitive layer and a protective layer disposed on the conductive support, wherein the protective layer comprises a polymer obtained by polymerizing a compound having a chain polymerizable functional group,

the photosensitive layer in contact with the protective layer comprises a hole transport material and an electron transport material, and

a ratio (a/b) of a molecular weight of the hole transport material a to a molecular weight of the electron transport material b is 1.40 or more and 1.90 or less,

the electron transport material comprises a compound represented by the following formula (6),

the compound represented by the following formula (6) comprises a compound represented by the following formula (7) or (8);

in the formula (6), R 61 to R 64 each independently represents a hydrogen atom, an alkyl group having 1 or more and 20 or less carbon atoms which may be substituted, or an alkenyl group having 2 or more and 20 or less carbon atoms which may be substituted, R 61 and R 62 or R 63 and R 64 may be bonded to each other to form a cyclic structure, and X represents an organic residue having a molecular weight of 120 or more and 250 or less;

in the formula (7), R 71 to R 73 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms;

in the formula (8), R 81 to R 84 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having 1 or more and 6 or less carbon atoms.