JPH10198053A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the variation of electrostatic characteristics such as potential by electrification and residual potential even after repeated use, to stabilize image characteristics such as sensitivity, line thickening and image blurring and to improve durability by incorporating an epoxy compd. and a hindered amine compd. or a hindered phenol compd. having a specified partial structure into a photosensitive layer. SOLUTION: When a photosensitive layer contg. at least a carrier generating material and a carrier transferring material as essential constituents is formed on an electrically conductive substrate to obtain an electrophotographic photoreceptor, an epoxy compd. and a hindered amine compd. having a partial structure represented by formula I or a hindered phenol compd. having a partial structure represented by formula II are incorporated into the photosensitive layer. In the formula I, R1 is H, satd. or unsatd. alkyl, satd. or unsatd. aralkyl or satd. or unsatd. acyl. In the formula II, R2 is 1-8C alkyl.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member for forming an electrostatic latent image. More specifically, the present invention relates to an electrophotographic photosensitive member having excellent environmental resistance.

[0002]

2. Description of the Related Art Conventionally, as an electrophotographic photosensitive member, an inorganic photosensitive member having a photosensitive layer mainly composed of an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, and silicon has been widely used. However, these are not always satisfactory in sensitivity, thermal stability, moisture resistance, durability, and the like. In addition, some inorganic photoreceptors contain substances that are harmful to the human body in the photoreceptor, and thus pose a problem in disposal. Some have.

In order to overcome the disadvantages of these inorganic photoconductors, research and development of organic photoconductors having a photosensitive layer containing various organic photoconductive compounds as main components have been actively conducted in recent years. In particular, a function-separated type photoreceptor in which the carrier generation function and the carrier transport function are respectively assigned to different substances allows each material to be selected from a wide range, and a photoreceptor having any performance can be relatively easily formed. Many studies have been made because they can be produced, and some of them have been put to practical use.

The surface layer of such an organic photoreceptor is subjected to electrical and mechanical external forces such as corona charging, toner development, transfer to paper, and cleaning, so that it is required to have durability against these. The fact copying machine, when using the photoreceptor in the printer, ozone photoreceptor occurred in charging electrode, nitrogen oxides (NO _x) for receiving the surface deterioration by ultraviolet rays or the like at the time of discharge products and the exposure of such , Resistance to these is also required.

As one technical measure against such photoreceptor deterioration, it has been proposed to add various deterioration inhibitors and stabilizers to the photoreceptor. For example, a method of adding a benzotriazole compound known as an ultraviolet absorber is described in JP-A-58-120260, and a method of adding a paraphenylenediamine compound to a photoreceptor is described in JP-A-63-52.
No. 146, JP-A-63-584 discloses a method of adding a dihydroquinoline compound to a photoreceptor as an ozone deterioration inhibitor.
No. 55, and a method of adding a spiroindane, spirochroman, hindered amine, or hindered phenol compound to a photoreceptor as an antioxidant is disclosed in JP-A-63-7185.
No. 6, No. 63-71857, No. 63-18355,
No. 63-73255, organic acid esters, α
A method of adding a keto acid ester or an aryl ketone compound to a photoreceptor;
Nos. 53553 and 63-153554.

However, ultraviolet light in these additives, ozone, although the effect of such NO _x is reduced, sensitivity, sometimes residual potential even deteriorated. In recent years, in order to improve the performance of equipment, there has been a demand for mounting a photosensitive member having higher sensitivity and high printing durability on a copying machine and a printer. The durability of conventional photoconductors is insufficient because it is difficult to remove the object from the periphery of the photoconductor.

[0007]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to keep the static electricity characteristics such as the charged potential and the residual potential unchanged even when used repeatedly, and to reduce the sensitivity, thickening of characters, image blur, etc. An object of the present invention is to provide an electrophotographic photosensitive member having stable image characteristics and excellent durability.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a photosensitive layer containing at least a carrier generating substance and a carrier transporting substance as main components on a conductive support. Wherein the photosensitive layer contains an epoxy compound A and a hindered amine or a hindered phenol compound having a partial structure represented by the following general formula (B-1) or (B-2) in the electrophotographic photoreceptor. It can be achieved by using an electrophotographic photosensitive member.

Further, the following general formula (B-1) or (B
It has been found that the same effect can be obtained also by adding a compound C having a hindered amine or hindered phenol structure and an epoxy structure in the same molecule shown in -2) to an electrophotographic photosensitive member.

That is, the object of the present invention is achieved by adopting the following constitution.

(1) In an electrophotographic photosensitive member having a photosensitive layer having at least a carrier-generating substance and a carrier-transporting substance as constituents on a conductive support, an epoxy compound is contained in the photosensitive layer and the following general formula (B) An electrophotographic photoreceptor comprising a hindered amine compound having a partial structure represented by formula (B-1) or a hindered phenol compound having a partial structure represented by the following formula (B-2).

[0012]

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(In the formula, R ₁ represents a hydrogen atom, a saturated or unsaturated alkyl group, an aralkyl group or an acyl group, and R ₂ represents an alkyl group having 1 to 8 carbon atoms.) In an electrophotographic photosensitive member having a photosensitive layer having at least a carrier-generating substance and a carrier-transporting substance as main components on a photosensitive support, the photosensitive layer may be represented by the following general formula (B-1) or (B-2). An electrophotographic photosensitive member comprising a compound C having a hindered amine or hindered phenol structure and an epoxy structure in the same molecule.

[0014]

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(Wherein, R ₁ represents a hydrogen atom, a saturated or unsaturated alkyl group, an aralkyl group or an acyl group, and R ₂ represents an alkyl group having 1 to 8 carbon atoms). In -1), R ₁ represents a hydrogen atom, a saturated or unsaturated alkyl group, an aralkyl group or an acyl group. Specific examples of the alkyl group and aralkyl group of R ₁ include a methyl group, an ethyl group, -A propenyl group or a benzyl group. Specific examples of the saturated or unsaturated acyl group for R ₁ include an acetyl group, a crotonyl group, and a benzoyl group.

In the general formula (B-2), R ₂ has 1 carbon atom.
To 8 alkyl groups. Specific examples of the alkyl group for R ₂ include a methyl group, an ethyl group, an isopropyl group, and a t-butyl group.

Next, specific examples of the compound of the present invention will be described, but the compound of the present invention is not limited thereto.

The epoxy compound according to the present invention includes:
Epoxy compounds derived by epoxidizing those unsaturated bonds with an aliphatic cyclic ester compound or an aliphatic long-chain alkyl ester having an unsaturated bond as a mother skeleton are preferred. More specifically, the following compounds can be mentioned. These can be synthesized according to known literature, or commercially available stabilizers for vinyl chloride resins can be used.

[0019]

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The compounds having a hindered amine structure or a hindered phenol structure according to the present invention include the following compounds. These can be synthesized by publicly known literature, or those commercially available as high molecular weight antioxidants can be used. Incidentally, both the hindered amine structure and the hindered phenol structure may be contained in the same compound.

[0021]

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[0022]

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[0023]

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[0024]

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The compounds having a hindered amine structure or a hindered phenol structure according to the present invention and having an epoxy structure in the same molecule include the following compounds. Also in this case, both the hindered amine structure and the hindered phenol structure may be contained in the same compound.

[0026]

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[0027]

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[0028]

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Next, synthesis examples of typical compounds according to the present invention will be described.

Synthesis Example 1 Synthesis of bis (1-benzyl-2,2,6,6-tetramethyl-4-piperidinyl) maleate ester Dimethyl maleate (2.9 g;
0.02 mol) and 1-benzyl-2,2,6,6-tetramethyl-4-piperidinol (9.9 g; 0.04 mol) were added to xylene (50 ml), and stirred at 110 ° C.
Heat to the top. Next, at the same temperature, lithium amide (0.1
5 g) is added thereto, and the mixture is heated to reflux for 3 hours and reacted. After allowing the reaction to cool, it is poured into a 1% aqueous acetic acid solution (100 ml), and the organic matter is extracted with toluene.

After washing the toluene layer with water, it is dried with sodium sulfate. After removing toluene, the residue was purified by a silica gel column (eluent: hexane: ethyl acetate = 9: 1) to obtain bis (1-benzyl-2,2,6,6, maleate).
6-Tetramethyl-4-piperidinyl) ester is obtained. (5.9 g; y.51%) (Synthesis Example 2 Synthesis of Exemplified Compound C-8) Bis (1-benzyl-2,2,6,6-tetramethyl-4-maleate)
Piperidinyl) ester (5.7 g; 0.01 mol)
Ethyl ether (30 ml) was added to
A solution of peracetic acid / acetic acid (3 ml) is slowly added dropwise. After completion of the dropwise addition, the mixture is gradually heated and reacted under heating and reflux for about 30 minutes. After the reaction, the reaction product is poured into water (100 ml), and the organic matter is extracted with ether.

After washing the ether layer with water, it was dried with magnesium sulfate. After removing the ether, the residue is purified by a silica gel column (eluent hexane: acetone = 19: 1) to obtain Exemplified Compound C-8. (2.4 g; y.
40%) The electrophotographic photoreceptor of the present invention has excellent electrophotographic properties,
A highly durable photoreceptor that suppresses the effects of discharge products generated by corona charging and provides stable potential characteristics and image quality even when used repeatedly.

The layer structure of the photoreceptor of the present invention may be a single layer structure in which a carrier generating substance and a carrier transporting substance are dispersed in a binder resin, or a carrier generating layer containing a carrier generating substance and a carrier containing a carrier transporting substance. A configuration in which a transport layer is stacked may be used.

Further, if necessary, an intermediate layer may be provided between the conductive support and the photosensitive layer, and a protective layer may be provided on the photosensitive layer. The compound according to the present invention may be added to any layer in the photosensitive layer. However, since it is considered that deterioration mainly proceeds from the surface, it is desirable to add the compound to at least the outermost surface layer of the photosensitive layer. When having a protective layer,
These layers are also added as necessary.

When the epoxy compound A and the compound having a hindered amine or hindered phenol structure are separately added, the compound of the present invention may be added in an amount of 0.1 to 20% by weight in each layer. %, More preferably 0.5 to 5% by weight. When the hindered amine or hindered phenol structure and the epoxy structure are in the same molecule, the weight ratio in the layer is 0.1 to 0.1.
20% by weight, more preferably 1 to 10% by weight is added.

As the carrier generating substance used in the photoreceptor of the present invention, any known substances can be used.
For example, various phthalocyanine compounds, azo compounds, pyrylium compounds, perylene compounds, cyanine compounds,
Squarium compounds and polycyclic quinone compounds can be used.

As the carrier transporting substance used in the photoreceptor of the present invention, any known substances can be used. For example, a triarylamine compound, a triarylaminestyryl compound, a hydrazone compound and a pyrazoline compound can be used.

The binder resin used in the photoreceptor of the present invention includes, for example, polystyrene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, Alkyd resin, polycarbonate resin, silicone resin, melamine resin, and two of repeating units of these resins
In addition to a copolymer resin containing at least one of these, and an insulating resin thereof, a polymer organic semiconductor such as poly-N-vinylcarbazole may be used.

The layer constituting the photoreceptor of the present invention is formed by dispersing or dispersing the compound of the present invention in a suitable solvent together with a binder resin, and, if necessary, a carrier transporting substance and a carrier generating substance. It can be formed by applying and drying using a dip coater or the like.

As the solvent used for preparing the dispersion,
For example, hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and 1,2-dichloroethane; ketones such as methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; methanol, ethanol, propanol and butanol Alcohols and their derivatives such as methylcellosolve and ethylcellosolve; ethers such as tetrahydrofuran and 1,4-dioxane; amines such as pyridine and diethylamine; nitrogen compounds such as amides such as N, N-dimethylformamide. Other fatty acids and phenols; one or more of sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate;

Next, as the conductive support for supporting the photosensitive layer, a metal plate or metal drum of aluminum, nickel, or the like, a plastic film on which aluminum, tin oxide, indium oxide, or the like is deposited, or a conductive material is applied. Paper, plastic film and drums can be used.

Further, a dye for correcting color sensitivity may be added to the photoreceptor of the present invention. Further, other additives such as an antioxidant may be added in combination.

[0043]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.

Example 1 A polyamide resin "CM8" was placed on an aluminum-deposited PET base.
000 "(manufactured by Toray Industries, Inc.) in 100 parts of a mixed solvent of methanol: n-butanol = 9: 1 was applied by dip coating to form an intermediate layer having a thickness of 0.5 μm.

On top of that, a carrier-generating substance (G-1) 1
0 parts, polyvinyl butyral resin "S-REC BX-
L "(manufactured by Sekisui Chemical Co., Ltd.), 4 parts, and a liquid in which 500 parts of a methyl ethyl ketone: cyclohexanone = 19: 1 liquid (500 parts) was dispersed and applied by using a sand grinder, and the resultant was dip-coated to a film thickness of 0.3 μm.
Was formed.

Next, the carrier transporting substance (P-1) 75
Parts, Exemplified Compound A-2 of the present invention and Exemplified Compound B-
4 in 5 parts, polycarbonate resin "Iupilon Z-20"
A solution prepared by dissolving 100 parts of "0" (manufactured by Mitsubishi Gas Chemical Company) in 1500 parts of THF was dip-coated on the carrier generating layer to form a 25 [mu] m-thick charge transport layer. Thus, Example Photoconductor 1 was prepared.

Example 2 An example photoconductor 2 was prepared in the same manner as in Example 1, except that Exemplified Compound B-4 in Example 1 was changed to B-7.

Example 3 A photoconductor 3 was prepared in the same manner as in Example 1, except that Exemplified Compound A-2 in Example 1 was changed to A-4 and Exemplified Compound B-4 was changed to B-5. Produced.

Example 4 The same procedure as in Example 1 was repeated except that Exemplified Compound A-2 in Example 1 was changed to A-5 and Exemplified Compound B-4 was changed to B-11. Produced.

Example 5 A photoconductor 5 was prepared in the same manner as in Example 1, except that Exemplified Compounds A-2 and B-4 in Example 1 were changed to Exemplified Compound C-5 by 10 parts.

Example 6 A photoconductor 6 of Example 1 was prepared in the same manner as in Example 1, except that Exemplified Compounds C-2 and B-4 were changed to 10 parts.

Example 7 A photoconductor 7 was prepared in the same manner as in Example 1, except that Exemplified Compounds A-2 and B-4 in Example 1 were replaced with Exemplified Compound C-10 by 10 parts.

Example 8 A photoconductor 8 was prepared in the same manner as in Example 1, except that Exemplified Compounds A-2 and B-4 in Example 1 were replaced with Exemplified Compound C-12 by 10 parts.

Comparative Example 1 A comparative example photoreceptor 1 was prepared in the same manner as in Example 1 except that the exemplified compounds A-2 and B-4 in Example 1 were omitted.

Comparative Example 2 A comparative example photoreceptor 2 was prepared in the same manner as in Example 1, except that Exemplified Compounds A-2 and B-4 in Example 1 were changed to Exemplified Compound B-4 by 10 parts.

Comparative Example 3 A comparative example photoreceptor 3 was prepared in the same manner as in Example 1, except that Exemplified Compound B-7 was changed to 10 parts of Exemplified Compounds A-2 and B-4.

Comparative Example 4 A comparative example photoreceptor 4 was prepared in the same manner as in Example 1 except that Exemplified Compound A-2 and B-4 in Example 1 were changed to Exemplified Compound A-2 by 10 parts.

Comparative Example 5 A comparative example photoreceptor 5 was prepared in the same manner as in Example 1 except that Exemplified Compounds A-2 and B-4 in Example 1 were changed to Exemplified Compound A-4 in 10 parts.

[0059]

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Evaluation 1 The photoreceptors obtained in each of the examples and comparative examples were exposed to an ozone exposure apparatus for 1 hour in an environment having an ozone concentration of 100 ppm, and the characteristics of the electrophotographic photoreceptors before and after the exposure were compared.

For evaluation of characteristics, an electrostatic copying test apparatus EPA81 was used.
00 (manufactured by Kawaguchi Electric Co., Ltd.), charged at −6 kV for 5 seconds, then exposed to a receiving potential Va (V) when left for 5 seconds in a dark place, and then exposed to 10 lux white light, Exposure amount E1 / 2 (lu) required for the potential to attenuate by half
x. sec), and the chargeability and the sensitivity were evaluated.

A photoreceptor of the same composition is separately attached to a cylindrical substrate, and a NO _x exposure tank using fuming nitric acid (NO ₂ concentration of about 5
(about ppm). After exposure and after standing for 20 minutes, a copier “Konica U-BI” manufactured by Konica Corporation
X4045 ", a standard chart was copied, and the image characteristics (image blur) of the obtained image were visually evaluated based on Comparative Example 1. Table 1 shows the results.

[0063]

[Table 1]

Evaluation 2 A photosensitive drum having a photosensitive layer having the same composition as that of Examples 1, 2, 5, and 6 applied to a cylindrical aluminum substrate was used for a copying machine “Konica U-BIX404” manufactured by Konica Corporation.
5 ”, high temperature and high humidity environment (33 ° C; 80% RH)
Was performed 10,000 times, and black potential Vb, gray potential Vg, and residual potential Vr were measured initially and after 10,000 repetitions. The image characteristics (image blur) after 10,000 repetitions were visually evaluated. Table 2 shows the results.

[0065]

[Table 2]

As apparent from Tables 1 and 2,
The electrophotographic photoreceptor using the compound according to the present invention shows stable electric characteristics and image characteristics even when repeatedly used, and is found to be an electrophotographic photoreceptor excellent in durability.

[0067]

According to the present invention, an electrophotograph having excellent durability, in which the electrical properties such as the charging potential and the residual potential do not change even when repeatedly used, and the image properties such as sensitivity, thickening of characters and image blur are stable. A photoreceptor can be provided.

Claims (2)

[Claims] 1. An electrophotographic photoreceptor comprising a conductive support and a photosensitive layer containing at least a carrier-generating substance and a carrier-transporting substance as constituents, wherein the photosensitive layer comprises an epoxy compound and a compound represented by the following general formula (B) An electrophotographic photoreceptor comprising a hindered amine compound having a partial structure represented by formula (B-1) or a hindered phenol compound having a partial structure represented by the following formula (B-2). Embedded image (In the formula, R ₁ represents a hydrogen atom, a saturated or unsaturated alkyl group, an aralkyl group or an acyl group, and R ₂ represents an alkyl group having 1 to 8 carbon atoms.) 2. An electrophotographic photosensitive member having a photosensitive layer having at least a carrier-generating substance and a carrier-transporting substance as main components on a conductive support, wherein the photosensitive layer has the following general formula (B-1) or An electrophotographic photoreceptor comprising a compound C having a hindered amine or hindered phenol structure represented by (B-2) and an epoxy structure in the same molecule. Embedded image (In the formula, R ₁ represents a hydrogen atom, a saturated or unsaturated alkyl group, an aralkyl group or an acyl group, and R ₂ represents an alkyl group having 1 to 8 carbon atoms.)