JPH0254271A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body having an excellent adhesive property and excellent image quality stability with temp. and humidity changes by incorporating specific resin binders into the photosensitive body. CONSTITUTION:The resin binders expressed by the general formulas I, II and III are incorporated into a charge generating layer as the resin binder thereof. In the formulas I, II and III, n denotes an integer; R denotes H or C3H7; x denotes >=73wt.%; y denotes 4 to 24wt.% z denotes 3 to 24wt.%. The weight average mol. wt. of the resin expressed by the formula I and the weight average mol. wt. the resin expressed by the formula II are preferably in a 1,000 to 100,000 range and the weight average mol. wt. of the resin expressed by the formula III is preferably in a 50,000 to 350,000 range. The photosensitive body which has the excellent adhesive property, the excellent electrophotographic characteristics such as electrostatic chargeability, dark attenuation and sensitiv ity and the excellent repetitive characteristic and moisture resistance is obtd. in this way.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electrophotographic photoreceptor.

[Conventional technology]

Conventionally, in electrophotographic photoreceptors that use photoconductive substances as photosensitive materials, selenium and zinc oxide have been used.

Inorganic photoconductive materials such as titanium oxide and cadmium oxide have been mainly used. But these.

Generally, many of them are highly toxic, and there are problems with how to dispose of them.

On the other hand, the use of organic photoconductive compounds is generally more effective than the use of inorganic photoconductive materials.

It has low toxicity, is transparent, flexible, and lightweight.

Surface smoothness 9 Since it is advantageous in terms of price, etc.
Recently, it has been widely studied. Among them, functionally separated electrophotographic photoreceptors, which are provided with a charge generation layer that generates charge carriers by light absorption and a charge transport layer that transports the generated charge carriers by an electric field, have conventionally used organic photoconductive compounds. Rapid progress has been made in recent years because the sensitivity, which was a major drawback of the photoreceptors used, can be greatly improved.

When these composites are applied to an electrophotographic device using a photoreceptor using the Carlson method, an electrostatic latent image is first formed on the surface of the photoreceptor, and then a developer, generally called toner, charged with the same or different sign is applied. It is possible to develop the toner image with an agent and transfer and fix the toner image onto another substrate 9, such as paper, to obtain a copy.

[Problem to be solved by the invention]

Electrophotographic photoreceptors are used in copiers, laser beam blinkers (
It is installed in light emission diode printers (hereinafter abbreviated as LBP), light emission diode printers (hereinafter abbreviated as LEDP), etc.
Recently, the printing speed of these devices has become much faster, and the devices themselves are becoming smaller, and the process time per print (charging-exposure-development-erasing time) is also becoming shorter. Therefore, in terms of electrophotographic properties, the photoreceptor has fast photoresponsiveness, high sensitivity, and excellent charging properties, and in terms of image quality, it satisfies stability against environmental changes and stability in continuous printing. 1. In terms of mechanical strength, there has been an increasing demand for higher depth adhesion of photoreceptor films.

However, by repeating a series of steps such as rapid charging, exposure, development, and erasing, the charging properties of the photoreceptor change and the sensitivity decreases, and as a result, the transferred image becomes unclear, or the so-called There have been problems such as deterioration in image quality called fog and peeling of the film on the electrophotographic photoreceptor.

The present inventors have proposed a method for preventing changes in the chargeability of the photoreceptor, deterioration in sensitivity, and deterioration in image quality among these drawbacks (Specification of % Intercondylar No. 62-277737). By using this method, it is possible to obtain an electrophotographic photoreceptor with good image quality and less change in electrophotographic characteristics even with environmental changes, especially changes in temperature and humidity, even during continuous printing. Although there is no practical problem with the adhesion of the film, it is expected that the printing speed of printers will become faster in the future and the number of prints per side of the photoreceptor will increase. In this case, it is necessary to improve the adhesion of the film from the viewpoint of the mechanical life of the photoreceptor. It is known to use polyvinyl formal resin, polyvinyl butyral resin, or phenoxy resin as a resin binder used as a binder for the charge generation layer (% opening/closing 60-2).
No. 02448, No. 61-210361, No. 61-23
No. 5844, No. 58-105154 and JP-A-60-2
32554). Although these publications show remarkable effects in improving adhesion, they are unsatisfactory in terms of electrophotographic properties. That is, in a continuous printing test, a decrease in charging potential (Vo) and a decrease in sensitivity occur.

Decreased density and fogging occur. In addition, the performance of the photoreceptor is
It changes significantly due to environmental changes, especially environmental humidity, and due to a decrease in charging potential. The problem is that image defects such as black spots, white spots, and fog are more likely to occur.

The present invention has been made in view of the above points, and it is an object of the present invention to obtain an electrophotographic photoreceptor that has excellent adhesion and excellent image quality stability against changes in temperature and humidity. .

[Means to solve the problem]

The present invention relates to an electrophotographic photoreceptor having a charge generation layer containing an organic pigment that generates charges and a charge transport layer containing a charge transport agent on a conductive substrate.

As the resin binder of the charge generation layer, general 2m(11) and (IIN) 1(I) [in formulas (I) (b) and ([1), n is a positive integer, R is H
Or C3H71X is 73 wt% or more, y is 4 to 24 w
t % +2 indicates 3 to 24 wt %. The present invention relates to an electrophotographic photoreceptor comprising a resin binder represented by the following formula.

The electrophotographic photoreceptor according to the present invention will be described in detail below.

First, in the present invention, the conductive substrate is a conductive body such as paper or plastic film subjected to conductivity treatment, a plastic film laminated with metal foil such as aluminum, a metal plate, or a metal drum.

In the present invention, the charge-generating organic pigment contained in the charge-generating layer is an azoxybenzene-based pigment.

Disazo series, trisazo series, benzimidazole series, polycyclic quinoline series, indigoid series, quinacridone series, 7
Pigments known to generate charges, such as talocyanine-based, perylene-based, methine-based pigments, can be used. These pigments are described in, for example, JP-A-47-37543 and JP-A-47-3.
No. 7544, No. 47-18543, No. 47-1854
No. 4, No. 48-43942, No. 48-70538,
No. 49-1231, No. 49-105536, No. 50
This method is disclosed in Japanese Patent No. 75214 and No. 50-92738. Among these pigments, phthalocyanine pigments are preferred from the viewpoint of the balance of electrophotographic properties. Also, among the phthalocyanine pigments, JP-A-58
-182640 and European Patent Application Publication No. 9
The τ, bi, v and p type metal-free 7-talocyanines described in Japanese Patent No. 2255 are preferred.

τ, τ′, v and η′ type gold metal phthalocyanines.

It has high sensitivity up to long wavelengths K and is effective as an electrophotographic photoreceptor for printers equipped with diode lasers. In addition to these, any organic pigment that generates charge carriers upon irradiation with light can be used.

(-, the resin represented by the general formula (1), (QI[Il) is an essential component.

The resin represented by the general formula (]) is already a known resin and 2
For example, Milesox XL-225, Milesox XL-22
5L, Miresox XL-225LL (manufactured by Mitsui Toatsu Chemical Co., Ltd.), etc. can be commercially produced manually. General formula (
The weight average molecular weight of the resin represented by I) is t,ooo~
Preferably it is in the range of 100,000. 1,00
If it is less than 0, the mechanical strength of the charge generation layer tends to be poor, and if it exceeds 100,000, the workability during formation of the charge generation layer tends to be poor.

The resin represented by the general formula (II) is already a known resin and can be obtained commercially, for example, as YP50 (manufactured by Toto Kasei). The weight average molecular weight of the resin represented by the general formula ([[l is preferably in the range of t, ooo to 100,000. In the case of t, ooo ungrooved,
Electric charge is generated! -The resin strength of 100,
If it exceeds 000, workability during formation of the charge generation layer tends to deteriorate.

The resin shown in the general formula (old) is already a well-known resin.2For example, Φ2000-L,
0 (manufactured by Denki Kagaku Kogyo). The weight average molecular weight of the resin represented by the general formula ([) is preferably in the range of 50,000 to 350,000. If it is less than 50,000, the dispersibility of the charge generation layer coating solution will be poor and it will be difficult to form a uniform charge generation layer.
As a resin binder, resins represented by the above general formulas (l\n) and (l) are essential components, but general formulas (I), (I
It is preferable to use in combination a resin containing an incyanate group that reacts with the hydroxyl group of the resin (II and D).

7 general formulas used in the present invention (bow (■) and (IIl)
The resin containing an incyanate group that reacts with the hydroxyl group of the resin is an incyanate resin having more than one isocyanate group in 9 molecules, and from the viewpoint of oral stability of the charge generation layer coating liquid, the isocyanate group is Blocked isocyanate, which is masked with a blocking agent such as phenol, is preferred.

Further, commercially available resins containing incyanate groups that react with the hydroxyl groups of the resins of general formulas (1)J■) and (Ill) are Coronate 2507. It can be obtained as Coronate 2513°, Coronate 2515 (manufactured by Nippon Polyurethane), etc.

The amount of the resin binder in the charge generation layer is preferably 5 to 200 parts by weight, more preferably 10 to 100 parts by weight, based on 160 parts by weight of the organic pigment that generates charges. 5
If the amount is less than 1 part by weight, the adhesion will be poor, and the film of the charge generation layer will tend to be uneven and uneven, resulting in poor image quality. When it exceeds 200 heavy lids.

Sensitivity tends to decrease and residual potential increases.

It is also commonly used in charge generation layers in electrophotographic photoreceptors.

A plasticizer, fluidity imparting agent, and pinhole control agent can be used as necessary.

Examples of the plasticizer include halogenated paraffin, dimethylnaphthalene, and dibutyl phthalate. Examples of the fluidity imparting agent include Modaflow (manufactured by Monnant Chemical Co., Ltd.) and Acronal 4F (manufactured by Kusufu Co., Ltd.), and examples of the pinhole control agent include benzoin and dimethyl phthalate. Each of these is preferably used in an amount of 5% by weight or less based on the charge-generating organic pigment.

How to form a charge generation layer is! A solution containing a uniform mixture of organic pigments, resin binders, curing agents, additives, etc. that generate electrical charges in a solvent is applied onto the conductive substrate (undercoat layer, if there is one) by dip coating or spray coating. It can be formed by applying a coating using a coating method such as a coating method, a roll coating method, an applicator coating method, a wire bar coating method, or the like, and drying it.

In this case, the solvent used is acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, ethyl acetate, cellosolve, xylene, methanol, methylene chloride.

1, 1.2-1) Solvents include chloroethane, isopropyl alcohol, isobutyl alcohol, n-butyl alcohol, and trichloroethane.

The thickness of the charge generation layer is 0.001 to 10 μm, preferably 0.1 to 5 μm. If this thickness is less than 0.001, it will be difficult to uniformly form the m load generation layer,
When the thickness exceeds 10 μm, the electron beam characteristics tend to deteriorate.

A charge transport layer is provided on the L&charge generation layer formed as described above. The charge transport layer '1 contains a charge transport substance, a binder and other additives.

The charge transport substance used in the charge transport layer includes fluorene, fluorenone, 47-sinitro-9-fluorenone,
4H-indeno(1,2,6)thiophen-4-one,
λ7-sinitrodibenzothiophene-5-oxide,
1-bromopyrene, 2-phenylpyrene, carbazole, 3-phenylcarbasol, 2-phenylindole, 2-phenylnaphthalene, oxazole, oxadiazole, oxatriazole, triphenylamine.

imidazole, chrysene, tetrafen, acridene,
Various food hydrazones, styryl compounds, poly-N-vinylcarbasol, halogenated fluorol, 1-phenyl-3-(4-diethylaminosteryl)-5-(4-diethylaminophenyl)pyrazoline , polyvinyl bire 7.2-phenyl-4-(4-diethylaminophenyl)-5-phenyloxazole, polyhinyl indoquinoxaline, 1.1-bis(p-diethylaminophenyl)-4,4-diphenyl-1 ,3
-butadiene, polyvinylbenzotheophene, polyvinylanthracene, polyvinylacridine.

Examples include polyvinylpyrazoline and derivatives thereof.

Silicone resin is used as a binder for the charge transport layer.

Polyamide resin, polyurethane resin, polyester resin, epoxy resin, polycarbonate resin.

Polystyrene resin, polymethyl methacrylate resin.

Polyacrylamide resin, polybutadiene resin.

Polyisoprene resin, phenolic resin, melamine resin,
Ethyl cellulose resin, nitrocellulose resin, polyvinyl alcohol resin, polyvinyl formal resin, polychloroprene resin, polyvinyl butyral resin, alkyl vinyl-fluorine copolymer, cycloargyl vinyl-fluorine copolymer.

Vinyl acetate resin, polyacrylonitrile resin, urea resin, acrylonitrile-styrene copolymer.

Examples include maleic anhydride-styrene copolymer, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer, and pre-dated products thereof.

Heat and/or photocurable resins can also be used.

In any case, there are no particular limitations as long as the resin is electrically insulating and can form a film under normal conditions. These binding agents! The amount is preferably 400 parts by weight or less per 100 parts by weight of the charge transport material so as not to deteriorate the electrophotographic properties, and for low-molecular charge transport materials, the amount is preferably 50 parts by weight or more in view of film properties.

Further, the same additives as in the charge generation layer, such as a plasticizer, a fluidity imparting agent, a pinhole control agent, etc., can be used in the charge transport layer, if necessary. Each additive is preferably present in an amount of 5 parts by weight or less based on the charge transport material.

To form the charge transport layer, the charge transport material, binder, and additives are uniformly dissolved in the same solvent used to create the charge generation layer, and then this solution is applied onto the charge generation layer by dip coating. It can be formed by coating using a coating method such as , spray coating, roll coating, applicator coating, wire per coating, etc., and drying.

The thickness of the charge transport layer is 5 to 50 μm, preferably 8 to 30 μm.
It is μm. If it is less than 5 μm, the initial potential will be low and 5 μm.
If it exceeds 0 μm, sensitivity tends to decrease.

The electrophotographic photoreceptor of the present invention preferably has an undercoat layer between the conductive substrate and the charge generation layer from the viewpoint of stabilizing image quality (especially preventing fogging).

The undercoat layer is a layer mainly composed of resin, and the resin used is, for example, polyamide resin.

Polyurethane resin, polyvinyl butyral resin.

Melamine resin, casein, phenolic resin, epoxy resin, ethylene-vinyl acetate copolymer resin.

Examples include ethylene-acrylic acid copolymer resin. These resins may be used alone or in combination of two or more.

As a method for forming the undercoat layer, a solution prepared by dissolving the resin in an appropriate solvent is applied onto the conductive substrate by a coating method such as a dip coating method, a spray coating method, a roll coating method, an applicator coating method, a wire per coating method, or the like. It can be formed by coating and drying. The thickness of the lower bow layer is 0.01 to 5.0μ
m, preferably 0.05 to zOμm. If the thickness is less than 0.01, it becomes difficult to form a uniform charge generation layer, and black spots and white spots tend to occur, resulting in a decrease in image quality. Furthermore, if the distance exceeds 5°08 m, residual potential accumulates significantly, and as the number of sheets printed increases, printing density tends to decrease and fogging tends to occur.

In the electrophotographic photoreceptor of the present invention, a charge generation layer and a charge transport layer are sequentially laminated on a conductive substrate.

A protective layer may be further formed thereon. The thickness of the protective layer is 0.01 to 10 μm, preferably 0.1 to 3 μm. If it is less than 0.01 μm, it will have little effect as a protective layer and its durability will be poor, and if it exceeds 10 μm, it will have poor sensitivity.
Residual potential tends to increase.

When printing is performed using the electrophotographic photoreceptor of the present invention, it is charged and exposed in the same manner as before.

All you have to do is develop it, transfer the image onto plain paper, and fix it.

〔Example〕

Next, the present invention will be explained in detail based on examples.

The present invention is not limited to this. Each material used in the examples below is listed below. Abbreviations are shown in parentheses.

(1) Charge-generating organic pigment τ metal-free phthalocyanine (τ-H2P c ) (:
Manufactured by Toyo Ink] (2) Charge transport substance butadiene derivative: 1,1-bis(p-dietheraminophenyl)-4,4-diphenyl-1°3-butadiene (FBDI) (3) Binder Required binder polyamide resin: Ml 276←≠≠ solid content 1
00qb [manufactured by Nippon Rilsan] Melamine resin: Melan 2000 (ML2000) solid content 50% [manufactured by Hitachi Chemical] I3) Binder for charge generation layer (xt-ut
Resin of general formula (1) 2XL-225A solid content 100 cm [manufactured by Maruzen Oil] Resin of general formula (■): YP-50 Solid content 100% [manufactured by Tobu Kasei] General formula ([[ Resin of I): +20 Solid content 100% [manufactured by Denki Kagaku Kogyo] Silicone varnish: KR2,14←M-Kikite Block-in 7 Anate: Coronate 2507 Solid content 80% [
Made by Nippon Polyurethane] FC) Charge transport layer binder polycarbonate resin Newpilon 3-3000 (UP
3000) Solid content 100chi [Mitsubishi Gas Kagakuchi] Comparative Example 1 3.5g of M1276, &5g of ML2000 and 0.3g.
21 g of trimellitic acid was completely dissolved in 93 g of a 1:1 mixed solvent of methanol and methylene chloride. This solution was applied with an applicator onto an aluminum plate (thickness Q of the conductive substrate, 1 rm), and dried at 120° C. for 20 minutes to form a subbing layer with a thickness of 0.3 μm.

Next, 15g0T H2PO, Z5g +20°20
g of Coronate 2507 and 75 g of tetrahydrofuran were kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.). The obtained pigment dispersion was applied onto the undercoat layer using an applicator and heated at 120°C for 30°C.
A charge generation layer having a thickness of 0.3 μm was formed by drying for 1 minute.

Next, a, og of PBD and 7.0 g of UP3000 were mixed with methylene chloride and 1:1.2-trichloroethane.
It was completely dissolved in 90 g of the mixed solvent of 1. This solution was applied onto the charge generation layer having the undercoat layer using an applicator and dried at 120° C. for 30 minutes to form a charge transport layer with a thickness of 18 μm. .

Comparative Example 2 A sublayer having a thickness of 0.6 μm was formed on an aluminum plate (conductive substrate thickness: 0.1[1]) using the materials and procedures shown in Comparative Example 1.

Next, Z5g's τH2PC, 3,6H's YP-50°7
．． 2 g of Coronate 2507 and 86.7 g of tetrahydrofuran were kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.). The obtained pigment dispersion was applied onto the undercoat layer using an applicator and heated at 120°C.
This was dried for 30 minutes to form a charge generation layer with a thickness of 0.4 μm.

Next, using the substance and operation shown in Comparative Example 1, a film thickness of 18
9. Form a charge transport layer with a thickness of μm to form an electrophotographic photoreceptor.

Comparative Example 3 25 g of τ-H2P c + Z 5 g of +20 2
0 g of Coronate 2507 and 7.5 g of tetrahydrofuran were ball milled (3-inch bot mill manufactured by Nihon Kagaku Togyo).
The mixture was kneaded for 8 hours. The obtained pigment dispersion was applied to an aluminum plate (thickness of the conductive substrate, Q, I Ml
) and dried at 120°C for 30 minutes to a film thickness of 0.
A charge generation layer of 8 μm was formed.

Next, using the substance and operation shown in Comparative Example 1, a film thickness of 18
A charge transport layer with a thickness of .mu.m was formed, and a secondary photographic photoreceptor was formed.

Comparative Example 4 2.5g fH2PO, 3.6g YP-507,
2 g of Coronate 2507 and 86.7 g of tetrahydrofuran were kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.). The obtained pigment dispersion was transferred to a sialuminium plate (conductive substrate thickness: 0.11 g) using a 7 precoater.
m) and dried at 120°C for 30 minutes until the film thickness was 0.
．． A charge generation layer of 8 μm was formed.

Next, using the substance and operation shown in Comparative Example 1, a film thickness of 18
A charge transport layer with a thickness of μm was formed to form an electrophotographic photoreceptor.

Comparative Example 5 A descending layer with a thickness of 0.6 μm was formed on an aluminum plate (conductive substrate thickness: 0.1 m1) using the materials and procedures shown in Comparative Example 1.

Next, 2.5 g of τH2P CI 3.6 g of XL2
25゜12.6g Coronate 2507 and 81.3g
of tetrahydrofuran using a ball mill (manufactured by Nippon Kagaku Togyo 3)
The mixture was kneaded for 8 hours using a small-sized bot mill. Coat the obtained pigment dispersion onto the undercoat layer using the entire applicator.
,, It was dried at 120° C. for 30 minutes to form a charge generation layer with a thickness of 0.4 μm.

Next, using the materials and procedures shown in Comparative Example 1, a film thickness of 1
Forming a charge transport layer of 8 μm to form an electrophotographic photoreceptor 1
~Ta.

Example 1 Using the materials and procedures shown in Comparative Example 1, a film with a thickness of 0.7 μm was formed on an aluminum plate (the thickness of the conductive substrate was 0.11 to 1 m).
A subbing layer was formed.

Next, 15g of τH2PC, 0.25g of XL225°0, 25H of YP50.2g of ◆20. &4g of Coronate 2507 and 86.6g of tetrahydrofuran were kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.). The obtained pigment dispersion was applied onto the undercoat layer using an applicator and dried at 120° C. for 30 minutes to form a charge generation layer having a thickness of 0.5 μm.

Next, in Comparative Example 1, a film thickness of 18
A charge transport layer with a thickness of μm was formed to form an electrophotographic photoreceptor.

Example 2 Using the materials and procedures shown in Comparative Example 1, an undercoat layer with a thickness of 0.3 μm was formed on an aluminum plate (conductive substrate thickness Q, 1 us).

Next, 2. ．． 5g of τ-H2PC, 1.5g of XL-2
25° 0.5g YP-50, 0.5g 20.8.
9 g of Coronate 2507 and 86.1 g of tetrahydrofuran were kneaded for 8 hours using a ball mill (Nippon Kagaku Togyo Ura 3 Sun Bot Mill). The obtained pigment dispersion was applied onto the upper and lower sublayers using an applicator and dried at 120° C. for 30 minutes to form a charge generation layer having a thickness of 0.5 μm.

Next, using the substance and operation shown in Comparative Example 1, a film thickness of 18
Form a charge transport layer of μm and form an electrophotographic photoreceptor (7
Ta.

Example 3 Using the substance and procedure shown in Comparative Example 1, a film with a thickness of 0.9 μm was formed on an aluminum plate (conductive substrate thickness Q, 1 rm).
A subbing layer was formed.

Next, zsg of T H2Pc, 0.25g of XL-2
25゜2.0g YP-50,0,25g≠20.5
．． 7 g of Coronate 2507 and 89.3 g of tetrahydrofuran were kneaded for 8 hours using a ball mill (3-inch bot mill manufactured by Nihon Kagaku Togyo Co., Ltd.). The obtained pigment dispersion was applied onto the undercoat layer using an applicator and heated at 120°C.
This was dried for 30 minutes to form a charge generation layer with a thickness of 0.5 μm.

Next, using the substance and operation shown in Comparative Example 1, a film thickness of 18
A charge transport layer with a thickness of μm was formed to form an electrophotographic photoreceptor.

Coating film appearance, electrophotographic properties, durability, 78Qnm of the charge generation layer of the electrophotographic photoreceptor obtained in the comparative examples and examples.
The half-life exposure and images were evaluated.

The appearance of the coating film was evaluated visually.

The electrophotographic characteristics are 6 QOMnX 7 Qfffn
Measurements were made using an electrostatic recording paper tester (5P-428 manufactured by J-Kuchi Denki Co., Ltd.) on an electrophotographic photoreceptor cut into corners. 1st
Initial potential VO in the table indicates the charged potential when the sample is set on a rotating disk of 5P-428 and then rotated at 1000 rotations/rotation speed while a corona of about -5 kV is left for 10 seconds, dark decay. V is the potential decay when left for 30 seconds in the dark (Vt = ¥3o/Vo
X 100 and Vx represent the potential after 30 seconds), and the half-reduction exposure amount E5n represents the light amount value at the trench where the potential is halved by irradiation with 101 ux white light. residual potential v
The feces shows the potential after irradiation with white light for 60 seconds.

The durability test was conducted using a fragment of an electrophotographic photoreceptor (5QOnX 7
QfffO angle) with corona charging (surface potential -1000V±
100V) and static elimination (wavelength 500nm: exposure amount 50m)
J/m! ! ) was repeated υ 10,000 times.

Table 1 shows the initial values of the electrophotographic properties and the values after the durability test. The initial value and durability test value of 780 nm half-life exposure 8780
0). The measurement method is to corona charge the photoreceptor so that the surface potential is 1700V in advance.
10 m5e of semiconductor laser light with a wavelength of 780 nm
It was determined from the amount of energy required for the surface potential of the photoreceptor to attenuate to -350V by irradiation with c. The results are shown in Table 1.

In addition, pieces of the obtained electrophotographic photoreceptor were cut into pieces with a diameter of 60 mm,
It was pasted on a 247 m long aluminum tube and 9 images were tested using an evaluation machine (negative charge 1 reversal development method).

The image quality after being left for 72 hours at 40° C. and 80% relative humidity was evaluated. The results are shown in Table 1.

As is clear from the results shown in Table 1, the electrophotographic photoreceptors of Examples 1 to 3 according to the present invention had extremely good coating film appearances of charge generation layers, excellent charging properties, and Ili:so. , all of which are 1.6 ux-s or less.

5t8o has an excellent sensitivity of less than 3.4 mJ/rn2. The dark decay is small, and even after corona charging and neutralization are repeated 10,000 times, the electrophotographic properties do not deteriorate, showing properties equivalent to those at the initial stage, and exhibiting excellent durability. In addition, because of its high sensitivity, the gradation is good even after the humidity test. On the other hand, in the electrophotographic photoreceptors of Comparative Examples 1 to 5, the appearance of the coating film of the charge generation layer was inferior to that of the photoreceptor of the present invention, and after corona charging and neutralization were repeated 10,000 times, the residual potential was Increased.

Sensitivity decreases and durability deteriorates. Additionally, black spots appear on the image quality after the humidity test. Furthermore, the tonality is poor due to the low sensitivity.

As is clear from the above, the electrophotographic photoreceptors of Examples 1 to 3 have excellent adhesion and chargeability.

Excellent electrophotographic properties such as dark decay and sensitivity.

It also has excellent repeatability and moisture resistance.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention has excellent adhesion and electrophotographic properties such as chargeability, dark decay, and sensitivity, and
It also has excellent repeatability and moisture resistance.

Claims (1)

[Scope of Claims] 1. In an electrophotographic photoreceptor having a charge generation layer containing an organic pigment that generates a charge and a charge transport layer containing a charge transport agent on a conductive substrate, a resin binder of the charge generation layer is provided. General formulas (I), (II) and (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (III) [In formulas (I), (II) and (III), n is a positive integer, R is H or C_3H_7, x is 73 wt% or more, y is 4 to 2
4wt%, z represents 3 to 24wt%]. 2. The resin binder of the charge generation layer has the general formula (I)
, (II) and (III) and a resin containing an isocyanate group that reacts with the -OH groups of the resins of general formulas (I), (II) and (III). Electrophotographic photoreceptor. 3. The electrophotographic photoreceptor according to claim 1 or 2, further comprising an undercoat layer between the conductive substrate and the charge generation layer.