JPH0210365A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having stable initial potential, small dark attenuation, superior ozone resistance and abrasion resistance by incorporating a specified 1,4-dihydrotetrazine compd. into a charge transfer layer. CONSTITUTION:The title electrophotographic sensitive body is constituted of an electroconductive base body, a charge generating layer, and a charge transfer layer as essential constituting elements, and a 1,4-dihydrotetrazine compd. expressed by the formula is incorporated into the charge transfer layer. In the formula, R1 is H or (un)substituted alkyl group, (un)substituted heterocyclic group, etc.; R2 is (un)substituted alkyl group, (un)substituted aryl group, or (un)substituted heterocyclic group. Thus, an electrophotographic sensitive body having stable initial potential, small dark attenuation, high ozone resistance and abrasion resistance, is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more specifically, 1.4
- A highly sensitive and highly durable electrophotographic photoreceptor containing a dihydrotetrazine compound in its charge transport layer.

[Problems to be solved by conventional techniques and inventions] In recent years,
The development of copiers and printers that use electrophotography has been remarkable, with various forms and types of models being developed depending on their uses, and correspondingly, a wide variety of photoreceptors used in these machines are being developed. . Conventionally, inorganic compounds have been mainly used as electrophotographic photoreceptors due to their sensitivity and durability. For example, zinc oxide, cadmium sulfide, selenium, etc. can be mentioned.

However, these often use harmful substances, and their disposal becomes a problem and causes pollution. Furthermore, when selenium, which has good sensitivity, is used, it is necessary to form a thin film on a conductive substrate by a vapor deposition method or the like, resulting in poor productivity and increased costs. In recent years, amorphous silicon has attracted attention as a non-polluting inorganic photoreceptor, and research and development thereof is progressing. However, although this method is excellent in sensitivity, since the plasma CVD method is mainly used when forming a thin film, its productivity is extremely poor, and both the photoreceptor cost and the running cost are large.

On the other hand, organic photoreceptors can be incinerated, have the advantage of being non-polluting, and can be easily mass-produced as thin films can be formed by coating.Therefore, costs can be significantly reduced. It also has the advantage of being able to be processed into various shapes depending on the application.However, organic photoreceptors still have problems with their sensitivity and durability. There is a strong desire for the emergence of organic photoreceptors with photoreceptors.

Various methods have been proposed to improve sensitivity, but
Currently, functionally separated photoreceptors, which mainly have a two-layer structure in which the functions are separated into a charge generation layer and a charge transport layer, have become mainstream. For example, charges generated in the charge generation layer by exposure to light are injected into the charge transport layer and transported to the surface by the charge transport layer, forming an electrostatic latent image on the surface of the photoreceptor. Compared to the single-layer type, the function-separated type has a smaller possibility that generated charges will be captured, and the charges can be efficiently transported to the photoreceptor surface without each layer having its own function inhibited (U.S. Patent No. 2803541 No. 11aloid Company
As the organic charge generating material used in the L charge generating layer, compounds that absorb the energy of irradiated light and efficiently generate charges are selectively used. ), metal-free phthalocyanine pigments (Japanese Patent Application Laid-open No. 143346/1982), metal phthalocyanine pigments (Japanese Patent Application Laid-open No. 16538/1983),
Squarium salt (Japanese Unexamined Patent Publication No. 53-27033) and the like can be mentioned.

As the charge transport material used in the charge transport layer, it is necessary to select a compound that has high charge injection efficiency from the charge generation layer and also has high charge mobility within the charge transport layer. For this purpose, compounds with low ionization potential and compounds that easily generate radical cations are selected, such as triarylamine derivatives (Japanese Patent Laid-Open No. 53-47260) and hydrazone derivatives (Japanese Patent Laid-Open No. 57-101844).
Publication No.), oxadiazole derivatives (Japanese Patent Publication No. 34-54
66), pyrazoline derivatives (Japanese Patent Publication No. 52-418
No. 8), stilbene derivatives (JP-A-58-1980)
No. 43), triphenylmethane derivatives (Special Publication No. 45)
-555 Publication) etc. have been proposed.

However, the charge mobility of these materials is small compared to that of inorganic materials, and the sensitivity is still unsatisfactory.

Furthermore, in a series of electrophotographic processes such as charging, exposure, development, transfer, and static elimination, the photoreceptor is placed under extremely harsh conditions, and its ozone resistance and abrasion resistance are particularly problematic. Durability is also required for the materials used in the photoreceptor, and although binders and protective layers are also being developed, a satisfactory material has not yet been obtained.

[Means to solve the problem]

In order to solve the above problems and obtain an electrophotographic photoreceptor with high sensitivity and high durability, the present inventors have made extensive studies and found that an electrophotographic photoreceptor containing a specific 1,4-dihydrotetrazine compound in the charge transport layer It was discovered that a photographic photoreceptor has excellent sensitivity and durability, leading to the present invention.

That is, the present invention provides an electrophotographic photoreceptor comprising a conductive support, a charge generation layer, and a charge transport layer as essential components, according to the general formula (1) (wherein R is a hydrogen atom, substituted or unsubstituted). Substituted alkyl group, substituted or unsubstituted heterocyclic group, substituted or phenyl group (R
3 is a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a halogen atom, or a mercapto group.

), a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthranyl group, R2 is a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, Represents either a substituted or unsubstituted aralkyl group. The present invention provides an electrophotographic photoreceptor comprising a 1,4-dihydrotetrazine compound represented by the following formula in a charge transport layer.

An example of applying a 1,4-dihydrotetrazine compound to an electrophotographic photoreceptor is described in JP-A-60-195550, but the 1,4-dihydrotetrazine compound used in the present invention has a high sensitivity. , which is even more excellent in terms of durability, etc.

In formula (1), R8 represents any one of a hydrogen atom, a substituted or unsubstituted noalkyl group, a heterocyclic group, an aralkyl group, a naphthyl group, an anthranyl group, or a specific substituted or unsubstituted phenyl group; From the viewpoint of the performance of the resulting compound, those having 1 to 18 carbon atoms are preferred. More preferred are a methyl group, an ethyl group, a phenyl group, a tolyl group, a methoxyphenyl group, and a methyl group.

On the other hand, in formula (1), R2 represents a substituted or unsubstituted alkyl group, aryl group, heterocyclic group, or aralkyl group; From this point of view, those having 1 to 14 carbon atoms are preferred. More preferred examples include phenyl, methoxyphnyl, tolyl, naphthyl, and anthranyl groups.

The 1,4-dihydrotetrazine compound represented by the general formula (1) can be easily synthesized, and the synthesis method thereof is not limited. For example, a method of obtaining a hydrazone compound of an aldehyde by oxidizing it (Jersey, Journal of the American Chemical Society, Vol. 91, No. 10, 2)
443 pages, 1969), a method for reacting azine dichloride with hydrazine (Chemisier Berichte,
116, p. 2261, 1983), a method for trimerizing and cyclizing hydrazinothioketones in the presence of a base (Journal Op Chemical Society, 3389)
Page, 1950), etc., can be synthesized by any method.

Examples of the 1,4-dihydrotetrazine compounds used in the present invention include those listed in Nα1 to Nα72 below, but the present invention is not limited thereto.

C11゜ CH2 (Nα3) (No, 4) 0CR3 OCR.

(N117) C.I. (Part 17) (Na19) (Na21) (N[18) (N1118) (N1120) (NIL22) (Nail) (Part 13) (N1115) (Number 23) C.I.

C11s CR3 (Na12) (Ki 14) (Na16) 0CHz OC113 (Number 25) (No, 26) (NLL27) OCH co CH3 (Magnetic 31) (Patient 32) CH3 CH co (Ki 28) (Number 29) Hi (Sou 30) (Na33) (Na34) C11゜ Hs (Ken 35) OCHz CH30 (Na36) (llh37) (Patient 38) CH.

C.I.

(Na43) OCI+3 (Ki 44) (Magic 39) (Ki 40) CI+3 (N[L42) (Nu 45) (Floor 46) (patient 47) (Na54) C11゜ CH2 (Na53) C.I. (Ilh4B) C.I.

(N1149) (Improvement 50) (Magnetic 55) CHs CR3 (Ilh51) (Kan 52) (Fish 56) (57) C■.

(lk66) (Taki68) CH3 (Ilh69) CHs C113 (11h59) OS (Arashi61) Cll5 (Na67) (Na64) CH3 (Na62) (Na63) (llh70) CH2 (Arashi71) (Arashi65) Ct (Patient 72) These 1,4-dihydrotetrazine compounds can be used alone or in combination of two or more.

These compounds are soluble in many solvents, such as aromatic solvents such as benzene, toluene, xylene, tetralin, and chlorobenzene; dichloromethane, chloroform,
Halogen solvents such as trichlorethylene and tetrachloroethylene; Ester solvents such as methyl acetate, ethyl acetate, propyl acetate, methyl formate, and ethyl formate; acetone,
It is soluble in ketone solvents such as methyl ethyl ketone; ether solvents such as diethyl ether, dipropyl ether, and tetrahydrofuran; alcohol solvents such as methanol, ethanol, and isopropyl alcohol; and dimethylformamide, dimethylacetamide, and dimethyl sulfoxide.

In producing an electrophotographic photoreceptor, a charge generation layer and a charge transport layer are formed in the form of a thin film on a conductive support. As the base material of the conductive support, metals such as aluminum and nickel, metal-deposited polymer films, metal-laminated polymer films, etc. can be used, and the conductive support is configured in the form of a drum or sheet. .

The charge generation layer is made of a charge generation material and, if necessary, a binder and additives, and can be produced by a method such as a vapor deposition method, a plasma CVD method, or a coating method.

The charge generating material is not particularly limited, and any organic charge generating material or inorganic charge generating material is suitable as long as it absorbs irradiated light of a specific wavelength and can efficiently generate charges. It can be used.

Examples of organic charge generating materials include perylene pigments, polycyclic quinone pigments, metal-free phthalocyanine pigments, metal phthalocyanine pigments, bisazo pigments, trisazo pigments, thiapyrylium salts, squareium salts, and azulenium pigments. A charge generation layer can be formed by dispersing it in a binder and coating it. Inorganic charge generating materials include selenium, selenium alloys, cadmium sulfide,
Examples include zinc oxide and amorphous silicon.

The thickness of the formed charge generation layer is preferably 0.1 to 2.0 -, more preferably 0.2 to 1.0/I11.

1 represented by the general formula (1) on the top of the charge generation layer.

A charge transport layer containing a 4-dihydrotetrazine compound is formed into a thin film. A coating method is mainly used to form a thin film, in which a 1,4-dihydrotetrazine compound represented by formula (1) is dissolved in a solvent together with a binder if necessary, and coated on the charge generation layer. All you have to do is process it and then dry it.

The solvent to be used is not particularly limited as long as it dissolves the 1,4-dihydrotetrazine compound and the optional binder and does not dissolve the charge generation layer.

The binder used as necessary is not particularly limited as long as it is an insulating resin, and examples thereof include condensation polymers such as polycarbonate, polyarylate, polyester, and polyamide; polyethylene, polystyrene, styrene-acrylic copolymer, Polyacrylate, polymethacrylate, polyvinyl butyral, polyacrylonitrile, polyacrylamide, acrylonitrile-butadiene copolymer,
Addition polymers such as polyvinyl chloride; polysulfone, polyethersulfone, silicone resin, etc. can all be used, and one or more types can be used in combination.

The amount of the binder used is 1°4-
The weight ratio is from 0.1 to 3, preferably from 0.1 to 2, relative to the dihydrotetrazine compound. If the amount of binder is greater than this, the concentration of the charge transport material in the charge transport layer will be low, resulting in poor sensitivity.

Further, in the present invention, it is also possible to use a combination of known charge transport materials as described above, if necessary.

The method of coating the charge transport layer is not limited, and examples include Eva,
Bar coater, calendar coater, gravure coater,
A blade coater, spin coater, dip coater, etc. can all be used.

The thickness of the charge transport layer thus formed is 10
50I1m is preferable, and 1O to 3m is more preferable.
0I! Im. If it is larger than this, it will take more time to transport the charge, and the probability that the charge will be captured will also increase, causing a decrease in sensitivity. On the other hand, if it is smaller than this, the mechanical strength will decrease and the life of the photoreceptor will be shortened, which is not preferable. As described above, an electrophotographic photoreceptor containing a 1,4-dihydrotetrazine compound represented by the general formula (1) in the charge transport layer can be produced. An undercoat layer, adhesive layer, or barrier layer may be provided between the charge generation layers, if necessary, and these layers may be made of, for example, polyvinyl butyral, phenol resin, polyamide resin, or the like. Furthermore, a surface protective layer can also be provided on the surface of the photoreceptor.

When using the electrophotographic photoreceptor thus obtained, first, the surface of the photoreceptor is negatively charged using a corona charger or the like. After being charged, charges are generated within the charge generation layer by exposure to light, and the positive charges are injected into the charge transport layer, which are transported through the charge transport layer to the surface, neutralizing the negative charges on the surface. Ru. On the other hand, negative charges remain in the unexposed areas, which form an electrostatic latent image. Toner adheres to this area, and is transferred and fixed onto paper or the like.

Further, in the present invention, it is also possible to produce an electrophotographic photoreceptor by first providing a charge transport layer on a conductive support and then providing a charge generation layer thereon. In this case, the surface of the photoreceptor is first positively charged, and after exposure, the generated negative charges neutralize the surface potential of the photoreceptor, and the positive charges are transported to the conductive support through the charge transport layer. It's going to happen.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples.

Synthesis Example 1 22.6 g of benzaldehyde-p-anisylhydrazone was placed in a 11-3-bottle flask equipped with a stirrer and a thermometer, and dissolved in 500 g of diethyl ether. Add 4g of sodium hydroxide there, then add 50g of iodine,
Stirred at room temperature for 15 hours. The reaction mixture was washed three times with a 5% aqueous hydrochloric acid solution, twice with an aqueous sodium thiosulfate solution, and once with water. Then, diethyl ether was distilled off, and the remaining solid was collected using a silica gel column (toluene/hexane = 1/1).
1,4-bis(p-anisyl")-2,5-diphenyl-1,4-dihydro-S-tetrazine 17.3g
(77%).

Synthesis Example 2 Log of sodium methoxide was placed in an 11-hole flask equipped with a stirrer, a thermometer, and a dropping funnel, and dissolved in 500 g of anhydrous methanol. A methanol solution of 37.5 g of 9-(10-diethylamine)anthranyl-β-phenylhydrazinothioketone was slowly added dropwise thereto at room temperature. After refluxing for 5 hours, the mixture was cooled to room temperature, and the precipitated yellow crystals were collected by filtration. This product was recrystallized from hexane/ethyl acetate (1/1) and 2.5bis-(9-
(10-diethylamino)anthranyl)-1,4-diphenyl-1,4-dihydro-S-tetrazine 22.7
g (72%) was obtained.

Example-1 5 g of vanadyl phthalocyanine and 5 g of butyral resin (S-LEC BM-2, manufactured by Tsukiki Kagaku ■) were dissolved in 90 rId of cyclohexanone and kneaded in a ball mill for 24 hours. The resulting dispersion was applied onto an aluminum plate using a bar coater so that the film thickness after drying would be 0.5 trm, and dried to form a charge generation layer.

Next, 5 g of the 1,4-dihydrotetrazine compound (Nα19) obtained in Synthesis Example 1 and 5 g of polycarbonate resin (Lexan 141-111, manufactured by Engineering Plastics ■) were dissolved in 901 ml of methylene chloride. A charge transport layer was formed by coating the thus formed charge generation layer with a blade coater so that the film thickness after drying was 25-2.

The electrophotographic photoreceptor produced in this way was tested using an electrostatic copying paper tester SP-428 manufactured by Kawaguchi Electric Seisakusho.
, 5kV of corona voltage, the initial surface potential v0 was -770V. The surface potential V after being left in the dark for 5 seconds was -760V.

Next, a semiconductor laser with an oscillation wavelength of 780 rv is irradiated,
Half exposure 1t! When I calculated t y t, it was 0.7
μJ/c+w"t', residual potential vlI is -25V
Met.

Next, after repeating the above operation 5000 times, vOr V5
+El/2. When Vll was measured, each was -76
0V.

-760V, 0.7μJ/cm", -26V T!
It was found that the performance as a photoreceptor has hardly deteriorated and it exhibits high durability.

Examples 2 to 14 Photoreceptors were prepared in the same manner as in Example 1, except that the compounds shown in Table 1 were used as charge transport materials, and their performance was evaluated. The results are shown in Table-1.

Table 1 Continued Example 15 In Example 1, X-type metal-free phthalocyanine was used as a charge transport material in place of vanadyl phthalocyanine, and the formula (2
A photoreceptor was prepared in exactly the same manner except that 1,2,4,5-tetrakis(p-tolyl)-1,4-dihydro-S-tetrazine shown in 4) was used, and its performance was evaluated. The initial surface potential v0 is -740ν, and the surface potential V after being left for 5 seconds in a dark place is -735v.When irradiated with a semiconductor laser with a zero oscillation wavelength of 780n-, the half-reduction exposure it E + 7□ is 0.5 uJ/cm! There is te,
The residual potential v7 was -4.5V.

Also, vo after repeating the above operation 5000 times.

When VS, El/□, and VR were measured, they were each -7.
25V, 715V, 0.5#J/cm", -6
, 4V"i?, and its performance as a photoreceptor has hardly deteriorated, indicating high durability.

〔Effect of the invention〕

The electrophotographic photoreceptor of the present invention, which is characterized by containing a 1,4-dihydrotetrazine compound in its charge transport layer, has a stable initial potential, small dark decay, and high sensitivity. In addition, it shows little deterioration due to repeated use and has excellent ozone resistance and abrasion resistance.

Claims (1)

[Claims] In an electrophotographic photoreceptor having a conductive support, a charge generation layer, and a charge transport layer as essential components, general formula (1) ▲Mathematical formula, chemical formula, table, etc.▼(1) (In the formula, R_1 is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aralkyl group, a phenyl group represented by ▲numerical formula, chemical formula, table, etc.) (R_3 is a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a halogen atom, or a mercapto group), a substituted or unsubstituted naphthyl group, or a substituted or unsubstituted anthranyl group. , R_
2 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, or a substituted or unsubstituted aralkyl group. ) An electrophotographic photoreceptor comprising a 1,4-dihydrotetrazine compound represented by the following formula in a charge transport layer.