Electrophotographic photosensitive member, process cartridge, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-10539889-B2
Application number	US-201916260255-A
Country	US
Kind code	B2
Filing date	Jan 29, 2019
Priority date	Jan 31, 2018
Publication date	Jan 21, 2020
Grant date	Jan 21, 2020

Abstract

An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer of a single layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. An optical response time is at least 0.05 milliseconds and no greater than 0.85 milliseconds. The binder resin includes a polycarbonate resin including a repeating unit represented by general formula (1) shown below and a repeating unit represented by general formula (2) shown below.

First claim

What is claimed is:

1. An electrophotographic photosensitive member comprising a conductive substrate and a photosensitive layer of a single layer, wherein
the photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin,
an optical response time is at least 0.05 milliseconds and no greater than 0.85 milliseconds,
the optical response time is a time from irradiation to decay, the irradiation being a time of a start of irradiation of a surface of the photosensitive layer charged to +800 V with pulse light having a wavelength of 780 nm, the decay being a time when a surface potential of the photosensitive layer decays from +800 V to +400 V,
an optical intensity of the pulse light is set so that the surface potential of the photosensitive layer becomes +200 V from +800 V when 400 milliseconds elapse after the irradiation of the surface of the photosensitive layer charged to +800 V with the pulse light,
the binder resin includes a polycarbonate resin including a repeating unit represented by a general formula (1) shown below and a repeating unit represented by a general formula (2) shown below, and
the hole transport material is a compound represented by a chemical formula (16-HT7), (17-HT19), or (18-HT21) shown below,

where in the general formula (1),
R 1 , R 2 , R 3 , and R 4 each represent, independently of one another, a hydrogen atom, an alkyl group having a carbon number of at least 1 and no greater than 3 and optionally substituted by a halogen atom, or an aryl group having a carbon number of at least 6 and no greater than 14, and
R 3 and R 4 may be bonded together to form a ring of a divalent group represented by a general formula (X) shown below,
in the general formula (2),
R 5 and R 6 each represent, independently of each other, a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 3 and optionally substituted by a substituent, and
W represents a single bond, —O—, or —CO—,

where in the general formula (X),
t represents an integer of at least 1 and no greater than 3, and
* represents a bond,

2. The electrophotographic photosensitive member according to claim 1 , wherein
a ratio m HTM /m ETM of a mass m HTM of the hole transport material to a mass m ETM of the electron transport material is at least 1.2 and no greater than 4.0.

3. The electrophotographic photosensitive member according to claim 1 , wherein
a mass m HTM of the hole transport material, a mass m ETM of the electron transport material, and a mass m R of the binder resin satisfy a relational expression (A):
[( m HTM +m ETM )/ m R ]>1.30  (A).

4. The electrophotographic photosensitive member according to claim 1 , wherein
a content of the hole transport material relative to a mass of the photosensitive layer is at least 35% by mass and no greater than 65% by mass.

5. The electrophotographic photosensitive member according to claim 1 , wherein
the optical response time is at least 0.05 milliseconds and no greater than 0.60 milliseconds.

6. The electrophotographic photosensitive member according to claim 1 , wherein
the repeating unit represented by the general formula (1) is a repeating unit represented by any one of chemical formulas (1-1), (1-2), (1-3), and (1-4) shown below,

7. The electrophotographic photosensitive member according to claim 6 , wherein
the polycarbonate resin is any one of:
a first polycarbonate resin including a repeating unit represented by the chemical formula (1-1) shown below and a repeating unit represented by a chemical formula (2-1) shown below;
a second polycarbonate resin including a repeating unit represented by the chemical formula (1-2) shown below and the repeating unit represented by the chemical formula (2-1);
a third polycarbonate resin including a repeating unit represented by the chemical formula (1-3) shown below and the repeating unit represented by the chemical formula (2-1);
a fourth polycarbonate resin including a repeating unit represented by the chemical formula (1-4) shown below and a repeating unit represented by a chemical formula (2-2) shown below;
a fifth polycarbonate resin including the repeating unit represented by the chemical formula (1-1) and a repeating unit represented by a chemical formula (2-3) shown below;
a sixth polycarbonate resin including the repeating unit represented by the chemical formula (1-2) and the repeating unit represented by the chemical formula (2-3);
a seventh polycarbonate resin including the repeating unit represented by the chemical formula (1-2) and a repeating unit represented by a chemical formula (2-4) shown below; and
an eighth polycarbonate resin including the repeating unit represented by the chemical formula (1-1) and the repeating unit represented by the chemical formula (2-2),

8. The electrophotographic photosensitive member according to claim 1 , wherein
the repeating unit represented by the general formula (2) is a repeating unit represented by any one of chemical formulas (2-1), (2-2), (2-3), and (2-4) shown below,

9. The electrophotographic photosensitive member according to claim 1 , wherein
the electron transport material includes at least one of compounds represented by general formulas (21), (22), and (23) shown below,

where in the general formula (21), R 11 and R 12 each represent, independently of each other, an alkyl group having a carbon number of at least 1 and no greater than 6, an alkoxy group having a carbon number of at least 1 and no greater than 6, an aryl group having a carbon number of at least 6 and no greater than 14, or an aralkyl group having a carbon number of at least 7 and no greater than 20,
in the general formula (22), R 21 , R 22 , and R 23 each represent, independently of one another, a halogen atom, an alkyl group having a carbon number of at least 1 and no greater than 6, an alkoxy group having a carbon number of at least 1 and no greater than 6, an aryl group having a carbon number of at least 6 and no greater than 14 and optionally substituted by a halogen atom, an aralkyl group having a carbon number of at least 7 and no greater than 20, or a heterocyclic group having at least 5 members and no greater than 14 members, and
in the general formula (23), R 31 and R 32 each represent, independently of each other, a halogen atom, an amino group, an alkyl group having a carbon number of at least 1 and no greater than 6, an alkoxy group having a carbon number of at least 1 and no greater than 6, or an aryl group having a carbon number of at least 6 and no greater than 14 and optionally substituted by a substituent.

10. The electrophotographic photosensitive member according to claim 1 , wherein
the electron transport material includes at least one of compounds represented by general formulas (ET1), (ET2), and (ET3) shown below,

Assignees

• Kyocera Document Solutions Inc

Inventors

• Iwashita Yuko
• Hamasaki Kazunari
• Sugimoto Kazutaka

Classifications

• G03G5/0564 Primary

  Polycarbonates · CPC title

• G03G21/18

  using a processing cartridge {, whereby the process cartridge comprises at least two image processing means in a single unit} · CPC title

• G03G5/04

  Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor · CPC title

• G03G5/0609

  containing oxygen · CPC title

• G03G5/0696

  Phthalocyanines · CPC title