Granted Patent B2

US 12,429,784 · App. 17/816,028 · Granted Sep 30, 2025

Inventors: Kohei Makisumi (Shizuoka, JP); Kaname Watariguchi (Kanagawa, JP); Kenichi Kaku (Shizuoka, JP); Haruyuki Tsuji (Kanagawa, JP)

Assignee: CANON KABUSHIKI KAISHA

G03G5/047G03G5/0696G03G5/144G03G15/75

Abstract

Claims (68)

1. An electrophotographic photosensitive member, comprising:

a support;

a charge-generating layer formed on the support; and

a charge-transporting layer formed on the charge-generating layer;

the electrophotographic photosensitive member being an organic photosensitive member;

the charge-generating layer containing a hydroxygallium phthalocyanine pigment, the hydroxygallium phthalocyanine pigment containing (i) crystal grains of a crystal form showing peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in an X-ray diffraction spectrum using a CuKα ray, and (ii) N-methylformamide; and

the charge-transporting layer contains a triarylamine compound represented by (CTM-1) and a triarylamine compound represented by (CTM-2) as charge-transporting substances

wherein, in an EV curve graph that is obtained at a temperature of 23.5 [° C.] and a relative humidity of 50 [% RH] having a horizontal axis representing I exp and a vertical axis representing V exp ,

when V r [V] is V exp at I exp =0.500 [μJ/cm 2 ],

S max [V·μJ/cm 2 ] is a maximum value of S=I exp ·(V exp −V r ) in a range of I exp =0.000 to 0.030 [μJ/cm 2 ],

S i =I i ·(V i −V r ) [V·μJ/cm 2 ] is a product of a light amount I i [μJ/cm 2 ] on the horizontal axis and a potential V i [V] on the vertical axis at a point of intersection between an approximate straight line in a range of I exp =0.000 to 0.010 [μJ/cm 2 ] and an approximate straight line in a range of I exp =0.490 to 0.500 [μJ/cm 2 ], and

AR≤0.10 when AR is S i /S max , and

V r [V] satisfies V r ≤30, and the EV curve is measured by steps comprising

(1) setting a surface potential of the electrophotographic photosensitive member to 0 [V];

(2) charging the electrophotographic photosensitive member for 0.005 second so that an absolute value of an initial surface potential of the electrophotographic photosensitive member becomes V 0 [V];

(3) after 0.02 second from start of the charging, continuously exposing the electrophotographic photosensitive member to light having a wavelength of 805 [nm] and an intensity of 25 [mW/cm 2 ] for “t” second(s) so as to achieve an exposure amount of I exp [μJ/cm 2 ];

(4): after 0.06 second from the start of the charging, measuring an absolute value of a surface potential of the electrophotographic photosensitive member after the exposure which is represented by V exp [V];

(5) repeating operations (1) to (4) while changing I exp from 0.000 [μJ/cm 2 ] to 1.000 [μJ/cm 2 ] at intervals of 0.001 [μJ/cm 2 ], in order to obtain V exp [V] corresponding to each I exp ; and

(6) V exp [V] at t=0 and I exp =0.000 [μJ/cm 2 ] in operation (3) is a charged potential V d [V], and the V 0 [V] in operation (2) is set such that V d [V] is 300 V.

2. The electrophotographic photosensitive member according to claim 1 , wherein AR≤0.09.

3. The electrophotographic photosensitive member according to claim 1 , wherein LR max ≥2,000 when V exp and I exp at a time when the S becomes S max are respectively represented by V max and I max , and (V max −V r )/I max is represented by LR max .

4. The electrophotographic photosensitive member according to claim 3 , wherein LR max 23,000.

5. The electrophotographic photosensitive member according to claim 1 , further comprising an undercoat layer formed between the support and the charge-generating layer;

the undercoat layer comprises a polyamide resin, and titanium oxide particles subjected to surface treatment with a compound represented by formula (1)

when R 1 represents a methyl group, an ethyl group, an acetyl group or a 2-methoxyethyl group, R 2 represents a hydrogen atom or a methyl group, m+n=3, m is an integer of 0 or more, and n is an integer of 1 or more, wherein

14.0≤a/b≤19.1 (A) when a is a ratio of a volume of the titanium oxide particles to a volume of the polyamide resin in the undercoat layer and b [μm] is an average primary particle diameter of the titanium oxide particles.

6. A process cartridge, comprising:

an electrophotographic photosensitive member; and

at least one member selected from the group consisting of a charging unit, a developing unit and a cleaning unit;

the process cartridge integrally supporting the electrophotographic photosensitive member and the at least one member, 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, and a charge-transporting layer formed on the charge-generating layer;

the electrophotographic photosensitive member being an organic photosensitive member;

the charge-generating layer containing a hydroxygallium phthalocyanine pigment, the hydroxygallium phthalocyanine pigment containing (i) crystal grains of a crystal form showing peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in an X-ray diffraction spectrum using a CuKα ray, and (ii)N-methylformamide; and

the charge-transporting layer contains a triarylamine compound represented by (CTM-1) and a triarylamine compound represented by (CTM-2) as charge-transporting substances

wherein, in an EV curve graph that is obtained at a temperature of 23.5 [° C.] and a relative humidity of 50 [% RH] having a horizontal axis representing I exp and a vertical axis representing V exp ,

when V r [V] is V exp at I exp =0.500 [μJ/cm 2 ],

S max [V·μJ/cm 2 ] is a maximum value of S=I exp ·(V exp −V r ) in a range of I exp =0.000 to 0.030 [μJ/cm 2 ],

S i =I i (V i −V r ) [V·μJ/cm 2 ] is a product of a light amount I i [μJ/cm 2 ] on the horizontal axis and a potential V i [V] on the vertical axis at a point of intersection between an approximate straight line in a range of I exp =0.000 to 0.010 [μJ/cm 2 ] and an approximate straight line in a range of I exp =0.490 to 0.500 [μJ/cm 2 ], and

AR≤0.10 when AR is S i /S max , and

V r [V] satisfies V r ≤30, and the EV curve is measured by steps comprising

(1) setting a surface potential of the electrophotographic photosensitive member to 0 [V];

(2) charging the electrophotographic photosensitive member for 0.005 second so that an absolute value of an initial surface potential of the electrophotographic photosensitive member becomes V 0 [V];

(3) after 0.02 second from start of the charging, continuously exposing the electrophotographic photosensitive member to light having a wavelength of 805 [nm] and an intensity of 25 [mW/cm 2 ] for “t” second(s) so as to achieve an exposure amount of I exp [μJ/cm 2 ];

(4): after 0.06 second from the start of the charging, measuring an absolute value of a surface potential of the electrophotographic photosensitive member after the exposure which is represented by V exp [V];

(5) repeating operations (1) to (4) while changing I exp from 0.000 [μJ/cm 2 ] to 1.000 [μJ/cm 2 ] at intervals of 0.001 [μJ/cm 2 ], in order to obtain V exp [V] corresponding to each I exp ; and

(6) V exp [V] at t=0 and I exp =0.000 [μJ/cm 2 ] in operation (3) is a charged potential V d [V], and the V 0 [V] in operation (2) is set such that V d [V] is 300 V.

7. An electrophotographic apparatus, comprising:

an electrophotographic photosensitive member;

a charging unit;

an image exposing unit;

a developing unit; and

a transferring unit,

the electrophotographic photosensitive member comprising a support, a charge-generating layer formed on the support, and a charge-transporting layer formed on the charge-generating layer;

the electrophotographic photosensitive member being an organic photosensitive member;

the charge-generating layer containing a hydroxygallium phthalocyanine pigment, the hydroxygallium phthalocyanine pigment containing (i) crystal grains of a crystal form showing peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in an X-ray diffraction spectrum using a CuKα ray, and (ii)N-methylformamide; and

the charge-transporting layer contains a triarylamine compound represented by (CTM-1) and a triarylamine compound represented by (CTM-2) as charge-transporting substances

wherein, in an EV curve graph that is obtained at a temperature of 23.5 [° C.] and a relative humidity of 50 [% RH] having a horizontal axis representing I exp and a vertical axis representing V exp ,

when V r [V] is V exp at I exp =0.500 [μJ/cm 2 ],

S max [V·μJ/cm 2 ] is a maximum value of S=I exp ·(V exp −V r ) in a range of I exp =0.000 to 0.030 [μJ/cm 2 ],

S i =I i ·(V i -V r ) [V·μJ/cm 2 ] is a product of a light amount I i [μJ/cm 2 ] on the horizontal axis and a potential V i [V] on the vertical axis at a point of intersection between an approximate straight line in a range of I exp =0.000 to 0.010 [μJ/cm 2 ] and an approximate straight line in a range of I exp =0.490 to 0.500 [μJ/cm 2 ], and

AR≤0.10 when AR is S i /S max , and

V r [V] satisfies V r ≤30, and the EV curve is measured by steps comprising

(1) setting a surface potential of the electrophotographic photosensitive member to 0 [V];

(2) charging the electrophotographic photosensitive member for 0.005 second so that an absolute value of an initial surface potential of the electrophotographic photosensitive member becomes V 0 [V];

(3) after 0.02 second from start of the charging, continuously exposing the electrophotographic photosensitive member to light having a wavelength of 805 [nm] and an intensity of 25 [mW/cm 2 ] for “t” second(s) so as to achieve an exposure amount of I exp [μJ/cm 2 ];

(4): after 0.06 second from the start of the charging, measuring an absolute value of a surface potential of the electrophotographic photosensitive member after the exposure which is represented by V exp [V];

(5) repeating operations (1) to (4) while changing I exp from 0.000 [μJ/cm 2 ] to 1.000 [μJ/cm 2 ] at intervals of 0.001 [μJ/cm 2 ], in order to obtain V exp [V] corresponding to each I exp ; and

(6) V exp [V] at t=0 and I exp =0.000 [μJ/cm 2 ] in operation (3) is a charged potential V d [V], and the V 0 [V] in operation (2) is set such that V d [V] is 300 V.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (84)